Merge branch 'mw_dev' into shallow-clone-local

257 files changed, 3182 insertions, 1720 deletions

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index bcad84b8b..ce14dd0fb 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -120,7 +120,61 @@ jobs:
             CMAKE_OPTIONS: -DUSE_HTTPS=mbedTLS -DUSE_SHA1=HTTPS -DREGEX_BACKEND=pcre -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=valgrind -DUSE_GSSAPI=ON -DUSE_SSH=ON
             CMAKE_GENERATOR: Ninja
           os: ubuntu-latest
-        - name: "Linux (MemorySanitizer)"
+        - name: "macOS"
+          id: macos
+          os: macos-10.15
+          env:
+            CC: clang
+            CMAKE_OPTIONS: -DREGEX_BACKEND=regcomp_l -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=leaks -DUSE_GSSAPI=ON
+            PKG_CONFIG_PATH: /usr/local/opt/openssl/lib/pkgconfig
+            SKIP_SSH_TESTS: true
+            SKIP_NEGOTIATE_TESTS: true
+          setup-script: osx
+        - name: "Windows (amd64, Visual Studio)"
+          id: windows-amd64-vs
+          os: windows-2019
+          env:
+            ARCH: amd64
+            CMAKE_GENERATOR: Visual Studio 16 2019
+            CMAKE_OPTIONS: -A x64 -DWIN32_LEAKCHECK=ON -DDEPRECATE_HARD=ON
+            SKIP_SSH_TESTS: true
+            SKIP_NEGOTIATE_TESTS: true
+        - name: "Windows (x86, Visual Studio)"
+          id: windows-x86-vs
+          os: windows-2019
+          env:
+            ARCH: x86
+            CMAKE_GENERATOR: Visual Studio 16 2019
+            CMAKE_OPTIONS: -A Win32 -DWIN32_LEAKCHECK=ON -DDEPRECATE_HARD=ON -DUSE_SHA1=HTTPS -DUSE_BUNDLED_ZLIB=ON
+            SKIP_SSH_TESTS: true
+            SKIP_NEGOTIATE_TESTS: true
+        - name: "Windows (amd64, mingw)"
+          id: windows-amd64-mingw
+          os: windows-2019
+          setup-script: mingw
+          env:
+            ARCH: amd64
+            CMAKE_GENERATOR: MinGW Makefiles
+            CMAKE_OPTIONS: -DDEPRECATE_HARD=ON
+            BUILD_TEMP: D:\Temp
+            BUILD_PATH: D:\Temp\mingw64\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files (x86)\CMake\bin
+            SKIP_SSH_TESTS: true
+            SKIP_NEGOTIATE_TESTS: true
+        - name: "Windows (x86, mingw)"
+          id: windows-x86-mingw
+          os: windows-2019
+          setup-script: mingw
+          env:
+            ARCH: x86
+            CMAKE_GENERATOR: MinGW Makefiles
+            CMAKE_OPTIONS: -DDEPRECATE_HARD=ON
+            BUILD_TEMP: D:\Temp
+            BUILD_PATH: D:\Temp\mingw32\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files (x86)\CMake\bin
+            SKIP_SSH_TESTS: true
+            SKIP_NEGOTIATE_TESTS: true
+
+        # Sanitizers
+        - name: "Sanitizer (Memory)"
           id: memorysanitizer
           container:
             name: focal
@@ -134,7 +188,7 @@ jobs:
             ASAN_SYMBOLIZER_PATH: /usr/bin/llvm-symbolizer-10
             UBSAN_OPTIONS: print_stacktrace=1
           os: ubuntu-latest
-        - name: "Linux (UndefinedBehaviorSanitizer)"
+        - name: "Sanitizer (UndefinedBehavior)"
           id: ubsanitizer
           container:
             name: focal
@@ -148,7 +202,7 @@ jobs:
             ASAN_SYMBOLIZER_PATH: /usr/bin/llvm-symbolizer-10
             UBSAN_OPTIONS: print_stacktrace=1
           os: ubuntu-latest
-        - name: "Linux (ThreadSanitizer)"
+        - name: "Sanitizer (Thread)"
           id: threadsanitizer
           container:
             name: focal
@@ -163,56 +217,34 @@ jobs:
             UBSAN_OPTIONS: print_stacktrace=1
             TSAN_OPTIONS: suppressions=/home/libgit2/source/script/thread-sanitizer.supp second_deadlock_stack=1
           os: ubuntu-latest
-        - name: "macOS"
+
+        # Experimental: SHA256 support
+        - name: "Linux (SHA256, Xenial, Clang, OpenSSL)"
+          id: xenial-clang-openssl
+          container:
+            name: xenial
+          env:
+            CC: clang
+            CMAKE_GENERATOR: Ninja
+            CMAKE_OPTIONS: -DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=valgrind -DUSE_GSSAPI=ON -DUSE_SSH=ON
+          os: ubuntu-latest
+        - name: "macOS (SHA256)"
           id: macos
           os: macos-10.15
           env:
             CC: clang
-            CMAKE_OPTIONS: -DREGEX_BACKEND=regcomp_l -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=leaks -DUSE_GSSAPI=ON
+            CMAKE_OPTIONS: -DREGEX_BACKEND=regcomp_l -DDEPRECATE_HARD=ON -DUSE_LEAK_CHECKER=leaks -DUSE_GSSAPI=ON -DEXPERIMENTAL_SHA256=ON
             PKG_CONFIG_PATH: /usr/local/opt/openssl/lib/pkgconfig
             SKIP_SSH_TESTS: true
             SKIP_NEGOTIATE_TESTS: true
           setup-script: osx
-        - name: "Windows (amd64, Visual Studio)"
+        - name: "Windows (SHA256, amd64, Visual Studio)"
           id: windows-amd64-vs
           os: windows-2019
           env:
             ARCH: amd64
             CMAKE_GENERATOR: Visual Studio 16 2019
-            CMAKE_OPTIONS: -A x64 -DWIN32_LEAKCHECK=ON -DDEPRECATE_HARD=ON
-            SKIP_SSH_TESTS: true
-            SKIP_NEGOTIATE_TESTS: true
-        - name: "Windows (x86, Visual Studio)"
-          id: windows-x86-vs
-          os: windows-2019
-          env:
-            ARCH: x86
-            CMAKE_GENERATOR: Visual Studio 16 2019
-            CMAKE_OPTIONS: -A Win32 -DWIN32_LEAKCHECK=ON -DDEPRECATE_HARD=ON -DUSE_SHA1=HTTPS -DUSE_BUNDLED_ZLIB=ON
-            SKIP_SSH_TESTS: true
-            SKIP_NEGOTIATE_TESTS: true
-        - name: "Windows (amd64, mingw)"
-          id: windows-amd64-mingw
-          os: windows-2019
-          setup-script: mingw
-          env:
-            ARCH: amd64
-            CMAKE_GENERATOR: MinGW Makefiles
-            CMAKE_OPTIONS: -DDEPRECATE_HARD=ON
-            BUILD_TEMP: D:\Temp
-            BUILD_PATH: D:\Temp\mingw64\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files (x86)\CMake\bin
-            SKIP_SSH_TESTS: true
-            SKIP_NEGOTIATE_TESTS: true
-        - name: "Windows (x86, mingw)"
-          id: windows-x86-mingw
-          os: windows-2019
-          setup-script: mingw
-          env:
-            ARCH: x86
-            CMAKE_GENERATOR: MinGW Makefiles
-            CMAKE_OPTIONS: -DDEPRECATE_HARD=ON
-            BUILD_TEMP: D:\Temp
-            BUILD_PATH: D:\Temp\mingw32\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Program Files (x86)\CMake\bin
+            CMAKE_OPTIONS: -A x64 -DWIN32_LEAKCHECK=ON -DDEPRECATE_HARD=ON -DEXPERIMENTAL_SHA256=ON
             SKIP_SSH_TESTS: true
             SKIP_NEGOTIATE_TESTS: true
       fail-fast: false
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2b5a2842c..cf3b62246 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,6 +15,9 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/cmake")
 # Build options
 #
 
+# Experimental features
+option(EXPERIMENTAL_SHA256     "Enable experimental SHA256 support (for R&D/testing)"  OFF)
+
 # Optional subsystems
 option(BUILD_SHARED_LIBS       "Build Shared Library (OFF for Static)"                  ON)
 option(BUILD_TESTS             "Build Tests using the Clar suite"                       ON)
@@ -107,6 +110,7 @@ include(IdeSplitSources)
 include(FeatureSummary)
 include(EnableWarnings)
 include(DefaultCFlags)
+include(ExperimentalFeatures)
 
 
 #
diff --git a/cmake/ExperimentalFeatures.cmake b/cmake/ExperimentalFeatures.cmake
new file mode 100644
index 000000000..f23bfe376
--- /dev/null
+++ b/cmake/ExperimentalFeatures.cmake
@@ -0,0 +1,12 @@
+if(EXPERIMENTAL_SHA256)
+	add_feature_info("SHA256 API" ON "experimental SHA256 APIs")
+
+	set(EXPERIMENTAL 1)
+	set(GIT_EXPERIMENTAL_SHA256 1)
+else()
+	add_feature_info("SHA256 API" OFF "experimental SHA256 APIs")
+endif()
+
+if(EXPERIMENTAL)
+	set(LIBGIT2_FILENAME "${LIBGIT2_FILENAME}-experimental")
+endif()
diff --git a/examples/cat-file.c b/examples/cat-file.c
index b81e9a8da..741edb484 100644
--- a/examples/cat-file.c
+++ b/examples/cat-file.c
@@ -49,7 +49,7 @@ static void show_blob(const git_blob *blob)
 static void show_tree(const git_tree *tree)
 {
 	size_t i, max_i = (int)git_tree_entrycount(tree);
-	char oidstr[GIT_OID_HEXSZ + 1];
+	char oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 	const git_tree_entry *te;
 
 	for (i = 0; i < max_i; ++i) {
@@ -70,7 +70,7 @@ static void show_tree(const git_tree *tree)
 static void show_commit(const git_commit *commit)
 {
 	unsigned int i, max_i;
-	char oidstr[GIT_OID_HEXSZ + 1];
+	char oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 
 	git_oid_tostr(oidstr, sizeof(oidstr), git_commit_tree_id(commit));
 	printf("tree %s\n", oidstr);
@@ -90,7 +90,7 @@ static void show_commit(const git_commit *commit)
 
 static void show_tag(const git_tag *tag)
 {
-	char oidstr[GIT_OID_HEXSZ + 1];
+	char oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 
 	git_oid_tostr(oidstr, sizeof(oidstr), git_tag_target_id(tag));;
 	printf("object %s\n", oidstr);
@@ -125,7 +125,7 @@ int lg2_cat_file(git_repository *repo, int argc, char *argv[])
 {
 	struct catfile_options o = { ".", NULL, 0, 0 };
 	git_object *obj = NULL;
-	char oidstr[GIT_OID_HEXSZ + 1];
+	char oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 
 	parse_opts(&o, argc, argv);
 
@@ -133,7 +133,7 @@ int lg2_cat_file(git_repository *repo, int argc, char *argv[])
 			"Could not resolve", o.rev);
 
 	if (o.verbose) {
-		char oidstr[GIT_OID_HEXSZ + 1];
+		char oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 		git_oid_tostr(oidstr, sizeof(oidstr), git_object_id(obj));
 
 		printf("%s %s\n--\n",
diff --git a/examples/fetch.c b/examples/fetch.c
index 2b5ed1112..bbd882cfb 100644
--- a/examples/fetch.c
+++ b/examples/fetch.c
@@ -15,17 +15,17 @@ static int progress_cb(const char *str, int len, void *data)
  */
 static int update_cb(const char *refname, const git_oid *a, const git_oid *b, void *data)
 {
-	char a_str[GIT_OID_HEXSZ+1], b_str[GIT_OID_HEXSZ+1];
+	char a_str[GIT_OID_SHA1_HEXSIZE+1], b_str[GIT_OID_SHA1_HEXSIZE+1];
 	(void)data;
 
 	git_oid_fmt(b_str, b);
-	b_str[GIT_OID_HEXSZ] = '\0';
+	b_str[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	if (git_oid_is_zero(a)) {
 		printf("[new]     %.20s %s\n", b_str, refname);
 	} else {
 		git_oid_fmt(a_str, a);
-		a_str[GIT_OID_HEXSZ] = '\0';
+		a_str[GIT_OID_SHA1_HEXSIZE] = '\0';
 		printf("[updated] %.10s..%.10s %s\n", a_str, b_str, refname);
 	}
 
diff --git a/examples/for-each-ref.c b/examples/for-each-ref.c
index 020dab474..a0706741a 100644
--- a/examples/for-each-ref.c
+++ b/examples/for-each-ref.c
@@ -5,7 +5,7 @@ static int show_ref(git_reference *ref, void *data)
 {
 	git_repository *repo = data;
 	git_reference *resolved = NULL;
-	char hex[GIT_OID_HEXSZ+1];
+	char hex[GIT_OID_SHA1_HEXSIZE+1];
 	const git_oid *oid;
 	git_object *obj;
 	
@@ -16,7 +16,7 @@ static int show_ref(git_reference *ref, void *data)
 	
 	oid = git_reference_target(resolved ? resolved : ref);
 	git_oid_fmt(hex, oid);
-	hex[GIT_OID_HEXSZ] = 0;
+	hex[GIT_OID_SHA1_HEXSIZE] = 0;
 	check_lg2(git_object_lookup(&obj, repo, oid, GIT_OBJECT_ANY),
 			  "Unable to lookup object", hex);
 	
diff --git a/examples/general.c b/examples/general.c
index 2127ec0e1..7f44cd786 100644
--- a/examples/general.c
+++ b/examples/general.c
@@ -129,7 +129,7 @@ int lg2_general(git_repository *repo, int argc, char** argv)
  */
 static void oid_parsing(git_oid *oid)
 {
-	char out[GIT_OID_HEXSZ+1];
+	char out[GIT_OID_SHA1_HEXSIZE+1];
 	char hex[] = "4a202b346bb0fb0db7eff3cffeb3c70babbd2045";
 
 	printf("*Hex to Raw*\n");
@@ -142,7 +142,11 @@ static void oid_parsing(git_oid *oid)
 	 * this throughout the example for storing the value of the current SHA
 	 * key we're working with.
 	 */
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid_fromstr(oid, hex, GIT_OID_SHA1);
+#else
 	git_oid_fromstr(oid, hex);
+#endif
 
 	/*
 	 * Once we've converted the string into the oid value, we can get the raw
@@ -152,7 +156,7 @@ static void oid_parsing(git_oid *oid)
 	 * char hex value.
 	 */
 	printf("\n*Raw to Hex*\n");
-	out[GIT_OID_HEXSZ] = '\0';
+	out[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	/**
 	 * If you have a oid, you can easily get the hex value of the SHA as well.
@@ -173,7 +177,7 @@ static void oid_parsing(git_oid *oid)
  */
 static void object_database(git_repository *repo, git_oid *oid)
 {
-	char oid_hex[GIT_OID_HEXSZ+1] = { 0 };
+	char oid_hex[GIT_OID_SHA1_HEXSIZE+1] = { 0 };
 	const unsigned char *data;
 	const char *str_type;
 	int error;
@@ -266,7 +270,7 @@ static void commit_writing(git_repository *repo)
 	git_tree *tree;
 	git_commit *parent;
 	git_signature *author, *committer;
-	char oid_hex[GIT_OID_HEXSZ+1] = { 0 };
+	char oid_hex[GIT_OID_SHA1_HEXSIZE+1] = { 0 };
 
 	printf("\n*Commit Writing*\n");
 
@@ -287,9 +291,14 @@ static void commit_writing(git_repository *repo)
 	 * parents.  Here we're creating oid objects to create the commit with,
 	 * but you can also use
 	 */
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid_fromstr(&tree_id, "f60079018b664e4e79329a7ef9559c8d9e0378d1", GIT_OID_SHA1);
+	git_oid_fromstr(&parent_id, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1);
+#else
 	git_oid_fromstr(&tree_id, "f60079018b664e4e79329a7ef9559c8d9e0378d1");
-	git_tree_lookup(&tree, repo, &tree_id);
 	git_oid_fromstr(&parent_id, "5b5b025afb0b4c913b4c338a42934a3863bf3644");
+#endif
+	git_tree_lookup(&tree, repo, &tree_id);
 	git_commit_lookup(&parent, repo, &parent_id);
 
 	/**
@@ -345,7 +354,7 @@ static void commit_parsing(git_repository *repo)
 	const git_signature *author, *cmtter;
 	git_commit *commit, *parent;
 	git_oid oid;
-	char oid_hex[GIT_OID_HEXSZ+1];
+	char oid_hex[GIT_OID_SHA1_HEXSIZE+1];
 	const char *message;
 	unsigned int parents, p;
 	int error;
@@ -353,7 +362,11 @@ static void commit_parsing(git_repository *repo)
 
 	printf("\n*Commit Parsing*\n");
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid_fromstr(&oid, "8496071c1b46c854b31185ea97743be6a8774479", GIT_OID_SHA1);
+#else
 	git_oid_fromstr(&oid, "8496071c1b46c854b31185ea97743be6a8774479");
+#endif
 
 	error = git_commit_lookup(&commit, repo, &oid);
 	check_error(error, "looking up commit");
@@ -422,7 +435,11 @@ static void tag_parsing(git_repository *repo)
 	 * We create an oid for the tag object if we know the SHA and look it up
 	 * the same way that we would a commit (or any other object).
 	 */
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid_fromstr(&oid, "b25fa35b38051e4ae45d4222e795f9df2e43f1d1", GIT_OID_SHA1);
+#else
 	git_oid_fromstr(&oid, "b25fa35b38051e4ae45d4222e795f9df2e43f1d1");
+#endif
 
 	error = git_tag_lookup(&tag, repo, &oid);
 	check_error(error, "looking up tag");
@@ -470,7 +487,11 @@ static void tree_parsing(git_repository *repo)
 	/**
 	 * Create the oid and lookup the tree object just like the other objects.
 	 */
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid_fromstr(&oid, "f60079018b664e4e79329a7ef9559c8d9e0378d1", GIT_OID_SHA1);
+#else
 	git_oid_fromstr(&oid, "f60079018b664e4e79329a7ef9559c8d9e0378d1");
+#endif
 	git_tree_lookup(&tree, repo, &oid);
 
 	/**
@@ -524,7 +545,11 @@ static void blob_parsing(git_repository *repo)
 
 	printf("\n*Blob Parsing*\n");
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid_fromstr(&oid, "1385f264afb75a56a5bec74243be9b367ba4ca08", GIT_OID_SHA1);
+#else
 	git_oid_fromstr(&oid, "1385f264afb75a56a5bec74243be9b367ba4ca08");
+#endif
 	git_blob_lookup(&blob, repo, &oid);
 
 	/**
@@ -566,7 +591,11 @@ static void revwalking(git_repository *repo)
 
 	printf("\n*Revwalking*\n");
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid_fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1);
+#else
 	git_oid_fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644");
+#endif
 
 	/**
 	 * To use the revwalker, create a new walker, tell it how you want to sort
@@ -679,7 +708,7 @@ static void reference_listing(git_repository *repo)
 
 	for (i = 0; i < ref_list.count; ++i) {
 		git_reference *ref;
-		char oid_hex[GIT_OID_HEXSZ+1] = GIT_OID_HEX_ZERO;
+		char oid_hex[GIT_OID_SHA1_HEXSIZE+1] = GIT_OID_SHA1_HEXZERO;
 		const char *refname;
 
 		refname = ref_list.strings[i];
diff --git a/examples/log.c b/examples/log.c
index 9060f3f3e..4b0a95dcd 100644
--- a/examples/log.c
+++ b/examples/log.c
@@ -329,7 +329,7 @@ static void print_time(const git_time *intime, const char *prefix)
 /** Helper to print a commit object. */
 static void print_commit(git_commit *commit, struct log_options *opts)
 {
-	char buf[GIT_OID_HEXSZ + 1];
+	char buf[GIT_OID_SHA1_HEXSIZE + 1];
 	int i, count;
 	const git_signature *sig;
 	const char *scan, *eol;
diff --git a/examples/ls-remote.c b/examples/ls-remote.c
index 03ed887d1..24caae712 100644
--- a/examples/ls-remote.c
+++ b/examples/ls-remote.c
@@ -34,7 +34,7 @@ static int use_remote(git_repository *repo, char *name)
 		goto cleanup;
 
 	for (i = 0; i < refs_len; i++) {
-		char oid[GIT_OID_HEXSZ + 1] = {0};
+		char oid[GIT_OID_SHA1_HEXSIZE + 1] = {0};
 		git_oid_fmt(oid, &refs[i]->oid);
 		printf("%s\t%s\n", oid, refs[i]->name);
 	}
diff --git a/examples/rev-list.c b/examples/rev-list.c
index d10f16690..cf8ac30c6 100644
--- a/examples/rev-list.c
+++ b/examples/rev-list.c
@@ -26,7 +26,7 @@ int lg2_rev_list(git_repository *repo, int argc, char **argv)
 	git_revwalk *walk;
 	git_oid oid;
 	git_sort_t sort;
-	char buf[GIT_OID_HEXSZ+1];
+	char buf[GIT_OID_SHA1_HEXSIZE+1];
 
 	check_lg2(revwalk_parse_options(&sort, &args), "parsing options", NULL);
 
@@ -36,7 +36,7 @@ int lg2_rev_list(git_repository *repo, int argc, char **argv)
 
 	while (!git_revwalk_next(&oid, walk)) {
 		git_oid_fmt(buf, &oid);
-		buf[GIT_OID_HEXSZ] = '\0';
+		buf[GIT_OID_SHA1_HEXSIZE] = '\0';
 		printf("%s\n", buf);
 	}
 
@@ -140,8 +140,14 @@ static int revwalk_parse_revs(git_repository *repo, git_revwalk *walk, struct ar
 			if (push_spec(repo, walk, curr, hide) == 0)
 				continue;
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+			if ((error = git_oid_fromstr(&oid, curr, GIT_OID_SHA1)))
+				return error;
+#else
 			if ((error = git_oid_fromstr(&oid, curr)))
 				return error;
+#endif
+
 			if ((error = push_commit(walk, &oid, hide)))
 				return error;
 		}
diff --git a/examples/rev-parse.c b/examples/rev-parse.c
index 90258c101..3f68d79b7 100644
--- a/examples/rev-parse.c
+++ b/examples/rev-parse.c
@@ -65,7 +65,7 @@ static void parse_opts(struct parse_state *ps, int argc, char *argv[])
 static int parse_revision(git_repository *repo, struct parse_state *ps)
 {
 	git_revspec rs;
-	char str[GIT_OID_HEXSZ + 1];
+	char str[GIT_OID_SHA1_HEXSIZE + 1];
 
 	check_lg2(git_revparse(&rs, repo, ps->spec), "Could not parse", ps->spec);
 
diff --git a/examples/show-index.c b/examples/show-index.c
index 7aaa45e65..fb797e04b 100644
--- a/examples/show-index.c
+++ b/examples/show-index.c
@@ -20,8 +20,8 @@ int lg2_show_index(git_repository *repo, int argc, char **argv)
 	size_t i, ecount;
 	char *dir = ".";
 	size_t dirlen;
-	char out[GIT_OID_HEXSZ+1];
-	out[GIT_OID_HEXSZ] = '\0';
+	char out[GIT_OID_SHA1_HEXSIZE+1];
+	out[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	if (argc > 2)
 		fatal("usage: showindex [<repo-dir>]", NULL);
diff --git a/fuzzers/commit_graph_fuzzer.c b/fuzzers/commit_graph_fuzzer.c
index 1c46d78c7..9c1443e52 100644
--- a/fuzzers/commit_graph_fuzzer.c
+++ b/fuzzers/commit_graph_fuzzer.c
@@ -37,7 +37,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 	git_commit_graph_entry e;
 	git_str commit_graph_buf = GIT_STR_INIT;
 	unsigned char hash[GIT_HASH_SHA1_SIZE];
-	git_oid oid = {{0}};
+	git_oid oid = GIT_OID_NONE;
 	bool append_hash = false;
 
 	if (size < 4)
@@ -62,7 +62,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 		memcpy(commit_graph_buf.ptr, data, size);
 		memcpy(commit_graph_buf.ptr + size, hash, GIT_HASH_SHA1_SIZE);
 
-		memcpy(oid.id, hash, GIT_OID_RAWSZ);
+		memcpy(oid.id, hash, GIT_OID_SHA1_SIZE);
 	} else {
 		git_str_attach_notowned(&commit_graph_buf, (char *)data, size);
 	}
@@ -75,7 +75,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 		goto cleanup;
 
 	/* Search for any oid, just to exercise that codepath. */
-	if (git_commit_graph_entry_find(&e, &file, &oid, GIT_OID_HEXSZ) < 0)
+	if (git_commit_graph_entry_find(&e, &file, &oid, GIT_OID_SHA1_HEXSIZE) < 0)
 		goto cleanup;
 
 cleanup:
diff --git a/fuzzers/midx_fuzzer.c b/fuzzers/midx_fuzzer.c
index 4c3124e47..21fb90361 100644
--- a/fuzzers/midx_fuzzer.c
+++ b/fuzzers/midx_fuzzer.c
@@ -36,7 +36,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 	git_midx_entry e;
 	git_str midx_buf = GIT_STR_INIT;
 	unsigned char hash[GIT_HASH_SHA1_SIZE];
-	git_oid oid = {{0}};
+	git_oid oid = GIT_OID_NONE;
 	bool append_hash = false;
 
 	if (size < 4)
@@ -61,7 +61,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 		memcpy(midx_buf.ptr, data, size);
 		memcpy(midx_buf.ptr + size, hash, GIT_HASH_SHA1_SIZE);
 
-		memcpy(oid.id, hash, GIT_OID_RAWSZ);
+		memcpy(oid.id, hash, GIT_OID_SHA1_SIZE);
 	} else {
 		git_str_attach_notowned(&midx_buf, (char *)data, size);
 	}
@@ -70,7 +70,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 		goto cleanup;
 
 	/* Search for any oid, just to exercise that codepath. */
-	if (git_midx_entry_find(&e, &idx, &oid, GIT_OID_HEXSZ) < 0)
+	if (git_midx_entry_find(&e, &idx, &oid, GIT_OID_SHA1_HEXSIZE) < 0)
 		goto cleanup;
 
 cleanup:
diff --git a/fuzzers/packfile_fuzzer.c b/fuzzers/packfile_fuzzer.c
index 23ecaf80f..52a813760 100644
--- a/fuzzers/packfile_fuzzer.c
+++ b/fuzzers/packfile_fuzzer.c
@@ -36,10 +36,19 @@ int LLVMFuzzerInitialize(int *argc, char ***argv)
 		fprintf(stderr, "Failed to limit maximum pack object count\n");
 		abort();
 	}
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	if (git_odb_new(&odb, NULL) < 0) {
+		fprintf(stderr, "Failed to create the odb\n");
+		abort();
+	}
+#else
 	if (git_odb_new(&odb) < 0) {
 		fprintf(stderr, "Failed to create the odb\n");
 		abort();
 	}
+#endif
+
 	if (git_mempack_new(&mempack) < 0) {
 		fprintf(stderr, "Failed to create the mempack\n");
 		abort();
@@ -90,11 +99,19 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 	if (git_indexer_append(indexer, data, size, &stats) < 0)
 		goto cleanup;
 	if (append_hash) {
+#ifdef GIT_EXPERIMENTAL_SHA256
+		if (git_odb_hash(&oid, data, size, GIT_OBJECT_BLOB, GIT_OID_SHA1) < 0) {
+			fprintf(stderr, "Failed to compute the SHA1 hash\n");
+			abort();
+		}
+#else
 		if (git_odb_hash(&oid, data, size, GIT_OBJECT_BLOB) < 0) {
 			fprintf(stderr, "Failed to compute the SHA1 hash\n");
 			abort();
 		}
-		if (git_indexer_append(indexer, &oid.id, GIT_OID_RAWSZ, &stats) < 0) {
+#endif
+
+		if (git_indexer_append(indexer, &oid.id, GIT_OID_SHA1_SIZE, &stats) < 0) {
 			goto cleanup;
 		}
 	}
diff --git a/include/git2.h b/include/git2.h
index 2961cc3e5..3457e5f04 100644
--- a/include/git2.h
+++ b/include/git2.h
@@ -28,6 +28,7 @@
 #include "git2/diff.h"
 #include "git2/email.h"
 #include "git2/errors.h"
+#include "git2/experimental.h"
 #include "git2/filter.h"
 #include "git2/global.h"
 #include "git2/graph.h"
diff --git a/include/git2/common.h b/include/git2/common.h
index 4e47488d7..defa24a6a 100644
--- a/include/git2/common.h
+++ b/include/git2/common.h
@@ -106,11 +106,6 @@ GIT_BEGIN_DECL
 #define GIT_PATH_MAX 4096
 
 /**
- * The string representation of the null object ID.
- */
-#define GIT_OID_HEX_ZERO "0000000000000000000000000000000000000000"
-
-/**
  * Return the version of the libgit2 library
  * being currently used.
  *
diff --git a/include/git2/deprecated.h b/include/git2/deprecated.h
index c32abeeb7..52864ebe1 100644
--- a/include/git2/deprecated.h
+++ b/include/git2/deprecated.h
@@ -777,6 +777,12 @@ typedef git_trace_cb git_trace_callback;
  */
 /**@{*/
 
+#ifndef GIT_EXPERIMENTAL_SHA256
+# define GIT_OID_RAWSZ    GIT_OID_SHA1_SIZE
+# define GIT_OID_HEXSZ    GIT_OID_SHA1_HEXSIZE
+# define GIT_OID_HEX_ZERO GIT_OID_SHA1_HEXZERO
+#endif
+
 GIT_EXTERN(int) git_oid_iszero(const git_oid *id);
 
 /**@}*/
diff --git a/include/git2/diff.h b/include/git2/diff.h
index 3839f0033..850d215a6 100644
--- a/include/git2/diff.h
+++ b/include/git2/diff.h
@@ -274,7 +274,7 @@ typedef struct {
 
 	/**
 	 * Represents the known length of the `id` field, when
-	 * converted to a hex string.  It is generally `GIT_OID_HEXSZ`, unless this
+	 * converted to a hex string.  It is generally `GIT_OID_SHA1_HEXSIZE`, unless this
 	 * delta was created from reading a patch file, in which case it may be
 	 * abbreviated to something reasonable, like 7 characters.
 	 */
diff --git a/include/git2/odb.h b/include/git2/odb.h
index 0ffe3f328..c7d6a894c 100644
--- a/include/git2/odb.h
+++ b/include/git2/odb.h
@@ -38,6 +38,25 @@ typedef enum {
  */
 typedef int GIT_CALLBACK(git_odb_foreach_cb)(const git_oid *id, void *payload);
 
+/** Options for configuring a loose object backend. */
+typedef struct {
+	unsigned int version; /**< version for the struct */
+
+	/**
+	 * Type of object IDs to use for this object database, or
+	 * 0 for default (currently SHA1).
+	 */
+	git_oid_t oid_type;
+} git_odb_options;
+
+/* The current version of the diff options structure */
+#define GIT_ODB_OPTIONS_VERSION 1
+
+/* Stack initializer for odb options.  Alternatively use
+ * `git_odb_options_init` programmatic initialization.
+ */
+#define GIT_ODB_OPTIONS_INIT { GIT_ODB_OPTIONS_VERSION }
+
 /**
  * Create a new object database with no backends.
  *
@@ -46,9 +65,14 @@ typedef int GIT_CALLBACK(git_odb_foreach_cb)(const git_oid *id, void *payload);
  *
  * @param out location to store the database pointer, if opened.
  *			Set to NULL if the open failed.
+ * @param opts the options for this object database or NULL for defaults
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_odb_new(git_odb **out, const git_odb_options *opts);
+#else
 GIT_EXTERN(int) git_odb_new(git_odb **out);
+#endif
 
 /**
  * Create a new object database and automatically add
@@ -64,9 +88,17 @@ GIT_EXTERN(int) git_odb_new(git_odb **out);
  * @param out location to store the database pointer, if opened.
  *			Set to NULL if the open failed.
  * @param objects_dir path of the backends' "objects" directory.
+ * @param opts the options for this object database or NULL for defaults
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_odb_open(
+	git_odb **out,
+	const char *objects_dir,
+	const git_odb_options *opts);
+#else
 GIT_EXTERN(int) git_odb_open(git_odb **out, const char *objects_dir);
+#endif
 
 /**
  * Add an on-disk alternate to an existing Object DB.
@@ -117,7 +149,7 @@ GIT_EXTERN(int) git_odb_read(git_odb_object **out, git_odb *db, const git_oid *i
  * This method queries all available ODB backends
  * trying to match the 'len' first hexadecimal
  * characters of the 'short_id'.
- * The remaining (GIT_OID_HEXSZ-len)*4 bits of
+ * The remaining (GIT_OID_SHA1_HEXSIZE-len)*4 bits of
  * 'short_id' must be 0s.
  * 'len' must be at least GIT_OID_MINPREFIXLEN,
  * and the prefix must be long enough to identify
@@ -218,7 +250,7 @@ typedef struct git_odb_expand_id {
  *
  * The given array will be updated in place: for each abbreviated ID that is
  * unique in the database, and of the given type (if specified),
- * the full object ID, object ID length (`GIT_OID_HEXSZ`) and type will be
+ * the full object ID, object ID length (`GIT_OID_SHA1_HEXSIZE`) and type will be
  * written back to the array. For IDs that are not found (or are ambiguous),
  * the array entry will be zeroed.
  *
@@ -435,18 +467,28 @@ GIT_EXTERN(int) git_odb_write_multi_pack_index(
 	git_odb *db);
 
 /**
- * Determine the object-ID (sha1 hash) of a data buffer
+ * Determine the object-ID (sha1 or sha256 hash) of a data buffer
  *
- * The resulting SHA-1 OID will be the identifier for the data
- * buffer as if the data buffer it were to written to the ODB.
+ * The resulting OID will be the identifier for the data buffer as if
+ * the data buffer it were to written to the ODB.
  *
  * @param out the resulting object-ID.
  * @param data data to hash
  * @param len size of the data
- * @param type of the data to hash
+ * @param object_type of the data to hash
+ * @param oid_type the oid type to hash to
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_odb_hash(
+	git_oid *out,
+	const void *data,
+	size_t len,
+	git_object_t object_type,
+	git_oid_t oid_type);
+#else
 GIT_EXTERN(int) git_odb_hash(git_oid *out, const void *data, size_t len, git_object_t type);
+#endif
 
 /**
  * Read a file from disk and fill a git_oid with the object id
@@ -458,10 +500,19 @@ GIT_EXTERN(int) git_odb_hash(git_oid *out, const void *data, size_t len, git_obj
  *
  * @param out oid structure the result is written into.
  * @param path file to read and determine object id for
- * @param type the type of the object that will be hashed
+ * @param object_type of the data to hash
+ * @param oid_type the oid type to hash to
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_odb_hashfile(
+	git_oid *out,
+	const char *path,
+	git_object_t object_type,
+	git_oid_t oid_type);
+#else
 GIT_EXTERN(int) git_odb_hashfile(git_oid *out, const char *path, git_object_t type);
+#endif
 
 /**
  * Create a copy of an odb_object
diff --git a/include/git2/odb_backend.h b/include/git2/odb_backend.h
index 5ad777b17..a31d1b782 100644
--- a/include/git2/odb_backend.h
+++ b/include/git2/odb_backend.h
@@ -34,18 +34,63 @@ GIT_BEGIN_DECL
  */
 GIT_EXTERN(int) git_odb_backend_pack(git_odb_backend **out, const char *objects_dir);
 
+typedef enum {
+	GIT_ODB_BACKEND_LOOSE_FSYNC = (1 << 0)
+} git_odb_backend_loose_flag_t;
+
+/** Options for configuring a loose object backend. */
+typedef struct {
+	unsigned int version; /**< version for the struct */
+
+	/** A combination of the `git_odb_backend_loose_flag_t` types. */
+	uint32_t flags;
+
+	/**
+	 * zlib compression level to use (0-9), where 1 is the fastest
+	 * at the expense of larger files, and 9 produces the best
+	 * compression at the expense of speed.  0 indicates that no
+	 * compression should be performed.  -1 is the default (currently
+	 * optimizing for speed).
+	 */
+	int compression_level;
+
+	/** Permissions to use creating a directory or 0 for defaults */
+	unsigned int dir_mode;
+
+	/** Permissions to use creating a file or 0 for defaults */
+	unsigned int file_mode;
+
+	/**
+	 * Type of object IDs to use for this object database, or
+	 * 0 for default (currently SHA1).
+	 */
+	git_oid_t oid_type;
+} git_odb_backend_loose_options;
+
+/* The current version of the diff options structure */
+#define GIT_ODB_BACKEND_LOOSE_OPTIONS_VERSION 1
+
+/* Stack initializer for odb loose backend options.  Alternatively use
+ * `git_odb_backend_loose_options_init` programmatic initialization.
+ */
+#define GIT_ODB_BACKEND_LOOSE_OPTIONS_INIT \
+	{ GIT_ODB_BACKEND_LOOSE_OPTIONS_VERSION, 0, -1 }
+
 /**
  * Create a backend for loose objects
  *
  * @param out location to store the odb backend pointer
  * @param objects_dir the Git repository's objects directory
- * @param compression_level zlib compression level to use
- * @param do_fsync whether to do an fsync() after writing
- * @param dir_mode permissions to use creating a directory or 0 for defaults
- * @param file_mode permissions to use creating a file or 0 for defaults
+ * @param opts options for the loose object backend or NULL
  *
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_odb_backend_loose(
+	git_odb_backend **out,
+	const char *objects_dir,
+	git_odb_backend_loose_options *opts);
+#else
 GIT_EXTERN(int) git_odb_backend_loose(
 	git_odb_backend **out,
 	const char *objects_dir,
@@ -53,6 +98,7 @@ GIT_EXTERN(int) git_odb_backend_loose(
 	int do_fsync,
 	unsigned int dir_mode,
 	unsigned int file_mode);
+#endif
 
 /**
  * Create a backend out of a single packfile
@@ -87,6 +133,8 @@ struct git_odb_stream {
 	unsigned int mode;
 	void *hash_ctx;
 
+	git_oid_t oid_type;
+
 	git_object_size_t declared_size;
 	git_object_size_t received_bytes;
 
diff --git a/include/git2/oid.h b/include/git2/oid.h
index 549df4eab..399b7b907 100644
--- a/include/git2/oid.h
+++ b/include/git2/oid.h
@@ -9,6 +9,7 @@
 
 #include "common.h"
 #include "types.h"
+#include "experimental.h"
 
 /**
  * @file git2/oid.h
@@ -19,11 +20,76 @@
  */
 GIT_BEGIN_DECL
 
-/** Size (in bytes) of a raw/binary oid */
-#define GIT_OID_RAWSZ 20
+/** The type of object id. */
+typedef enum {
 
-/** Size (in bytes) of a hex formatted oid */
-#define GIT_OID_HEXSZ (GIT_OID_RAWSZ * 2)
+#ifdef GIT_EXPERIMENTAL_SHA256
+	GIT_OID_SHA1 = 1,  /**< SHA1 */
+	GIT_OID_SHA256 = 2 /**< SHA256 */
+#else
+	GIT_OID_SHA1 = 1   /**< SHA1 */
+#endif
+
+} git_oid_t;
+
+/*
+ * SHA1 is currently the only supported object ID type.
+ */
+
+/** SHA1 is currently libgit2's default oid type. */
+#define GIT_OID_DEFAULT         GIT_OID_SHA1
+
+/** Size (in bytes) of a raw/binary sha1 oid */
+#define GIT_OID_SHA1_SIZE       20
+/** Size (in bytes) of a hex formatted sha1 oid */
+#define GIT_OID_SHA1_HEXSIZE   (GIT_OID_SHA1_SIZE * 2)
+
+/**
+ * The binary representation of the null sha1 object ID.
+ */
+#ifndef GIT_EXPERIMENTAL_SHA256
+# define GIT_OID_SHA1_ZERO   { { 0 } }
+#else
+# define GIT_OID_SHA1_ZERO   { GIT_OID_SHA1, { 0 } }
+#endif
+
+/**
+ * The string representation of the null sha1 object ID.
+ */
+#define GIT_OID_SHA1_HEXZERO   "0000000000000000000000000000000000000000"
+
+/*
+ * Experimental SHA256 support is a breaking change to the API.
+ * This exists for application compatibility testing.
+ */
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+
+/** Size (in bytes) of a raw/binary sha256 oid */
+# define GIT_OID_SHA256_SIZE     32
+/** Size (in bytes) of a hex formatted sha256 oid */
+# define GIT_OID_SHA256_HEXSIZE (GIT_OID_SHA256_SIZE * 2)
+
+/**
+ * The binary representation of the null sha256 object ID.
+ */
+# define GIT_OID_SHA256_ZERO { GIT_OID_SHA256, { 0 } }
+
+/**
+ * The string representation of the null sha256 object ID.
+ */
+# define GIT_OID_SHA256_HEXZERO "0000000000000000000000000000000000000000000000000000000000000000"
+
+#endif
+
+/* Maximum possible object ID size in raw / hex string format. */
+#ifndef GIT_EXPERIMENTAL_SHA256
+# define GIT_OID_MAX_SIZE        GIT_OID_SHA1_SIZE
+# define GIT_OID_MAX_HEXSIZE     GIT_OID_SHA1_HEXSIZE
+#else
+# define GIT_OID_MAX_SIZE        GIT_OID_SHA256_SIZE
+# define GIT_OID_MAX_HEXSIZE     GIT_OID_SHA256_HEXSIZE
+#endif
 
 /** Minimum length (in number of hex characters,
  * i.e. packets of 4 bits) of an oid prefix */
@@ -31,29 +97,50 @@ GIT_BEGIN_DECL
 
 /** Unique identity of any object (commit, tree, blob, tag). */
 typedef struct git_oid {
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	/** type of object id */
+	unsigned char type;
+#endif
+
 	/** raw binary formatted id */
-	unsigned char id[GIT_OID_RAWSZ];
+	unsigned char id[GIT_OID_MAX_SIZE];
 } git_oid;
 
 /**
  * Parse a hex formatted object id into a git_oid.
  *
+ * The appropriate number of bytes for the given object ID type will
+ * be read from the string - 40 bytes for SHA1, 64 bytes for SHA256.
+ * The given string need not be NUL terminated.
+ *
  * @param out oid structure the result is written into.
  * @param str input hex string; must be pointing at the start of
  *		the hex sequence and have at least the number of bytes
- *		needed for an oid encoded in hex (40 bytes).
+ *		needed for an oid encoded in hex (40 bytes for sha1,
+ *		256 bytes for sha256).
+ * @param type the type of object id
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_oid_fromstr(git_oid *out, const char *str, git_oid_t type);
+#else
 GIT_EXTERN(int) git_oid_fromstr(git_oid *out, const char *str);
+#endif
 
 /**
- * Parse a hex formatted null-terminated string into a git_oid.
+ * Parse a hex formatted NUL-terminated string into a git_oid.
  *
  * @param out oid structure the result is written into.
  * @param str input hex string; must be null-terminated.
+ * @param type the type of object id
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_oid_fromstrp(git_oid *out, const char *str, git_oid_t type);
+#else
 GIT_EXTERN(int) git_oid_fromstrp(git_oid *out, const char *str);
+#endif
 
 /**
  * Parse N characters of a hex formatted object id into a git_oid.
@@ -64,9 +151,14 @@ GIT_EXTERN(int) git_oid_fromstrp(git_oid *out, const char *str);
  * @param out oid structure the result is written into.
  * @param str input hex string of at least size `length`
  * @param length length of the input string
+ * @param type the type of object id
  * @return 0 or an error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_oid_fromstrn(git_oid *out, const char *str, size_t length, git_oid_t type);
+#else
 GIT_EXTERN(int) git_oid_fromstrn(git_oid *out, const char *str, size_t length);
+#endif
 
 /**
  * Copy an already raw oid into a git_oid structure.
@@ -75,16 +167,21 @@ GIT_EXTERN(int) git_oid_fromstrn(git_oid *out, const char *str, size_t length);
  * @param raw the raw input bytes to be copied.
  * @return 0 on success or error code
  */
+#ifdef GIT_EXPERIMENTAL_SHA256
+GIT_EXTERN(int) git_oid_fromraw(git_oid *out, const unsigned char *raw, git_oid_t type);
+#else
 GIT_EXTERN(int) git_oid_fromraw(git_oid *out, const unsigned char *raw);
+#endif
 
 /**
  * Format a git_oid into a hex string.
  *
  * @param out output hex string; must be pointing at the start of
  *		the hex sequence and have at least the number of bytes
- *		needed for an oid encoded in hex (40 bytes). Only the
- *		oid digits are written; a '\\0' terminator must be added
- *		by the caller if it is required.
+ *		needed for an oid encoded in hex (40 bytes for SHA1,
+ *		64 bytes for SHA256). Only the oid digits are written;
+ *		a '\\0' terminator must be added by the caller if it is
+ *		required.
  * @param id oid structure to format.
  * @return 0 on success or error code
  */
@@ -94,7 +191,7 @@ GIT_EXTERN(int) git_oid_fmt(char *out, const git_oid *id);
  * Format a git_oid into a partial hex string.
  *
  * @param out output hex string; you say how many bytes to write.
- *		If the number of bytes is > GIT_OID_HEXSZ, extra bytes
+ *		If the number of bytes is > GIT_OID_SHA1_HEXSIZE, extra bytes
  *		will be zeroed; if not, a '\0' terminator is NOT added.
  * @param n number of characters to write into out string
  * @param id oid structure to format.
@@ -110,9 +207,10 @@ GIT_EXTERN(int) git_oid_nfmt(char *out, size_t n, const git_oid *id);
  *
  * @param out output hex string; must be pointing at the start of
  *		the hex sequence and have at least the number of bytes
- *		needed for an oid encoded in hex (41 bytes). Only the
- *		oid digits are written; a '\\0' terminator must be added
- *		by the caller if it is required.
+ *		needed for an oid encoded in hex (41 bytes for SHA1,
+ *		65 bytes for SHA256). Only the oid digits are written;
+ *		a '\\0' terminator must be added by the caller if it
+ *		is required.
  * @param id oid structure to format.
  * @return 0 on success, non-zero callback return value, or error code
  */
@@ -134,7 +232,9 @@ GIT_EXTERN(char *) git_oid_tostr_s(const git_oid *oid);
 /**
  * Format a git_oid into a buffer as a hex format c-string.
  *
- * If the buffer is smaller than GIT_OID_HEXSZ+1, then the resulting
+ * If the buffer is smaller than the size of a hex-formatted oid string
+ * plus an additional byte (GIT_OID_SHA_HEXSIZE + 1 for SHA1 or
+ * GIT_OID_SHA256_HEXSIZE + 1 for SHA256), then the resulting
  * oid c-string will be truncated to n-1 characters (but will still be
  * NUL-byte terminated).
  *
diff --git a/include/git2/sys/odb_backend.h b/include/git2/sys/odb_backend.h
index 8598f94e5..c42abd370 100644
--- a/include/git2/sys/odb_backend.h
+++ b/include/git2/sys/odb_backend.h
@@ -36,7 +36,7 @@ struct git_odb_backend {
 		void **, size_t *, git_object_t *, git_odb_backend *, const git_oid *);
 
 	/* To find a unique object given a prefix of its oid.  The oid given
-	 * must be so that the remaining (GIT_OID_HEXSZ - len)*4 bits are 0s.
+	 * must be so that the remaining (GIT_OID_SHA1_HEXSIZE - len)*4 bits are 0s.
 	 */
 	int GIT_CALLBACK(read_prefix)(
 		git_oid *, void **, size_t *, git_object_t *,
diff --git a/include/git2/version.h b/include/git2/version.h
index d591904fd..09f4ae3e4 100644
--- a/include/git2/version.h
+++ b/include/git2/version.h
@@ -11,13 +11,13 @@
  * The version string for libgit2.  This string follows semantic
  * versioning (v2) guidelines.
  */
-#define LIBGIT2_VERSION        "1.5.0"
+#define LIBGIT2_VERSION        "1.6.0-alpha"
 
 /** The major version number for this version of libgit2. */
 #define LIBGIT2_VER_MAJOR      1
 
 /** The minor version number for this version of libgit2. */
-#define LIBGIT2_VER_MINOR      5
+#define LIBGIT2_VER_MINOR      6
 
 /** The revision ("teeny") version number for this version of libgit2. */
 #define LIBGIT2_VER_REVISION   0
@@ -31,9 +31,9 @@
  * a prerelease name like "beta" or "rc1".  For final releases, this will
  * be `NULL`.
  */
-#define LIBGIT2_VER_PRERELEASE NULL
+#define LIBGIT2_VER_PRERELEASE "alpha"
 
 /** The library ABI soversion for this version of libgit2. */
-#define LIBGIT2_SOVERSION      "1.5"
+#define LIBGIT2_SOVERSION      "1.6"
 
 #endif
diff --git a/package.json b/package.json
index 8676fe513..8ef46d761 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "libgit2",
-  "version": "1.5.0",
+  "version": "1.6.0-alpha",
   "repo": "https://github.com/libgit2/libgit2",
   "description": " A cross-platform, linkable library implementation of Git that you can use in your application.",
   "install": "mkdir build && cd build && cmake .. && cmake --build ."
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index d16cfe538..b81ad272f 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -70,7 +70,11 @@ check_function_exists(qsort_s GIT_QSORT_S)
 
 # random / entropy data
 
-check_function_exists(getentropy GIT_RAND_GETENTROPY)
+# The flag has been unset to prevent issues
+# related to Linux GLIBC version dependency
+
+# check_function_exists(getentropy GIT_RAND_GETENTROPY)
+unset(GIT_RAND_GETENTROPY)
 check_function_exists(getloadavg GIT_RAND_GETLOADAVG)
 
 # determine architecture of the machine
@@ -171,12 +175,6 @@ endif()
 add_feature_info(iconv GIT_USE_ICONV "iconv encoding conversion support")
 
 #
-# Configure support
-#
-
-configure_file(features.h.in git2/sys/features.h)
-
-#
 # Include child projects
 #
 
diff --git a/src/cli/CMakeLists.txt b/src/cli/CMakeLists.txt
index 4f347e93f..46f4d63b5 100644
--- a/src/cli/CMakeLists.txt
+++ b/src/cli/CMakeLists.txt
@@ -1,5 +1,7 @@
 set(CLI_INCLUDES
-	"${libgit2_BINARY_DIR}/src"
+	"${libgit2_BINARY_DIR}/src/util"
+	"${libgit2_BINARY_DIR}/include"
+	"${libgit2_BINARY_DIR}/include/git2"
 	"${libgit2_SOURCE_DIR}/src/util"
 	"${libgit2_SOURCE_DIR}/src/cli"
 	"${libgit2_SOURCE_DIR}/include")
@@ -39,6 +41,7 @@ target_link_libraries(git2_cli ${CLI_LIBGIT2_LIBRARY} ${LIBGIT2_SYSTEM_LIBS})
 
 set_target_properties(git2_cli PROPERTIES C_STANDARD 90)
 set_target_properties(git2_cli PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${libgit2_BINARY_DIR})
+set_target_properties(git2_cli PROPERTIES OUTPUT_NAME ${LIBGIT2_FILENAME})
 
 ide_split_sources(git2_cli)
 
diff --git a/src/cli/cmd_hash_object.c b/src/cli/cmd_hash_object.c
index 5cfe9146a..a64db8823 100644
--- a/src/cli/cmd_hash_object.c
+++ b/src/cli/cmd_hash_object.c
@@ -64,8 +64,13 @@ static int hash_buf(git_odb *odb, git_str *buf, git_object_t type)
 		if (git_odb_write(&oid, odb, buf->ptr, buf->size, type) < 0)
 			return cli_error_git();
 	} else {
+#ifdef GIT_EXPERIMENTAL_SHA256
+		if (git_odb_hash(&oid, buf->ptr, buf->size, type, GIT_OID_SHA1) < 0)
+			return cli_error_git();
+#else
 		if (git_odb_hash(&oid, buf->ptr, buf->size, type) < 0)
 			return cli_error_git();
+#endif
 	}
 
 	if (printf("%s\n", git_oid_tostr_s(&oid)) < 0)
diff --git a/src/libgit2/CMakeLists.txt b/src/libgit2/CMakeLists.txt
index 0c7ddddba..3462b795e 100644
--- a/src/libgit2/CMakeLists.txt
+++ b/src/libgit2/CMakeLists.txt
@@ -8,7 +8,9 @@ set_target_properties(libgit2 PROPERTIES C_EXTENSIONS OFF)
 include(PkgBuildConfig)
 
 set(LIBGIT2_INCLUDES
-	"${PROJECT_BINARY_DIR}/src"
+	"${PROJECT_BINARY_DIR}/src/util"
+	"${PROJECT_BINARY_DIR}/include"
+	"${PROJECT_BINARY_DIR}/include/git2"
 	"${PROJECT_SOURCE_DIR}/src/libgit2"
 	"${PROJECT_SOURCE_DIR}/src/util"
 	"${PROJECT_SOURCE_DIR}/include")
@@ -109,7 +111,7 @@ if(SONAME)
 	endif()
 endif()
 
-pkg_build_config(NAME libgit2
+pkg_build_config(NAME "${LIBGIT2_FILENAME}"
 	VERSION ${libgit2_VERSION}
 	DESCRIPTION "The git library, take 2"
 	LIBS_SELF git2
@@ -122,10 +124,26 @@ if(MSVC_IDE)
 	set_source_files_properties(win32/precompiled.c COMPILE_FLAGS "/Ycprecompiled.h")
 endif()
 
+# support experimental features and functionality
+
+configure_file(experimental.h.in "${PROJECT_BINARY_DIR}/include/git2/experimental.h")
+
+# translate filenames in the git2.h so that they match the install directory
+# (allows for side-by-side installs of libgit2 and libgit2-experimental.)
+
+FILE(READ "${PROJECT_SOURCE_DIR}/include/git2.h" LIBGIT2_INCLUDE)
+STRING(REGEX REPLACE "#include \"git2\/" "#include \"${LIBGIT2_FILENAME}/" LIBGIT2_INCLUDE "${LIBGIT2_INCLUDE}")
+FILE(WRITE "${PROJECT_BINARY_DIR}/include/${LIBGIT2_FILENAME}.h" ${LIBGIT2_INCLUDE})
+
 # Install
+
 install(TARGETS libgit2package
 	RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
 	LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
 	ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
-install(DIRECTORY ${PROJECT_SOURCE_DIR}/include/git2 DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
-install(FILES ${PROJECT_SOURCE_DIR}/include/git2.h DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+install(DIRECTORY ${PROJECT_SOURCE_DIR}/include/git2/
+        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${LIBGIT2_FILENAME}")
+install(FILES ${PROJECT_BINARY_DIR}/include/git2/experimental.h
+        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${LIBGIT2_FILENAME}")
+install(FILES "${PROJECT_BINARY_DIR}/include/${LIBGIT2_FILENAME}.h"
+        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
diff --git a/src/libgit2/annotated_commit.c b/src/libgit2/annotated_commit.c
index e48947679..7bd8b6077 100644
--- a/src/libgit2/annotated_commit.c
+++ b/src/libgit2/annotated_commit.c
@@ -40,7 +40,7 @@ static int annotated_commit_init(
 		goto done;
 
 	git_oid_fmt(annotated_commit->id_str, git_commit_id(commit));
-	annotated_commit->id_str[GIT_OID_HEXSZ] = '\0';
+	annotated_commit->id_str[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	if (!description)
 		description = annotated_commit->id_str;
diff --git a/src/libgit2/annotated_commit.h b/src/libgit2/annotated_commit.h
index 444a2ed10..c87eaa805 100644
--- a/src/libgit2/annotated_commit.h
+++ b/src/libgit2/annotated_commit.h
@@ -41,7 +41,7 @@ struct git_annotated_commit {
 	const char *ref_name;
 	const char *remote_url;
 
-	char id_str[GIT_OID_HEXSZ+1];
+	char id_str[GIT_OID_SHA1_HEXSIZE+1];
 };
 
 extern int git_annotated_commit_from_head(git_annotated_commit **out,
diff --git a/src/libgit2/attr_file.c b/src/libgit2/attr_file.c
index 0eb881a9b..afa8ec7b3 100644
--- a/src/libgit2/attr_file.c
+++ b/src/libgit2/attr_file.c
@@ -135,7 +135,7 @@ int git_attr_file__load(
 		break;
 	case GIT_ATTR_FILE_SOURCE_INDEX: {
 		if ((error = attr_file_oid_from_index(&id, repo, entry->path)) < 0 ||
-			(error = git_blob_lookup(&blob, repo, &id)) < 0)
+		    (error = git_blob_lookup(&blob, repo, &id)) < 0)
 			return error;
 
 		/* Do not assume that data straight from the ODB is NULL-terminated;
diff --git a/src/libgit2/blame.c b/src/libgit2/blame.c
index a6ab43efd..b70cd615e 100644
--- a/src/libgit2/blame.c
+++ b/src/libgit2/blame.c
@@ -72,6 +72,8 @@ static git_blame_hunk *new_hunk(
 	hunk->final_start_line_number = start;
 	hunk->orig_start_line_number = orig_start;
 	hunk->orig_path = path ? git__strdup(path) : NULL;
+	git_oid_clear(&hunk->orig_commit_id, GIT_OID_SHA1);
+	git_oid_clear(&hunk->final_commit_id, GIT_OID_SHA1);
 
 	return hunk;
 }
diff --git a/src/libgit2/branch.c b/src/libgit2/branch.c
index 2dd7d2bb4..4cbd1e26f 100644
--- a/src/libgit2/branch.c
+++ b/src/libgit2/branch.c
@@ -134,9 +134,9 @@ int git_branch_create(
 	const git_commit *commit,
 	int force)
 {
-	char commit_id[GIT_OID_HEXSZ + 1];
+	char commit_id[GIT_OID_SHA1_HEXSIZE + 1];
 
-	git_oid_tostr(commit_id, GIT_OID_HEXSZ + 1, git_commit_id(commit));
+	git_oid_tostr(commit_id, GIT_OID_SHA1_HEXSIZE + 1, git_commit_id(commit));
 	return create_branch(ref_out, repository, branch_name, commit, commit_id, force);
 }
 
diff --git a/src/libgit2/cherrypick.c b/src/libgit2/cherrypick.c
index 9ec4962b9..04812b1c6 100644
--- a/src/libgit2/cherrypick.c
+++ b/src/libgit2/cherrypick.c
@@ -106,10 +106,10 @@ static int cherrypick_state_cleanup(git_repository *repo)
 
 static int cherrypick_seterr(git_commit *commit, const char *fmt)
 {
-	char commit_oidstr[GIT_OID_HEXSZ + 1];
+	char commit_oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 
 	git_error_set(GIT_ERROR_CHERRYPICK, fmt,
-		git_oid_tostr(commit_oidstr, GIT_OID_HEXSZ + 1, git_commit_id(commit)));
+		git_oid_tostr(commit_oidstr, GIT_OID_SHA1_HEXSIZE + 1, git_commit_id(commit)));
 
 	return -1;
 }
@@ -173,7 +173,7 @@ int git_cherrypick(
 	git_cherrypick_options opts;
 	git_reference *our_ref = NULL;
 	git_commit *our_commit = NULL;
-	char commit_oidstr[GIT_OID_HEXSZ + 1];
+	char commit_oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 	const char *commit_msg, *commit_summary;
 	git_str their_label = GIT_STR_INIT;
 	git_index *index = NULL;
diff --git a/src/libgit2/commit.c b/src/libgit2/commit.c
index 43d04b2c0..75cc8837c 100644
--- a/src/libgit2/commit.c
+++ b/src/libgit2/commit.c
@@ -57,11 +57,13 @@ static int git_commit__create_buffer_internal(
 	GIT_ASSERT_ARG(out);
 	GIT_ASSERT_ARG(tree);
 
-	git_oid__writebuf(out, "tree ", tree);
+	if (git_object__write_oid_header(out, "tree ", tree) < 0)
+		goto on_error;
 
 	for (i = 0; i < git_array_size(*parents); i++) {
 		parent = git_array_get(*parents, i);
-		git_oid__writebuf(out, "parent ", parent);
+		if (git_object__write_oid_header(out, "parent ", parent) < 0)
+			goto on_error;
 	}
 
 	git_signature__writebuf(out, "author ", author);
@@ -409,10 +411,12 @@ static int commit_parse(git_commit *commit, const char *data, size_t size, unsig
 
 	/* The tree is always the first field */
 	if (!(flags & GIT_COMMIT_PARSE_QUICK)) {
-	    if (git_oid__parse(&commit->tree_id, &buffer, buffer_end, "tree ") < 0)
+		if (git_object__parse_oid_header(&commit->tree_id,
+				&buffer, buffer_end, "tree ",
+				GIT_OID_SHA1) < 0)
 			goto bad_buffer;
 	} else {
-		size_t tree_len = strlen("tree ") + GIT_OID_HEXSZ + 1;
+		size_t tree_len = strlen("tree ") + GIT_OID_SHA1_HEXSIZE + 1;
 		if (buffer + tree_len > buffer_end)
 			goto bad_buffer;
 		buffer += tree_len;
@@ -595,7 +599,7 @@ const char *git_commit_summary(git_commit *commit)
 				while (*next && git__isspace_nonlf(*next)) {
 					++next;
 				}
-				if (!*next || *next == '\n') 
+				if (!*next || *next == '\n')
 					break;
 			}
 			/* record the beginning of contiguous whitespace runs */
diff --git a/src/libgit2/commit_graph.c b/src/libgit2/commit_graph.c
index 10947acec..322d24b19 100644
--- a/src/libgit2/commit_graph.c
+++ b/src/libgit2/commit_graph.c
@@ -138,19 +138,19 @@ static int commit_graph_parse_oid_lookup(
 		struct git_commit_graph_chunk *chunk_oid_lookup)
 {
 	uint32_t i;
-	unsigned char *oid, *prev_oid, zero_oid[GIT_OID_RAWSZ] = {0};
+	unsigned char *oid, *prev_oid, zero_oid[GIT_OID_SHA1_SIZE] = {0};
 
 	if (chunk_oid_lookup->offset == 0)
 		return commit_graph_error("missing OID Lookup chunk");
 	if (chunk_oid_lookup->length == 0)
 		return commit_graph_error("empty OID Lookup chunk");
-	if (chunk_oid_lookup->length != file->num_commits * GIT_OID_RAWSZ)
+	if (chunk_oid_lookup->length != file->num_commits * GIT_OID_SHA1_SIZE)
 		return commit_graph_error("OID Lookup chunk has wrong length");
 
 	file->oid_lookup = oid = (unsigned char *)(data + chunk_oid_lookup->offset);
 	prev_oid = zero_oid;
-	for (i = 0; i < file->num_commits; ++i, oid += GIT_OID_RAWSZ) {
-		if (git_oid_raw_cmp(prev_oid, oid) >= 0)
+	for (i = 0; i < file->num_commits; ++i, oid += GIT_OID_SHA1_SIZE) {
+		if (git_oid_raw_cmp(prev_oid, oid, GIT_OID_SHA1_SIZE) >= 0)
 			return commit_graph_error("OID Lookup index is non-monotonic");
 		prev_oid = oid;
 	}
@@ -167,7 +167,7 @@ static int commit_graph_parse_commit_data(
 		return commit_graph_error("missing Commit Data chunk");
 	if (chunk_commit_data->length == 0)
 		return commit_graph_error("empty Commit Data chunk");
-	if (chunk_commit_data->length != file->num_commits * (GIT_OID_RAWSZ + 16))
+	if (chunk_commit_data->length != file->num_commits * (GIT_OID_SHA1_SIZE + 16))
 		return commit_graph_error("Commit Data chunk has wrong length");
 
 	file->commit_data = data + chunk_commit_data->offset;
@@ -210,7 +210,7 @@ int git_commit_graph_file_parse(
 
 	GIT_ASSERT_ARG(file);
 
-	if (size < sizeof(struct git_commit_graph_header) + GIT_OID_RAWSZ)
+	if (size < sizeof(struct git_commit_graph_header) + GIT_OID_SHA1_SIZE)
 		return commit_graph_error("commit-graph is too short");
 
 	hdr = ((struct git_commit_graph_header *)data);
@@ -227,7 +227,7 @@ int git_commit_graph_file_parse(
 	 * headers, and a special zero chunk.
 	 */
 	last_chunk_offset = sizeof(struct git_commit_graph_header) + (1 + hdr->chunks) * 12;
-	trailer_offset = size - GIT_OID_RAWSZ;
+	trailer_offset = size - GIT_OID_SHA1_SIZE;
 	checksum_size = GIT_HASH_SHA1_SIZE;
 
 	if (trailer_offset < last_chunk_offset)
@@ -436,15 +436,15 @@ static int git_commit_graph_entry_get_byindex(
 		return GIT_ENOTFOUND;
 	}
 
-	commit_data = file->commit_data + pos * (GIT_OID_RAWSZ + 4 * sizeof(uint32_t));
-	git_oid_fromraw(&e->tree_oid, commit_data);
-	e->parent_indices[0] = ntohl(*((uint32_t *)(commit_data + GIT_OID_RAWSZ)));
+	commit_data = file->commit_data + pos * (GIT_OID_SHA1_SIZE + 4 * sizeof(uint32_t));
+	git_oid__fromraw(&e->tree_oid, commit_data, GIT_OID_SHA1);
+	e->parent_indices[0] = ntohl(*((uint32_t *)(commit_data + GIT_OID_SHA1_SIZE)));
 	e->parent_indices[1] = ntohl(
-			*((uint32_t *)(commit_data + GIT_OID_RAWSZ + sizeof(uint32_t))));
+			*((uint32_t *)(commit_data + GIT_OID_SHA1_SIZE + sizeof(uint32_t))));
 	e->parent_count = (e->parent_indices[0] != GIT_COMMIT_GRAPH_MISSING_PARENT)
 			+ (e->parent_indices[1] != GIT_COMMIT_GRAPH_MISSING_PARENT);
-	e->generation = ntohl(*((uint32_t *)(commit_data + GIT_OID_RAWSZ + 2 * sizeof(uint32_t))));
-	e->commit_time = ntohl(*((uint32_t *)(commit_data + GIT_OID_RAWSZ + 3 * sizeof(uint32_t))));
+	e->generation = ntohl(*((uint32_t *)(commit_data + GIT_OID_SHA1_SIZE + 2 * sizeof(uint32_t))));
+	e->commit_time = ntohl(*((uint32_t *)(commit_data + GIT_OID_SHA1_SIZE + 3 * sizeof(uint32_t))));
 
 	e->commit_time |= (e->generation & UINT64_C(0x3)) << UINT64_C(32);
 	e->generation >>= 2u;
@@ -471,7 +471,7 @@ static int git_commit_graph_entry_get_byindex(
 		}
 	}
 
-	git_oid_fromraw(&e->sha1, &file->oid_lookup[pos * GIT_OID_RAWSZ]);
+	git_oid__fromraw(&e->sha1, &file->oid_lookup[pos * GIT_OID_SHA1_SIZE], GIT_OID_SHA1);
 	return 0;
 }
 
@@ -524,27 +524,27 @@ int git_commit_graph_entry_find(
 	hi = ntohl(file->oid_fanout[(int)short_oid->id[0]]);
 	lo = ((short_oid->id[0] == 0x0) ? 0 : ntohl(file->oid_fanout[(int)short_oid->id[0] - 1]));
 
-	pos = git_pack__lookup_sha1(file->oid_lookup, GIT_OID_RAWSZ, lo, hi, short_oid->id);
+	pos = git_pack__lookup_sha1(file->oid_lookup, GIT_OID_SHA1_SIZE, lo, hi, short_oid->id);
 
 	if (pos >= 0) {
 		/* An object matching exactly the oid was found */
 		found = 1;
-		current = file->oid_lookup + (pos * GIT_OID_RAWSZ);
+		current = file->oid_lookup + (pos * GIT_OID_SHA1_SIZE);
 	} else {
 		/* No object was found */
 		/* pos refers to the object with the "closest" oid to short_oid */
 		pos = -1 - pos;
 		if (pos < (int)file->num_commits) {
-			current = file->oid_lookup + (pos * GIT_OID_RAWSZ);
+			current = file->oid_lookup + (pos * GIT_OID_SHA1_SIZE);
 
 			if (!git_oid_raw_ncmp(short_oid->id, current, len))
 				found = 1;
 		}
 	}
 
-	if (found && len != GIT_OID_HEXSZ && pos + 1 < (int)file->num_commits) {
+	if (found && len != GIT_OID_SHA1_HEXSIZE && pos + 1 < (int)file->num_commits) {
 		/* Check for ambiguousity */
-		const unsigned char *next = current + GIT_OID_RAWSZ;
+		const unsigned char *next = current + GIT_OID_SHA1_SIZE;
 
 		if (!git_oid_raw_ncmp(short_oid->id, next, len))
 			found = 2;
@@ -1020,7 +1020,7 @@ static int commit_graph_write(
 	git_vector_foreach (&w->commits, i, packed_commit) {
 		error = git_str_put(&oid_lookup,
 			(const char *)&packed_commit->sha1.id,
-			GIT_OID_RAWSZ);
+			GIT_OID_SHA1_SIZE);
 
 		if (error < 0)
 			goto cleanup;
@@ -1037,7 +1037,7 @@ static int commit_graph_write(
 
 		error = git_str_put(&commit_data,
 			(const char *)&packed_commit->tree_oid.id,
-			GIT_OID_RAWSZ);
+			GIT_OID_SHA1_SIZE);
 
 		if (error < 0)
 			goto cleanup;
diff --git a/src/libgit2/commit_list.c b/src/libgit2/commit_list.c
index 4585508bc..511d7291f 100644
--- a/src/libgit2/commit_list.c
+++ b/src/libgit2/commit_list.c
@@ -172,7 +172,7 @@ int git_commit_list_parse(git_revwalk *walk, git_commit_list_node *commit)
 	if (cgraph_file) {
 		git_commit_graph_entry e;
 
-		error = git_commit_graph_entry_find(&e, cgraph_file, &commit->oid, GIT_OID_RAWSZ);
+		error = git_commit_graph_entry_find(&e, cgraph_file, &commit->oid, GIT_OID_SHA1_SIZE);
 		if (error == 0 && git__is_uint16(e.parent_count)) {
 			size_t i;
 			commit->generation = (uint32_t)e.generation;
diff --git a/src/libgit2/describe.c b/src/libgit2/describe.c
index 1033eac50..20a171aa5 100644
--- a/src/libgit2/describe.c
+++ b/src/libgit2/describe.c
@@ -368,7 +368,7 @@ static int find_unique_abbrev_size(
 	if ((error = git_repository_odb__weakptr(&odb, repo)) < 0)
 		return error;
 
-	while (size < GIT_OID_HEXSZ) {
+	while (size < GIT_OID_SHA1_HEXSIZE) {
 		if ((error = git_odb_exists_prefix(&dummy, odb, oid_in, size)) == 0) {
 			*out = (int) size;
 			return 0;
@@ -383,7 +383,7 @@ static int find_unique_abbrev_size(
 	}
 
 	/* If we didn't find any shorter prefix, we have to do the whole thing */
-	*out = GIT_OID_HEXSZ;
+	*out = GIT_OID_SHA1_HEXSIZE;
 
 	return 0;
 }
@@ -397,7 +397,7 @@ static int show_suffix(
 {
 	int error, size = 0;
 
-	char hex_oid[GIT_OID_HEXSZ];
+	char hex_oid[GIT_OID_SHA1_HEXSIZE];
 
 	if ((error = find_unique_abbrev_size(&size, repo, id, abbrev_size)) < 0)
 		return error;
@@ -414,7 +414,7 @@ static int show_suffix(
 #define MAX_CANDIDATES_TAGS FLAG_BITS - 1
 
 static int describe_not_found(const git_oid *oid, const char *message_format) {
-	char oid_str[GIT_OID_HEXSZ + 1];
+	char oid_str[GIT_OID_SHA1_HEXSIZE + 1];
 	git_oid_tostr(oid_str, sizeof(oid_str), oid);
 
 	git_error_set(GIT_ERROR_DESCRIBE, message_format, oid_str);
@@ -525,7 +525,7 @@ static int describe(
 		if (annotated_cnt && (git_pqueue_size(&list) == 0)) {
 			/*
 			if (debug) {
-				char oid_str[GIT_OID_HEXSZ + 1];
+				char oid_str[GIT_OID_SHA1_HEXSIZE + 1];
 				git_oid_tostr(oid_str, sizeof(oid_str), &c->oid);
 
 				fprintf(stderr, "finished search at %s\n", oid_str);
@@ -592,7 +592,7 @@ static int describe(
 			"head", "lightweight", "annotated",
 		};
 
-		char oid_str[GIT_OID_HEXSZ + 1];
+		char oid_str[GIT_OID_SHA1_HEXSIZE + 1];
 
 		if (debug) {
 			for (cur_match = 0; cur_match < match_cnt; cur_match++) {
@@ -816,7 +816,7 @@ static int git_describe__format(
 
 	/* If we didn't find *any* tags, we fall back to the commit's id */
 	if (result->fallback_to_id) {
-		char hex_oid[GIT_OID_HEXSZ + 1] = {0};
+		char hex_oid[GIT_OID_SHA1_HEXSIZE + 1] = {0};
 		int size = 0;
 
 		if ((error = find_unique_abbrev_size(
diff --git a/src/libgit2/diff.c b/src/libgit2/diff.c
index 9840d6050..20a18c4b9 100644
--- a/src/libgit2/diff.c
+++ b/src/libgit2/diff.c
@@ -290,7 +290,7 @@ static int flush_hunk(git_oid *result, git_hash_ctx *ctx)
 	    (error = git_hash_init(ctx)) < 0)
 		return error;
 
-	for (i = 0; i < GIT_OID_RAWSZ; i++) {
+	for (i = 0; i < GIT_OID_SHA1_SIZE; i++) {
 		carry += result->id[i] + hash.id[i];
 		result->id[i] = (unsigned char)carry;
 		carry >>= 8;
@@ -381,6 +381,10 @@ int git_diff_patchid(git_oid *out, git_diff *diff, git_diff_patchid_options *opt
 	if ((error = (flush_hunk(&args.result, &args.ctx))) < 0)
 		goto out;
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	args.result.type = GIT_OID_SHA1;
+#endif
+
 	git_oid_cpy(out, &args.result);
 
 out:
diff --git a/src/libgit2/diff_file.c b/src/libgit2/diff_file.c
index c7e9fbeee..5f4336658 100644
--- a/src/libgit2/diff_file.c
+++ b/src/libgit2/diff_file.c
@@ -144,6 +144,7 @@ int git_diff_file_content__init_from_src(
 
 	if (!src->blob && !src->buf) {
 		fc->flags |= GIT_DIFF_FLAG__NO_DATA;
+		git_oid_clear(&fc->file->id, GIT_OID_SHA1);
 	} else {
 		fc->flags |= GIT_DIFF_FLAG__LOADED;
 		fc->file->flags |= GIT_DIFF_FLAG_VALID_ID;
@@ -153,7 +154,7 @@ int git_diff_file_content__init_from_src(
 			git_blob_dup((git_blob **)&fc->blob, (git_blob *) src->blob);
 			fc->file->size = git_blob_rawsize(src->blob);
 			git_oid_cpy(&fc->file->id, git_blob_id(src->blob));
-			fc->file->id_abbrev = GIT_OID_HEXSZ;
+			fc->file->id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 			fc->map.len  = (size_t)fc->file->size;
 			fc->map.data = (char *)git_blob_rawcontent(src->blob);
@@ -161,10 +162,10 @@ int git_diff_file_content__init_from_src(
 			fc->flags |= GIT_DIFF_FLAG__FREE_BLOB;
 		} else {
 			int error;
-			if ((error = git_odb_hash(&fc->file->id, src->buf, src->buflen, GIT_OBJECT_BLOB)) < 0)
+			if ((error = git_odb__hash(&fc->file->id, src->buf, src->buflen, GIT_OBJECT_BLOB, GIT_OID_SHA1)) < 0)
 				return error;
 			fc->file->size = src->buflen;
-			fc->file->id_abbrev = GIT_OID_HEXSZ;
+			fc->file->id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 			fc->map.len  = src->buflen;
 			fc->map.data = (char *)src->buf;
@@ -177,7 +178,7 @@ int git_diff_file_content__init_from_src(
 static int diff_file_content_commit_to_str(
 	git_diff_file_content *fc, bool check_status)
 {
-	char oid[GIT_OID_HEXSZ+1];
+	char oid[GIT_OID_SHA1_HEXSIZE+1];
 	git_str content = GIT_STR_INIT;
 	const char *status = "";
 
@@ -410,8 +411,9 @@ static int diff_file_content_load_workdir(
 
 	/* once data is loaded, update OID if we didn't have it previously */
 	if (!error && (fc->file->flags & GIT_DIFF_FLAG_VALID_ID) == 0) {
-		error = git_odb_hash(
-			&fc->file->id, fc->map.data, fc->map.len, GIT_OBJECT_BLOB);
+		error = git_odb__hash(
+			&fc->file->id, fc->map.data, fc->map.len,
+			GIT_OBJECT_BLOB, GIT_OID_SHA1);
 		fc->file->flags |= GIT_DIFF_FLAG_VALID_ID;
 	}
 
diff --git a/src/libgit2/diff_generate.c b/src/libgit2/diff_generate.c
index cfaefba66..a88ce8c32 100644
--- a/src/libgit2/diff_generate.c
+++ b/src/libgit2/diff_generate.c
@@ -61,6 +61,9 @@ static git_diff_delta *diff_delta__alloc(
 	}
 	delta->status = status;
 
+	git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
+	git_oid_clear(&delta->new_file.id, GIT_OID_SHA1);
+
 	return delta;
 }
 
@@ -188,13 +191,15 @@ static int diff_delta__from_one(
 		delta->old_file.size = entry->file_size;
 		delta->old_file.flags |= GIT_DIFF_FLAG_EXISTS;
 		git_oid_cpy(&delta->old_file.id, &entry->id);
-		delta->old_file.id_abbrev = GIT_OID_HEXSZ;
+		git_oid_clear(&delta->new_file.id, GIT_OID_SHA1);
+		delta->old_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 	} else /* ADDED, IGNORED, UNTRACKED */ {
 		delta->new_file.mode = entry->mode;
 		delta->new_file.size = entry->file_size;
 		delta->new_file.flags |= GIT_DIFF_FLAG_EXISTS;
+		git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
 		git_oid_cpy(&delta->new_file.id, &entry->id);
-		delta->new_file.id_abbrev = GIT_OID_HEXSZ;
+		delta->new_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 	}
 
 	delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
@@ -249,14 +254,14 @@ static int diff_delta__from_two(
 		delta->old_file.size = old_entry->file_size;
 		delta->old_file.mode = old_mode;
 		git_oid_cpy(&delta->old_file.id, old_id);
-		delta->old_file.id_abbrev = GIT_OID_HEXSZ;
+		delta->old_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 		delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID |
 			GIT_DIFF_FLAG_EXISTS;
 	}
 
 	if (!git_index_entry_is_conflict(new_entry)) {
 		git_oid_cpy(&delta->new_file.id, new_id);
-		delta->new_file.id_abbrev = GIT_OID_HEXSZ;
+		delta->new_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 		delta->new_file.size = new_entry->file_size;
 		delta->new_file.mode = new_mode;
 		delta->old_file.flags |= GIT_DIFF_FLAG_EXISTS;
@@ -598,6 +603,7 @@ int git_diff__oid_for_file(
 	entry.mode = mode;
 	entry.file_size = (uint32_t)size;
 	entry.path = (char *)path;
+	git_oid_clear(&entry.id, GIT_OID_SHA1);
 
 	return git_diff__oid_for_entry(out, diff, &entry, mode, NULL);
 }
@@ -618,7 +624,7 @@ int git_diff__oid_for_entry(
 	GIT_ASSERT(d->type == GIT_DIFF_TYPE_GENERATED);
 	diff = (git_diff_generated *)d;
 
-	memset(out, 0, sizeof(*out));
+	git_oid_clear(out, GIT_OID_SHA1);
 
 	if (git_repository_workdir_path(&full_path, diff->base.repo, entry.path) < 0)
 		return -1;
@@ -654,7 +660,7 @@ int git_diff__oid_for_entry(
 			git_error_clear();
 		}
 	} else if (S_ISLNK(mode)) {
-		error = git_odb__hashlink(out, full_path.ptr);
+		error = git_odb__hashlink(out, full_path.ptr, GIT_OID_SHA1);
 		diff->base.perf.oid_calculations++;
 	} else if (!git__is_sizet(entry.file_size)) {
 		git_error_set(GIT_ERROR_NOMEMORY, "file size overflow (for 32-bits) on '%s'",
@@ -669,7 +675,8 @@ int git_diff__oid_for_entry(
 			error = fd;
 		else {
 			error = git_odb__hashfd_filtered(
-				out, fd, (size_t)entry.file_size, GIT_OBJECT_BLOB, fl);
+				out, fd, (size_t)entry.file_size,
+				GIT_OBJECT_BLOB, GIT_OID_SHA1, fl);
 			p_close(fd);
 			diff->base.perf.oid_calculations++;
 		}
@@ -778,7 +785,7 @@ static int maybe_modified(
 	git_diff_generated *diff,
 	diff_in_progress *info)
 {
-	git_oid noid;
+	git_oid noid = GIT_OID_SHA1_ZERO;
 	git_delta_t status = GIT_DELTA_MODIFIED;
 	const git_index_entry *oitem = info->oitem;
 	const git_index_entry *nitem = info->nitem;
@@ -792,8 +799,6 @@ static int maybe_modified(
 	if (!diff_pathspec_match(&matched_pathspec, diff, oitem))
 		return 0;
 
-	memset(&noid, 0, sizeof(noid));
-
 	/* on platforms with no symlinks, preserve mode of existing symlinks */
 	if (S_ISLNK(omode) && S_ISREG(nmode) && new_is_workdir &&
 		!(diff->diffcaps & GIT_DIFFCAPS_HAS_SYMLINKS))
@@ -1695,11 +1700,11 @@ int git_diff__commit(
 	*out = NULL;
 
 	if ((parents = git_commit_parentcount(commit)) > 1) {
-		char commit_oidstr[GIT_OID_HEXSZ + 1];
+		char commit_oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 
 		error = -1;
 		git_error_set(GIT_ERROR_INVALID, "commit %s is a merge commit",
-			git_oid_tostr(commit_oidstr, GIT_OID_HEXSZ + 1, git_commit_id(commit)));
+			git_oid_tostr(commit_oidstr, GIT_OID_SHA1_HEXSIZE + 1, git_commit_id(commit)));
 		goto on_error;
 	}
 
diff --git a/src/libgit2/diff_print.c b/src/libgit2/diff_print.c
index 6c5a2cdc8..3077e11e1 100644
--- a/src/libgit2/diff_print.c
+++ b/src/libgit2/diff_print.c
@@ -53,8 +53,8 @@ static int diff_print_info_init__common(
 			return -1;
 	}
 
-	if (pi->id_strlen > GIT_OID_HEXSZ)
-		pi->id_strlen = GIT_OID_HEXSZ;
+	if (pi->id_strlen > GIT_OID_SHA1_HEXSIZE)
+		pi->id_strlen = GIT_OID_SHA1_HEXSIZE;
 
 	memset(&pi->line, 0, sizeof(pi->line));
 	pi->line.old_lineno = -1;
@@ -212,7 +212,7 @@ static int diff_print_one_raw(
 	git_str *out = pi->buf;
 	int id_abbrev;
 	char code = git_diff_status_char(delta->status);
-	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
+	char start_oid[GIT_OID_SHA1_HEXSIZE+1], end_oid[GIT_OID_SHA1_HEXSIZE+1];
 
 	GIT_UNUSED(progress);
 
@@ -235,7 +235,7 @@ static int diff_print_one_raw(
 	git_oid_tostr(end_oid, pi->id_strlen + 1, &delta->new_file.id);
 
 	git_str_printf(
-		out, (pi->id_strlen <= GIT_OID_HEXSZ) ?
+		out, (pi->id_strlen <= GIT_OID_SHA1_HEXSIZE) ?
 			":%06o %06o %s... %s... %c" : ":%06o %06o %s %s %c",
 		delta->old_file.mode, delta->new_file.mode, start_oid, end_oid, code);
 
@@ -273,7 +273,7 @@ static int diff_print_oid_range(
 	git_str *out, const git_diff_delta *delta, int id_strlen,
 	bool print_index)
 {
-	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
+	char start_oid[GIT_OID_SHA1_HEXSIZE+1], end_oid[GIT_OID_SHA1_HEXSIZE+1];
 
 	if (delta->old_file.mode &&
 			id_strlen > delta->old_file.id_abbrev) {
diff --git a/src/libgit2/diff_tform.c b/src/libgit2/diff_tform.c
index 913d649b0..8c0c1b7fc 100644
--- a/src/libgit2/diff_tform.c
+++ b/src/libgit2/diff_tform.c
@@ -364,6 +364,7 @@ static int insert_delete_side_of_split(
 	memset(&deleted->new_file, 0, sizeof(deleted->new_file));
 	deleted->new_file.path = deleted->old_file.path;
 	deleted->new_file.flags |= GIT_DIFF_FLAG_VALID_ID;
+	git_oid_clear(&deleted->new_file.id, GIT_OID_SHA1);
 
 	return git_vector_insert(onto, deleted);
 }
@@ -397,6 +398,7 @@ static int apply_splits_and_deletes(
 			memset(&delta->old_file, 0, sizeof(delta->old_file));
 			delta->old_file.path = delta->new_file.path;
 			delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
+			git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
 		}
 
 		/* clean up delta before inserting into new list */
@@ -995,6 +997,7 @@ find_best_matches:
 				memset(&src->new_file, 0, sizeof(src->new_file));
 				src->new_file.path = src->old_file.path;
 				src->new_file.flags |= GIT_DIFF_FLAG_VALID_ID;
+				git_oid_clear(&src->new_file.id, GIT_OID_SHA1);
 
 				num_updates++;
 
@@ -1020,6 +1023,7 @@ find_best_matches:
 				memset(&src->old_file, 0, sizeof(src->old_file));
 				src->old_file.path = src->new_file.path;
 				src->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
+				git_oid_clear(&src->old_file.id, GIT_OID_SHA1);
 
 				src->flags &= ~GIT_DIFF_FLAG__TO_SPLIT;
 				num_rewrites--;
diff --git a/src/libgit2/email.c b/src/libgit2/email.c
index e19a2928c..0a75021c8 100644
--- a/src/libgit2/email.c
+++ b/src/libgit2/email.c
@@ -130,11 +130,11 @@ static int append_header(
 	const git_signature *author,
 	git_email_create_options *opts)
 {
-	char id[GIT_OID_HEXSZ];
+	char id[GIT_OID_SHA1_HEXSIZE];
 	int error;
 
 	if ((error = git_oid_fmt(id, commit_id)) < 0 ||
-	    (error = git_str_printf(out, "From %.*s %s\n", GIT_OID_HEXSZ, id, EMAIL_TIMESTAMP)) < 0 ||
+	    (error = git_str_printf(out, "From %.*s %s\n", GIT_OID_SHA1_HEXSIZE, id, EMAIL_TIMESTAMP)) < 0 ||
 	    (error = git_str_printf(out, "From: %s <%s>\n", author->name, author->email)) < 0 ||
 	    (error = append_date(out, &author->when)) < 0 ||
 	    (error = append_subject(out, patch_idx, patch_count, summary, opts)) < 0)
diff --git a/src/libgit2/experimental.h.in b/src/libgit2/experimental.h.in
new file mode 100644
index 000000000..3d6e931e2
--- /dev/null
+++ b/src/libgit2/experimental.h.in
@@ -0,0 +1,6 @@
+#ifndef INCLUDE_experimental_h__
+#define INCLUDE_experimental_h__
+
+#cmakedefine GIT_EXPERIMENTAL_SHA256 1
+
+#endif
diff --git a/src/libgit2/fetch.c b/src/libgit2/fetch.c
index e9f30d9bc..5c2fee617 100644
--- a/src/libgit2/fetch.c
+++ b/src/libgit2/fetch.c
@@ -13,6 +13,7 @@
 #include "git2/transport.h"
 #include "git2/sys/remote.h"
 
+#include "oid.h"
 #include "remote.h"
 #include "refspec.h"
 #include "pack.h"
@@ -75,7 +76,7 @@ static int maybe_want_oid(git_remote *remote, git_refspec *spec)
 	oid_head = git__calloc(1, sizeof(git_remote_head));
 	GIT_ERROR_CHECK_ALLOC(oid_head);
 
-	git_oid_fromstr(&oid_head->oid, spec->src);
+	git_oid__fromstr(&oid_head->oid, spec->src, GIT_OID_SHA1);
 
 	if (spec->dst) {
 		oid_head->name = git__strdup(spec->dst);
@@ -140,7 +141,7 @@ static int filter_wants(git_remote *remote, const git_fetch_options *opts)
 
 	/* Handle explicitly specified OID specs */
 	git_vector_foreach(&remote->active_refspecs, i, spec) {
-		if (!git_oid__is_hexstr(spec->src))
+		if (!git_oid__is_hexstr(spec->src, GIT_OID_SHA1))
 			continue;
 
 		if (!(remote_caps & oid_mask)) {
diff --git a/src/libgit2/fetchhead.c b/src/libgit2/fetchhead.c
index 6511124ef..0ebfe5c43 100644
--- a/src/libgit2/fetchhead.c
+++ b/src/libgit2/fetchhead.c
@@ -105,7 +105,7 @@ static int fetchhead_ref_write(
 	git_filebuf *file,
 	git_fetchhead_ref *fetchhead_ref)
 {
-	char oid[GIT_OID_HEXSZ + 1];
+	char oid[GIT_OID_SHA1_HEXSIZE + 1];
 	const char *type, *name;
 	int head = 0;
 
@@ -113,7 +113,7 @@ static int fetchhead_ref_write(
 	GIT_ASSERT_ARG(fetchhead_ref);
 
 	git_oid_fmt(oid, &fetchhead_ref->oid);
-	oid[GIT_OID_HEXSZ] = '\0';
+	oid[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	if (git__prefixcmp(fetchhead_ref->ref_name, GIT_REFS_HEADS_DIR) == 0) {
 		type = "branch ";
@@ -196,13 +196,13 @@ static int fetchhead_ref_parse(
 		*is_merge = 1;
 	}
 
-	if (strlen(oid_str) != GIT_OID_HEXSZ) {
+	if (strlen(oid_str) != GIT_OID_SHA1_HEXSIZE) {
 		git_error_set(GIT_ERROR_FETCHHEAD,
 			"invalid object ID in FETCH_HEAD line %"PRIuZ, line_num);
 		return -1;
 	}
 
-	if (git_oid_fromstr(oid, oid_str) < 0) {
+	if (git_oid__fromstr(oid, oid_str, GIT_OID_SHA1) < 0) {
 		const git_error *oid_err = git_error_last();
 		const char *err_msg = oid_err ? oid_err->message : "invalid object ID";
 
diff --git a/src/libgit2/ident.c b/src/libgit2/ident.c
index 53095864e..bf9a4998e 100644
--- a/src/libgit2/ident.c
+++ b/src/libgit2/ident.c
@@ -42,7 +42,7 @@ static int ident_find_id(
 static int ident_insert_id(
 	git_str *to, const git_str *from, const git_filter_source *src)
 {
-	char oid[GIT_OID_HEXSZ+1];
+	char oid[GIT_OID_SHA1_HEXSIZE+1];
 	const char *id_start, *id_end, *from_end = from->ptr + from->size;
 	size_t need_size;
 
@@ -57,7 +57,7 @@ static int ident_insert_id(
 		return GIT_PASSTHROUGH;
 
 	need_size = (size_t)(id_start - from->ptr) +
-		5 /* "$Id: " */ + GIT_OID_HEXSZ + 2 /* " $" */ +
+		5 /* "$Id: " */ + GIT_OID_SHA1_HEXSIZE + 2 /* " $" */ +
 		(size_t)(from_end - id_end);
 
 	if (git_str_grow(to, need_size) < 0)
@@ -65,7 +65,7 @@ static int ident_insert_id(
 
 	git_str_set(to, from->ptr, (size_t)(id_start - from->ptr));
 	git_str_put(to, "$Id: ", 5);
-	git_str_put(to, oid, GIT_OID_HEXSZ);
+	git_str_put(to, oid, GIT_OID_SHA1_HEXSIZE);
 	git_str_put(to, " $", 2);
 	git_str_put(to, id_end, (size_t)(from_end - id_end));
 
diff --git a/src/libgit2/index.c b/src/libgit2/index.c
index f44c507d3..1821f6027 100644
--- a/src/libgit2/index.c
+++ b/src/libgit2/index.c
@@ -74,7 +74,7 @@ struct entry_short {
 	uint32_t uid;
 	uint32_t gid;
 	uint32_t file_size;
-	unsigned char oid[GIT_OID_RAWSZ];
+	unsigned char oid[GIT_OID_SHA1_SIZE];
 	uint16_t flags;
 	char path[1]; /* arbitrary length */
 };
@@ -88,7 +88,7 @@ struct entry_long {
 	uint32_t uid;
 	uint32_t gid;
 	uint32_t file_size;
-	unsigned char oid[GIT_OID_RAWSZ];
+	unsigned char oid[GIT_OID_SHA1_SIZE];
 	uint16_t flags;
 	uint16_t flags_extended;
 	char path[1]; /* arbitrary length */
@@ -2354,14 +2354,16 @@ static int read_reuc(git_index *index, const char *buffer, size_t size)
 		for (i = 0; i < 3; i++) {
 			if (!lost->mode[i])
 				continue;
-			if (size < 20) {
+			if (size < GIT_OID_SHA1_SIZE) {
 				index_entry_reuc_free(lost);
 				return index_error_invalid("reading reuc entry oid");
 			}
 
-			git_oid_fromraw(&lost->oid[i], (const unsigned char *) buffer);
-			size -= 20;
-			buffer += 20;
+			if (git_oid__fromraw(&lost->oid[i], (const unsigned char *) buffer, GIT_OID_SHA1) < 0)
+				return -1;
+
+			size -= GIT_OID_SHA1_SIZE;
+			buffer += GIT_OID_SHA1_SIZE;
 		}
 
 		/* entry was read successfully - insert into reuc vector */
@@ -2482,7 +2484,7 @@ static int read_entry(
 	entry.file_size = ntohl(source.file_size);
 	entry.flags = ntohs(source.flags);
 
-	if (git_oid_fromraw(&entry.id, source.oid) < 0)
+	if (git_oid__fromraw(&entry.id, source.oid, GIT_OID_SHA1) < 0)
 		return -1;
 
 	if (entry.flags & GIT_INDEX_ENTRY_EXTENDED) {
@@ -2805,7 +2807,7 @@ static int write_disk_entry(git_filebuf *file, git_index_entry *entry, const cha
 	ondisk.uid = htonl(entry->uid);
 	ondisk.gid = htonl(entry->gid);
 	ondisk.file_size = htonl((uint32_t)entry->file_size);
-	git_oid_raw_cpy(ondisk.oid, entry->id.id);
+	git_oid_raw_cpy(ondisk.oid, entry->id.id, GIT_OID_SHA1_SIZE);
 	ondisk.flags = htons(entry->flags);
 
 	if (entry->flags & GIT_INDEX_ENTRY_EXTENDED) {
@@ -2968,7 +2970,7 @@ static int create_reuc_extension_data(git_str *reuc_buf, git_index_reuc_entry *r
 	}
 
 	for (i = 0; i < 3; i++) {
-		if (reuc->mode[i] && (error = git_str_put(reuc_buf, (char *)&reuc->oid[i].id, GIT_OID_RAWSZ)) < 0)
+		if (reuc->mode[i] && (error = git_str_put(reuc_buf, (char *)&reuc->oid[i].id, GIT_OID_SHA1_SIZE)) < 0)
 			return error;
 	}
 
diff --git a/src/libgit2/indexer.c b/src/libgit2/indexer.c
index afb9ce81a..62bb70393 100644
--- a/src/libgit2/indexer.c
+++ b/src/libgit2/indexer.c
@@ -68,7 +68,7 @@ struct git_indexer {
 	git_odb *odb;
 
 	/* Fields for calculating the packfile trailer (hash of everything before it) */
-	char inbuf[GIT_OID_RAWSZ];
+	char inbuf[GIT_OID_SHA1_SIZE];
 	size_t inbuf_len;
 	git_hash_ctx trailer;
 };
@@ -272,7 +272,7 @@ static int advance_delta_offset(git_indexer *idx, git_object_t type)
 	GIT_ASSERT_ARG(type == GIT_OBJECT_REF_DELTA || type == GIT_OBJECT_OFS_DELTA);
 
 	if (type == GIT_OBJECT_REF_DELTA) {
-		idx->off += GIT_OID_RAWSZ;
+		idx->off += GIT_OID_SHA1_SIZE;
 	} else {
 		off64_t base_off;
 		int error = get_delta_base(&base_off, idx->pack, &w, &idx->off, type, idx->entry_start);
@@ -444,6 +444,11 @@ static int store_object(git_indexer *idx)
 		git__free(pentry);
 		goto on_error;
 	}
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	oid.type = GIT_OID_SHA1;
+#endif
+
 	entry_size = idx->off - entry_start;
 	if (entry_start > UINT31_MAX) {
 		entry->offset = UINT32_MAX;
@@ -544,7 +549,7 @@ static int hash_and_save(git_indexer *idx, git_rawobj *obj, off64_t entry_start)
 	entry = git__calloc(1, sizeof(*entry));
 	GIT_ERROR_CHECK_ALLOC(entry);
 
-	if (git_odb__hashobj(&oid, obj) < 0) {
+	if (git_odb__hashobj(&oid, obj, GIT_OID_SHA1) < 0) {
 		git_error_set(GIT_ERROR_INDEXER, "failed to hash object");
 		goto on_error;
 	}
@@ -587,25 +592,25 @@ static void hash_partially(git_indexer *idx, const uint8_t *data, size_t size)
 		return;
 
 	/* Easy case, dump the buffer and the data minus the last 20 bytes */
-	if (size >= GIT_OID_RAWSZ) {
+	if (size >= GIT_OID_SHA1_SIZE) {
 		git_hash_update(&idx->trailer, idx->inbuf, idx->inbuf_len);
-		git_hash_update(&idx->trailer, data, size - GIT_OID_RAWSZ);
+		git_hash_update(&idx->trailer, data, size - GIT_OID_SHA1_SIZE);
 
-		data += size - GIT_OID_RAWSZ;
-		memcpy(idx->inbuf, data, GIT_OID_RAWSZ);
-		idx->inbuf_len = GIT_OID_RAWSZ;
+		data += size - GIT_OID_SHA1_SIZE;
+		memcpy(idx->inbuf, data, GIT_OID_SHA1_SIZE);
+		idx->inbuf_len = GIT_OID_SHA1_SIZE;
 		return;
 	}
 
 	/* We can just append */
-	if (idx->inbuf_len + size <= GIT_OID_RAWSZ) {
+	if (idx->inbuf_len + size <= GIT_OID_SHA1_SIZE) {
 		memcpy(idx->inbuf + idx->inbuf_len, data, size);
 		idx->inbuf_len += size;
 		return;
 	}
 
 	/* We need to partially drain the buffer and then append */
-	to_keep   = GIT_OID_RAWSZ - size;
+	to_keep   = GIT_OID_SHA1_SIZE - size;
 	to_expell = idx->inbuf_len - to_keep;
 
 	git_hash_update(&idx->trailer, idx->inbuf, to_expell);
@@ -900,7 +905,7 @@ static int index_path(git_str *path, git_indexer *idx, const char *suffix)
 		slash--;
 
 	if (git_str_grow(path, slash + 1 + strlen(prefix) +
-					 GIT_OID_HEXSZ + strlen(suffix) + 1) < 0)
+					 GIT_OID_SHA1_HEXSIZE + strlen(suffix) + 1) < 0)
 		return -1;
 
 	git_str_truncate(path, slash);
@@ -917,7 +922,7 @@ static int index_path(git_str *path, git_indexer *idx, const char *suffix)
  */
 static int seek_back_trailer(git_indexer *idx)
 {
-	idx->pack->mwf.size -= GIT_OID_RAWSZ;
+	idx->pack->mwf.size -= GIT_OID_SHA1_SIZE;
 	return git_mwindow_free_all(&idx->pack->mwf);
 }
 
@@ -977,7 +982,7 @@ static int inject_object(git_indexer *idx, git_oid *id)
 	if ((error = append_to_pack(idx, empty_checksum, checksum_size)) < 0)
 		goto cleanup;
 
-	idx->pack->mwf.size += GIT_OID_RAWSZ;
+	idx->pack->mwf.size += GIT_OID_SHA1_SIZE;
 
 	pentry = git__calloc(1, sizeof(struct git_pack_entry));
 	GIT_ERROR_CHECK_ALLOC(pentry);
@@ -1040,13 +1045,13 @@ static int fix_thin_pack(git_indexer *idx, git_indexer_progress *stats)
 	}
 
 	/* curpos now points to the base information, which is an OID */
-	base_info = git_mwindow_open(&idx->pack->mwf, &w, curpos, GIT_OID_RAWSZ, &left);
+	base_info = git_mwindow_open(&idx->pack->mwf, &w, curpos, GIT_OID_SHA1_SIZE, &left);
 	if (base_info == NULL) {
 		git_error_set(GIT_ERROR_INDEXER, "failed to map delta information");
 		return -1;
 	}
 
-	git_oid_fromraw(&base, base_info);
+	git_oid__fromraw(&base, base_info, GIT_OID_SHA1);
 	git_mwindow_close(&w);
 
 	if (has_entry(idx, &base))
@@ -1269,7 +1274,7 @@ int git_indexer_commit(git_indexer *idx, git_indexer_progress *stats)
 
 	/* Write out the object names (SHA-1 hashes) */
 	git_vector_foreach(&idx->objects, i, entry) {
-		git_filebuf_write(&index_file, &entry->oid.id, GIT_OID_RAWSZ);
+		git_filebuf_write(&index_file, &entry->oid.id, GIT_OID_SHA1_SIZE);
 	}
 
 	/* Write out the CRC32 values */
diff --git a/src/libgit2/iterator.c b/src/libgit2/iterator.c
index bc6f766ce..1ee8e25f5 100644
--- a/src/libgit2/iterator.c
+++ b/src/libgit2/iterator.c
@@ -1271,7 +1271,7 @@ static int filesystem_iterator_entry_hash(
 	int error;
 
 	if (S_ISDIR(entry->st.st_mode)) {
-		memset(&entry->id, 0, GIT_OID_RAWSZ);
+		memset(&entry->id, 0, GIT_OID_SHA1_SIZE);
 		return 0;
 	}
 
@@ -1281,7 +1281,7 @@ static int filesystem_iterator_entry_hash(
 
 	if (!(error = git_str_joinpath(&fullpath, iter->root, entry->path)) &&
 	    !(error = git_path_validate_str_length(iter->base.repo, &fullpath)))
-		error = git_odb_hashfile(&entry->id, fullpath.ptr, GIT_OBJECT_BLOB);
+		error = git_odb__hashfile(&entry->id, fullpath.ptr, GIT_OBJECT_BLOB, GIT_OID_SHA1);
 
 	git_str_dispose(&fullpath);
 	return error;
@@ -1529,6 +1529,8 @@ static void filesystem_iterator_set_current(
 
 	if (iter->base.flags & GIT_ITERATOR_INCLUDE_HASH)
 		git_oid_cpy(&iter->entry.id, &entry->id);
+	else
+		git_oid_clear(&iter->entry.id, GIT_OID_SHA1);
 
 	iter->entry.path = entry->path;
 
diff --git a/src/libgit2/merge.c b/src/libgit2/merge.c
index 641b32632..df2cefb29 100644
--- a/src/libgit2/merge.c
+++ b/src/libgit2/merge.c
@@ -611,13 +611,13 @@ int git_repository_mergehead_foreach(
 	buffer = merge_head_file.ptr;
 
 	while ((line = git__strsep(&buffer, "\n")) != NULL) {
-		if (strlen(line) != GIT_OID_HEXSZ) {
+		if (strlen(line) != GIT_OID_SHA1_HEXSIZE) {
 			git_error_set(GIT_ERROR_INVALID, "unable to parse OID - invalid length");
 			error = -1;
 			goto cleanup;
 		}
 
-		if ((error = git_oid_fromstr(&oid, line)) < 0)
+		if ((error = git_oid__fromstr(&oid, line, GIT_OID_SHA1)) < 0)
 			goto cleanup;
 
 		if ((error = cb(&oid, payload)) != 0) {
@@ -1061,7 +1061,7 @@ static int index_entry_similarity_calc(
 	const git_merge_options *opts)
 {
 	git_blob *blob;
-	git_diff_file diff_file = {{{0}}};
+	git_diff_file diff_file = { GIT_OID_SHA1_ZERO };
 	git_object_size_t blobsize;
 	int error;
 
diff --git a/src/libgit2/midx.c b/src/libgit2/midx.c
index 67eab9acb..51b2d6cc7 100644
--- a/src/libgit2/midx.c
+++ b/src/libgit2/midx.c
@@ -115,19 +115,19 @@ static int midx_parse_oid_lookup(
 		struct git_midx_chunk *chunk_oid_lookup)
 {
 	uint32_t i;
-	unsigned char *oid, *prev_oid, zero_oid[GIT_OID_RAWSZ] = {0};
+	unsigned char *oid, *prev_oid, zero_oid[GIT_OID_SHA1_SIZE] = {0};
 
 	if (chunk_oid_lookup->offset == 0)
 		return midx_error("missing OID Lookup chunk");
 	if (chunk_oid_lookup->length == 0)
 		return midx_error("empty OID Lookup chunk");
-	if (chunk_oid_lookup->length != idx->num_objects * GIT_OID_RAWSZ)
+	if (chunk_oid_lookup->length != idx->num_objects * GIT_OID_SHA1_SIZE)
 		return midx_error("OID Lookup chunk has wrong length");
 
 	idx->oid_lookup = oid = (unsigned char *)(data + chunk_oid_lookup->offset);
 	prev_oid = zero_oid;
-	for (i = 0; i < idx->num_objects; ++i, oid += GIT_OID_RAWSZ) {
-		if (git_oid_raw_cmp(prev_oid, oid) >= 0)
+	for (i = 0; i < idx->num_objects; ++i, oid += GIT_OID_SHA1_SIZE) {
+		if (git_oid_raw_cmp(prev_oid, oid, GIT_OID_SHA1_SIZE) >= 0)
 			return midx_error("OID Lookup index is non-monotonic");
 		prev_oid = oid;
 	}
@@ -188,7 +188,7 @@ int git_midx_parse(
 
 	GIT_ASSERT_ARG(idx);
 
-	if (size < sizeof(struct git_midx_header) + GIT_OID_RAWSZ)
+	if (size < sizeof(struct git_midx_header) + GIT_OID_SHA1_SIZE)
 		return midx_error("multi-pack index is too short");
 
 	hdr = ((struct git_midx_header *)data);
@@ -365,7 +365,7 @@ bool git_midx_needs_refresh(
 	}
 
 	checksum_size = GIT_HASH_SHA1_SIZE;
-	bytes_read = p_pread(fd, checksum, checksum_size, st.st_size - GIT_OID_RAWSZ);
+	bytes_read = p_pread(fd, checksum, checksum_size, st.st_size - GIT_OID_SHA1_SIZE);
 	p_close(fd);
 
 	if (bytes_read != (ssize_t)checksum_size)
@@ -392,27 +392,27 @@ int git_midx_entry_find(
 	hi = ntohl(idx->oid_fanout[(int)short_oid->id[0]]);
 	lo = ((short_oid->id[0] == 0x0) ? 0 : ntohl(idx->oid_fanout[(int)short_oid->id[0] - 1]));
 
-	pos = git_pack__lookup_sha1(idx->oid_lookup, GIT_OID_RAWSZ, lo, hi, short_oid->id);
+	pos = git_pack__lookup_sha1(idx->oid_lookup, GIT_OID_SHA1_SIZE, lo, hi, short_oid->id);
 
 	if (pos >= 0) {
 		/* An object matching exactly the oid was found */
 		found = 1;
-		current = idx->oid_lookup + (pos * GIT_OID_RAWSZ);
+		current = idx->oid_lookup + (pos * GIT_OID_SHA1_SIZE);
 	} else {
 		/* No object was found */
 		/* pos refers to the object with the "closest" oid to short_oid */
 		pos = -1 - pos;
 		if (pos < (int)idx->num_objects) {
-			current = idx->oid_lookup + (pos * GIT_OID_RAWSZ);
+			current = idx->oid_lookup + (pos * GIT_OID_SHA1_SIZE);
 
 			if (!git_oid_raw_ncmp(short_oid->id, current, len))
 				found = 1;
 		}
 	}
 
-	if (found && len != GIT_OID_HEXSZ && pos + 1 < (int)idx->num_objects) {
+	if (found && len != GIT_OID_SHA1_HEXSIZE && pos + 1 < (int)idx->num_objects) {
 		/* Check for ambiguousity */
-		const unsigned char *next = current + GIT_OID_RAWSZ;
+		const unsigned char *next = current + GIT_OID_SHA1_SIZE;
 
 		if (!git_oid_raw_ncmp(short_oid->id, next, len))
 			found = 2;
@@ -443,7 +443,7 @@ int git_midx_entry_find(
 		return midx_error("invalid index into the packfile names table");
 	e->pack_index = pack_index;
 	e->offset = offset;
-	git_oid_fromraw(&e->sha1, current);
+	git_oid__fromraw(&e->sha1, current, GIT_OID_SHA1);
 	return 0;
 }
 
@@ -459,7 +459,7 @@ int git_midx_foreach_entry(
 	GIT_ASSERT_ARG(idx);
 
 	for (i = 0; i < idx->num_objects; ++i) {
-		if ((error = git_oid_fromraw(&oid, &idx->oid_lookup[i * GIT_OID_RAWSZ])) < 0)
+		if ((error = git_oid__fromraw(&oid, &idx->oid_lookup[i * GIT_OID_SHA1_SIZE], GIT_OID_SHA1)) < 0)
 			return error;
 
 		if ((error = cb(&oid, data)) != 0)
@@ -748,7 +748,7 @@ static int midx_write(
 
 	/* Fill the OID Lookup table. */
 	git_vector_foreach (&object_entries, i, entry) {
-		error = git_str_put(&oid_lookup, (char *)&entry->sha1.id, GIT_OID_RAWSZ);
+		error = git_str_put(&oid_lookup, (char *)&entry->sha1.id, GIT_OID_SHA1_SIZE);
 		if (error < 0)
 			goto cleanup;
 	}
diff --git a/src/libgit2/notes.c b/src/libgit2/notes.c
index d1a2b0f64..1b1935330 100644
--- a/src/libgit2/notes.c
+++ b/src/libgit2/notes.c
@@ -460,7 +460,7 @@ int git_note_commit_read(
 {
 	int error;
 	git_tree *tree = NULL;
-	char target[GIT_OID_HEXSZ + 1];
+	char target[GIT_OID_SHA1_HEXSIZE + 1];
 
 	git_oid_tostr(target, sizeof(target), oid);
 
@@ -507,7 +507,7 @@ int git_note_commit_create(
 {
 	int error;
 	git_tree *tree = NULL;
-	char target[GIT_OID_HEXSZ + 1];
+	char target[GIT_OID_SHA1_HEXSIZE + 1];
 
 	git_oid_tostr(target, sizeof(target), oid);
 
@@ -578,7 +578,7 @@ int git_note_commit_remove(
 {
 	int error;
 	git_tree *tree = NULL;
-	char target[GIT_OID_HEXSZ + 1];
+	char target[GIT_OID_SHA1_HEXSIZE + 1];
 
 	git_oid_tostr(target, sizeof(target), oid);
 
@@ -698,12 +698,12 @@ static int process_entry_path(
 	buf.ptr[j] = '\0';
 	buf.size = j;
 
-	if (j != GIT_OID_HEXSZ) {
+	if (j != GIT_OID_SHA1_HEXSIZE) {
 		/* This is not a note entry */
 		goto cleanup;
 	}
 
-	error = git_oid_fromstr(annotated_object_id, buf.ptr);
+	error = git_oid__fromstr(annotated_object_id, buf.ptr, GIT_OID_SHA1);
 
 cleanup:
 	git_str_dispose(&buf);
diff --git a/src/libgit2/object.c b/src/libgit2/object.c
index b828f88f6..d45465678 100644
--- a/src/libgit2/object.c
+++ b/src/libgit2/object.c
@@ -21,7 +21,6 @@
 
 bool git_object__strict_input_validation = true;
 
-extern int git_odb_hash(git_oid *out, const void *data, size_t len, git_object_t type);
 size_t git_object__size(git_object_t type);
 
 typedef struct {
@@ -87,7 +86,7 @@ int git_object__from_raw(
 	GIT_ERROR_CHECK_ALLOC(object);
 	object->cached.flags = GIT_CACHE_STORE_PARSED;
 	object->cached.type = type;
-	if ((error = git_odb_hash(&object->cached.oid, data, size, type)) < 0)
+	if ((error = git_odb__hash(&object->cached.oid, data, size, type, GIT_OID_SHA1)) < 0)
 		return error;
 
 	/* Parse raw object data */
@@ -193,10 +192,10 @@ int git_object_lookup_prefix(
 	if (error < 0)
 		return error;
 
-	if (len > GIT_OID_HEXSZ)
-		len = GIT_OID_HEXSZ;
+	if (len > GIT_OID_SHA1_HEXSIZE)
+		len = GIT_OID_SHA1_HEXSIZE;
 
-	if (len == GIT_OID_HEXSZ) {
+	if (len == GIT_OID_SHA1_HEXSIZE) {
 		git_cached_obj *cached = NULL;
 
 		/* We want to match the full id : we can first look up in the cache,
@@ -230,11 +229,11 @@ int git_object_lookup_prefix(
 			error = git_odb_read(&odb_obj, odb, id);
 		}
 	} else {
-		git_oid short_oid = {{ 0 }};
+		git_oid short_oid = GIT_OID_SHA1_ZERO;
 
 		git_oid__cpy_prefix(&short_oid, id, len);
 
-		/* If len < GIT_OID_HEXSZ (a strict short oid was given), we have
+		/* If len < GIT_OID_SHA1_HEXSIZE (a strict short oid was given), we have
 		 * 2 options :
 		 * - We always search in the cache first. If we find that short oid is
 		 *	ambiguous, we can stop. But in all the other cases, we must then
@@ -259,7 +258,7 @@ int git_object_lookup_prefix(
 }
 
 int git_object_lookup(git_object **object_out, git_repository *repo, const git_oid *id, git_object_t type) {
-	return git_object_lookup_prefix(object_out, repo, id, GIT_OID_HEXSZ, type);
+	return git_object_lookup_prefix(object_out, repo, id, GIT_OID_SHA1_HEXSIZE, type);
 }
 
 void git_object_free(git_object *object)
@@ -358,12 +357,12 @@ static int dereference_object(git_object **dereferenced, git_object *obj)
 static int peel_error(int error, const git_oid *oid, git_object_t type)
 {
 	const char *type_name;
-	char hex_oid[GIT_OID_HEXSZ + 1];
+	char hex_oid[GIT_OID_SHA1_HEXSIZE + 1];
 
 	type_name = git_object_type2string(type);
 
 	git_oid_fmt(hex_oid, oid);
-	hex_oid[GIT_OID_HEXSZ] = '\0';
+	hex_oid[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	git_error_set(GIT_ERROR_OBJECT, "the git_object of id '%s' can not be "
 		"successfully peeled into a %s (git_object_t=%i).", hex_oid, type_name, type);
@@ -502,7 +501,7 @@ static int git_object__short_id(git_str *out, const git_object *obj)
 {
 	git_repository *repo;
 	int len = GIT_ABBREV_DEFAULT, error;
-	git_oid id = {{0}};
+	git_oid id = GIT_OID_SHA1_ZERO;
 	git_odb *odb;
 
 	GIT_ASSERT_ARG(out);
@@ -516,12 +515,16 @@ static int git_object__short_id(git_str *out, const git_object *obj)
 	if ((error = git_repository_odb(&odb, repo)) < 0)
 		return error;
 
-	while (len < GIT_OID_HEXSZ) {
+	while (len < GIT_OID_SHA1_HEXSIZE) {
 		/* set up short oid */
 		memcpy(&id.id, &obj->cached.oid.id, (len + 1) / 2);
 		if (len & 1)
 			id.id[len / 2] &= 0xf0;
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+		id.type = GIT_OID_SHA1;
+#endif
+
 		error = git_odb_exists_prefix(NULL, odb, &id, len);
 		if (error != GIT_EAMBIGUOUS)
 			break;
@@ -600,3 +603,53 @@ int git_object_rawcontent_is_valid(
 
 	return error;
 }
+
+int git_object__parse_oid_header(
+	git_oid *oid,
+	const char **buffer_out,
+	const char *buffer_end,
+	const char *header,
+	git_oid_t oid_type)
+{
+	const size_t sha_len = GIT_OID_SHA1_HEXSIZE;
+	const size_t header_len = strlen(header);
+
+	const char *buffer = *buffer_out;
+
+	if (buffer + (header_len + sha_len + 1) > buffer_end)
+		return -1;
+
+	if (memcmp(buffer, header, header_len) != 0)
+		return -1;
+
+	if (buffer[header_len + sha_len] != '\n')
+		return -1;
+
+	if (git_oid__fromstr(oid, buffer + header_len, oid_type) < 0)
+		return -1;
+
+	*buffer_out = buffer + (header_len + sha_len + 1);
+
+	return 0;
+}
+
+int git_object__write_oid_header(
+	git_str *buf,
+	const char *header,
+	const git_oid *oid)
+{
+	size_t hex_size = git_oid_hexsize(git_oid_type(oid));
+	char hex_oid[GIT_OID_MAX_HEXSIZE];
+
+	if (!hex_size) {
+		git_error_set(GIT_ERROR_INVALID, "unknown type");
+		return -1;
+	}
+
+	git_oid_fmt(hex_oid, oid);
+	git_str_puts(buf, header);
+	git_str_put(buf, hex_oid, hex_size);
+	git_str_putc(buf, '\n');
+
+	return git_str_oom(buf) ? -1 : 0;
+}
diff --git a/src/libgit2/object.h b/src/libgit2/object.h
index 66be57557..980e8627e 100644
--- a/src/libgit2/object.h
+++ b/src/libgit2/object.h
@@ -45,9 +45,17 @@ int git_object__resolve_to_type(git_object **obj, git_object_t type);
 
 git_object_t git_object_stringn2type(const char *str, size_t len);
 
-int git_oid__parse(git_oid *oid, const char **buffer_out, const char *buffer_end, const char *header);
+int git_object__parse_oid_header(
+	git_oid *oid,
+	const char **buffer_out,
+	const char *buffer_end,
+	const char *header,
+	git_oid_t oid_type);
 
-void git_oid__writebuf(git_str *buf, const char *header, const git_oid *oid);
+int git_object__write_oid_header(
+	git_str *buf,
+	const char *header,
+	const git_oid *oid);
 
 bool git_object__is_valid(
 	git_repository *repo, const git_oid *id, git_object_t expected_type);
diff --git a/src/libgit2/odb.c b/src/libgit2/odb.c
index 7b98c72ee..aa2dd3cb2 100644
--- a/src/libgit2/odb.c
+++ b/src/libgit2/odb.c
@@ -105,11 +105,12 @@ int git_odb__format_object_header(
 	return 0;
 }
 
-int git_odb__hashobj(git_oid *id, git_rawobj *obj)
+int git_odb__hashobj(git_oid *id, git_rawobj *obj, git_oid_t oid_type)
 {
 	git_str_vec vec[2];
 	char header[64];
 	size_t hdrlen;
+	git_hash_algorithm_t algorithm;
 	int error;
 
 	GIT_ASSERT_ARG(id);
@@ -120,6 +121,11 @@ int git_odb__hashobj(git_oid *id, git_rawobj *obj)
 		return -1;
 	}
 
+	if (!(algorithm = git_oid_algorithm(oid_type))) {
+		git_error_set(GIT_ERROR_INVALID, "unknown oid type");
+		return -1;
+	}
+
 	if (!obj->data && obj->len != 0) {
 		git_error_set(GIT_ERROR_INVALID, "invalid object");
 		return -1;
@@ -134,7 +140,11 @@ int git_odb__hashobj(git_oid *id, git_rawobj *obj)
 	vec[1].data = obj->data;
 	vec[1].len = obj->len;
 
-	return git_hash_vec(id->id, vec, 2, GIT_HASH_ALGORITHM_SHA1);
+#ifdef GIT_EXPERIMENTAL_SHA256
+	id->type = oid_type;
+#endif
+
+	return git_hash_vec(id->id, vec, 2, algorithm);
 }
 
 
@@ -195,24 +205,35 @@ void git_odb_object_free(git_odb_object *object)
 	git_cached_obj_decref(object);
 }
 
-int git_odb__hashfd(git_oid *out, git_file fd, size_t size, git_object_t type)
+int git_odb__hashfd(
+	git_oid *out,
+	git_file fd,
+	size_t size,
+	git_object_t object_type,
+	git_oid_t oid_type)
 {
 	size_t hdr_len;
 	char hdr[64], buffer[GIT_BUFSIZE_FILEIO];
 	git_hash_ctx ctx;
+	git_hash_algorithm_t algorithm;
 	ssize_t read_len = 0;
 	int error = 0;
 
-	if (!git_object_typeisloose(type)) {
+	if (!git_object_typeisloose(object_type)) {
 		git_error_set(GIT_ERROR_INVALID, "invalid object type for hash");
 		return -1;
 	}
 
-	if ((error = git_hash_ctx_init(&ctx, GIT_HASH_ALGORITHM_SHA1)) < 0)
+	if (!(algorithm = git_oid_algorithm(oid_type))) {
+		git_error_set(GIT_ERROR_INVALID, "unknown oid type");
+		return -1;
+	}
+
+	if ((error = git_hash_ctx_init(&ctx, algorithm)) < 0)
 		return error;
 
 	if ((error = git_odb__format_object_header(&hdr_len, hdr,
-		sizeof(hdr), size, type)) < 0)
+		sizeof(hdr), size, object_type)) < 0)
 		goto done;
 
 	if ((error = git_hash_update(&ctx, hdr, hdr_len)) < 0)
@@ -237,19 +258,28 @@ int git_odb__hashfd(git_oid *out, git_file fd, size_t size, git_object_t type)
 
 	error = git_hash_final(out->id, &ctx);
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	out->type = oid_type;
+#endif
+
 done:
 	git_hash_ctx_cleanup(&ctx);
 	return error;
 }
 
 int git_odb__hashfd_filtered(
-	git_oid *out, git_file fd, size_t size, git_object_t type, git_filter_list *fl)
+	git_oid *out,
+	git_file fd,
+	size_t size,
+	git_object_t object_type,
+	git_oid_t oid_type,
+	git_filter_list *fl)
 {
 	int error;
 	git_str raw = GIT_STR_INIT;
 
 	if (!fl)
-		return git_odb__hashfd(out, fd, size, type);
+		return git_odb__hashfd(out, fd, size, object_type, oid_type);
 
 	/* size of data is used in header, so we have to read the whole file
 	 * into memory to apply filters before beginning to calculate the hash
@@ -261,7 +291,7 @@ int git_odb__hashfd_filtered(
 		error = git_filter_list__convert_buf(&post, fl, &raw);
 
 		if (!error)
-			error = git_odb_hash(out, post.ptr, post.size, type);
+			error = git_odb__hash(out, post.ptr, post.size, object_type, oid_type);
 
 		git_str_dispose(&post);
 	}
@@ -269,7 +299,7 @@ int git_odb__hashfd_filtered(
 	return error;
 }
 
-int git_odb__hashlink(git_oid *out, const char *path)
+int git_odb__hashlink(git_oid *out, const char *path, git_oid_t oid_type)
 {
 	struct stat st;
 	int size;
@@ -303,20 +333,24 @@ int git_odb__hashlink(git_oid *out, const char *path)
 		GIT_ASSERT(read_len <= size);
 		link_data[read_len] = '\0';
 
-		result = git_odb_hash(out, link_data, read_len, GIT_OBJECT_BLOB);
+		result = git_odb__hash(out, link_data, read_len, GIT_OBJECT_BLOB, oid_type);
 		git__free(link_data);
 	} else {
 		int fd = git_futils_open_ro(path);
 		if (fd < 0)
 			return -1;
-		result = git_odb__hashfd(out, fd, size, GIT_OBJECT_BLOB);
+		result = git_odb__hashfd(out, fd, size, GIT_OBJECT_BLOB, oid_type);
 		p_close(fd);
 	}
 
 	return result;
 }
 
-int git_odb_hashfile(git_oid *out, const char *path, git_object_t type)
+int git_odb__hashfile(
+	git_oid *out,
+	const char *path,
+	git_object_t object_type,
+	git_oid_t oid_type)
 {
 	uint64_t size;
 	int fd, error = 0;
@@ -333,14 +367,38 @@ int git_odb_hashfile(git_oid *out, const char *path, git_object_t type)
 		goto done;
 	}
 
-	error = git_odb__hashfd(out, fd, (size_t)size, type);
+	error = git_odb__hashfd(out, fd, (size_t)size, object_type, oid_type);
 
 done:
 	p_close(fd);
 	return error;
 }
 
-int git_odb_hash(git_oid *id, const void *data, size_t len, git_object_t type)
+#ifdef GIT_EXPERIMENTAL_SHA256
+int git_odb_hashfile(
+	git_oid *out,
+	const char *path,
+	git_object_t object_type,
+	git_oid_t oid_type)
+{
+	return git_odb__hashfile(out, path, object_type, oid_type);
+}
+#else
+int git_odb_hashfile(
+	git_oid *out,
+	const char *path,
+	git_object_t object_type)
+{
+	return git_odb__hashfile(out, path, object_type, GIT_OID_SHA1);
+}
+#endif
+
+int git_odb__hash(
+	git_oid *id,
+	const void *data,
+	size_t len,
+	git_object_t object_type,
+	git_oid_t oid_type)
 {
 	git_rawobj raw;
 
@@ -348,10 +406,31 @@ int git_odb_hash(git_oid *id, const void *data, size_t len, git_object_t type)
 
 	raw.data = (void *)data;
 	raw.len = len;
-	raw.type = type;
+	raw.type = object_type;
+
+	return git_odb__hashobj(id, &raw, oid_type);
+}
 
-	return git_odb__hashobj(id, &raw);
+#ifdef GIT_EXPERIMENTAL_SHA256
+int git_odb_hash(
+	git_oid *out,
+	const void *data,
+	size_t len,
+	git_object_t object_type,
+	git_oid_t oid_type)
+{
+	return git_odb__hash(out, data, len, object_type, oid_type);
+}
+#else
+int git_odb_hash(
+	git_oid *out,
+	const void *data,
+	size_t len,
+	git_object_t type)
+{
+	return git_odb__hash(out, data, len, type, GIT_OID_SHA1);
 }
+#endif
 
 /**
  * FAKE WSTREAM
@@ -442,11 +521,28 @@ static int backend_sort_cmp(const void *a, const void *b)
 	return (backend_b->priority - backend_a->priority);
 }
 
-int git_odb_new(git_odb **out)
+static void normalize_options(
+	git_odb_options *opts,
+	const git_odb_options *given_opts)
+{
+	git_odb_options init = GIT_ODB_OPTIONS_INIT;
+
+	if (given_opts)
+		memcpy(opts, given_opts, sizeof(git_odb_options));
+	else
+		memcpy(opts, &init, sizeof(git_odb_options));
+
+	if (!opts->oid_type)
+		opts->oid_type = GIT_OID_DEFAULT;
+}
+
+int git_odb__new(git_odb **out, const git_odb_options *opts)
 {
 	git_odb *db = git__calloc(1, sizeof(*db));
 	GIT_ERROR_CHECK_ALLOC(db);
 
+	normalize_options(&db->options, opts);
+
 	if (git_mutex_init(&db->lock) < 0) {
 		git__free(db);
 		return -1;
@@ -468,6 +564,18 @@ int git_odb_new(git_odb **out)
 	return 0;
 }
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+int git_odb_new(git_odb **out, const git_odb_options *opts)
+{
+	return git_odb__new(out, opts);
+}
+#else
+int git_odb_new(git_odb **out)
+{
+	return git_odb__new(out, NULL);
+}
+#endif
+
 static int add_backend_internal(
 	git_odb *odb, git_odb_backend *backend,
 	int priority, bool is_alternate, ino_t disk_inode)
@@ -575,6 +683,7 @@ int git_odb__add_default_backends(
 	struct stat st;
 	ino_t inode;
 	git_odb_backend *loose, *packed;
+	git_odb_backend_loose_options loose_opts = GIT_ODB_BACKEND_LOOSE_OPTIONS_INIT;
 
 	/* TODO: inodes are not really relevant on Win32, so we need to find
 	 * a cross-platform workaround for this */
@@ -609,8 +718,13 @@ int git_odb__add_default_backends(
 	git_mutex_unlock(&db->lock);
 #endif
 
+	if (db->do_fsync)
+		loose_opts.flags |= GIT_ODB_BACKEND_LOOSE_FSYNC;
+
+	loose_opts.oid_type = db->options.oid_type;
+
 	/* add the loose object backend */
-	if (git_odb_backend_loose(&loose, objects_dir, -1, db->do_fsync, 0, 0) < 0 ||
+	if (git_odb__backend_loose(&loose, objects_dir, &loose_opts) < 0 ||
 		add_backend_internal(db, loose, git_odb__loose_priority, as_alternates, inode) < 0)
 		return -1;
 
@@ -707,7 +821,10 @@ int git_odb_set_commit_graph(git_odb *odb, git_commit_graph *cgraph)
 	return error;
 }
 
-int git_odb_open(git_odb **out, const char *objects_dir)
+int git_odb__open(
+	git_odb **out,
+	const char *objects_dir,
+	const git_odb_options *opts)
 {
 	git_odb *db;
 
@@ -716,7 +833,7 @@ int git_odb_open(git_odb **out, const char *objects_dir)
 
 	*out = NULL;
 
-	if (git_odb_new(&db) < 0)
+	if (git_odb__new(&db, opts) < 0)
 		return -1;
 
 	if (git_odb__add_default_backends(db, objects_dir, 0, 0) < 0) {
@@ -914,7 +1031,7 @@ static int odb_exists_prefix_1(git_oid *out, git_odb *db,
 {
 	size_t i;
 	int error = GIT_ENOTFOUND, num_found = 0;
-	git_oid last_found = {{0}}, found;
+	git_oid last_found = GIT_OID_NONE, found;
 
 	if ((error = git_mutex_lock(&db->lock)) < 0) {
 		git_error_set(GIT_ERROR_ODB, "failed to acquire the odb lock");
@@ -965,7 +1082,7 @@ int git_odb_exists_prefix(
 	git_oid *out, git_odb *db, const git_oid *short_id, size_t len)
 {
 	int error;
-	git_oid key = {{0}};
+	git_oid key = GIT_OID_NONE;
 
 	GIT_ASSERT_ARG(db);
 	GIT_ASSERT_ARG(short_id);
@@ -973,7 +1090,7 @@ int git_odb_exists_prefix(
 	if (len < GIT_OID_MINPREFIXLEN)
 		return git_odb__error_ambiguous("prefix length too short");
 
-	if (len >= GIT_OID_HEXSZ) {
+	if (len >= git_oid_hexsize(db->options.oid_type)) {
 		if (git_odb_exists(db, short_id)) {
 			if (out)
 				git_oid_cpy(out, short_id);
@@ -1002,11 +1119,13 @@ int git_odb_expand_ids(
 	git_odb_expand_id *ids,
 	size_t count)
 {
-	size_t i;
+	size_t hex_size, i;
 
 	GIT_ASSERT_ARG(db);
 	GIT_ASSERT_ARG(ids);
 
+	hex_size = git_oid_hexsize(db->options.oid_type);
+
 	for (i = 0; i < count; i++) {
 		git_odb_expand_id *query = &ids[i];
 		int error = GIT_EAMBIGUOUS;
@@ -1015,13 +1134,13 @@ int git_odb_expand_ids(
 			query->type = GIT_OBJECT_ANY;
 
 		/* if we have a short OID, expand it first */
-		if (query->length >= GIT_OID_MINPREFIXLEN && query->length < GIT_OID_HEXSZ) {
+		if (query->length >= GIT_OID_MINPREFIXLEN && query->length < hex_size) {
 			git_oid actual_id;
 
 			error = odb_exists_prefix_1(&actual_id, db, &query->id, query->length, false);
 			if (!error) {
 				git_oid_cpy(&query->id, &actual_id);
-				query->length = GIT_OID_HEXSZ;
+				query->length = (unsigned short)hex_size;
 			}
 		}
 
@@ -1029,7 +1148,7 @@ int git_odb_expand_ids(
 		 * now we ought to have a 40-char OID, either because we've expanded it
 		 * or because the user passed a full OID. Ensure its type is right.
 		 */
-		if (query->length >= GIT_OID_HEXSZ) {
+		if (query->length >= hex_size) {
 			git_object_t actual_type;
 
 			error = odb_otype_fast(&actual_type, db, &query->id);
@@ -1049,7 +1168,7 @@ int git_odb_expand_ids(
 		/* the object is missing or ambiguous */
 		case GIT_ENOTFOUND:
 		case GIT_EAMBIGUOUS:
-			memset(&query->id, 0, sizeof(git_oid));
+			git_oid_clear(&query->id, db->options.oid_type);
 			query->length = 0;
 			query->type = 0;
 			break;
@@ -1157,7 +1276,7 @@ int git_odb__read_header_or_object(
 		error = odb_read_header_1(len_p, type_p, db, id, true);
 
 	if (error == GIT_ENOTFOUND)
-		return git_odb__error_notfound("cannot read header for", id, GIT_OID_HEXSZ);
+		return git_odb__error_notfound("cannot read header for", id, git_oid_hexsize(db->options.oid_type));
 
 	/* we found the header; return early */
 	if (!error)
@@ -1179,8 +1298,11 @@ int git_odb__read_header_or_object(
 	return error;
 }
 
-static int odb_read_1(git_odb_object **out, git_odb *db, const git_oid *id,
-		bool only_refreshed)
+static int odb_read_1(
+	git_odb_object **out,
+	git_odb *db,
+	const git_oid *id,
+	bool only_refreshed)
 {
 	size_t i;
 	git_rawobj raw;
@@ -1224,7 +1346,7 @@ static int odb_read_1(git_odb_object **out, git_odb *db, const git_oid *id,
 		return GIT_ENOTFOUND;
 
 	if (git_odb__strict_hash_verification) {
-		if ((error = git_odb_hash(&hashed, raw.data, raw.len, raw.type)) < 0)
+		if ((error = git_odb__hash(&hashed, raw.data, raw.len, raw.type, db->options.oid_type)) < 0)
 			goto out;
 
 		if (!git_oid_equal(id, &hashed)) {
@@ -1268,7 +1390,7 @@ int git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id)
 		error = odb_read_1(out, db, id, true);
 
 	if (error == GIT_ENOTFOUND)
-		return git_odb__error_notfound("no match for id", id, GIT_OID_HEXSZ);
+		return git_odb__error_notfound("no match for id", id, git_oid_hexsize(git_oid_type(id)));
 
 	return error;
 }
@@ -1305,7 +1427,7 @@ static int read_prefix_1(git_odb_object **out, git_odb *db,
 {
 	size_t i;
 	int error = 0;
-	git_oid found_full_oid = {{0}};
+	git_oid found_full_oid = GIT_OID_NONE;
 	git_rawobj raw = {0};
 	void *data = NULL;
 	bool found = false;
@@ -1365,7 +1487,7 @@ static int read_prefix_1(git_odb_object **out, git_odb *db,
 	if (git_odb__strict_hash_verification) {
 		git_oid hash;
 
-		if ((error = git_odb_hash(&hash, raw.data, raw.len, raw.type)) < 0)
+		if ((error = git_odb__hash(&hash, raw.data, raw.len, raw.type, db->options.oid_type)) < 0)
 			goto out;
 
 		if (!git_oid_equal(&found_full_oid, &hash)) {
@@ -1391,19 +1513,22 @@ out:
 int git_odb_read_prefix(
 	git_odb_object **out, git_odb *db, const git_oid *short_id, size_t len)
 {
-	git_oid key = {{0}};
+	git_oid key = GIT_OID_NONE;
+	size_t hex_size;
 	int error;
 
 	GIT_ASSERT_ARG(out);
 	GIT_ASSERT_ARG(db);
 
+	hex_size = git_oid_hexsize(db->options.oid_type);
+
 	if (len < GIT_OID_MINPREFIXLEN)
 		return git_odb__error_ambiguous("prefix length too short");
 
-	if (len > GIT_OID_HEXSZ)
-		len = GIT_OID_HEXSZ;
+	if (len > hex_size)
+		len = hex_size;
 
-	if (len == GIT_OID_HEXSZ) {
+	if (len == hex_size) {
 		*out = git_cache_get_raw(odb_cache(db), short_id);
 		if (*out != NULL)
 			return 0;
@@ -1463,7 +1588,7 @@ int git_odb_write(
 	GIT_ASSERT_ARG(oid);
 	GIT_ASSERT_ARG(db);
 
-	if ((error = git_odb_hash(oid, data, len, type)) < 0)
+	if ((error = git_odb__hash(oid, data, len, type, db->options.oid_type)) < 0)
 		return error;
 
 	if (git_oid_is_zero(oid))
@@ -1564,10 +1689,11 @@ int git_odb_open_wstream(
 	ctx = git__malloc(sizeof(git_hash_ctx));
 	GIT_ERROR_CHECK_ALLOC(ctx);
 
-	if ((error = git_hash_ctx_init(ctx, GIT_HASH_ALGORITHM_SHA1)) < 0 ||
-		(error = hash_header(ctx, size, type)) < 0)
+	if ((error = git_hash_ctx_init(ctx, git_oid_algorithm(db->options.oid_type))) < 0 ||
+	    (error = hash_header(ctx, size, type)) < 0)
 		goto done;
 
+	(*stream)->oid_type = db->options.oid_type;
 	(*stream)->hash_ctx = ctx;
 	(*stream)->declared_size = size;
 	(*stream)->received_bytes = 0;
@@ -1612,6 +1738,10 @@ int git_odb_stream_finalize_write(git_oid *out, git_odb_stream *stream)
 
 	git_hash_final(out->id, stream->hash_ctx);
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	out->type = stream->oid_type;
+#endif
+
 	if (git_odb__freshen(stream->backend->odb, out))
 		return 0;
 
@@ -1786,10 +1916,11 @@ int git_odb_refresh(struct git_odb *db)
 
 int git_odb__error_mismatch(const git_oid *expected, const git_oid *actual)
 {
-	char expected_oid[GIT_OID_HEXSZ + 1], actual_oid[GIT_OID_HEXSZ + 1];
+	char expected_oid[GIT_OID_MAX_HEXSIZE + 1],
+	     actual_oid[GIT_OID_MAX_HEXSIZE + 1];
 
-	git_oid_tostr(expected_oid, sizeof(expected_oid), expected);
-	git_oid_tostr(actual_oid, sizeof(actual_oid), actual);
+	git_oid_tostr(expected_oid, git_oid_hexsize(git_oid_type(expected)) + 1, expected);
+	git_oid_tostr(actual_oid, git_oid_hexsize(git_oid_type(actual)) + 1, actual);
 
 	git_error_set(GIT_ERROR_ODB, "object hash mismatch - expected %s but got %s",
 		expected_oid, actual_oid);
@@ -1801,7 +1932,7 @@ int git_odb__error_notfound(
 	const char *message, const git_oid *oid, size_t oid_len)
 {
 	if (oid != NULL) {
-		char oid_str[GIT_OID_HEXSZ + 1];
+		char oid_str[GIT_OID_MAX_HEXSIZE + 1];
 		git_oid_tostr(oid_str, oid_len+1, oid);
 		git_error_set(GIT_ERROR_ODB, "object not found - %s (%.*s)",
 			message, (int) oid_len, oid_str);
@@ -1819,7 +1950,7 @@ static int error_null_oid(int error, const char *message)
 
 int git_odb__error_ambiguous(const char *message)
 {
-	git_error_set(GIT_ERROR_ODB, "ambiguous SHA1 prefix - %s", message);
+	git_error_set(GIT_ERROR_ODB, "ambiguous OID prefix - %s", message);
 	return GIT_EAMBIGUOUS;
 }
 
diff --git a/src/libgit2/odb.h b/src/libgit2/odb.h
index 5aa4cc84a..7a712e202 100644
--- a/src/libgit2/odb.h
+++ b/src/libgit2/odb.h
@@ -10,6 +10,7 @@
 #include "common.h"
 
 #include "git2/odb.h"
+#include "git2/odb_backend.h"
 #include "git2/oid.h"
 #include "git2/types.h"
 #include "git2/sys/commit_graph.h"
@@ -46,6 +47,7 @@ struct git_odb_object {
 struct git_odb {
 	git_refcount rc;
 	git_mutex lock;  /* protects backends */
+	git_odb_options options;
 	git_vector backends;
 	git_cache own_cache;
 	git_commit_graph *cgraph;
@@ -72,7 +74,7 @@ int git_odb__add_default_backends(
  * Hash a git_rawobj internally.
  * The `git_rawobj` is supposed to be previously initialized
  */
-int git_odb__hashobj(git_oid *id, git_rawobj *obj);
+int git_odb__hashobj(git_oid *id, git_rawobj *obj, git_oid_t oid_type);
 
 /*
  * Format the object header such as it would appear in the on-disk object
@@ -89,14 +91,24 @@ int git_odb__format_object_header(size_t *out_len, char *hdr, size_t hdr_size, g
  * The fd is never closed, not even on error. It must be opened and closed
  * by the caller
  */
-int git_odb__hashfd(git_oid *out, git_file fd, size_t size, git_object_t type);
+int git_odb__hashfd(
+	git_oid *out,
+	git_file fd,
+	size_t size,
+	git_object_t object_type,
+	git_oid_t oid_type);
 
 /*
  * Hash an open file descriptor applying an array of filters
  * Acts just like git_odb__hashfd with the addition of filters...
  */
 int git_odb__hashfd_filtered(
-	git_oid *out, git_file fd, size_t len, git_object_t type, git_filter_list *fl);
+	git_oid *out,
+	git_file fd,
+	size_t len,
+	git_object_t object_type,
+	git_oid_t oid_type,
+	git_filter_list *fl);
 
 /*
  * Hash a `path`, assuming it could be a POSIX symlink: if the path is a
@@ -106,7 +118,7 @@ int git_odb__hashfd_filtered(
  * The hash type for this call is always `GIT_OBJECT_BLOB` because
  * symlinks may only point to blobs.
  */
-int git_odb__hashlink(git_oid *out, const char *path);
+int git_odb__hashlink(git_oid *out, const char *path, git_oid_t oid_type);
 
 /**
  * Generate a GIT_EMISMATCH error for the ODB.
@@ -146,4 +158,31 @@ int git_odb__freshen(git_odb *db, const git_oid *id);
 /* fully free the object; internal method, DO NOT EXPORT */
 void git_odb_object__free(void *object);
 
+/* SHA256 support */
+
+int git_odb__new(git_odb **out, const git_odb_options *opts);
+
+int git_odb__open(
+	git_odb **out,
+	const char *objects_dir,
+	const git_odb_options *opts);
+
+int git_odb__hash(
+	git_oid *out,
+	const void *data,
+	size_t len,
+	git_object_t object_type,
+	git_oid_t oid_type);
+
+int git_odb__hashfile(
+	git_oid *out,
+	const char *path,
+	git_object_t object_type,
+	git_oid_t oid_type);
+
+GIT_EXTERN(int) git_odb__backend_loose(
+	git_odb_backend **out,
+	const char *objects_dir,
+	git_odb_backend_loose_options *opts);
+
 #endif
diff --git a/src/libgit2/odb_loose.c b/src/libgit2/odb_loose.c
index 463e24fa5..d1abbe233 100644
--- a/src/libgit2/odb_loose.c
+++ b/src/libgit2/odb_loose.c
@@ -46,10 +46,8 @@ typedef struct {
 typedef struct loose_backend {
 	git_odb_backend parent;
 
-	int object_zlib_level; /** loose object zlib compression level. */
-	int fsync_object_files; /** loose object file fsync flag. */
-	mode_t object_file_mode;
-	mode_t object_dir_mode;
+	git_odb_backend_loose_options options;
+	size_t oid_hexsize;
 
 	size_t objects_dirlen;
 	char objects_dir[GIT_FLEX_ARRAY];
@@ -59,13 +57,19 @@ typedef struct loose_backend {
  * in order to locate objects matching a short oid.
  */
 typedef struct {
+	loose_backend *backend;
+
 	size_t dir_len;
-	unsigned char short_oid[GIT_OID_HEXSZ]; /* hex formatted oid to match */
+
+	/* Hex formatted oid to match (and its length) */
+	unsigned char short_oid[GIT_OID_MAX_HEXSIZE];
 	size_t short_oid_len;
-	int found;				/* number of matching
-						 * objects already found */
-	unsigned char res_oid[GIT_OID_HEXSZ];	/* hex formatted oid of
-						 * the object found */
+
+	/* Number of matching objects found so far */
+	int found;
+
+	/* Hex formatted oid of the object found */
+	unsigned char res_oid[GIT_OID_MAX_HEXSIZE];
 } loose_locate_object_state;
 
 
@@ -78,20 +82,17 @@ typedef struct {
 static int object_file_name(
 	git_str *name, const loose_backend *be, const git_oid *id)
 {
-	size_t alloclen;
-
-	/* expand length for object root + 40 hex sha1 chars + 2 * '/' + '\0' */
-	GIT_ERROR_CHECK_ALLOC_ADD(&alloclen, be->objects_dirlen, GIT_OID_HEXSZ);
-	GIT_ERROR_CHECK_ALLOC_ADD(&alloclen, alloclen, 3);
-	if (git_str_grow(name, alloclen) < 0)
-		return -1;
+	/* append loose object filename: aa/aaa... (41 bytes plus NUL) */
+	size_t path_size = be->oid_hexsize + 1;
 
 	git_str_set(name, be->objects_dir, be->objects_dirlen);
 	git_fs_path_to_dir(name);
 
-	/* loose object filename: aa/aaa... (41 bytes) */
+	if (git_str_grow_by(name, path_size + 1) < 0)
+		return -1;
+
 	git_oid_pathfmt(name->ptr + name->size, id);
-	name->size += GIT_OID_HEXSZ + 1;
+	name->size += path_size;
 	name->ptr[name->size] = '\0';
 
 	return 0;
@@ -100,7 +101,9 @@ static int object_file_name(
 static int object_mkdir(const git_str *name, const loose_backend *be)
 {
 	return git_futils_mkdir_relative(
-		name->ptr + be->objects_dirlen, be->objects_dir, be->object_dir_mode,
+		name->ptr + be->objects_dirlen,
+		be->objects_dir,
+		be->options.dir_mode,
 		GIT_MKDIR_PATH | GIT_MKDIR_SKIP_LAST | GIT_MKDIR_VERIFY_DIR, NULL);
 }
 
@@ -461,8 +464,9 @@ static int locate_object(
 /* Explore an entry of a directory and see if it matches a short oid */
 static int fn_locate_object_short_oid(void *state, git_str *pathbuf) {
 	loose_locate_object_state *sstate = (loose_locate_object_state *)state;
+	size_t hex_size = sstate->backend->oid_hexsize;
 
-	if (git_str_len(pathbuf) - sstate->dir_len != GIT_OID_HEXSZ - 2) {
+	if (git_str_len(pathbuf) - sstate->dir_len != hex_size - 2) {
 		/* Entry cannot be an object. Continue to next entry */
 		return 0;
 	}
@@ -477,7 +481,9 @@ static int fn_locate_object_short_oid(void *state, git_str *pathbuf) {
 			if (!sstate->found) {
 				sstate->res_oid[0] = sstate->short_oid[0];
 				sstate->res_oid[1] = sstate->short_oid[1];
-				memcpy(sstate->res_oid+2, pathbuf->ptr+sstate->dir_len, GIT_OID_HEXSZ-2);
+				memcpy(sstate->res_oid + 2,
+				       pathbuf->ptr+sstate->dir_len,
+				       hex_size - 2);
 			}
 			sstate->found++;
 		}
@@ -503,7 +509,7 @@ static int locate_object_short_oid(
 	int error;
 
 	/* prealloc memory for OBJ_DIR/xx/xx..38x..xx */
-	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, dir_len, GIT_OID_HEXSZ);
+	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, dir_len, backend->oid_hexsize);
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, 3);
 	if (git_str_grow(object_location, alloc_len) < 0)
 		return -1;
@@ -527,6 +533,7 @@ static int locate_object_short_oid(
 		return git_odb__error_notfound("no matching loose object for prefix",
 			short_oid, len);
 
+	state.backend = backend;
 	state.dir_len = git_str_len(object_location);
 	state.short_oid_len = len;
 	state.found = 0;
@@ -545,12 +552,12 @@ static int locate_object_short_oid(
 		return git_odb__error_ambiguous("multiple matches in loose objects");
 
 	/* Convert obtained hex formatted oid to raw */
-	error = git_oid_fromstr(res_oid, (char *)state.res_oid);
+	error = git_oid__fromstr(res_oid, (char *)state.res_oid, backend->options.oid_type);
 	if (error)
 		return error;
 
 	/* Update the location according to the oid obtained */
-	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, dir_len, GIT_OID_HEXSZ);
+	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, dir_len, backend->oid_hexsize);
 	GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, 2);
 
 	git_str_truncate(object_location, dir_len);
@@ -559,20 +566,12 @@ static int locate_object_short_oid(
 
 	git_oid_pathfmt(object_location->ptr + dir_len, res_oid);
 
-	object_location->size += GIT_OID_HEXSZ + 1;
+	object_location->size +=  backend->oid_hexsize + 1;
 	object_location->ptr[object_location->size] = '\0';
 
 	return 0;
 }
 
-
-
-
-
-
-
-
-
 /***********************************************************
  *
  * LOOSE BACKEND PUBLIC API
@@ -595,7 +594,7 @@ static int loose_backend__read_header(size_t *len_p, git_object_t *type_p, git_o
 
 	if (locate_object(&object_path, (loose_backend *)backend, oid) < 0) {
 		error = git_odb__error_notfound("no matching loose object",
-			oid, GIT_OID_HEXSZ);
+			oid, ((struct loose_backend *)backend)->oid_hexsize);
 	} else if ((error = read_header_loose(&raw, &object_path)) == 0) {
 		*len_p = raw.len;
 		*type_p = raw.type;
@@ -617,7 +616,7 @@ static int loose_backend__read(void **buffer_p, size_t *len_p, git_object_t *typ
 
 	if (locate_object(&object_path, (loose_backend *)backend, oid) < 0) {
 		error = git_odb__error_notfound("no matching loose object",
-			oid, GIT_OID_HEXSZ);
+			oid, ((struct loose_backend *)backend)->oid_hexsize);
 	} else if ((error = read_loose(&raw, &object_path)) == 0) {
 		*buffer_p = raw.data;
 		*len_p = raw.len;
@@ -634,17 +633,19 @@ static int loose_backend__read_prefix(
 	void **buffer_p,
 	size_t *len_p,
 	git_object_t *type_p,
-	git_odb_backend *backend,
+	git_odb_backend *_backend,
 	const git_oid *short_oid,
 	size_t len)
 {
+	struct loose_backend *backend = (struct loose_backend *)_backend;
 	int error = 0;
 
-	GIT_ASSERT_ARG(len >= GIT_OID_MINPREFIXLEN && len <= GIT_OID_HEXSZ);
+	GIT_ASSERT_ARG(len >= GIT_OID_MINPREFIXLEN &&
+	               len <= backend->oid_hexsize);
 
-	if (len == GIT_OID_HEXSZ) {
+	if (len == backend->oid_hexsize) {
 		/* We can fall back to regular read method */
-		error = loose_backend__read(buffer_p, len_p, type_p, backend, short_oid);
+		error = loose_backend__read(buffer_p, len_p, type_p, _backend, short_oid);
 		if (!error)
 			git_oid_cpy(out_oid, short_oid);
 	} else {
@@ -703,15 +704,18 @@ static int loose_backend__exists_prefix(
 }
 
 struct foreach_state {
+	struct loose_backend *backend;
 	size_t dir_len;
 	git_odb_foreach_cb cb;
 	void *data;
 };
 
-GIT_INLINE(int) filename_to_oid(git_oid *oid, const char *ptr)
+GIT_INLINE(int) filename_to_oid(struct loose_backend *backend, git_oid *oid, const char *ptr)
 {
-	int v, i = 0;
-	if (strlen(ptr) != GIT_OID_HEXSZ+1)
+	int v;
+	size_t i = 0;
+
+	if (strlen(ptr) != backend->oid_hexsize + 1)
 		return -1;
 
 	if (ptr[2] != '/') {
@@ -725,7 +729,7 @@ GIT_INLINE(int) filename_to_oid(git_oid *oid, const char *ptr)
 	oid->id[0] = (unsigned char) v;
 
 	ptr += 3;
-	for (i = 0; i < 38; i += 2) {
+	for (i = 0; i < backend->oid_hexsize - 2; i += 2) {
 		v = (git__fromhex(ptr[i]) << 4) | git__fromhex(ptr[i + 1]);
 		if (v < 0)
 			return -1;
@@ -733,6 +737,10 @@ GIT_INLINE(int) filename_to_oid(git_oid *oid, const char *ptr)
 		oid->id[1 + i/2] = (unsigned char) v;
 	}
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	oid->type = backend->options.oid_type;
+#endif
+
 	return 0;
 }
 
@@ -741,7 +749,7 @@ static int foreach_object_dir_cb(void *_state, git_str *path)
 	git_oid oid;
 	struct foreach_state *state = (struct foreach_state *) _state;
 
-	if (filename_to_oid(&oid, path->ptr + state->dir_len) < 0)
+	if (filename_to_oid(state->backend, &oid, path->ptr + state->dir_len) < 0)
 		return 0;
 
 	return git_error_set_after_callback_function(
@@ -778,6 +786,7 @@ static int loose_backend__foreach(git_odb_backend *_backend, git_odb_foreach_cb
 		return -1;
 
 	memset(&state, 0, sizeof(state));
+	state.backend = backend;
 	state.cb = cb;
 	state.data = data;
 	state.dir_len = git_str_len(&buf);
@@ -825,9 +834,10 @@ static void loose_backend__writestream_free(git_odb_stream *_stream)
 static int filebuf_flags(loose_backend *backend)
 {
 	int flags = GIT_FILEBUF_TEMPORARY |
-		(backend->object_zlib_level << GIT_FILEBUF_DEFLATE_SHIFT);
+		(backend->options.compression_level << GIT_FILEBUF_DEFLATE_SHIFT);
 
-	if (backend->fsync_object_files || git_repository__fsync_gitdir)
+	if ((backend->options.flags & GIT_ODB_BACKEND_LOOSE_FSYNC) ||
+	    git_repository__fsync_gitdir)
 		flags |= GIT_FILEBUF_FSYNC;
 
 	return flags;
@@ -863,7 +873,7 @@ static int loose_backend__writestream(git_odb_stream **stream_out, git_odb_backe
 
 	if (git_str_joinpath(&tmp_path, backend->objects_dir, "tmp_object") < 0 ||
 		git_filebuf_open(&stream->fbuf, tmp_path.ptr, filebuf_flags(backend),
-			backend->object_file_mode) < 0 ||
+			backend->options.file_mode) < 0 ||
 		stream->stream.write((git_odb_stream *)stream, hdr, hdrlen) < 0)
 	{
 		git_filebuf_cleanup(&stream->fbuf);
@@ -997,6 +1007,7 @@ static int loose_backend__readstream(
 	loose_readstream *stream = NULL;
 	git_hash_ctx *hash_ctx = NULL;
 	git_str object_path = GIT_STR_INIT;
+	git_hash_algorithm_t algorithm;
 	obj_hdr hdr;
 	int error = 0;
 
@@ -1013,7 +1024,7 @@ static int loose_backend__readstream(
 
 	if (locate_object(&object_path, backend, oid) < 0) {
 		error = git_odb__error_notfound("no matching loose object",
-			oid, GIT_OID_HEXSZ);
+			oid, backend->oid_hexsize);
 		goto done;
 	}
 
@@ -1023,9 +1034,11 @@ static int loose_backend__readstream(
 	hash_ctx = git__malloc(sizeof(git_hash_ctx));
 	GIT_ERROR_CHECK_ALLOC(hash_ctx);
 
-	if ((error = git_hash_ctx_init(hash_ctx, GIT_HASH_ALGORITHM_SHA1)) < 0 ||
-		(error = git_futils_mmap_ro_file(&stream->map, object_path.ptr)) < 0 ||
-		(error = git_zstream_init(&stream->zstream, GIT_ZSTREAM_INFLATE)) < 0)
+	algorithm = git_oid_algorithm(backend->options.oid_type);
+
+	if ((error = git_hash_ctx_init(hash_ctx, algorithm)) < 0 ||
+	    (error = git_futils_mmap_ro_file(&stream->map, object_path.ptr)) < 0 ||
+	    (error = git_zstream_init(&stream->zstream, GIT_ZSTREAM_INFLATE)) < 0)
 		goto done;
 
 	/* check for a packlike loose object */
@@ -1081,7 +1094,7 @@ static int loose_backend__write(git_odb_backend *_backend, const git_oid *oid, c
 
 	if (git_str_joinpath(&final_path, backend->objects_dir, "tmp_object") < 0 ||
 		git_filebuf_open(&fbuf, final_path.ptr, filebuf_flags(backend),
-			backend->object_file_mode) < 0)
+			backend->options.file_mode) < 0)
 	{
 		error = -1;
 		goto cleanup;
@@ -1124,13 +1137,34 @@ static void loose_backend__free(git_odb_backend *_backend)
 	git__free(_backend);
 }
 
-int git_odb_backend_loose(
+static void normalize_options(
+	git_odb_backend_loose_options *opts,
+	const git_odb_backend_loose_options *given_opts)
+{
+	git_odb_backend_loose_options init = GIT_ODB_BACKEND_LOOSE_OPTIONS_INIT;
+
+	if (given_opts)
+		memcpy(opts, given_opts, sizeof(git_odb_backend_loose_options));
+	else
+		memcpy(opts, &init, sizeof(git_odb_backend_loose_options));
+
+	if (opts->compression_level < 0)
+		opts->compression_level = Z_BEST_SPEED;
+
+	if (opts->dir_mode == 0)
+		opts->dir_mode = GIT_OBJECT_DIR_MODE;
+
+	if (opts->file_mode == 0)
+		opts->file_mode = GIT_OBJECT_FILE_MODE;
+
+	if (opts->oid_type == 0)
+		opts->oid_type = GIT_OID_DEFAULT;
+}
+
+int git_odb__backend_loose(
 	git_odb_backend **backend_out,
 	const char *objects_dir,
-	int compression_level,
-	int do_fsync,
-	unsigned int dir_mode,
-	unsigned int file_mode)
+	git_odb_backend_loose_options *opts)
 {
 	loose_backend *backend;
 	size_t objects_dirlen, alloclen;
@@ -1148,22 +1182,12 @@ int git_odb_backend_loose(
 	backend->parent.version = GIT_ODB_BACKEND_VERSION;
 	backend->objects_dirlen = objects_dirlen;
 	memcpy(backend->objects_dir, objects_dir, objects_dirlen);
+
 	if (backend->objects_dir[backend->objects_dirlen - 1] != '/')
 		backend->objects_dir[backend->objects_dirlen++] = '/';
 
-	if (compression_level < 0)
-		compression_level = Z_BEST_SPEED;
-
-	if (dir_mode == 0)
-		dir_mode = GIT_OBJECT_DIR_MODE;
-
-	if (file_mode == 0)
-		file_mode = GIT_OBJECT_FILE_MODE;
-
-	backend->object_zlib_level = compression_level;
-	backend->fsync_object_files = do_fsync;
-	backend->object_dir_mode = dir_mode;
-	backend->object_file_mode = file_mode;
+	normalize_options(&backend->options, opts);
+	backend->oid_hexsize = git_oid_hexsize(backend->options.oid_type);
 
 	backend->parent.read = &loose_backend__read;
 	backend->parent.write = &loose_backend__write;
diff --git a/src/libgit2/odb_pack.c b/src/libgit2/odb_pack.c
index 818cc6125..49a655b44 100644
--- a/src/libgit2/odb_pack.c
+++ b/src/libgit2/odb_pack.c
@@ -177,7 +177,7 @@ static int pack_entry_find(struct git_pack_entry *e,
  * a prefix of an identifier.
  * Sets GIT_EAMBIGUOUS if short oid is ambiguous.
  * This method assumes that len is between
- * GIT_OID_MINPREFIXLEN and GIT_OID_HEXSZ.
+ * GIT_OID_MINPREFIXLEN and GIT_OID_SHA1_HEXSIZE.
  */
 static int pack_entry_find_prefix(
 	struct git_pack_entry *e,
@@ -273,7 +273,7 @@ static int pack_entry_find(struct git_pack_entry *e, struct pack_backend *backen
 	size_t i;
 
 	if (backend->midx &&
-		git_midx_entry_find(&midx_entry, backend->midx, oid, GIT_OID_HEXSZ) == 0 &&
+		git_midx_entry_find(&midx_entry, backend->midx, oid, GIT_OID_SHA1_HEXSIZE) == 0 &&
 		midx_entry.pack_index < git_vector_length(&backend->midx_packs)) {
 		e->offset = midx_entry.offset;
 		git_oid_cpy(&e->sha1, &midx_entry.sha1);
@@ -282,21 +282,21 @@ static int pack_entry_find(struct git_pack_entry *e, struct pack_backend *backen
 	}
 
 	if (last_found &&
-		git_pack_entry_find(e, last_found, oid, GIT_OID_HEXSZ) == 0)
+		git_pack_entry_find(e, last_found, oid, GIT_OID_SHA1_HEXSIZE) == 0)
 		return 0;
 
 	git_vector_foreach(&backend->packs, i, p) {
 		if (p == last_found)
 			continue;
 
-		if (git_pack_entry_find(e, p, oid, GIT_OID_HEXSZ) == 0) {
+		if (git_pack_entry_find(e, p, oid, GIT_OID_SHA1_HEXSIZE) == 0) {
 			backend->last_found = p;
 			return 0;
 		}
 	}
 
 	return git_odb__error_notfound(
-		"failed to find pack entry", oid, GIT_OID_HEXSZ);
+		"failed to find pack entry", oid, GIT_OID_SHA1_HEXSIZE);
 }
 
 static int pack_entry_find_prefix(
@@ -307,7 +307,7 @@ static int pack_entry_find_prefix(
 {
 	int error;
 	size_t i;
-	git_oid found_full_oid = {{0}};
+	git_oid found_full_oid = GIT_OID_SHA1_ZERO;
 	bool found = false;
 	struct git_pack_file *last_found = backend->last_found, *p;
 	git_midx_entry midx_entry;
@@ -605,7 +605,7 @@ static int pack_backend__read_prefix(
 	if (len < GIT_OID_MINPREFIXLEN)
 		error = git_odb__error_ambiguous("prefix length too short");
 
-	else if (len >= GIT_OID_HEXSZ) {
+	else if (len >= GIT_OID_SHA1_HEXSIZE) {
 		/* We can fall back to regular read method */
 		error = pack_backend__read(buffer_p, len_p, type_p, backend, short_oid);
 		if (!error)
diff --git a/src/libgit2/oid.c b/src/libgit2/oid.c
index fb92174ab..6cc21641d 100644
--- a/src/libgit2/oid.c
+++ b/src/libgit2/oid.c
@@ -14,13 +14,13 @@
 #include <limits.h>
 
 const git_oid git_oid__empty_blob_sha1 =
-	{{ 0xe6, 0x9d, 0xe2, 0x9b, 0xb2, 0xd1, 0xd6, 0x43, 0x4b, 0x8b,
-	   0x29, 0xae, 0x77, 0x5a, 0xd8, 0xc2, 0xe4, 0x8c, 0x53, 0x91 }};
+	GIT_OID_INIT(GIT_OID_SHA1,
+	  { 0xe6, 0x9d, 0xe2, 0x9b, 0xb2, 0xd1, 0xd6, 0x43, 0x4b, 0x8b,
+	    0x29, 0xae, 0x77, 0x5a, 0xd8, 0xc2, 0xe4, 0x8c, 0x53, 0x91 });
 const git_oid git_oid__empty_tree_sha1 =
-	{{ 0x4b, 0x82, 0x5d, 0xc6, 0x42, 0xcb, 0x6e, 0xb9, 0xa0, 0x60,
-	   0xe5, 0x4b, 0xf8, 0xd6, 0x92, 0x88, 0xfb, 0xee, 0x49, 0x04 }};
-
-static char to_hex[] = "0123456789abcdef";
+	GIT_OID_INIT(GIT_OID_SHA1,
+	  { 0x4b, 0x82, 0x5d, 0xc6, 0x42, 0xcb, 0x6e, 0xb9, 0xa0, 0x60,
+	    0xe5, 0x4b, 0xf8, 0xd6, 0x92, 0x88, 0xfb, 0xee, 0x49, 0x04 });
 
 static int oid_error_invalid(const char *msg)
 {
@@ -28,21 +28,31 @@ static int oid_error_invalid(const char *msg)
 	return -1;
 }
 
-int git_oid_fromstrn(git_oid *out, const char *str, size_t length)
+int git_oid__fromstrn(
+	git_oid *out,
+	const char *str,
+	size_t length,
+	git_oid_t type)
 {
-	size_t p;
+	size_t size, p;
 	int v;
 
 	GIT_ASSERT_ARG(out);
 	GIT_ASSERT_ARG(str);
 
+	if (!(size = git_oid_size(type)))
+		return oid_error_invalid("unknown type");
+
 	if (!length)
 		return oid_error_invalid("too short");
 
-	if (length > GIT_OID_HEXSZ)
+	if (length > git_oid_hexsize(type))
 		return oid_error_invalid("too long");
 
-	memset(out->id, 0, GIT_OID_RAWSZ);
+#ifdef GIT_EXPERIMENTAL_SHA256
+	out->type = type;
+#endif
+	memset(out->id, 0, size);
 
 	for (p = 0; p < length; p++) {
 		v = git__fromhex(str[p]);
@@ -55,87 +65,128 @@ int git_oid_fromstrn(git_oid *out, const char *str, size_t length)
 	return 0;
 }
 
-int git_oid_fromstrp(git_oid *out, const char *str)
+int git_oid__fromstrp(git_oid *out, const char *str, git_oid_t type)
 {
-	return git_oid_fromstrn(out, str, strlen(str));
+	return git_oid__fromstrn(out, str, strlen(str), type);
 }
 
-int git_oid_fromstr(git_oid *out, const char *str)
+int git_oid__fromstr(git_oid *out, const char *str, git_oid_t type)
 {
-	return git_oid_fromstrn(out, str, GIT_OID_HEXSZ);
+	return git_oid__fromstrn(out, str, git_oid_hexsize(type), type);
 }
 
-GIT_INLINE(char) *fmt_one(char *str, unsigned int val)
+#ifdef GIT_EXPERIMENTAL_SHA256
+int git_oid_fromstrn(
+	git_oid *out,
+	const char *str,
+	size_t length,
+	git_oid_t type)
 {
-	*str++ = to_hex[val >> 4];
-	*str++ = to_hex[val & 0xf];
-	return str;
+	return git_oid__fromstrn(out, str, length, type);
 }
 
+int git_oid_fromstrp(git_oid *out, const char *str, git_oid_t type)
+{
+	return git_oid_fromstrn(out, str, strlen(str), type);
+}
+
+int git_oid_fromstr(git_oid *out, const char *str, git_oid_t type)
+{
+	return git_oid_fromstrn(out, str, git_oid_hexsize(type), type);
+}
+#else
+int git_oid_fromstrn(
+	git_oid *out,
+	const char *str,
+	size_t length)
+{
+	return git_oid__fromstrn(out, str, length, GIT_OID_SHA1);
+}
+
+int git_oid_fromstrp(git_oid *out, const char *str)
+{
+	return git_oid__fromstrn(out, str, strlen(str), GIT_OID_SHA1);
+}
+
+int git_oid_fromstr(git_oid *out, const char *str)
+{
+	return git_oid__fromstrn(out, str, GIT_OID_SHA1_HEXSIZE, GIT_OID_SHA1);
+}
+#endif
+
 int git_oid_nfmt(char *str, size_t n, const git_oid *oid)
 {
-	size_t i, max_i;
+	size_t hex_size;
 
 	if (!oid) {
 		memset(str, 0, n);
 		return 0;
 	}
-	if (n > GIT_OID_HEXSZ) {
-		memset(&str[GIT_OID_HEXSZ], 0, n - GIT_OID_HEXSZ);
-		n = GIT_OID_HEXSZ;
-	}
 
-	max_i = n / 2;
+	if (!(hex_size = git_oid_hexsize(git_oid_type(oid))))
+		return oid_error_invalid("unknown type");
 
-	for (i = 0; i < max_i; i++)
-		str = fmt_one(str, oid->id[i]);
-
-	if (n & 1)
-		*str++ = to_hex[oid->id[i] >> 4];
+	if (n > hex_size) {
+		memset(&str[hex_size], 0, n - hex_size);
+		n = hex_size;
+	}
 
+	git_oid_fmt_substr(str, oid, 0, n);
 	return 0;
 }
 
 int git_oid_fmt(char *str, const git_oid *oid)
 {
-	return git_oid_nfmt(str, GIT_OID_HEXSZ, oid);
+	return git_oid_nfmt(str, git_oid_hexsize(git_oid_type(oid)), oid);
 }
 
 int git_oid_pathfmt(char *str, const git_oid *oid)
 {
-	size_t i;
+	size_t hex_size;
 
-	str = fmt_one(str, oid->id[0]);
-	*str++ = '/';
-	for (i = 1; i < sizeof(oid->id); i++)
-		str = fmt_one(str, oid->id[i]);
+	if (!(hex_size = git_oid_hexsize(git_oid_type(oid))))
+		return oid_error_invalid("unknown type");
 
+	git_oid_fmt_substr(str, oid, 0, 2);
+	str[2] = '/';
+	git_oid_fmt_substr(&str[3], oid, 2, (hex_size - 2));
 	return 0;
 }
 
 char *git_oid_tostr_s(const git_oid *oid)
 {
 	char *str = GIT_THREADSTATE->oid_fmt;
-	git_oid_nfmt(str, GIT_OID_HEXSZ + 1, oid);
+	git_oid_nfmt(str, git_oid_hexsize(git_oid_type(oid)) + 1, oid);
 	return str;
 }
 
 char *git_oid_allocfmt(const git_oid *oid)
 {
-	char *str = git__malloc(GIT_OID_HEXSZ + 1);
-	if (!str)
+	size_t hex_size = git_oid_hexsize(git_oid_type(oid));
+	char *str = git__malloc(hex_size + 1);
+
+	if (!hex_size || !str)
+		return NULL;
+
+	if (git_oid_nfmt(str, hex_size + 1, oid) < 0) {
+		git__free(str);
 		return NULL;
-	git_oid_nfmt(str, GIT_OID_HEXSZ + 1, oid);
+	}
+
 	return str;
 }
 
 char *git_oid_tostr(char *out, size_t n, const git_oid *oid)
 {
+	size_t hex_size;
+
 	if (!out || n == 0)
 		return "";
 
-	if (n > GIT_OID_HEXSZ + 1)
-		n = GIT_OID_HEXSZ + 1;
+	hex_size = oid ? git_oid_hexsize(git_oid_type(oid)) : 0;
+
+	if (n > hex_size + 1)
+		n = hex_size + 1;
 
 	git_oid_nfmt(out, n - 1, oid); /* allow room for terminating NUL */
 	out[n - 1] = '\0';
@@ -143,51 +194,44 @@ char *git_oid_tostr(char *out, size_t n, const git_oid *oid)
 	return out;
 }
 
-int git_oid__parse(
-	git_oid *oid, const char **buffer_out,
-	const char *buffer_end, const char *header)
+int git_oid__fromraw(git_oid *out, const unsigned char *raw, git_oid_t type)
 {
-	const size_t sha_len = GIT_OID_HEXSZ;
-	const size_t header_len = strlen(header);
-
-	const char *buffer = *buffer_out;
-
-	if (buffer + (header_len + sha_len + 1) > buffer_end)
-		return -1;
+	size_t size;
 
-	if (memcmp(buffer, header, header_len) != 0)
-		return -1;
-
-	if (buffer[header_len + sha_len] != '\n')
-		return -1;
-
-	if (git_oid_fromstr(oid, buffer + header_len) < 0)
-		return -1;
-
-	*buffer_out = buffer + (header_len + sha_len + 1);
+	if (!(size = git_oid_size(type)))
+		return oid_error_invalid("unknown type");
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	out->type = type;
+#endif
+	memcpy(out->id, raw, size);
 	return 0;
 }
 
-void git_oid__writebuf(git_str *buf, const char *header, const git_oid *oid)
+#ifdef GIT_EXPERIMENTAL_SHA256
+int git_oid_fromraw(git_oid *out, const unsigned char *raw, git_oid_t type)
 {
-	char hex_oid[GIT_OID_HEXSZ];
-
-	git_oid_fmt(hex_oid, oid);
-	git_str_puts(buf, header);
-	git_str_put(buf, hex_oid, GIT_OID_HEXSZ);
-	git_str_putc(buf, '\n');
+	return git_oid__fromraw(out, raw, type);
 }
-
+#else
 int git_oid_fromraw(git_oid *out, const unsigned char *raw)
 {
-	memcpy(out->id, raw, sizeof(out->id));
-	return 0;
+	return git_oid__fromraw(out, raw, GIT_OID_SHA1);
 }
+#endif
 
 int git_oid_cpy(git_oid *out, const git_oid *src)
 {
-	return git_oid_raw_cpy(out->id, src->id);
+	size_t size;
+
+	if (!(size = git_oid_size(git_oid_type(src))))
+		return oid_error_invalid("unknown type");
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	out->type = src->type;
+#endif
+
+	return git_oid_raw_cpy(out->id, src->id, size);
 }
 
 int git_oid_cmp(const git_oid *a, const git_oid *b)
@@ -202,6 +246,11 @@ int git_oid_equal(const git_oid *a, const git_oid *b)
 
 int git_oid_ncmp(const git_oid *oid_a, const git_oid *oid_b, size_t len)
 {
+#ifdef GIT_EXPERIMENTAL_SHA256
+	if (oid_a->type != oid_b->type)
+		return oid_a->type - oid_b->type;
+#endif
+
 	return git_oid_raw_ncmp(oid_a->id, oid_b->id, len);
 }
 
@@ -209,9 +258,10 @@ int git_oid_strcmp(const git_oid *oid_a, const char *str)
 {
 	const unsigned char *a;
 	unsigned char strval;
+	long size = (long)git_oid_size(git_oid_type(oid_a));
 	int hexval;
 
-	for (a = oid_a->id; *str && (a - oid_a->id) < GIT_OID_RAWSZ; ++a) {
+	for (a = oid_a->id; *str && (a - oid_a->id) < size; ++a) {
 		if ((hexval = git__fromhex(*str++)) < 0)
 			return -1;
 		strval = (unsigned char)(hexval << 4);
@@ -235,8 +285,16 @@ int git_oid_streq(const git_oid *oid_a, const char *str)
 int git_oid_is_zero(const git_oid *oid_a)
 {
 	const unsigned char *a = oid_a->id;
-	unsigned int i;
-	for (i = 0; i < GIT_OID_RAWSZ; ++i, ++a)
+	size_t size = git_oid_size(git_oid_type(oid_a)), i;
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	if (!oid_a->type)
+		return 1;
+	else if (!size)
+		return 0;
+#endif
+
+	for (i = 0; i < size; ++i, ++a)
 		if (*a != 0)
 			return 0;
 	return 1;
@@ -393,7 +451,7 @@ int git_oid_shorten_add(git_oid_shorten *os, const char *text_oid)
 	idx = 0;
 	is_leaf = false;
 
-	for (i = 0; i < GIT_OID_HEXSZ; ++i) {
+	for (i = 0; i < GIT_OID_SHA1_HEXSIZE; ++i) {
 		int c = git__fromhex(text_oid[i]);
 		trie_node *node;
 
diff --git a/src/libgit2/oid.h b/src/libgit2/oid.h
index abae9a4b2..d775e180b 100644
--- a/src/libgit2/oid.h
+++ b/src/libgit2/oid.h
@@ -9,11 +9,79 @@
 
 #include "common.h"
 
+#include "git2/experimental.h"
 #include "git2/oid.h"
+#include "hash.h"
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+# define GIT_OID_NONE { 0, { 0 } }
+# define GIT_OID_INIT(type, ...) { type, __VA_ARGS__ }
+#else
+# define GIT_OID_NONE { { 0 } }
+# define GIT_OID_INIT(type, ...) { __VA_ARGS__ }
+#endif
 
 extern const git_oid git_oid__empty_blob_sha1;
 extern const git_oid git_oid__empty_tree_sha1;
 
+GIT_INLINE(git_oid_t) git_oid_type(const git_oid *oid)
+{
+#ifdef GIT_EXPERIMENTAL_SHA256
+	return oid->type;
+#else
+	GIT_UNUSED(oid);
+	return GIT_OID_SHA1;
+#endif
+}
+
+GIT_INLINE(size_t) git_oid_size(git_oid_t type)
+{
+	switch (type) {
+	case GIT_OID_SHA1:
+		return GIT_OID_SHA1_SIZE;
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	case GIT_OID_SHA256:
+		return GIT_OID_SHA256_SIZE;
+#endif
+
+	}
+
+	return 0;
+}
+
+GIT_INLINE(size_t) git_oid_hexsize(git_oid_t type)
+{
+	switch (type) {
+	case GIT_OID_SHA1:
+		return GIT_OID_SHA1_HEXSIZE;
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	case GIT_OID_SHA256:
+		return GIT_OID_SHA256_HEXSIZE;
+#endif
+
+	}
+
+	return 0;
+}
+
+GIT_INLINE(git_hash_algorithm_t) git_oid_algorithm(git_oid_t type)
+{
+	switch (type) {
+	case GIT_OID_SHA1:
+		return GIT_HASH_ALGORITHM_SHA1;
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	case GIT_OID_SHA256:
+		return GIT_HASH_ALGORITHM_SHA256;
+#endif
+
+	}
+
+	return 0;
+}
+
 /**
  * Format a git_oid into a newly allocated c-string.
  *
@@ -25,13 +93,42 @@ extern const git_oid git_oid__empty_tree_sha1;
  */
 char *git_oid_allocfmt(const git_oid *id);
 
+/**
+ * Format the requested nibbles of an object id.
+ *
+ * @param str the string to write into
+ * @param oid the oid structure to format
+ * @param start the starting number of nibbles
+ * @param count the number of nibbles to format
+ */
+GIT_INLINE(void) git_oid_fmt_substr(
+	char *str,
+	const git_oid *oid,
+	size_t start,
+	size_t count)
+{
+	static char hex[] = "0123456789abcdef";
+	size_t i, end = start + count, min = start / 2, max = end / 2;
+
+	if (start & 1)
+		*str++ = hex[oid->id[min++] & 0x0f];
+
+	for (i = min; i < max; i++) {
+		*str++ = hex[oid->id[i] >> 4];
+		*str++ = hex[oid->id[i] & 0x0f];
+	}
+
+	if (end & 1)
+		*str++ = hex[oid->id[i] >> 4];
+}
+
 GIT_INLINE(int) git_oid_raw_ncmp(
 	const unsigned char *sha1,
 	const unsigned char *sha2,
 	size_t len)
 {
-	if (len > GIT_OID_HEXSZ)
-		len = GIT_OID_HEXSZ;
+	if (len > GIT_OID_MAX_HEXSIZE)
+		len = GIT_OID_MAX_HEXSIZE;
 
 	while (len > 1) {
 		if (*sha1 != *sha2)
@@ -50,16 +147,18 @@ GIT_INLINE(int) git_oid_raw_ncmp(
 
 GIT_INLINE(int) git_oid_raw_cmp(
 	const unsigned char *sha1,
-	const unsigned char *sha2)
+	const unsigned char *sha2,
+	size_t size)
 {
-	return memcmp(sha1, sha2, GIT_OID_RAWSZ);
+	return memcmp(sha1, sha2, size);
 }
 
 GIT_INLINE(int) git_oid_raw_cpy(
 	unsigned char *dst,
-	const unsigned char *src)
+	const unsigned char *src,
+	size_t size)
 {
-	memcpy(dst, src, GIT_OID_RAWSZ);
+	memcpy(dst, src, size);
 	return 0;
 }
 
@@ -72,19 +171,30 @@ GIT_INLINE(int) git_oid_raw_cpy(
  */
 GIT_INLINE(int) git_oid__cmp(const git_oid *a, const git_oid *b)
 {
-	return git_oid_raw_cmp(a->id, b->id);
+#ifdef GIT_EXPERIMENTAL_SHA256
+	if (a->type != b->type)
+		return a->type - b->type;
+
+	return git_oid_raw_cmp(a->id, b->id, git_oid_size(a->type));
+#else
+	return git_oid_raw_cmp(a->id, b->id, git_oid_size(GIT_OID_SHA1));
+#endif
 }
 
 GIT_INLINE(void) git_oid__cpy_prefix(
 	git_oid *out, const git_oid *id, size_t len)
 {
+#ifdef GIT_EXPERIMENTAL_SHA256
+	out->type = id->type;
+#endif
+
 	memcpy(&out->id, id->id, (len + 1) / 2);
 
 	if (len & 1)
 		out->id[len / 2] &= 0xF0;
 }
 
-GIT_INLINE(bool) git_oid__is_hexstr(const char *str)
+GIT_INLINE(bool) git_oid__is_hexstr(const char *str, git_oid_t type)
 {
 	size_t i;
 
@@ -93,7 +203,30 @@ GIT_INLINE(bool) git_oid__is_hexstr(const char *str)
 			return false;
 	}
 
-	return (i == GIT_OID_HEXSZ);
+	return (i == git_oid_hexsize(type));
+}
+
+GIT_INLINE(void) git_oid_clear(git_oid *out, git_oid_t type)
+{
+	memset(out->id, 0, git_oid_size(type));
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	out->type = type;
+#endif
 }
 
+/* SHA256 support */
+
+int git_oid__fromstr(git_oid *out, const char *str, git_oid_t type);
+
+int git_oid__fromstrp(git_oid *out, const char *str, git_oid_t type);
+
+int git_oid__fromstrn(
+	git_oid *out,
+	const char *str,
+	size_t length,
+	git_oid_t type);
+
+int git_oid__fromraw(git_oid *out, const unsigned char *raw, git_oid_t type);
+
 #endif
diff --git a/src/libgit2/pack-objects.c b/src/libgit2/pack-objects.c
index 1aa6731b3..068231649 100644
--- a/src/libgit2/pack-objects.c
+++ b/src/libgit2/pack-objects.c
@@ -347,8 +347,8 @@ static int write_object(
 		goto done;
 
 	if (type == GIT_OBJECT_REF_DELTA) {
-		if ((error = write_cb(po->delta->id.id, GIT_OID_RAWSZ, cb_data)) < 0 ||
-			(error = git_hash_update(&pb->ctx, po->delta->id.id, GIT_OID_RAWSZ)) < 0)
+		if ((error = write_cb(po->delta->id.id, GIT_OID_SHA1_SIZE, cb_data)) < 0 ||
+			(error = git_hash_update(&pb->ctx, po->delta->id.id, GIT_OID_SHA1_SIZE)) < 0)
 			goto done;
 	}
 
@@ -668,7 +668,7 @@ static int write_pack(git_packbuilder *pb,
 	if ((error = git_hash_final(entry_oid.id, &pb->ctx)) < 0)
 		goto done;
 
-	error = write_cb(entry_oid.id, GIT_OID_RAWSZ, cb_data);
+	error = write_cb(entry_oid.id, GIT_OID_SHA1_SIZE, cb_data);
 
 done:
 	/* if callback cancelled writing, we must still free delta_data */
diff --git a/src/libgit2/pack.c b/src/libgit2/pack.c
index 16fe378bd..d428729ea 100644
--- a/src/libgit2/pack.c
+++ b/src/libgit2/pack.c
@@ -32,7 +32,7 @@ static int packfile_unpack_compressed(
  * Throws GIT_EAMBIGUOUSOIDPREFIX if short oid
  * is ambiguous within the pack.
  * This method assumes that len is between
- * GIT_OID_MINPREFIXLEN and GIT_OID_HEXSZ.
+ * GIT_OID_MINPREFIXLEN and GIT_OID_SHA1_HEXSIZE.
  */
 static int pack_entry_find_offset(
 		off64_t *offset_out,
@@ -1002,7 +1002,7 @@ int get_delta_base(
 		*curpos += used;
 	} else if (type == GIT_OBJECT_REF_DELTA) {
 		git_oid base_oid;
-		git_oid_fromraw(&base_oid, base_info);
+		git_oid__fromraw(&base_oid, base_info, GIT_OID_SHA1);
 
 		/* If we have the cooperative cache, search in it first */
 		if (p->has_cache) {
@@ -1025,7 +1025,7 @@ int get_delta_base(
 		}
 
 		/* The base entry _must_ be in the same pack */
-		if (pack_entry_find_offset(&base_offset, &unused, p, &base_oid, GIT_OID_HEXSZ) < 0)
+		if (pack_entry_find_offset(&base_offset, &unused, p, &base_oid, GIT_OID_SHA1_HEXSIZE) < 0)
 			return packfile_error("base entry delta is not in the same pack");
 		*curpos += 20;
 	} else
@@ -1083,7 +1083,7 @@ static int packfile_open_locked(struct git_pack_file *p)
 {
 	struct stat st;
 	struct git_pack_header hdr;
-	unsigned char sha1[GIT_OID_RAWSZ];
+	unsigned char sha1[GIT_OID_SHA1_SIZE];
 	unsigned char *idx_sha1;
 
 	if (pack_index_open_locked(p) < 0)
@@ -1131,12 +1131,12 @@ static int packfile_open_locked(struct git_pack_file *p)
 
 	/* Verify the pack matches its index. */
 	if (p->num_objects != ntohl(hdr.hdr_entries) ||
-	    p_pread(p->mwf.fd, sha1, GIT_OID_RAWSZ, p->mwf.size - GIT_OID_RAWSZ) < 0)
+	    p_pread(p->mwf.fd, sha1, GIT_OID_SHA1_SIZE, p->mwf.size - GIT_OID_SHA1_SIZE) < 0)
 		goto cleanup;
 
 	idx_sha1 = ((unsigned char *)p->index_map.data) + p->index_map.len - 40;
 
-	if (git_oid_raw_cmp(sha1, idx_sha1) != 0)
+	if (git_oid_raw_cmp(sha1, idx_sha1, GIT_OID_SHA1_SIZE) != 0)
 		goto cleanup;
 
 	if (git_mwindow_file_register(&p->mwf) < 0)
@@ -1362,7 +1362,7 @@ int git_pack_foreach_entry(
 			git_array_clear(oids);
 			GIT_ERROR_CHECK_ALLOC(oid);
 		}
-		git_oid_fromraw(oid, p->oids[i]);
+		git_oid__fromraw(oid, p->oids[i], GIT_OID_SHA1);
 	}
 
 	git_mutex_unlock(&p->lock);
@@ -1428,7 +1428,7 @@ int git_pack_foreach_entry_offset(
 						ntohl(*((uint32_t *)(large_offset_ptr + 4)));
 			}
 
-			git_oid_fromraw(&current_oid, (index + 20 * i));
+			git_oid__fromraw(&current_oid, (index + 20 * i), GIT_OID_SHA1);
 			if ((error = cb(&current_oid, current_offset, data)) != 0) {
 				error = git_error_set_after_callback(error);
 				goto cleanup;
@@ -1437,7 +1437,7 @@ int git_pack_foreach_entry_offset(
 	} else {
 		for (i = 0; i < p->num_objects; i++) {
 			current_offset = ntohl(*(const uint32_t *)(index + 24 * i));
-			git_oid_fromraw(&current_oid, (index + 24 * i + 4));
+			git_oid__fromraw(&current_oid, (index + 24 * i + 4), GIT_OID_SHA1);
 			if ((error = cb(&current_oid, current_offset, data)) != 0) {
 				error = git_error_set_after_callback(error);
 				goto cleanup;
@@ -1457,7 +1457,7 @@ int git_pack__lookup_sha1(const void *oid_lookup_table, size_t stride, unsigned
 
 	while (lo < hi) {
 		unsigned mi = (lo + hi) / 2;
-		int cmp = git_oid_raw_cmp(base + mi * stride, oid_prefix);
+		int cmp = git_oid_raw_cmp(base + mi * stride, oid_prefix, GIT_OID_SHA1_SIZE);
 
 		if (!cmp)
 			return mi;
@@ -1541,7 +1541,7 @@ static int pack_entry_find_offset(
 		}
 	}
 
-	if (found && len != GIT_OID_HEXSZ && pos + 1 < (int)p->num_objects) {
+	if (found && len != GIT_OID_SHA1_HEXSIZE && pos + 1 < (int)p->num_objects) {
 		/* Check for ambiguousity */
 		const unsigned char *next = current + stride;
 
@@ -1566,13 +1566,13 @@ static int pack_entry_find_offset(
 	}
 
 	*offset_out = offset;
-	git_oid_fromraw(found_oid, current);
+	git_oid__fromraw(found_oid, current, GIT_OID_SHA1);
 
 #ifdef INDEX_DEBUG_LOOKUP
 	{
-		unsigned char hex_sha1[GIT_OID_HEXSZ + 1];
+		unsigned char hex_sha1[GIT_OID_SHA1_HEXSIZE + 1];
 		git_oid_fmt(hex_sha1, found_oid);
-		hex_sha1[GIT_OID_HEXSZ] = '\0';
+		hex_sha1[GIT_OID_SHA1_HEXSIZE] = '\0';
 		printf("found lo=%d %s\n", lo, hex_sha1);
 	}
 #endif
@@ -1594,7 +1594,7 @@ int git_pack_entry_find(
 
 	GIT_ASSERT_ARG(p);
 
-	if (len == GIT_OID_HEXSZ && p->num_bad_objects) {
+	if (len == GIT_OID_SHA1_HEXSIZE && p->num_bad_objects) {
 		unsigned i;
 		for (i = 0; i < p->num_bad_objects; i++)
 			if (git_oid__cmp(short_oid, &p->bad_object_sha1[i]) == 0)
diff --git a/src/libgit2/parse.c b/src/libgit2/parse.c
index 0a10758bf..55d3cb10e 100644
--- a/src/libgit2/parse.c
+++ b/src/libgit2/parse.c
@@ -5,6 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 #include "parse.h"
+#include "oid.h"
 
 int git_parse_ctx_init(git_parse_ctx *ctx, const char *content, size_t content_len)
 {
@@ -103,11 +104,11 @@ int git_parse_advance_digit(int64_t *out, git_parse_ctx *ctx, int base)
 
 int git_parse_advance_oid(git_oid *out, git_parse_ctx *ctx)
 {
-	if (ctx->line_len < GIT_OID_HEXSZ)
+	if (ctx->line_len < GIT_OID_SHA1_HEXSIZE)
 		return -1;
-	if ((git_oid_fromstrn(out, ctx->line, GIT_OID_HEXSZ)) < 0)
+	if ((git_oid__fromstrn(out, ctx->line, GIT_OID_SHA1_HEXSIZE, GIT_OID_SHA1)) < 0)
 		return -1;
-	git_parse_advance_chars(ctx, GIT_OID_HEXSZ);
+	git_parse_advance_chars(ctx, GIT_OID_SHA1_HEXSIZE);
 	return 0;
 }
 
diff --git a/src/libgit2/patch_parse.c b/src/libgit2/patch_parse.c
index 78cd96252..ffdb99231 100644
--- a/src/libgit2/patch_parse.c
+++ b/src/libgit2/patch_parse.c
@@ -168,13 +168,13 @@ static int parse_header_oid(
 {
 	size_t len;
 
-	for (len = 0; len < ctx->parse_ctx.line_len && len < GIT_OID_HEXSZ; len++) {
+	for (len = 0; len < ctx->parse_ctx.line_len && len < GIT_OID_SHA1_HEXSIZE; len++) {
 		if (!git__isxdigit(ctx->parse_ctx.line[len]))
 			break;
 	}
 
-	if (len < GIT_OID_MINPREFIXLEN || len > GIT_OID_HEXSZ ||
-		git_oid_fromstrn(oid, ctx->parse_ctx.line, len) < 0)
+	if (len < GIT_OID_MINPREFIXLEN || len > GIT_OID_SHA1_HEXSIZE ||
+		git_oid__fromstrn(oid, ctx->parse_ctx.line, len, GIT_OID_SHA1) < 0)
 		return git_parse_err("invalid hex formatted object id at line %"PRIuZ,
 			ctx->parse_ctx.line_num);
 
@@ -1065,12 +1065,12 @@ static int check_patch(git_patch_parsed *patch)
 		return git_parse_err("patch with no hunks");
 
 	if (delta->status == GIT_DELTA_ADDED) {
-		memset(&delta->old_file.id, 0x0, sizeof(git_oid));
+		git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
 		delta->old_file.id_abbrev = 0;
 	}
 
 	if (delta->status == GIT_DELTA_DELETED) {
-		memset(&delta->new_file.id, 0x0, sizeof(git_oid));
+		git_oid_clear(&delta->new_file.id, GIT_OID_SHA1);
 		delta->new_file.id_abbrev = 0;
 	}
 
diff --git a/src/libgit2/push.c b/src/libgit2/push.c
index da8aebadd..d477b4f0d 100644
--- a/src/libgit2/push.c
+++ b/src/libgit2/push.c
@@ -118,6 +118,9 @@ static int parse_refspec(git_push *push, push_spec **spec, const char *str)
 	s = git__calloc(1, sizeof(*s));
 	GIT_ERROR_CHECK_ALLOC(s);
 
+	git_oid_clear(&s->loid, GIT_OID_SHA1);
+	git_oid_clear(&s->roid, GIT_OID_SHA1);
+
 	if (git_refspec__parse(&s->refspec, str, false) < 0) {
 		git_error_set(GIT_ERROR_INVALID, "invalid refspec %s", str);
 		goto on_error;
diff --git a/src/libgit2/reader.c b/src/libgit2/reader.c
index ba9775240..be29bb41c 100644
--- a/src/libgit2/reader.c
+++ b/src/libgit2/reader.c
@@ -125,7 +125,7 @@ static int workdir_reader_read(
 		goto done;
 
 	if (out_id || reader->index) {
-		if ((error = git_odb_hash(&id, out->ptr, out->size, GIT_OBJECT_BLOB)) < 0)
+		if ((error = git_odb__hash(&id, out->ptr, out->size, GIT_OBJECT_BLOB, GIT_OID_SHA1)) < 0)
 			goto done;
 	}
 
diff --git a/src/libgit2/rebase.c b/src/libgit2/rebase.c
index 5e48f0dfb..1970d5ddc 100644
--- a/src/libgit2/rebase.c
+++ b/src/libgit2/rebase.c
@@ -181,7 +181,8 @@ GIT_INLINE(int) rebase_readoid(
 	if ((error = rebase_readfile(str_out, state_path, filename)) < 0)
 		return error;
 
-	if (str_out->size != GIT_OID_HEXSZ || git_oid_fromstr(out, str_out->ptr) < 0) {
+	if (str_out->size != GIT_OID_SHA1_HEXSIZE ||
+	    git_oid__fromstr(out, str_out->ptr, GIT_OID_SHA1) < 0) {
 		git_error_set(GIT_ERROR_REBASE, "the file '%s' contains an invalid object ID", filename);
 		return -1;
 	}
@@ -363,7 +364,7 @@ int git_rebase_open(
 
 	git_str_rtrim(&orig_head_id);
 
-	if ((error = git_oid_fromstr(&rebase->orig_head_id, orig_head_id.ptr)) < 0)
+	if ((error = git_oid__fromstr(&rebase->orig_head_id, orig_head_id.ptr, GIT_OID_SHA1)) < 0)
 		goto done;
 
 	git_str_truncate(&path, state_path_len);
@@ -374,7 +375,7 @@ int git_rebase_open(
 
 	git_str_rtrim(&onto_id);
 
-	if ((error = git_oid_fromstr(&rebase->onto_id, onto_id.ptr)) < 0)
+	if ((error = git_oid__fromstr(&rebase->onto_id, onto_id.ptr, GIT_OID_SHA1)) < 0)
 		goto done;
 
 	if (!rebase->head_detached)
@@ -452,7 +453,7 @@ static const char *rebase_onto_name(const git_annotated_commit *onto)
 static int rebase_setupfiles_merge(git_rebase *rebase)
 {
 	git_str commit_filename = GIT_STR_INIT;
-	char id_str[GIT_OID_HEXSZ];
+	char id_str[GIT_OID_SHA1_HEXSIZE];
 	git_rebase_operation *operation;
 	size_t i;
 	int error = 0;
@@ -470,7 +471,7 @@ static int rebase_setupfiles_merge(git_rebase *rebase)
 		git_oid_fmt(id_str, &operation->id);
 
 		if ((error = rebase_setupfile(rebase, commit_filename.ptr, 0,
-				"%.*s\n", GIT_OID_HEXSZ, id_str)) < 0)
+				"%.*s\n", GIT_OID_SHA1_HEXSIZE, id_str)) < 0)
 			goto done;
 	}
 
@@ -481,7 +482,7 @@ done:
 
 static int rebase_setupfiles(git_rebase *rebase)
 {
-	char onto[GIT_OID_HEXSZ], orig_head[GIT_OID_HEXSZ];
+	char onto[GIT_OID_SHA1_HEXSIZE], orig_head[GIT_OID_SHA1_HEXSIZE];
 	const char *orig_head_name;
 
 	git_oid_fmt(onto, &rebase->onto_id);
@@ -497,8 +498,8 @@ static int rebase_setupfiles(git_rebase *rebase)
 
 	if (git_repository__set_orig_head(rebase->repo, &rebase->orig_head_id) < 0 ||
 		rebase_setupfile(rebase, HEAD_NAME_FILE, 0, "%s\n", orig_head_name) < 0 ||
-		rebase_setupfile(rebase, ONTO_FILE, 0, "%.*s\n", GIT_OID_HEXSZ, onto) < 0 ||
-		rebase_setupfile(rebase, ORIG_HEAD_FILE, 0, "%.*s\n", GIT_OID_HEXSZ, orig_head) < 0 ||
+		rebase_setupfile(rebase, ONTO_FILE, 0, "%.*s\n", GIT_OID_SHA1_HEXSIZE, onto) < 0 ||
+		rebase_setupfile(rebase, ORIG_HEAD_FILE, 0, "%.*s\n", GIT_OID_SHA1_HEXSIZE, orig_head) < 0 ||
 		rebase_setupfile(rebase, QUIET_FILE, 0, rebase->quiet ? "t\n" : "\n") < 0)
 		return -1;
 
@@ -813,7 +814,7 @@ static int rebase_next_merge(
 	git_indexwriter indexwriter = GIT_INDEXWRITER_INIT;
 	git_rebase_operation *operation;
 	git_checkout_options checkout_opts;
-	char current_idstr[GIT_OID_HEXSZ];
+	char current_idstr[GIT_OID_SHA1_HEXSIZE];
 	unsigned int parent_count;
 	int error;
 
@@ -842,7 +843,7 @@ static int rebase_next_merge(
 
 	if ((error = git_indexwriter_init_for_operation(&indexwriter, rebase->repo, &checkout_opts.checkout_strategy)) < 0 ||
 		(error = rebase_setupfile(rebase, MSGNUM_FILE, 0, "%" PRIuZ "\n", rebase->current+1)) < 0 ||
-		(error = rebase_setupfile(rebase, CURRENT_FILE, 0, "%.*s\n", GIT_OID_HEXSZ, current_idstr)) < 0 ||
+		(error = rebase_setupfile(rebase, CURRENT_FILE, 0, "%.*s\n", GIT_OID_SHA1_HEXSIZE, current_idstr)) < 0 ||
 		(error = git_merge_trees(&index, rebase->repo, parent_tree, head_tree, current_tree, &rebase->options.merge_options)) < 0 ||
 		(error = git_merge__check_result(rebase->repo, index)) < 0 ||
 		(error = git_checkout_index(rebase->repo, index, &checkout_opts)) < 0 ||
@@ -1102,7 +1103,7 @@ static int rebase_commit_merge(
 	git_reference *head = NULL;
 	git_commit *head_commit = NULL, *commit = NULL;
 	git_index *index = NULL;
-	char old_idstr[GIT_OID_HEXSZ], new_idstr[GIT_OID_HEXSZ];
+	char old_idstr[GIT_OID_SHA1_HEXSIZE], new_idstr[GIT_OID_SHA1_HEXSIZE];
 	int error;
 
 	operation = git_array_get(rebase->operations, rebase->current);
@@ -1122,7 +1123,7 @@ static int rebase_commit_merge(
 	git_oid_fmt(new_idstr, git_commit_id(commit));
 
 	if ((error = rebase_setupfile(rebase, REWRITTEN_FILE, O_CREAT|O_WRONLY|O_APPEND,
-		"%.*s %.*s\n", GIT_OID_HEXSZ, old_idstr, GIT_OID_HEXSZ, new_idstr)) < 0)
+		"%.*s %.*s\n", GIT_OID_SHA1_HEXSIZE, old_idstr, GIT_OID_SHA1_HEXSIZE, new_idstr)) < 0)
 		goto done;
 
 	git_oid_cpy(commit_id, git_commit_id(commit));
@@ -1341,10 +1342,10 @@ static int rebase_copy_notes(
 		tostr = end+1;
 		*end = '\0';
 
-		if (strlen(fromstr) != GIT_OID_HEXSZ ||
-			strlen(tostr) != GIT_OID_HEXSZ ||
-			git_oid_fromstr(&from, fromstr) < 0 ||
-			git_oid_fromstr(&to, tostr) < 0)
+		if (strlen(fromstr) != GIT_OID_SHA1_HEXSIZE ||
+			strlen(tostr) != GIT_OID_SHA1_HEXSIZE ||
+			git_oid__fromstr(&from, fromstr, GIT_OID_SHA1) < 0 ||
+			git_oid__fromstr(&to, tostr, GIT_OID_SHA1) < 0)
 			goto on_error;
 
 		if ((error = rebase_copy_note(rebase, notes_ref.ptr, &from, &to, committer)) < 0)
@@ -1372,14 +1373,14 @@ static int return_to_orig_head(git_rebase *rebase)
 	git_reference *terminal_ref = NULL, *branch_ref = NULL, *head_ref = NULL;
 	git_commit *terminal_commit = NULL;
 	git_str branch_msg = GIT_STR_INIT, head_msg = GIT_STR_INIT;
-	char onto[GIT_OID_HEXSZ];
+	char onto[GIT_OID_SHA1_HEXSIZE];
 	int error = 0;
 
 	git_oid_fmt(onto, &rebase->onto_id);
 
 	if ((error = git_str_printf(&branch_msg,
 			"rebase finished: %s onto %.*s",
-			rebase->orig_head_name, GIT_OID_HEXSZ, onto)) == 0 &&
+			rebase->orig_head_name, GIT_OID_SHA1_HEXSIZE, onto)) == 0 &&
 		(error = git_str_printf(&head_msg,
 			"rebase finished: returning to %s",
 			rebase->orig_head_name)) == 0 &&
diff --git a/src/libgit2/refdb_fs.c b/src/libgit2/refdb_fs.c
index 0f49b16bb..43283b3e4 100644
--- a/src/libgit2/refdb_fs.c
+++ b/src/libgit2/refdb_fs.c
@@ -158,9 +158,9 @@ static int packed_reload(refdb_fs_backend *backend)
 
 		/* parse "<OID> <refname>\n" */
 
-		if (git_oid_fromstr(&oid, scan) < 0)
+		if (git_oid__fromstr(&oid, scan, GIT_OID_SHA1) < 0)
 			goto parse_failed;
-		scan += GIT_OID_HEXSZ;
+		scan += GIT_OID_SHA1_HEXSIZE;
 
 		if (*scan++ != ' ')
 			goto parse_failed;
@@ -179,9 +179,9 @@ static int packed_reload(refdb_fs_backend *backend)
 		/* look for optional "^<OID>\n" */
 
 		if (*scan == '^') {
-			if (git_oid_fromstr(&oid, scan + 1) < 0)
+			if (git_oid__fromstr(&oid, scan + 1, GIT_OID_SHA1) < 0)
 				goto parse_failed;
-			scan += GIT_OID_HEXSZ + 1;
+			scan += GIT_OID_SHA1_HEXSIZE + 1;
 
 			if (scan < eof) {
 				if (!(eol = strchr(scan, '\n')))
@@ -218,15 +218,15 @@ static int loose_parse_oid(
 {
 	const char *str = git_str_cstr(file_content);
 
-	if (git_str_len(file_content) < GIT_OID_HEXSZ)
+	if (git_str_len(file_content) < GIT_OID_SHA1_HEXSIZE)
 		goto corrupted;
 
 	/* we need to get 40 OID characters from the file */
-	if (git_oid_fromstr(oid, str) < 0)
+	if (git_oid__fromstr(oid, str, GIT_OID_SHA1) < 0)
 		goto corrupted;
 
 	/* If the file is longer than 40 chars, the 41st must be a space */
-	str += GIT_OID_HEXSZ;
+	str += GIT_OID_SHA1_HEXSIZE;
 	if (*str == '\0' || git__isspace(*str))
 		return 0;
 
@@ -622,12 +622,12 @@ cmp_record_to_refname(const char *rec, size_t data_end, const char *ref_name)
 	int cmp_val;
 	const char *end;
 
-	rec += GIT_OID_HEXSZ + 1; /* <oid> + space */
-	if (data_end < GIT_OID_HEXSZ + 3) {
+	rec += GIT_OID_SHA1_HEXSIZE + 1; /* <oid> + space */
+	if (data_end < GIT_OID_SHA1_HEXSIZE + 3) {
 		/* an incomplete (corrupt) record is treated as less than ref_name */
 		return -1;
 	}
-	data_end -= GIT_OID_HEXSZ + 1;
+	data_end -= GIT_OID_SHA1_HEXSIZE + 1;
 
 	end = memchr(rec, '\n', data_end);
 	if (end)
@@ -708,11 +708,11 @@ static int packed_lookup(
 			const char *eol;
 			git_oid oid, peel, *peel_ptr = NULL;
 
-			if (data_end - rec < GIT_OID_HEXSZ ||
-			    git_oid_fromstr(&oid, rec) < 0) {
+			if (data_end - rec < GIT_OID_SHA1_HEXSIZE ||
+			    git_oid__fromstr(&oid, rec, GIT_OID_SHA1) < 0) {
 				goto parse_failed;
 			}
-			rec += GIT_OID_HEXSZ + 1;
+			rec += GIT_OID_SHA1_HEXSIZE + 1;
 			if (!(eol = memchr(rec, '\n', data_end - rec))) {
 				goto parse_failed;
 			}
@@ -724,8 +724,8 @@ static int packed_lookup(
 
 				if (*rec == '^') {
 					rec++;
-					if (data_end - rec < GIT_OID_HEXSZ ||
-						git_oid_fromstr(&peel, rec) < 0) {
+					if (data_end - rec < GIT_OID_SHA1_HEXSIZE ||
+						git_oid__fromstr(&peel, rec, GIT_OID_SHA1) < 0) {
 						goto parse_failed;
 					}
 					peel_ptr = &peel;
@@ -1108,7 +1108,7 @@ static int loose_commit(git_filebuf *file, const git_reference *ref)
 	GIT_ASSERT_ARG(ref);
 
 	if (ref->type == GIT_REFERENCE_DIRECT) {
-		char oid[GIT_OID_HEXSZ + 1];
+		char oid[GIT_OID_SHA1_HEXSIZE + 1];
 		git_oid_nfmt(oid, sizeof(oid), &ref->target.oid);
 
 		git_filebuf_printf(file, "%s\n", oid);
@@ -1224,7 +1224,7 @@ static int packed_find_peel(refdb_fs_backend *backend, struct packref *ref)
  */
 static int packed_write_ref(struct packref *ref, git_filebuf *file)
 {
-	char oid[GIT_OID_HEXSZ + 1];
+	char oid[GIT_OID_SHA1_HEXSIZE + 1];
 	git_oid_nfmt(oid, sizeof(oid), &ref->oid);
 
 	/*
@@ -1238,7 +1238,7 @@ static int packed_write_ref(struct packref *ref, git_filebuf *file)
 	 * The required peels have already been loaded into `ref->peel_target`.
 	 */
 	if (ref->flags & PACKREF_HAS_PEEL) {
-		char peel[GIT_OID_HEXSZ + 1];
+		char peel[GIT_OID_SHA1_HEXSIZE + 1];
 		git_oid_nfmt(peel, sizeof(peel), &ref->peel);
 
 		if (git_filebuf_printf(file, "%s %s\n^%s\n", oid, ref->name, peel) < 0)
@@ -2086,11 +2086,11 @@ static int serialize_reflog_entry(
 	const git_signature *committer,
 	const char *msg)
 {
-	char raw_old[GIT_OID_HEXSZ+1];
-	char raw_new[GIT_OID_HEXSZ+1];
+	char raw_old[GIT_OID_SHA1_HEXSIZE+1];
+	char raw_new[GIT_OID_SHA1_HEXSIZE+1];
 
-	git_oid_tostr(raw_old, GIT_OID_HEXSZ+1, oid_old);
-	git_oid_tostr(raw_new, GIT_OID_HEXSZ+1, oid_new);
+	git_oid_tostr(raw_old, GIT_OID_SHA1_HEXSIZE+1, oid_old);
+	git_oid_tostr(raw_new, GIT_OID_SHA1_HEXSIZE+1, oid_new);
 
 	git_str_clear(buf);
 
@@ -2192,7 +2192,7 @@ success:
 static int reflog_append(refdb_fs_backend *backend, const git_reference *ref, const git_oid *old, const git_oid *new, const git_signature *who, const char *message)
 {
 	int error, is_symbolic, open_flags;
-	git_oid old_id = {{0}}, new_id = {{0}};
+	git_oid old_id = GIT_OID_SHA1_ZERO, new_id = GIT_OID_SHA1_ZERO;
 	git_str buf = GIT_STR_INIT, path = GIT_STR_INIT;
 	git_repository *repo = backend->repo;
 
diff --git a/src/libgit2/reflog.c b/src/libgit2/reflog.c
index 1e9c0d4f1..eb0b7e48c 100644
--- a/src/libgit2/reflog.c
+++ b/src/libgit2/reflog.c
@@ -104,7 +104,7 @@ int git_reflog_append(git_reflog *reflog, const git_oid *new_oid, const git_sign
 	previous = git_reflog_entry_byindex(reflog, 0);
 
 	if (previous == NULL)
-		git_oid_fromstr(&entry->oid_old, GIT_OID_HEX_ZERO);
+		git_oid__fromstr(&entry->oid_old, GIT_OID_SHA1_HEXZERO, GIT_OID_SHA1);
 	else
 		git_oid_cpy(&entry->oid_old, &previous->oid_cur);
 
@@ -218,8 +218,10 @@ int git_reflog_drop(git_reflog *reflog, size_t idx, int rewrite_previous_entry)
 
 	/* If the oldest entry has just been removed... */
 	if (idx == entrycount - 1) {
+		git_oid zero = GIT_OID_SHA1_ZERO;
+
 		/* ...clear the oid_old member of the "new" oldest entry */
-		if (git_oid_fromstr(&entry->oid_old, GIT_OID_HEX_ZERO) < 0)
+		if (git_oid_cpy(&entry->oid_old, &zero) < 0)
 			return -1;
 
 		return 0;
diff --git a/src/libgit2/reflog.h b/src/libgit2/reflog.h
index 8c3895952..50d1056ed 100644
--- a/src/libgit2/reflog.h
+++ b/src/libgit2/reflog.h
@@ -16,7 +16,7 @@
 #define GIT_REFLOG_DIR_MODE 0777
 #define GIT_REFLOG_FILE_MODE 0666
 
-#define GIT_REFLOG_SIZE_MIN (2*GIT_OID_HEXSZ+2+17)
+#define GIT_REFLOG_SIZE_MIN (2*GIT_OID_SHA1_HEXSIZE+2+17)
 
 struct git_reflog_entry {
 	git_oid oid_old;
diff --git a/src/libgit2/refs.c b/src/libgit2/refs.c
index 5c875b95b..8e4abaccc 100644
--- a/src/libgit2/refs.c
+++ b/src/libgit2/refs.c
@@ -86,6 +86,8 @@ git_reference *git_reference__alloc(
 
 	if (peel != NULL)
 		git_oid_cpy(&ref->peel, peel);
+	else
+		git_oid_clear(&ref->peel, GIT_OID_SHA1);
 
 	return ref;
 }
diff --git a/src/libgit2/remote.c b/src/libgit2/remote.c
index 3d0593712..02d271d7d 100644
--- a/src/libgit2/remote.c
+++ b/src/libgit2/remote.c
@@ -1622,7 +1622,7 @@ int git_remote_prune(git_remote *remote, const git_remote_callbacks *callbacks)
 	const git_refspec *spec;
 	const char *refname;
 	int error;
-	git_oid zero_id = {{ 0 }};
+	git_oid zero_id = GIT_OID_SHA1_ZERO;
 
 	if (callbacks)
 		GIT_ERROR_CHECK_VERSION(callbacks, GIT_REMOTE_CALLBACKS_VERSION, "git_remote_callbacks");
@@ -1830,7 +1830,7 @@ static int update_one_tip(
 	}
 
 	if (error == GIT_ENOTFOUND) {
-		memset(&old, 0, sizeof(git_oid));
+		git_oid_clear(&old, GIT_OID_SHA1);
 		error = 0;
 
 		if (autotag && (error = git_vector_insert(update_heads, head)) < 0)
@@ -1892,10 +1892,10 @@ static int update_tips_for_spec(
 	}
 
 	/* Handle specified oid sources */
-	if (git_oid__is_hexstr(spec->src)) {
+	if (git_oid__is_hexstr(spec->src, GIT_OID_SHA1)) {
 		git_oid id;
 
-		if ((error = git_oid_fromstr(&id, spec->src)) < 0)
+		if ((error = git_oid__fromstr(&id, spec->src, GIT_OID_SHA1)) < 0)
 			goto on_error;
 
 		if (spec->dst &&
diff --git a/src/libgit2/repository.c b/src/libgit2/repository.c
index 809617276..761772d55 100644
--- a/src/libgit2/repository.c
+++ b/src/libgit2/repository.c
@@ -243,7 +243,7 @@ GIT_INLINE(int) validate_repo_path(git_str *path)
 	 */
 	static size_t suffix_len =
 		CONST_STRLEN("objects/pack/pack-.pack.lock") +
-		GIT_OID_HEXSZ;
+		GIT_OID_SHA1_HEXSIZE;
 
 	return git_fs_path_validate_str_length_with_suffix(
 		path, suffix_len);
@@ -867,7 +867,7 @@ static int _git_repository_open_ext_from_env(
 	else if (error < 0)
 		goto error;
 	else {
-		error = git_odb_open(&odb, git_str_cstr(&object_dir_buf));
+		error = git_odb__open(&odb, git_str_cstr(&object_dir_buf), NULL);
 		if (error < 0)
 			goto error;
 	}
@@ -1295,7 +1295,7 @@ int git_repository_odb__weakptr(git_odb **out, git_repository *repo)
 
 		if ((error = git_repository__item_path(&odb_path, repo,
 				GIT_REPOSITORY_ITEM_OBJECTS)) < 0 ||
-			(error = git_odb_new(&odb)) < 0)
+			(error = git_odb__new(&odb, NULL)) < 0)
 			return error;
 
 		GIT_REFCOUNT_OWN(odb, repo);
@@ -2958,14 +2958,14 @@ int git_repository__set_orig_head(git_repository *repo, const git_oid *orig_head
 {
 	git_filebuf file = GIT_FILEBUF_INIT;
 	git_str file_path = GIT_STR_INIT;
-	char orig_head_str[GIT_OID_HEXSZ];
+	char orig_head_str[GIT_OID_SHA1_HEXSIZE];
 	int error = 0;
 
 	git_oid_fmt(orig_head_str, orig_head);
 
 	if ((error = git_str_joinpath(&file_path, repo->gitdir, GIT_ORIG_HEAD_FILE)) == 0 &&
 		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_CREATE_LEADING_DIRS, GIT_MERGE_FILE_MODE)) == 0 &&
-		(error = git_filebuf_printf(&file, "%.*s\n", GIT_OID_HEXSZ, orig_head_str)) == 0)
+		(error = git_filebuf_printf(&file, "%.*s\n", GIT_OID_SHA1_HEXSIZE, orig_head_str)) == 0)
 		error = git_filebuf_commit(&file);
 
 	if (error < 0)
@@ -3078,7 +3078,7 @@ int git_repository_hashfile(
 		goto cleanup;
 	}
 
-	error = git_odb__hashfd_filtered(out, fd, (size_t)len, type, fl);
+	error = git_odb__hashfd_filtered(out, fd, (size_t)len, type, GIT_OID_SHA1, fl);
 
 cleanup:
 	if (fd >= 0)
diff --git a/src/libgit2/reset.c b/src/libgit2/reset.c
index e0d942e5e..9574819cb 100644
--- a/src/libgit2/reset.c
+++ b/src/libgit2/reset.c
@@ -188,9 +188,9 @@ int git_reset(
 	git_reset_t reset_type,
 	const git_checkout_options *checkout_opts)
 {
-	char to[GIT_OID_HEXSZ + 1];
+	char to[GIT_OID_SHA1_HEXSIZE + 1];
 
-	git_oid_tostr(to, GIT_OID_HEXSZ + 1, git_object_id(target));
+	git_oid_tostr(to, GIT_OID_SHA1_HEXSIZE + 1, git_object_id(target));
 	return reset(repo, target, to, reset_type, checkout_opts);
 }
 
diff --git a/src/libgit2/revert.c b/src/libgit2/revert.c
index d6ab6ae3c..1106dfe2f 100644
--- a/src/libgit2/revert.c
+++ b/src/libgit2/revert.c
@@ -107,10 +107,10 @@ static int revert_state_cleanup(git_repository *repo)
 
 static int revert_seterr(git_commit *commit, const char *fmt)
 {
-	char commit_oidstr[GIT_OID_HEXSZ + 1];
+	char commit_oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 
 	git_oid_fmt(commit_oidstr, git_commit_id(commit));
-	commit_oidstr[GIT_OID_HEXSZ] = '\0';
+	commit_oidstr[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	git_error_set(GIT_ERROR_REVERT, fmt, commit_oidstr);
 
@@ -176,7 +176,7 @@ int git_revert(
 	git_revert_options opts;
 	git_reference *our_ref = NULL;
 	git_commit *our_commit = NULL;
-	char commit_oidstr[GIT_OID_HEXSZ + 1];
+	char commit_oidstr[GIT_OID_SHA1_HEXSIZE + 1];
 	const char *commit_msg;
 	git_str their_label = GIT_STR_INIT;
 	git_index *index = NULL;
@@ -192,7 +192,7 @@ int git_revert(
 		return error;
 
 	git_oid_fmt(commit_oidstr, git_commit_id(commit));
-	commit_oidstr[GIT_OID_HEXSZ] = '\0';
+	commit_oidstr[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	if ((commit_msg = git_commit_summary(commit)) == NULL) {
 		error = -1;
diff --git a/src/libgit2/revparse.c b/src/libgit2/revparse.c
index 9bc28e9fc..2ed282159 100644
--- a/src/libgit2/revparse.c
+++ b/src/libgit2/revparse.c
@@ -19,7 +19,7 @@ static int maybe_sha_or_abbrev(git_object **out, git_repository *repo, const cha
 {
 	git_oid oid;
 
-	if (git_oid_fromstrn(&oid, spec, speclen) < 0)
+	if (git_oid__fromstrn(&oid, spec, speclen, GIT_OID_SHA1) < 0)
 		return GIT_ENOTFOUND;
 
 	return git_object_lookup_prefix(out, repo, &oid, speclen, GIT_OBJECT_ANY);
@@ -29,7 +29,7 @@ static int maybe_sha(git_object **out, git_repository *repo, const char *spec)
 {
 	size_t speclen = strlen(spec);
 
-	if (speclen != GIT_OID_HEXSZ)
+	if (speclen != GIT_OID_SHA1_HEXSIZE)
 		return GIT_ENOTFOUND;
 
 	return maybe_sha_or_abbrev(out, repo, spec, speclen);
@@ -110,7 +110,7 @@ static int revparse_lookup_object(
 	if (error != GIT_ENOTFOUND)
 		return error;
 
-	if ((strlen(spec) < GIT_OID_HEXSZ) &&
+	if ((strlen(spec) < GIT_OID_SHA1_HEXSIZE) &&
 		((error = maybe_abbrev(object_out, repo, spec)) != GIT_ENOTFOUND))
 			return error;
 
diff --git a/src/libgit2/tag.c b/src/libgit2/tag.c
index 792155a4b..908adbebf 100644
--- a/src/libgit2/tag.c
+++ b/src/libgit2/tag.c
@@ -75,7 +75,8 @@ static int tag_parse(git_tag *tag, const char *buffer, const char *buffer_end)
 	unsigned int i;
 	int error;
 
-	if (git_oid__parse(&tag->target, &buffer, buffer_end, "object ") < 0)
+	if (git_object__parse_oid_header(&tag->target,
+			&buffer, buffer_end, "object ", GIT_OID_SHA1) < 0)
 		return tag_error("object field invalid");
 
 	if (buffer + 5 >= buffer_end)
@@ -220,7 +221,9 @@ static int write_tag_annotation(
 	git_str tag = GIT_STR_INIT;
 	git_odb *odb;
 
-	git_oid__writebuf(&tag, "object ", git_object_id(target));
+	if (git_object__write_oid_header(&tag, "object ", git_object_id(target)) < 0)
+		goto on_error;
+
 	git_str_printf(&tag, "type %s\n", git_object_type2string(git_object_type(target)));
 	git_str_printf(&tag, "tag %s\n", tag_name);
 	git_signature__writebuf(&tag, "tagger ", tagger);
diff --git a/src/libgit2/threadstate.h b/src/libgit2/threadstate.h
index c10f26b59..f9e7ba7bf 100644
--- a/src/libgit2/threadstate.h
+++ b/src/libgit2/threadstate.h
@@ -13,7 +13,7 @@ typedef struct {
 	git_error *last_error;
 	git_error error_t;
 	git_str error_buf;
-	char oid_fmt[GIT_OID_HEXSZ+1];
+	char oid_fmt[GIT_OID_SHA1_HEXSIZE+1];
 } git_threadstate;
 
 extern int git_threadstate_global_init(void);
diff --git a/src/libgit2/transports/smart_pkt.c b/src/libgit2/transports/smart_pkt.c
index b42edd0d6..e679819fa 100644
--- a/src/libgit2/transports/smart_pkt.c
+++ b/src/libgit2/transports/smart_pkt.c
@@ -12,6 +12,7 @@
 #include "netops.h"
 #include "posix.h"
 #include "str.h"
+#include "oid.h"
 
 #include "git2/types.h"
 #include "git2/errors.h"
@@ -53,10 +54,11 @@ static int ack_pkt(git_pkt **out, const char *line, size_t len)
 	line += 4;
 	len -= 4;
 
-	if (len < GIT_OID_HEXSZ || git_oid_fromstr(&pkt->oid, line) < 0)
+	if (len < GIT_OID_SHA1_HEXSIZE ||
+	    git_oid__fromstr(&pkt->oid, line, GIT_OID_SHA1) < 0)
 		goto out_err;
-	line += GIT_OID_HEXSZ;
-	len -= GIT_OID_HEXSZ;
+	line += GIT_OID_SHA1_HEXSIZE;
+	len -= GIT_OID_SHA1_HEXSIZE;
 
 	if (len && line[0] == ' ') {
 		line++;
@@ -222,10 +224,11 @@ static int ref_pkt(git_pkt **out, const char *line, size_t len)
 	GIT_ERROR_CHECK_ALLOC(pkt);
 	pkt->type = GIT_PKT_REF;
 
-	if (len < GIT_OID_HEXSZ || git_oid_fromstr(&pkt->head.oid, line) < 0)
+	if (len < GIT_OID_SHA1_HEXSIZE ||
+	    git_oid__fromstr(&pkt->head.oid, line, GIT_OID_SHA1) < 0)
 		goto out_err;
-	line += GIT_OID_HEXSZ;
-	len -= GIT_OID_HEXSZ;
+	line += GIT_OID_SHA1_HEXSIZE;
+	len -= GIT_OID_SHA1_HEXSIZE;
 
 	if (git__prefixncmp(line, len, " "))
 		goto out_err;
@@ -530,7 +533,7 @@ int git_pkt_buffer_flush(git_str *buf)
 static int buffer_want_with_caps(const git_remote_head *head, transport_smart_caps *caps, git_str *buf)
 {
 	git_str str = GIT_STR_INIT;
-	char oid[GIT_OID_HEXSZ +1] = {0};
+	char oid[GIT_OID_SHA1_HEXSIZE +1] = {0};
 	size_t len;
 
 	/* Prefer multi_ack_detailed */
@@ -557,7 +560,7 @@ static int buffer_want_with_caps(const git_remote_head *head, transport_smart_ca
 	if (git_str_oom(&str))
 		return -1;
 
-	len = strlen("XXXXwant ") + GIT_OID_HEXSZ + 1 /* NUL */ +
+	len = strlen("XXXXwant ") + GIT_OID_SHA1_HEXSIZE + 1 /* NUL */ +
 		 git_str_len(&str) + 1 /* LF */;
 
 	if (len > 0xffff) {
@@ -605,7 +608,7 @@ int git_pkt_buffer_wants(
 	}
 
 	for (; i < count; ++i) {
-		char oid[GIT_OID_HEXSZ];
+		char oid[GIT_OID_SHA1_HEXSIZE];
 
 		head = refs[i];
 		if (head->local)
@@ -613,7 +616,7 @@ int git_pkt_buffer_wants(
 
 		git_oid_fmt(oid, &head->oid);
 		git_str_put(buf, pkt_want_prefix, strlen(pkt_want_prefix));
-		git_str_put(buf, oid, GIT_OID_HEXSZ);
+		git_str_put(buf, oid, GIT_OID_SHA1_HEXSIZE);
 		git_str_putc(buf, '\n');
 		if (git_str_oom(buf))
 			return -1;
@@ -624,7 +627,7 @@ int git_pkt_buffer_wants(
 
 int git_pkt_buffer_have(git_oid *oid, git_str *buf)
 {
-	char oidhex[GIT_OID_HEXSZ + 1];
+	char oidhex[GIT_OID_SHA1_HEXSIZE + 1];
 
 	memset(oidhex, 0x0, sizeof(oidhex));
 	git_oid_fmt(oidhex, oid);
diff --git a/src/libgit2/transports/smart_protocol.c b/src/libgit2/transports/smart_protocol.c
index 8cf027133..09778b335 100644
--- a/src/libgit2/transports/smart_protocol.c
+++ b/src/libgit2/transports/smart_protocol.c
@@ -643,12 +643,12 @@ static int gen_pktline(git_str *buf, git_push *push)
 {
 	push_spec *spec;
 	size_t i, len;
-	char old_id[GIT_OID_HEXSZ+1], new_id[GIT_OID_HEXSZ+1];
+	char old_id[GIT_OID_SHA1_HEXSIZE+1], new_id[GIT_OID_SHA1_HEXSIZE+1];
 
-	old_id[GIT_OID_HEXSZ] = '\0'; new_id[GIT_OID_HEXSZ] = '\0';
+	old_id[GIT_OID_SHA1_HEXSIZE] = '\0'; new_id[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	git_vector_foreach(&push->specs, i, spec) {
-		len = 2*GIT_OID_HEXSZ + 7 + strlen(spec->refspec.dst);
+		len = 2*GIT_OID_SHA1_HEXSIZE + 7 + strlen(spec->refspec.dst);
 
 		if (i == 0) {
 			++len; /* '\0' */
@@ -1020,7 +1020,7 @@ int git_smart__push(git_transport *transport, git_push *push)
 #ifdef PUSH_DEBUG
 {
 	git_remote_head *head;
-	char hex[GIT_OID_HEXSZ+1]; hex[GIT_OID_HEXSZ] = '\0';
+	char hex[GIT_OID_SHA1_HEXSIZE+1]; hex[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	git_vector_foreach(&push->remote->refs, i, head) {
 		git_oid_fmt(hex, &head->oid);
diff --git a/src/libgit2/tree-cache.c b/src/libgit2/tree-cache.c
index cd69e7bf8..19fad85ae 100644
--- a/src/libgit2/tree-cache.c
+++ b/src/libgit2/tree-cache.c
@@ -111,11 +111,11 @@ static int read_tree_internal(git_tree_cache **out,
 	/* The SHA1 is only there if it's not invalidated */
 	if (tree->entry_count >= 0) {
 		/* 160-bit SHA-1 for this tree and it's children */
-		if (buffer + GIT_OID_RAWSZ > buffer_end)
+		if (buffer + GIT_OID_SHA1_SIZE > buffer_end)
 			goto corrupted;
 
-		git_oid_fromraw(&tree->oid, (const unsigned char *)buffer);
-		buffer += GIT_OID_RAWSZ;
+		git_oid__fromraw(&tree->oid, (const unsigned char *)buffer, GIT_OID_SHA1);
+		buffer += GIT_OID_SHA1_SIZE;
 	}
 
 	/* Parse children: */
@@ -263,7 +263,7 @@ static void write_tree(git_str *out, git_tree_cache *tree)
 	git_str_printf(out, "%s%c%"PRIdZ" %"PRIuZ"\n", tree->name, 0, tree->entry_count, tree->children_count);
 
 	if (tree->entry_count != -1)
-		git_str_put(out, (char *)&tree->oid.id, GIT_OID_RAWSZ);
+		git_str_put(out, (char *)&tree->oid.id, GIT_OID_SHA1_SIZE);
 
 	for (i = 0; i < tree->children_count; i++)
 		write_tree(out, tree->children[i]);
diff --git a/src/libgit2/tree.c b/src/libgit2/tree.c
index a5371fd87..9a43d585c 100644
--- a/src/libgit2/tree.c
+++ b/src/libgit2/tree.c
@@ -89,7 +89,7 @@ static git_tree_entry *alloc_entry(const char *filename, size_t filename_len, co
 
 	if (GIT_ADD_SIZET_OVERFLOW(&tree_len, sizeof(git_tree_entry), filename_len) ||
 	    GIT_ADD_SIZET_OVERFLOW(&tree_len, tree_len, 1) ||
-	    GIT_ADD_SIZET_OVERFLOW(&tree_len, tree_len, GIT_OID_RAWSZ))
+	    GIT_ADD_SIZET_OVERFLOW(&tree_len, tree_len, GIT_OID_SHA1_SIZE))
 		return NULL;
 
 	entry = git__calloc(1, tree_len);
@@ -414,7 +414,7 @@ int git_tree__parse_raw(void *_tree, const char *data, size_t size)
 		if ((filename_len = nul - buffer) == 0 || filename_len > UINT16_MAX)
 			return tree_parse_error("failed to parse tree: can't parse filename", NULL);
 
-		if ((buffer_end - (nul + 1)) < GIT_OID_RAWSZ)
+		if ((buffer_end - (nul + 1)) < GIT_OID_SHA1_SIZE)
 			return tree_parse_error("failed to parse tree: can't parse OID", NULL);
 
 		/* Allocate the entry */
@@ -425,11 +425,11 @@ int git_tree__parse_raw(void *_tree, const char *data, size_t size)
 			entry->attr = attr;
 			entry->filename_len = (uint16_t)filename_len;
 			entry->filename = buffer;
-			git_oid_fromraw(&entry->oid, ((unsigned char *) buffer + filename_len + 1));
+			git_oid__fromraw(&entry->oid, ((unsigned char *) buffer + filename_len + 1), GIT_OID_SHA1);
 		}
 
 		buffer += filename_len + 1;
-		buffer += GIT_OID_RAWSZ;
+		buffer += GIT_OID_SHA1_SIZE;
 	}
 
 	return 0;
@@ -529,7 +529,7 @@ static int git_treebuilder__write_with_buffer(
 
 		git_str_printf(buf, "%o ", entry->attr);
 		git_str_put(buf, entry->filename, entry->filename_len + 1);
-		git_str_put(buf, (char *)entry->oid.id, GIT_OID_RAWSZ);
+		git_str_put(buf, (char *)entry->oid.id, GIT_OID_SHA1_SIZE);
 
 		if (git_str_oom(buf)) {
 			error = -1;
diff --git a/src/util/CMakeLists.txt b/src/util/CMakeLists.txt
index b2833954d..b12ce409b 100644
--- a/src/util/CMakeLists.txt
+++ b/src/util/CMakeLists.txt
@@ -4,8 +4,12 @@ add_library(util OBJECT)
 set_target_properties(util PROPERTIES C_STANDARD 90)
 set_target_properties(util PROPERTIES C_EXTENSIONS OFF)
 
+configure_file(git2_features.h.in git2_features.h)
+
 set(UTIL_INCLUDES
-	"${PROJECT_BINARY_DIR}/src"
+	"${PROJECT_BINARY_DIR}/src/util"
+	"${PROJECT_BINARY_DIR}/include"
+	"${PROJECT_BINARY_DIR}/include/git2"
 	"${PROJECT_SOURCE_DIR}/src/util"
 	"${PROJECT_SOURCE_DIR}/include")
 
diff --git a/src/features.h.in b/src/util/git2_features.h.in
index fbf0cab60..fbf0cab60 100644
--- a/src/features.h.in
+++ b/src/util/git2_features.h.in
diff --git a/src/util/git2_util.h b/src/util/git2_util.h
index ad3f1c71f..c62dc2419 100644
--- a/src/util/git2_util.h
+++ b/src/util/git2_util.h
@@ -7,8 +7,8 @@
 #ifndef INCLUDE_git2_util_h__
 #define INCLUDE_git2_util_h__
 
-#ifndef LIBGIT2_NO_FEATURES_H
-# include "git2/sys/features.h"
+#if !defined(LIBGIT2_NO_FEATURES_H)
+# include "git2_features.h"
 #endif
 
 #include "git2/common.h"
diff --git a/tests/clar/clar_libgit2.h b/tests/clar/clar_libgit2.h
index da3f41524..d2d9da0aa 100644
--- a/tests/clar/clar_libgit2.h
+++ b/tests/clar/clar_libgit2.h
@@ -5,6 +5,7 @@
 #include <git2.h>
 #include "common.h"
 #include "posix.h"
+#include "oid.h"
 
 /**
  * Replace for `clar_must_pass` that passes the last library error as the
@@ -136,13 +137,32 @@ GIT_INLINE(void) clar__assert_equal_oid(
 	const char *file, const char *func, int line, const char *desc,
 	const git_oid *one, const git_oid *two)
 {
-	if (git_oid_cmp(one, two)) {
-		char err[] = "\"........................................\" != \"........................................\"";
 
+	if (git_oid_equal(one, two))
+		return;
+
+	if (git_oid_type(one) != git_oid_type(two)) {
+		char err[64];
+
+		snprintf(err, 64, "different oid types: %d vs %d", git_oid_type(one), git_oid_type(two));
+		clar__fail(file, func, line, desc, err, 1);
+	} else if (git_oid_type(one) == GIT_OID_SHA1) {
+		char err[] = "\"........................................\" != \"........................................\"";
 		git_oid_fmt(&err[1], one);
 		git_oid_fmt(&err[47], two);
 
 		clar__fail(file, func, line, desc, err, 1);
+#ifdef GIT_EXPERIMENTAL_SHA256
+	} else if (one->type == GIT_OID_SHA256) {
+		char err[] = "\"................................................................\" != \"................................................................\"";
+
+		git_oid_fmt(&err[1], one);
+		git_oid_fmt(&err[71], one);
+
+		clar__fail(file, func, line, desc, err, 1);
+#endif
+	} else {
+		clar__fail(file, func, line, desc, "unknown oid types", 1);
 	}
 }
 
diff --git a/tests/libgit2/CMakeLists.txt b/tests/libgit2/CMakeLists.txt
index 27f421ad6..7f6fafe77 100644
--- a/tests/libgit2/CMakeLists.txt
+++ b/tests/libgit2/CMakeLists.txt
@@ -65,7 +65,7 @@ endif()
 
 include(AddClarTest)
 add_clar_test(libgit2_tests offline             -v -xonline)
-add_clar_test(libgit2_tests invasive            -v -score::ftruncate -sfilter::stream::bigfile -sodb::largefiles -siterator::workdir::filesystem_gunk -srepo::init -srepo::init::at_filesystem_root)
+add_clar_test(libgit2_tests invasive            -v -sfilter::stream::bigfile -sodb::largefiles -siterator::workdir::filesystem_gunk -srepo::init -srepo::init::at_filesystem_root)
 add_clar_test(libgit2_tests online              -v -sonline -xonline::customcert)
 add_clar_test(libgit2_tests online_customcert   -v -sonline::customcert)
 add_clar_test(libgit2_tests gitdaemon           -v -sonline::push)
diff --git a/tests/libgit2/apply/apply_helpers.c b/tests/libgit2/apply/apply_helpers.c
index 91cc51a71..e78b8ffcb 100644
--- a/tests/libgit2/apply/apply_helpers.c
+++ b/tests/libgit2/apply/apply_helpers.c
@@ -14,7 +14,7 @@ static int iterator_compare(const git_index_entry *entry, void *_data)
 	struct iterator_compare_data *data = (struct iterator_compare_data *)_data;
 
 	cl_assert_equal_i(GIT_INDEX_ENTRY_STAGE(entry), data->expected[data->idx].stage);
-	cl_git_pass(git_oid_fromstr(&expected_id, data->expected[data->idx].oid_str));
+	cl_git_pass(git_oid__fromstr(&expected_id, data->expected[data->idx].oid_str, GIT_OID_SHA1));
 	cl_assert_equal_oid(&entry->id, &expected_id);
 	cl_assert_equal_i(entry->mode, data->expected[data->idx].mode);
 	cl_assert_equal_s(entry->path, data->expected[data->idx].path);
diff --git a/tests/libgit2/apply/both.c b/tests/libgit2/apply/both.c
index 108963270..1331e7ea4 100644
--- a/tests/libgit2/apply/both.c
+++ b/tests/libgit2/apply/both.c
@@ -12,7 +12,7 @@ void test_apply_both__initialize(void)
 
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
 
-	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
@@ -42,8 +42,8 @@ void test_apply_both__generated_diff(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	git_oid_fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707");
-	git_oid_fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f");
+	git_oid__fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
+	git_oid__fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
 	cl_git_pass(git_commit_lookup(&b_commit, repo, &b_oid));
 
@@ -192,7 +192,7 @@ void test_apply_both__index_must_match_workdir(void)
 	memset(&idx_entry, 0, sizeof(git_index_entry));
 	idx_entry.mode = 0100644;
 	idx_entry.path = "asparagus.txt";
-	cl_git_pass(git_oid_fromstr(&idx_entry.id, "06d3fefb8726ab1099acc76e02dfb85e034b2538"));
+	cl_git_pass(git_oid__fromstr(&idx_entry.id, "06d3fefb8726ab1099acc76e02dfb85e034b2538", GIT_OID_SHA1));
 	cl_git_pass(git_index_add(index, &idx_entry));
 
 	cl_git_pass(git_index_write(index));
@@ -290,7 +290,7 @@ void test_apply_both__keeps_nonconflicting_changes(void)
 	memset(&idx_entry, 0, sizeof(git_index_entry));
 	idx_entry.mode = 0100644;
 	idx_entry.path = "beef.txt";
-	cl_git_pass(git_oid_fromstr(&idx_entry.id, "898d12687fb35be271c27c795a6b32c8b51da79e"));
+	cl_git_pass(git_oid__fromstr(&idx_entry.id, "898d12687fb35be271c27c795a6b32c8b51da79e", GIT_OID_SHA1));
 	cl_git_pass(git_index_add(index, &idx_entry));
 
 	cl_git_pass(git_index_remove(index, "bouilli.txt", 0));
@@ -386,7 +386,7 @@ void test_apply_both__honors_crlf_attributes(void)
 	cl_git_rmfile("merge-recursive/asparagus.txt");
 	cl_git_rmfile("merge-recursive/veal.txt");
 
-	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
diff --git a/tests/libgit2/apply/callbacks.c b/tests/libgit2/apply/callbacks.c
index 1b759dc9b..2f9af3101 100644
--- a/tests/libgit2/apply/callbacks.c
+++ b/tests/libgit2/apply/callbacks.c
@@ -12,7 +12,7 @@ void test_apply_callbacks__initialize(void)
 
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
 
-	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
diff --git a/tests/libgit2/apply/check.c b/tests/libgit2/apply/check.c
index 9e42365ed..d055d455b 100644
--- a/tests/libgit2/apply/check.c
+++ b/tests/libgit2/apply/check.c
@@ -12,7 +12,7 @@ void test_apply_check__initialize(void)
 
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
 
-	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
@@ -32,8 +32,8 @@ void test_apply_check__generate_diff(void)
 	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
 	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
 
-	cl_git_pass(git_oid_fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707"));
-	cl_git_pass(git_oid_fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f"));
+	cl_git_pass(git_oid__fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
 	cl_git_pass(git_commit_lookup(&b_commit, repo, &b_oid));
 
diff --git a/tests/libgit2/apply/index.c b/tests/libgit2/apply/index.c
index 9c9094cce..2dc0d53cb 100644
--- a/tests/libgit2/apply/index.c
+++ b/tests/libgit2/apply/index.c
@@ -12,7 +12,7 @@ void test_apply_index__initialize(void)
 
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
 
-	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
@@ -42,8 +42,8 @@ void test_apply_index__generate_diff(void)
 	size_t index_expected_cnt = sizeof(index_expected) /
 		sizeof(struct merge_index_entry);
 
-	git_oid_fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707");
-	git_oid_fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f");
+	git_oid__fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
+	git_oid__fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
 	cl_git_pass(git_commit_lookup(&b_commit, repo, &b_oid));
 
@@ -233,7 +233,7 @@ void test_apply_index__keeps_nonconflicting_changes(void)
 	memset(&idx_entry, 0, sizeof(git_index_entry));
 	idx_entry.mode = 0100644;
 	idx_entry.path = "beef.txt";
-	cl_git_pass(git_oid_fromstr(&idx_entry.id, "898d12687fb35be271c27c795a6b32c8b51da79e"));
+	cl_git_pass(git_oid__fromstr(&idx_entry.id, "898d12687fb35be271c27c795a6b32c8b51da79e", GIT_OID_SHA1));
 	cl_git_pass(git_index_add(index, &idx_entry));
 
 	cl_git_pass(git_index_remove(index, "bouilli.txt", 0));
@@ -279,7 +279,7 @@ void test_apply_index__can_apply_nonconflicting_file_changes(void)
 	memset(&idx_entry, 0, sizeof(git_index_entry));
 	idx_entry.mode = 0100644;
 	idx_entry.path = "asparagus.txt";
-	cl_git_pass(git_oid_fromstr(&idx_entry.id, "06d3fefb8726ab1099acc76e02dfb85e034b2538"));
+	cl_git_pass(git_oid__fromstr(&idx_entry.id, "06d3fefb8726ab1099acc76e02dfb85e034b2538", GIT_OID_SHA1));
 	cl_git_pass(git_index_add(index, &idx_entry));
 
 	cl_git_pass(git_index_write(index));
diff --git a/tests/libgit2/apply/tree.c b/tests/libgit2/apply/tree.c
index 5154f134f..667bb9d40 100644
--- a/tests/libgit2/apply/tree.c
+++ b/tests/libgit2/apply/tree.c
@@ -35,8 +35,8 @@ void test_apply_tree__one(void)
 		{ 0100644, "a7b066537e6be7109abfe4ff97b675d4e077da20", 0, "veal.txt" },
 	};
 
-	git_oid_fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707");
-	git_oid_fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f");
+	git_oid__fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
+	git_oid__fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f", GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
 	cl_git_pass(git_commit_lookup(&b_commit, repo, &b_oid));
@@ -75,7 +75,7 @@ void test_apply_tree__adds_file(void)
 		{ 0100644, "94d2c01087f48213bd157222d54edfefd77c9bba", 0, "veal.txt" },
 	};
 
-	git_oid_fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
 
diff --git a/tests/libgit2/apply/workdir.c b/tests/libgit2/apply/workdir.c
index d0d9c1aba..e1011d114 100644
--- a/tests/libgit2/apply/workdir.c
+++ b/tests/libgit2/apply/workdir.c
@@ -12,7 +12,7 @@ void test_apply_workdir__initialize(void)
 
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
 
-	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
@@ -42,8 +42,8 @@ void test_apply_workdir__generated_diff(void)
 	size_t workdir_expected_cnt = sizeof(workdir_expected) /
 		sizeof(struct merge_index_entry);
 
-	git_oid_fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707");
-	git_oid_fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f"); cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
+	git_oid__fromstr(&a_oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
+	git_oid__fromstr(&b_oid, "7c7bf85e978f1d18c0566f702d2cb7766b9c8d4f", GIT_OID_SHA1); cl_git_pass(git_commit_lookup(&a_commit, repo, &a_oid));
 	cl_git_pass(git_commit_lookup(&b_commit, repo, &b_oid));
 
 	cl_git_pass(git_commit_tree(&a_tree, a_commit));
@@ -171,7 +171,7 @@ void test_apply_workdir__modified_index_with_unmodified_workdir_is_ok(void)
 
 	idx_entry.mode = 0100644;
 	idx_entry.path = "veal.txt";
-	cl_git_pass(git_oid_fromstr(&idx_entry.id, "ffb36e513f5fdf8a6ba850a20142676a2ac4807d"));
+	cl_git_pass(git_oid__fromstr(&idx_entry.id, "ffb36e513f5fdf8a6ba850a20142676a2ac4807d", GIT_OID_SHA1));
 
 	cl_git_pass(git_index_add(index, &idx_entry));
 	cl_git_pass(git_index_remove(index, "asparagus.txt", 0));
diff --git a/tests/libgit2/blame/blame_helpers.c b/tests/libgit2/blame/blame_helpers.c
index 6b3ce677d..8aeaa5886 100644
--- a/tests/libgit2/blame/blame_helpers.c
+++ b/tests/libgit2/blame/blame_helpers.c
@@ -17,7 +17,7 @@ void hunk_message(size_t idx, const git_blame_hunk *hunk, const char *fmt, ...)
 void check_blame_hunk_index(git_repository *repo, git_blame *blame, int idx,
 		size_t start_line, size_t len, char boundary, const char *commit_id, const char *orig_path)
 {
-	char expected[GIT_OID_HEXSZ+1] = {0}, actual[GIT_OID_HEXSZ+1] = {0};
+	char expected[GIT_OID_SHA1_HEXSIZE+1] = {0}, actual[GIT_OID_SHA1_HEXSIZE+1] = {0};
 	const git_blame_hunk *hunk = git_blame_get_hunk_byindex(blame, idx);
 	cl_assert(hunk);
 
diff --git a/tests/libgit2/blame/getters.c b/tests/libgit2/blame/getters.c
index 66eaeecf9..c160cd383 100644
--- a/tests/libgit2/blame/getters.c
+++ b/tests/libgit2/blame/getters.c
@@ -10,11 +10,11 @@ void test_blame_getters__initialize(void)
 	git_blame_options opts = GIT_BLAME_OPTIONS_INIT;
 
 	git_blame_hunk hunks[] = {
-		{ 3, {{0}},  1, NULL, {{0}}, "a", 0},
-		{ 3, {{0}},  4, NULL, {{0}}, "b", 0},
-		{ 3, {{0}},  7, NULL, {{0}}, "c", 0},
-		{ 3, {{0}}, 10, NULL, {{0}}, "d", 0},
-		{ 3, {{0}}, 13, NULL, {{0}}, "e", 0},
+		{ 3, GIT_OID_SHA1_ZERO,  1, NULL, GIT_OID_SHA1_ZERO, "a", 0},
+		{ 3, GIT_OID_SHA1_ZERO,  4, NULL, GIT_OID_SHA1_ZERO, "b", 0},
+		{ 3, GIT_OID_SHA1_ZERO,  7, NULL, GIT_OID_SHA1_ZERO, "c", 0},
+		{ 3, GIT_OID_SHA1_ZERO, 10, NULL, GIT_OID_SHA1_ZERO, "d", 0},
+		{ 3, GIT_OID_SHA1_ZERO, 13, NULL, GIT_OID_SHA1_ZERO, "e", 0},
 	};
 
 	g_blame = git_blame__alloc(NULL, opts, "");
diff --git a/tests/libgit2/checkout/binaryunicode.c b/tests/libgit2/checkout/binaryunicode.c
index edb5cfaf5..b8c6c079e 100644
--- a/tests/libgit2/checkout/binaryunicode.c
+++ b/tests/libgit2/checkout/binaryunicode.c
@@ -3,6 +3,7 @@
 #include "repo/repo_helpers.h"
 #include "path.h"
 #include "futils.h"
+#include "odb.h"
 
 static git_repository *g_repo;
 
@@ -35,13 +36,13 @@ static void execute_test(void)
 	git_commit_free(commit);
 
 	/* Verify that the lenna.jpg file was checked out correctly */
-	cl_git_pass(git_oid_fromstr(&check, "8ab005d890fe53f65eda14b23672f60d9f4ec5a1"));
-	cl_git_pass(git_odb_hashfile(&oid, "binaryunicode/lenna.jpg", GIT_OBJECT_BLOB));
+	cl_git_pass(git_oid__fromstr(&check, "8ab005d890fe53f65eda14b23672f60d9f4ec5a1", GIT_OID_SHA1));
+	cl_git_pass(git_odb__hashfile(&oid, "binaryunicode/lenna.jpg", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &check);
 
 	/* Verify that the text file was checked out correctly */
-	cl_git_pass(git_oid_fromstr(&check, "965b223880dd4249e2c66a0cc0b4cffe1dc40f5a"));
-	cl_git_pass(git_odb_hashfile(&oid, "binaryunicode/utf16_withbom_noeol_crlf.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_oid__fromstr(&check, "965b223880dd4249e2c66a0cc0b4cffe1dc40f5a", GIT_OID_SHA1));
+	cl_git_pass(git_odb__hashfile(&oid, "binaryunicode/utf16_withbom_noeol_crlf.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &check);
 }
 
diff --git a/tests/libgit2/checkout/conflict.c b/tests/libgit2/checkout/conflict.c
index 4a9e4b9fa..b2eb939dc 100644
--- a/tests/libgit2/checkout/conflict.c
+++ b/tests/libgit2/checkout/conflict.c
@@ -49,7 +49,7 @@ static git_index *g_index;
 
 struct checkout_index_entry {
 	uint16_t mode;
-	char oid_str[GIT_OID_HEXSZ+1];
+	char oid_str[GIT_OID_SHA1_HEXSIZE+1];
 	int stage;
 	char path[128];
 };
@@ -104,7 +104,7 @@ static void create_index(struct checkout_index_entry *entries, size_t entries_le
 
 		entry.mode = entries[i].mode;
 		GIT_INDEX_ENTRY_STAGE_SET(&entry, entries[i].stage);
-		git_oid_fromstr(&entry.id, entries[i].oid_str);
+		git_oid__fromstr(&entry.id, entries[i].oid_str, GIT_OID_SHA1);
 		entry.path = entries[i].path;
 
 		cl_git_pass(git_index_add(g_index, &entry));
@@ -155,7 +155,7 @@ static void ensure_workdir_oid(const char *path, const char *oid_str)
 {
 	git_oid expected, actual;
 
-	cl_git_pass(git_oid_fromstr(&expected, oid_str));
+	cl_git_pass(git_oid__fromstr(&expected, oid_str, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&actual, g_repo, path, GIT_OBJECT_BLOB, NULL));
 	cl_assert_equal_oid(&expected, &actual);
 }
diff --git a/tests/libgit2/checkout/index.c b/tests/libgit2/checkout/index.c
index 6a80d22c5..6432cba84 100644
--- a/tests/libgit2/checkout/index.c
+++ b/tests/libgit2/checkout/index.c
@@ -791,15 +791,15 @@ static void add_conflict(git_index *index, const char *path)
 	entry.mode = 0100644;
 	entry.path = path;
 
-	git_oid_fromstr(&entry.id, "d427e0b2e138501a3d15cc376077a3631e15bd46");
+	git_oid__fromstr(&entry.id, "d427e0b2e138501a3d15cc376077a3631e15bd46", GIT_OID_SHA1);
 	GIT_INDEX_ENTRY_STAGE_SET(&entry, 1);
 	cl_git_pass(git_index_add(index, &entry));
 
-	git_oid_fromstr(&entry.id, "4e886e602529caa9ab11d71f86634bd1b6e0de10");
+	git_oid__fromstr(&entry.id, "4e886e602529caa9ab11d71f86634bd1b6e0de10", GIT_OID_SHA1);
 	GIT_INDEX_ENTRY_STAGE_SET(&entry, 2);
 	cl_git_pass(git_index_add(index, &entry));
 
-	git_oid_fromstr(&entry.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863");
+	git_oid__fromstr(&entry.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863", GIT_OID_SHA1);
 	GIT_INDEX_ENTRY_STAGE_SET(&entry, 3);
 	cl_git_pass(git_index_add(index, &entry));
 }
diff --git a/tests/libgit2/checkout/tree.c b/tests/libgit2/checkout/tree.c
index d4b57f5d1..65df00cd8 100644
--- a/tests/libgit2/checkout/tree.c
+++ b/tests/libgit2/checkout/tree.c
@@ -139,8 +139,8 @@ void test_checkout_tree__doesnt_write_unrequested_files_to_worktree(void)
 	git_commit* p_chomped_commit;
 	git_checkout_options opts = GIT_CHECKOUT_OPTIONS_INIT;
 
-	git_oid_fromstr(&master_oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
-	git_oid_fromstr(&chomped_oid, "e90810b8df3e80c413d903f631643c716887138d");
+	git_oid__fromstr(&master_oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
+	git_oid__fromstr(&chomped_oid, "e90810b8df3e80c413d903f631643c716887138d", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&p_master_commit, g_repo, &master_oid));
 	cl_git_pass(git_commit_lookup(&p_chomped_commit, g_repo, &chomped_oid));
 
@@ -615,7 +615,7 @@ void test_checkout_tree__donot_update_deleted_file_by_default(void)
 
 	cl_git_pass(git_repository_index(&index, g_repo));
 
-	cl_git_pass(git_oid_fromstr(&old_id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
+	cl_git_pass(git_oid__fromstr(&old_id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&old_commit, g_repo, &old_id));
 	cl_git_pass(git_reset(g_repo, (git_object *)old_commit, GIT_RESET_HARD, NULL));
 
@@ -625,7 +625,7 @@ void test_checkout_tree__donot_update_deleted_file_by_default(void)
 
 	cl_assert(!git_fs_path_exists("testrepo/branch_file.txt"));
 
-	cl_git_pass(git_oid_fromstr(&new_id, "099fabac3a9ea935598528c27f866e34089c2eff"));
+	cl_git_pass(git_oid__fromstr(&new_id, "099fabac3a9ea935598528c27f866e34089c2eff", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&new_commit, g_repo, &new_id));
 
 
@@ -941,16 +941,16 @@ static void create_conflict(const char *path)
 	memset(&entry, 0x0, sizeof(git_index_entry));
 	entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&entry, 1);
-	git_oid_fromstr(&entry.id, "d427e0b2e138501a3d15cc376077a3631e15bd46");
+	git_oid__fromstr(&entry.id, "d427e0b2e138501a3d15cc376077a3631e15bd46", GIT_OID_SHA1);
 	entry.path = path;
 	cl_git_pass(git_index_add(index, &entry));
 
 	GIT_INDEX_ENTRY_STAGE_SET(&entry, 2);
-	git_oid_fromstr(&entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf");
+	git_oid__fromstr(&entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf", GIT_OID_SHA1);
 	cl_git_pass(git_index_add(index, &entry));
 
 	GIT_INDEX_ENTRY_STAGE_SET(&entry, 3);
-	git_oid_fromstr(&entry.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863");
+	git_oid__fromstr(&entry.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863", GIT_OID_SHA1);
 	cl_git_pass(git_index_add(index, &entry));
 
 	cl_git_pass(git_index_write(index));
@@ -988,7 +988,7 @@ void test_checkout_tree__filemode_preserved_in_index(void)
 	cl_git_pass(git_repository_index(&index, g_repo));
 
 	/* test a freshly added executable */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -999,7 +999,7 @@ void test_checkout_tree__filemode_preserved_in_index(void)
 
 
 	/* Now start with a commit which has a text file */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -1010,7 +1010,7 @@ void test_checkout_tree__filemode_preserved_in_index(void)
 
 
 	/* And then check out to a commit which converts the text file to an executable */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "144344043ba4d4a405da03de3844aa829ae8be0e"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "144344043ba4d4a405da03de3844aa829ae8be0e", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -1021,7 +1021,7 @@ void test_checkout_tree__filemode_preserved_in_index(void)
 
 
 	/* Finally, check out the text file again and check that the exec bit is cleared */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -1063,7 +1063,7 @@ void test_checkout_tree__filemode_preserved_in_workdir(void)
 	opts.checkout_strategy = GIT_CHECKOUT_FORCE;
 
 	/* test a freshly added executable */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -1073,7 +1073,7 @@ void test_checkout_tree__filemode_preserved_in_workdir(void)
 
 
 	/* Now start with a commit which has a text file */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -1083,7 +1083,7 @@ void test_checkout_tree__filemode_preserved_in_workdir(void)
 
 
 	/* And then check out to a commit which converts the text file to an executable */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "144344043ba4d4a405da03de3844aa829ae8be0e"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "144344043ba4d4a405da03de3844aa829ae8be0e", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -1093,7 +1093,7 @@ void test_checkout_tree__filemode_preserved_in_workdir(void)
 
 
 	/* Finally, check out the text file again and check that the exec bit is cleared */
-	cl_git_pass(git_oid_fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9"));
+	cl_git_pass(git_oid__fromstr(&executable_oid, "cf80f8de9f1185bf3a05f993f6121880dd0cfbc9", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &executable_oid));
 
 	cl_git_pass(git_checkout_tree(g_repo, (const git_object *)commit, &opts));
@@ -1112,7 +1112,7 @@ void test_checkout_tree__removes_conflicts(void)
 	git_checkout_options opts = GIT_CHECKOUT_OPTIONS_INIT;
 	git_index *index;
 
-	cl_git_pass(git_oid_fromstr(&commit_id, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6"));
+	cl_git_pass(git_oid__fromstr(&commit_id, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &commit_id));
 
 	opts.checkout_strategy = GIT_CHECKOUT_FORCE;
@@ -1155,7 +1155,7 @@ void test_checkout_tree__removes_conflicts_only_by_pathscope(void)
 	git_index *index;
 	const char *path = "executable.txt";
 
-	cl_git_pass(git_oid_fromstr(&commit_id, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6"));
+	cl_git_pass(git_oid__fromstr(&commit_id, "afe4393b2b2a965f06acf2ca9658eaa01e0cd6b6", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &commit_id));
 
 	opts.checkout_strategy = GIT_CHECKOUT_FORCE;
@@ -1583,7 +1583,7 @@ static void modify_index_ondisk(void)
 	cl_git_pass(git_repository_open(&other_repo, git_repository_workdir(g_repo)));
 	cl_git_pass(git_repository_index(&other_index, other_repo));
 
-	cl_git_pass(git_oid_fromstr(&entry.id, "1385f264afb75a56a5bec74243be9b367ba4ca08"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "1385f264afb75a56a5bec74243be9b367ba4ca08", GIT_OID_SHA1));
 	entry.mode = 0100644;
 	entry.path = "README";
 
diff --git a/tests/libgit2/checkout/typechange.c b/tests/libgit2/checkout/typechange.c
index b888843f0..1fa2d3095 100644
--- a/tests/libgit2/checkout/typechange.c
+++ b/tests/libgit2/checkout/typechange.c
@@ -319,7 +319,7 @@ void test_checkout_typechange__status_char(void)
 	git_diff_options diffopts = GIT_DIFF_OPTIONS_INIT;
 	char expected[8] = {'M', 'M', 'R', 'T', 'D', 'R', 'A', 'R'};
 
-	git_oid_fromstr(&oid, "9b19edf33a03a0c59cdfc113bfa5c06179bf9b1a");
+	git_oid__fromstr(&oid, "9b19edf33a03a0c59cdfc113bfa5c06179bf9b1a", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, g_repo, &oid));
 	diffopts.flags |= GIT_DIFF_INCLUDE_TYPECHANGE;
 	cl_git_pass(git_diff__commit(&diff, g_repo, commit, &diffopts));
diff --git a/tests/libgit2/cherrypick/bare.c b/tests/libgit2/cherrypick/bare.c
index f90ce0226..664468899 100644
--- a/tests/libgit2/cherrypick/bare.c
+++ b/tests/libgit2/cherrypick/bare.c
@@ -32,10 +32,10 @@ void test_cherrypick_bare__automerge(void)
 		{ 0100644, "df6b290e0bd6a89b01d69f66687e8abf385283ca", 0, "file3.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e");
+	git_oid__fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 
-	git_oid_fromstr(&cherry_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	git_oid__fromstr(&cherry_oid, "cfc4f0999a8367568e049af4f72e452d40828a15", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 
 	cl_git_pass(git_cherrypick_commit(&index, repo, commit, head, 0, NULL));
@@ -62,10 +62,10 @@ void test_cherrypick_bare__conflicts(void)
 		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 3, "file3.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8");
+	git_oid__fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 
-	git_oid_fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110");
+	git_oid__fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 
 	cl_git_pass(git_cherrypick_commit(&index, repo, commit, head, 0, NULL));
@@ -89,10 +89,10 @@ void test_cherrypick_bare__orphan(void)
 		{ 0100644, "9ccb9bf50c011fd58dcbaa65df917bf79539717f", 0, "orphan.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e");
+	git_oid__fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 
-	git_oid_fromstr(&cherry_oid, "74f06b5bfec6d33d7264f73606b57a7c0b963819");
+	git_oid__fromstr(&cherry_oid, "74f06b5bfec6d33d7264f73606b57a7c0b963819", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 
 	cl_git_pass(git_cherrypick_commit(&index, repo, commit, head, 0, NULL));
diff --git a/tests/libgit2/cherrypick/workdir.c b/tests/libgit2/cherrypick/workdir.c
index 8fd1ecbdf..c16b7814a 100644
--- a/tests/libgit2/cherrypick/workdir.c
+++ b/tests/libgit2/cherrypick/workdir.c
@@ -57,7 +57,7 @@ void test_cherrypick_workdir__automerge(void)
 
 	cl_git_pass(git_signature_new(&signature, "Picker", "picker@example.org", time(NULL), 0));
 
-	git_oid_fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e");
+	git_oid__fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e", GIT_OID_SHA1);
 
 	for (i = 0; i < 3; ++i) {
 		git_commit *head = NULL, *commit = NULL;
@@ -67,7 +67,7 @@ void test_cherrypick_workdir__automerge(void)
 		cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 		cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-		git_oid_fromstr(&cherry_oid, cherrypick_oids[i]);
+		git_oid__fromstr(&cherry_oid, cherrypick_oids[i], GIT_OID_SHA1);
 		cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 		cl_git_pass(git_cherrypick(repo, commit, NULL));
 
@@ -110,7 +110,7 @@ void test_cherrypick_workdir__empty_result(void)
 
 	cl_git_pass(git_signature_new(&signature, "Picker", "picker@example.org", time(NULL), 0));
 
-	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	git_oid__fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15", GIT_OID_SHA1);
 
 	/* Create an untracked file that should not conflict */
 	cl_git_mkfile(TEST_REPO_PATH "/file4.txt", "");
@@ -119,7 +119,7 @@ void test_cherrypick_workdir__empty_result(void)
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, cherrypick_oid);
+	git_oid__fromstr(&cherry_oid, cherrypick_oid, GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 	cl_git_pass(git_cherrypick(repo, commit, NULL));
 
@@ -151,12 +151,12 @@ void test_cherrypick_workdir__conflicts(void)
 		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 3, "file3.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8");
+	git_oid__fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8", GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110");
+	git_oid__fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 	cl_git_pass(git_cherrypick(repo, commit, NULL));
 
@@ -259,12 +259,12 @@ void test_cherrypick_workdir__conflict_use_ours(void)
 	/* leave the index in a conflicted state, but checkout "ours" to the workdir */
 	opts.checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE | GIT_CHECKOUT_USE_OURS;
 
-	git_oid_fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8");
+	git_oid__fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8", GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110");
+	git_oid__fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 	cl_git_pass(git_cherrypick(repo, commit, &opts));
 
@@ -302,11 +302,11 @@ void test_cherrypick_workdir__rename(void)
 	opts.merge_opts.flags |= GIT_MERGE_FIND_RENAMES;
 	opts.merge_opts.rename_threshold = 50;
 
-	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	git_oid__fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, "2a26c7e88b285613b302ba76712bc998863f3cbc");
+	git_oid__fromstr(&cherry_oid, "2a26c7e88b285613b302ba76712bc998863f3cbc", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 	cl_git_pass(git_cherrypick(repo, commit, &opts));
 
@@ -337,11 +337,11 @@ void test_cherrypick_workdir__both_renamed(void)
 	opts.merge_opts.flags |= GIT_MERGE_FIND_RENAMES;
 	opts.merge_opts.rename_threshold = 50;
 
-	git_oid_fromstr(&head_oid, "44cd2ed2052c9c68f9a439d208e9614dc2a55c70");
+	git_oid__fromstr(&head_oid, "44cd2ed2052c9c68f9a439d208e9614dc2a55c70", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, "2a26c7e88b285613b302ba76712bc998863f3cbc");
+	git_oid__fromstr(&cherry_oid, "2a26c7e88b285613b302ba76712bc998863f3cbc", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 	cl_git_pass(git_cherrypick(repo, commit, &opts));
 
@@ -388,11 +388,11 @@ void test_cherrypick_workdir__merge_fails_without_mainline_specified(void)
 	git_commit *head, *commit;
 	git_oid head_oid, cherry_oid;
 
-	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	git_oid__fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff");
+	git_oid__fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 
 	cl_must_fail(git_cherrypick(repo, commit, NULL));
@@ -420,11 +420,11 @@ void test_cherrypick_workdir__merge_first_parent(void)
 
 	opts.mainline = 1;
 
-	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	git_oid__fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff");
+	git_oid__fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 
 	cl_git_pass(git_cherrypick(repo, commit, &opts));
@@ -452,11 +452,11 @@ void test_cherrypick_workdir__merge_second_parent(void)
 
 	opts.mainline = 2;
 
-	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	git_oid__fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff");
+	git_oid__fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
 
 	cl_git_pass(git_cherrypick(repo, commit, &opts));
diff --git a/tests/libgit2/commit/commit.c b/tests/libgit2/commit/commit.c
index fd574f7f2..140f87d0c 100644
--- a/tests/libgit2/commit/commit.c
+++ b/tests/libgit2/commit/commit.c
@@ -26,10 +26,10 @@ void test_commit_commit__create_unexisting_update_ref(void)
 	git_signature *s;
 	git_reference *ref;
 
-	git_oid_fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
 
-	git_oid_fromstr(&oid, "944c0f6e4dfa41595e6eb3ceecdb14f50fe18162");
+	git_oid__fromstr(&oid, "944c0f6e4dfa41595e6eb3ceecdb14f50fe18162", GIT_OID_SHA1);
 	cl_git_pass(git_tree_lookup(&tree, _repo, &oid));
 
 	cl_git_pass(git_signature_now(&s, "alice", "alice@example.com"));
@@ -59,10 +59,10 @@ void test_commit_commit__create_initial_commit(void)
 	git_signature *s;
 	git_reference *ref;
 
-	git_oid_fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
 
-	git_oid_fromstr(&oid, "944c0f6e4dfa41595e6eb3ceecdb14f50fe18162");
+	git_oid__fromstr(&oid, "944c0f6e4dfa41595e6eb3ceecdb14f50fe18162", GIT_OID_SHA1);
 	cl_git_pass(git_tree_lookup(&tree, _repo, &oid));
 
 	cl_git_pass(git_signature_now(&s, "alice", "alice@example.com"));
@@ -89,10 +89,10 @@ void test_commit_commit__create_initial_commit_parent_not_current(void)
 	git_commit *commit;
 	git_signature *s;
 
-	git_oid_fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
 
-	git_oid_fromstr(&oid, "944c0f6e4dfa41595e6eb3ceecdb14f50fe18162");
+	git_oid__fromstr(&oid, "944c0f6e4dfa41595e6eb3ceecdb14f50fe18162", GIT_OID_SHA1);
 	cl_git_pass(git_tree_lookup(&tree, _repo, &oid));
 
 	cl_git_pass(git_signature_now(&s, "alice", "alice@example.com"));
diff --git a/tests/libgit2/commit/parent.c b/tests/libgit2/commit/parent.c
index 18ce0bba6..1ec96babb 100644
--- a/tests/libgit2/commit/parent.c
+++ b/tests/libgit2/commit/parent.c
@@ -9,7 +9,7 @@ void test_commit_parent__initialize(void)
 
 	cl_git_pass(git_repository_open(&_repo, cl_fixture("testrepo.git")));
 
-	git_oid_fromstr(&oid, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+	git_oid__fromstr(&oid, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
 }
 
diff --git a/tests/libgit2/commit/parse.c b/tests/libgit2/commit/parse.c
index 04366d7d2..b313fc308 100644
--- a/tests/libgit2/commit/parse.c
+++ b/tests/libgit2/commit/parse.c
@@ -56,7 +56,8 @@ void test_commit_parse__header(void)
 		const char *line = testcase->line;
 		const char *line_end = line + strlen(line);
 
-		cl_git_pass(git_oid__parse(&oid, &line, line_end, testcase->header));
+		cl_git_pass(git_object__parse_oid_header(&oid,
+			&line, line_end, testcase->header, GIT_OID_SHA1));
 		cl_assert(line == line_end);
 	}
 
@@ -65,7 +66,8 @@ void test_commit_parse__header(void)
 		const char *line = testcase->line;
 		const char *line_end = line + strlen(line);
 
-		cl_git_fail(git_oid__parse(&oid, &line, line_end, testcase->header));
+		cl_git_fail(git_object__parse_oid_header(&oid,
+			&line, line_end, testcase->header, GIT_OID_SHA1));
 	}
 }
 
@@ -341,7 +343,7 @@ void test_commit_parse__details0(void) {
 		unsigned int parents, p;
 		git_commit *parent = NULL, *old_parent = NULL;
 
-		git_oid_fromstr(&id, commit_ids[i]);
+		git_oid__fromstr(&id, commit_ids[i], GIT_OID_SHA1);
 
 		cl_git_pass(git_commit_lookup(&commit, g_repo, &id));
 
@@ -531,7 +533,7 @@ corrupt signature\n";
 	git_buf_dispose(&signed_data);
 
 	/* Try to parse a tree */
-	cl_git_pass(git_oid_fromstr(&commit_id, "45dd856fdd4d89b884c340ba0e047752d9b085d6"));
+	cl_git_pass(git_oid__fromstr(&commit_id, "45dd856fdd4d89b884c340ba0e047752d9b085d6", GIT_OID_SHA1));
 	cl_git_fail_with(GIT_ENOTFOUND, git_commit_extract_signature(&signature, &signed_data, g_repo, &commit_id, NULL));
 	cl_assert_equal_i(GIT_ERROR_INVALID, git_error_last()->klass);
 
diff --git a/tests/libgit2/commit/write.c b/tests/libgit2/commit/write.c
index 5a9c9d5a5..890f7384b 100644
--- a/tests/libgit2/commit/write.c
+++ b/tests/libgit2/commit/write.c
@@ -51,10 +51,10 @@ void test_commit_write__from_memory(void)
    git_commit *parent;
    git_tree *tree;
 
-   git_oid_fromstr(&tree_id, tree_id_str);
+   git_oid__fromstr(&tree_id, tree_id_str, GIT_OID_SHA1);
    cl_git_pass(git_tree_lookup(&tree, g_repo, &tree_id));
 
-   git_oid_fromstr(&parent_id, parent_id_str);
+   git_oid__fromstr(&parent_id, parent_id_str, GIT_OID_SHA1);
    cl_git_pass(git_commit_lookup(&parent, g_repo, &parent_id));
 
    /* create signatures */
@@ -107,14 +107,14 @@ void test_commit_write__into_buf(void)
 	git_oid parent_id;
 	git_buf commit = GIT_BUF_INIT;
 
-	git_oid_fromstr(&tree_id, tree_id_str);
+	git_oid__fromstr(&tree_id, tree_id_str, GIT_OID_SHA1);
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &tree_id));
 
 	/* create signatures */
 	cl_git_pass(git_signature_new(&committer, committer_name, committer_email, 123456789, 60));
 	cl_git_pass(git_signature_new(&author, committer_name, committer_email, 987654321, 90));
 
-	git_oid_fromstr(&parent_id, parent_id_str);
+	git_oid__fromstr(&parent_id, parent_id_str, GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&parent, g_repo, &parent_id));
 
 	cl_git_pass(git_commit_create_buffer(&commit, g_repo, author, committer,
@@ -148,7 +148,7 @@ void test_commit_write__root(void)
 	git_reflog *log;
 	const git_reflog_entry *entry;
 
-	git_oid_fromstr(&tree_id, tree_id_str);
+	git_oid__fromstr(&tree_id, tree_id_str, GIT_OID_SHA1);
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &tree_id));
 
 	/* create signatures */
@@ -242,34 +242,34 @@ void test_commit_write__can_write_invalid_objects(void)
 	cl_git_pass(git_libgit2_opts(GIT_OPT_ENABLE_STRICT_OBJECT_CREATION, 0));
 
 	/* this is a valid tree and parent */
-	git_oid_fromstr(&tree_id, tree_id_str);
-	git_oid_fromstr(&parent_id, parent_id_str);
+	git_oid__fromstr(&tree_id, tree_id_str, GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, parent_id_str, GIT_OID_SHA1);
 
-	git_oid_fromstr(&expected_id, "c8571bbec3a72c4bcad31648902e5a453f1adece");
+	git_oid__fromstr(&expected_id, "c8571bbec3a72c4bcad31648902e5a453f1adece", GIT_OID_SHA1);
 	cl_git_pass(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	/* this is a wholly invented tree id */
-	git_oid_fromstr(&tree_id, "1234567890123456789012345678901234567890");
-	git_oid_fromstr(&parent_id, parent_id_str);
+	git_oid__fromstr(&tree_id, "1234567890123456789012345678901234567890", GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, parent_id_str, GIT_OID_SHA1);
 
-	git_oid_fromstr(&expected_id, "996008340b8e68d69bf3c28d7c57fb7ec3c8e202");
+	git_oid__fromstr(&expected_id, "996008340b8e68d69bf3c28d7c57fb7ec3c8e202", GIT_OID_SHA1);
 	cl_git_pass(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	/* this is a wholly invented parent id */
-	git_oid_fromstr(&tree_id, tree_id_str);
-	git_oid_fromstr(&parent_id, "1234567890123456789012345678901234567890");
+	git_oid__fromstr(&tree_id, tree_id_str, GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, "1234567890123456789012345678901234567890", GIT_OID_SHA1);
 
-	git_oid_fromstr(&expected_id, "d78f660cab89d9791ca6714b57978bf2a7e709fd");
+	git_oid__fromstr(&expected_id, "d78f660cab89d9791ca6714b57978bf2a7e709fd", GIT_OID_SHA1);
 	cl_git_pass(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	/* these are legitimate objects, but of the wrong type */
-	git_oid_fromstr(&tree_id, parent_id_str);
-	git_oid_fromstr(&parent_id, tree_id_str);
+	git_oid__fromstr(&tree_id, parent_id_str, GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, tree_id_str, GIT_OID_SHA1);
 
-	git_oid_fromstr(&expected_id, "5d80c07414e3f18792949699dfcacadf7748f361");
+	git_oid__fromstr(&expected_id, "5d80c07414e3f18792949699dfcacadf7748f361", GIT_OID_SHA1);
 	cl_git_pass(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 	cl_assert_equal_oid(&expected_id, &commit_id);
 }
@@ -279,23 +279,23 @@ void test_commit_write__can_validate_objects(void)
 	git_oid tree_id, parent_id, commit_id;
 
 	/* this is a valid tree and parent */
-	git_oid_fromstr(&tree_id, tree_id_str);
-	git_oid_fromstr(&parent_id, parent_id_str);
+	git_oid__fromstr(&tree_id, tree_id_str, GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, parent_id_str, GIT_OID_SHA1);
 	cl_git_pass(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 
 	/* this is a wholly invented tree id */
-	git_oid_fromstr(&tree_id, "1234567890123456789012345678901234567890");
-	git_oid_fromstr(&parent_id, parent_id_str);
+	git_oid__fromstr(&tree_id, "1234567890123456789012345678901234567890", GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, parent_id_str, GIT_OID_SHA1);
 	cl_git_fail(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 
 	/* this is a wholly invented parent id */
-	git_oid_fromstr(&tree_id, tree_id_str);
-	git_oid_fromstr(&parent_id, "1234567890123456789012345678901234567890");
+	git_oid__fromstr(&tree_id, tree_id_str, GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, "1234567890123456789012345678901234567890", GIT_OID_SHA1);
 	cl_git_fail(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 
 	/* these are legitimate objects, but of the wrong type */
-	git_oid_fromstr(&tree_id, parent_id_str);
-	git_oid_fromstr(&parent_id, tree_id_str);
+	git_oid__fromstr(&tree_id, parent_id_str, GIT_OID_SHA1);
+	git_oid__fromstr(&parent_id, tree_id_str, GIT_OID_SHA1);
 	cl_git_fail(create_commit_from_ids(&commit_id, &tree_id, &parent_id));
 }
 
diff --git a/tests/libgit2/core/oid.c b/tests/libgit2/core/oid.c
index 894feadf6..9fe4413b7 100644
--- a/tests/libgit2/core/oid.c
+++ b/tests/libgit2/core/oid.c
@@ -1,79 +1,188 @@
 #include "clar_libgit2.h"
 #include "oid.h"
 
-static git_oid id;
-static git_oid idp;
-static git_oid idm;
-const char *str_oid = "ae90f12eea699729ed24555e40b9fd669da12a12";
-const char *str_oid_p = "ae90f12eea699729ed";
-const char *str_oid_m = "ae90f12eea699729ed24555e40b9fd669da12a12THIS IS EXTRA TEXT THAT SHOULD GET IGNORED";
+static git_oid id_sha1;
+static git_oid idp_sha1;
+static git_oid idm_sha1;
+
+const char *str_oid_sha1 = "ae90f12eea699729ed24555e40b9fd669da12a12";
+const char *str_oid_sha1_p = "ae90f12eea699729ed";
+const char *str_oid_sha1_m = "ae90f12eea699729ed24555e40b9fd669da12a12THIS IS EXTRA TEXT THAT SHOULD GET IGNORED";
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+static git_oid id_sha256;
+static git_oid idp_sha256;
+static git_oid idm_sha256;
+
+const char *str_oid_sha256 = "d3e63d2f2e43d1fee23a74bf19a0ede156cba2d1bd602eba13de433cea1bb512";
+const char *str_oid_sha256_p = "d3e63d2f2e43d1fee2";
+const char *str_oid_sha256_m = "d3e63d2f2e43d1fee23a74bf19a0ede156cba2d1bd602eba13de433cea1bb512 GARBAGE EXTRA TEXT AT THE END";
+#endif
 
 void test_core_oid__initialize(void)
 {
-	cl_git_pass(git_oid_fromstr(&id, str_oid));
-	cl_git_pass(git_oid_fromstrp(&idp, str_oid_p));
-	cl_git_fail(git_oid_fromstrp(&idm, str_oid_m));
+	cl_git_pass(git_oid__fromstr(&id_sha1, str_oid_sha1, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstrp(&idp_sha1, str_oid_sha1_p, GIT_OID_SHA1));
+	cl_git_fail(git_oid__fromstrp(&idm_sha1, str_oid_sha1_m, GIT_OID_SHA1));
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	cl_git_pass(git_oid__fromstr(&id_sha256, str_oid_sha256, GIT_OID_SHA256));
+	cl_git_pass(git_oid__fromstrp(&idp_sha256, str_oid_sha256_p, GIT_OID_SHA256));
+	cl_git_fail(git_oid__fromstrp(&idm_sha256, str_oid_sha256_m, GIT_OID_SHA256));
+#endif
 }
 
-void test_core_oid__streq(void)
+void test_core_oid__streq_sha1(void)
 {
-	cl_assert_equal_i(0, git_oid_streq(&id, str_oid));
-	cl_assert_equal_i(-1, git_oid_streq(&id, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
+	cl_assert_equal_i(0, git_oid_streq(&id_sha1, str_oid_sha1));
+	cl_assert_equal_i(-1, git_oid_streq(&id_sha1, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
 
-	cl_assert_equal_i(-1, git_oid_streq(&id, "deadbeef"));
-	cl_assert_equal_i(-1, git_oid_streq(&id, "I'm not an oid.... :)"));
+	cl_assert_equal_i(-1, git_oid_streq(&id_sha1, "deadbeef"));
+	cl_assert_equal_i(-1, git_oid_streq(&id_sha1, "I'm not an oid.... :)"));
 
-	cl_assert_equal_i(0, git_oid_streq(&idp, "ae90f12eea699729ed0000000000000000000000"));
-	cl_assert_equal_i(0, git_oid_streq(&idp, "ae90f12eea699729ed"));
-	cl_assert_equal_i(-1, git_oid_streq(&idp, "ae90f12eea699729ed1"));
-	cl_assert_equal_i(-1, git_oid_streq(&idp, "ae90f12eea699729ec"));
-	cl_assert_equal_i(-1, git_oid_streq(&idp, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
+	cl_assert_equal_i(0, git_oid_streq(&idp_sha1, "ae90f12eea699729ed0000000000000000000000"));
+	cl_assert_equal_i(0, git_oid_streq(&idp_sha1, "ae90f12eea699729ed"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "ae90f12eea699729ed1"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "ae90f12eea699729ec"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
 
-	cl_assert_equal_i(-1, git_oid_streq(&idp, "deadbeef"));
-	cl_assert_equal_i(-1, git_oid_streq(&idp, "I'm not an oid.... :)"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "deadbeef"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "I'm not an oid.... :)"));
 }
 
-void test_core_oid__strcmp(void)
+void test_core_oid__streq_sha256(void)
 {
-	cl_assert_equal_i(0, git_oid_strcmp(&id, str_oid));
-	cl_assert(git_oid_strcmp(&id, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef") < 0);
+#ifdef GIT_EXPERIMENTAL_SHA256
+	cl_assert_equal_i(0, git_oid_streq(&id_sha256, str_oid_sha256));
+	cl_assert_equal_i(-1, git_oid_streq(&id_sha256, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
 
-	cl_assert(git_oid_strcmp(&id, "deadbeef") < 0);
-	cl_assert_equal_i(-1, git_oid_strcmp(&id, "I'm not an oid.... :)"));
+	cl_assert_equal_i(-1, git_oid_streq(&id_sha256, "deadbeef"));
+	cl_assert_equal_i(-1, git_oid_streq(&id_sha256, "I'm not an oid.... :)"));
 
-	cl_assert_equal_i(0, git_oid_strcmp(&idp, "ae90f12eea699729ed0000000000000000000000"));
-	cl_assert_equal_i(0, git_oid_strcmp(&idp, "ae90f12eea699729ed"));
-	cl_assert(git_oid_strcmp(&idp, "ae90f12eea699729ed1") < 0);
-	cl_assert(git_oid_strcmp(&idp, "ae90f12eea699729ec") > 0);
-	cl_assert(git_oid_strcmp(&idp, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef") < 0);
+	cl_assert_equal_i(0, git_oid_streq(&idp_sha256, "d3e63d2f2e43d1fee20000000000000000000000000000000000000000000000"));
+	cl_assert_equal_i(0, git_oid_streq(&idp_sha256, "d3e63d2f2e43d1fee2"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "d3e63d2f2e43d1fee21"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "d3e63d2f2e43d1fee1"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha256, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
 
-	cl_assert(git_oid_strcmp(&idp, "deadbeef") < 0);
-	cl_assert_equal_i(-1, git_oid_strcmp(&idp, "I'm not an oid.... :)"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "deadbeef"));
+	cl_assert_equal_i(-1, git_oid_streq(&idp_sha1, "I'm not an oid.... :)"));
+#endif
 }
 
-void test_core_oid__ncmp(void)
+void test_core_oid__strcmp_sha1(void)
 {
-	cl_assert(!git_oid_ncmp(&id, &idp, 0));
-	cl_assert(!git_oid_ncmp(&id, &idp, 1));
-	cl_assert(!git_oid_ncmp(&id, &idp, 2));
-	cl_assert(!git_oid_ncmp(&id, &idp, 17));
-	cl_assert(!git_oid_ncmp(&id, &idp, 18));
-	cl_assert(git_oid_ncmp(&id, &idp, 19));
-	cl_assert(git_oid_ncmp(&id, &idp, 40));
-	cl_assert(git_oid_ncmp(&id, &idp, 41));
-	cl_assert(git_oid_ncmp(&id, &idp, 42));
-
-	cl_assert(!git_oid_ncmp(&id, &id, 0));
-	cl_assert(!git_oid_ncmp(&id, &id, 1));
-	cl_assert(!git_oid_ncmp(&id, &id, 39));
-	cl_assert(!git_oid_ncmp(&id, &id, 40));
-	cl_assert(!git_oid_ncmp(&id, &id, 41));
+	cl_assert_equal_i(0, git_oid_strcmp(&id_sha1, str_oid_sha1));
+	cl_assert(git_oid_strcmp(&id_sha1, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef") < 0);
+
+	cl_assert(git_oid_strcmp(&id_sha1, "deadbeef") < 0);
+	cl_assert_equal_i(-1, git_oid_strcmp(&id_sha1, "I'm not an oid.... :)"));
+
+	cl_assert_equal_i(0, git_oid_strcmp(&idp_sha1, "ae90f12eea699729ed0000000000000000000000"));
+	cl_assert_equal_i(0, git_oid_strcmp(&idp_sha1, "ae90f12eea699729ed"));
+	cl_assert(git_oid_strcmp(&idp_sha1, "ae90f12eea699729ed1") < 0);
+	cl_assert(git_oid_strcmp(&idp_sha1, "ae90f12eea699729ec") > 0);
+	cl_assert(git_oid_strcmp(&idp_sha1, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef") < 0);
+
+	cl_assert(git_oid_strcmp(&idp_sha1, "deadbeef") < 0);
+	cl_assert_equal_i(-1, git_oid_strcmp(&idp_sha1, "I'm not an oid.... :)"));
+}
+
+void test_core_oid__strcmp_sha256(void)
+{
+#ifdef GIT_EXPERIMENTAL_SHA256
+	cl_assert_equal_i(0, git_oid_strcmp(&id_sha256, str_oid_sha256));
+	cl_assert(git_oid_strcmp(&id_sha256, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef") < 0);
+
+	cl_assert(git_oid_strcmp(&id_sha256, "deadbeef") < 0);
+	cl_assert_equal_i(-1, git_oid_strcmp(&id_sha256, "I'm not an oid.... :)"));
+
+	cl_assert_equal_i(0, git_oid_strcmp(&idp_sha256, "d3e63d2f2e43d1fee20000000000000000000000"));
+	cl_assert_equal_i(0, git_oid_strcmp(&idp_sha256, "d3e63d2f2e43d1fee2"));
+	cl_assert(git_oid_strcmp(&idp_sha256, "d3e63d2f2e43d1fee21") < 0);
+	cl_assert(git_oid_strcmp(&idp_sha256, "d3e63d2f2e43d1fee1") > 0);
+	cl_assert(git_oid_strcmp(&idp_sha256, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef") < 0);
+
+	cl_assert(git_oid_strcmp(&idp_sha256, "deadbeef") < 0);
+	cl_assert_equal_i(-1, git_oid_strcmp(&idp_sha256, "I'm not an oid.... :)"));
+#endif
+}
+
+void test_core_oid__ncmp_sha1(void)
+{
+	cl_assert(!git_oid_ncmp(&id_sha1, &idp_sha1, 0));
+	cl_assert(!git_oid_ncmp(&id_sha1, &idp_sha1, 1));
+	cl_assert(!git_oid_ncmp(&id_sha1, &idp_sha1, 2));
+	cl_assert(!git_oid_ncmp(&id_sha1, &idp_sha1, 17));
+	cl_assert(!git_oid_ncmp(&id_sha1, &idp_sha1, 18));
+	cl_assert(git_oid_ncmp(&id_sha1, &idp_sha1, 19));
+	cl_assert(git_oid_ncmp(&id_sha1, &idp_sha1, 40));
+	cl_assert(git_oid_ncmp(&id_sha1, &idp_sha1, 41));
+	cl_assert(git_oid_ncmp(&id_sha1, &idp_sha1, 42));
+
+	cl_assert(!git_oid_ncmp(&id_sha1, &id_sha1, 0));
+	cl_assert(!git_oid_ncmp(&id_sha1, &id_sha1, 1));
+	cl_assert(!git_oid_ncmp(&id_sha1, &id_sha1, 39));
+	cl_assert(!git_oid_ncmp(&id_sha1, &id_sha1, 40));
+	cl_assert(!git_oid_ncmp(&id_sha1, &id_sha1, 41));
+}
+
+void test_core_oid__ncmp_sha256(void)
+{
+#ifdef GIT_EXPERIMENTAL_SHA256
+	cl_assert(!git_oid_ncmp(&id_sha256, &idp_sha256, 0));
+	cl_assert(!git_oid_ncmp(&id_sha256, &idp_sha256, 1));
+	cl_assert(!git_oid_ncmp(&id_sha256, &idp_sha256, 2));
+	cl_assert(!git_oid_ncmp(&id_sha256, &idp_sha256, 17));
+	cl_assert(!git_oid_ncmp(&id_sha256, &idp_sha256, 18));
+	cl_assert(git_oid_ncmp(&id_sha256, &idp_sha256, 19));
+	cl_assert(git_oid_ncmp(&id_sha256, &idp_sha256, 40));
+	cl_assert(git_oid_ncmp(&id_sha256, &idp_sha256, 41));
+	cl_assert(git_oid_ncmp(&id_sha256, &idp_sha256, 42));
+	cl_assert(git_oid_ncmp(&id_sha256, &idp_sha256, 63));
+	cl_assert(git_oid_ncmp(&id_sha256, &idp_sha256, 64));
+	cl_assert(git_oid_ncmp(&id_sha256, &idp_sha256, 65));
+
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 0));
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 1));
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 39));
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 40));
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 41));
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 63));
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 64));
+	cl_assert(!git_oid_ncmp(&id_sha256, &id_sha256, 65));
+#endif
 }
 
 void test_core_oid__is_hexstr(void)
 {
-	cl_assert(git_oid__is_hexstr("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-	cl_assert(!git_oid__is_hexstr("deadbeefdeadbeef"));
-	cl_assert(!git_oid__is_hexstr("zeadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-	cl_assert(!git_oid__is_hexstr("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef1"));
+	cl_assert(git_oid__is_hexstr("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef", GIT_OID_SHA1));
+	cl_assert(!git_oid__is_hexstr("deadbeefdeadbeef", GIT_OID_SHA1));
+	cl_assert(!git_oid__is_hexstr("zeadbeefdeadbeefdeadbeefdeadbeefdeadbeef", GIT_OID_SHA1));
+	cl_assert(!git_oid__is_hexstr("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef1", GIT_OID_SHA1));
+}
+
+void test_core_oid__fmt_substr_sha1(void)
+{
+	char buf[GIT_OID_MAX_HEXSIZE + 1];
+
+	memset(buf, 0, GIT_OID_MAX_HEXSIZE + 1);
+	git_oid_fmt_substr(buf, &id_sha1, 0, 40);
+	cl_assert_equal_s(buf, str_oid_sha1);
+
+	memset(buf, 0, GIT_OID_MAX_HEXSIZE + 1);
+	git_oid_fmt_substr(buf, &id_sha1, 0, 18);
+	cl_assert_equal_s(buf, str_oid_sha1_p);
+
+	memset(buf, 0, GIT_OID_MAX_HEXSIZE + 1);
+	git_oid_fmt_substr(buf, &id_sha1, 0, 5);
+	cl_assert_equal_s(buf, "ae90f");
+
+	memset(buf, 0, GIT_OID_MAX_HEXSIZE + 1);
+	git_oid_fmt_substr(buf, &id_sha1, 5, 5);
+	cl_assert_equal_s(buf, "12eea");
+
+	memset(buf, 0, GIT_OID_MAX_HEXSIZE + 1);
+	git_oid_fmt_substr(buf, &id_sha1, 5, 6);
+	cl_assert_equal_s(buf, "12eea6");
 }
diff --git a/tests/libgit2/core/oidmap.c b/tests/libgit2/core/oidmap.c
index 7f98287a6..34374ceef 100644
--- a/tests/libgit2/core/oidmap.c
+++ b/tests/libgit2/core/oidmap.c
@@ -17,7 +17,7 @@ void test_core_oidmap__initialize(void)
 
 		test_oids[i].extra = i;
 
-		for (j = 0; j < GIT_OID_RAWSZ / 4; ++j) {
+		for (j = 0; j < GIT_OID_SHA1_SIZE / 4; ++j) {
 			test_oids[i].oid.id[j * 4    ] = (unsigned char)modi;
 			test_oids[i].oid.id[j * 4 + 1] = (unsigned char)(modi >> 8);
 			test_oids[i].oid.id[j * 4 + 2] = (unsigned char)(modi >> 16);
@@ -28,6 +28,9 @@ void test_core_oidmap__initialize(void)
 		test_oids[i].oid.id[ 9] = (unsigned char)(i >> 8);
 		test_oids[i].oid.id[10] = (unsigned char)(i >> 16);
 		test_oids[i].oid.id[11] = (unsigned char)(i >> 24);
+#ifdef GIT_EXPERIMENTAL_SHA256
+		test_oids[i].oid.type = GIT_OID_SHA1;
+#endif
 	}
 
 	cl_git_pass(git_oidmap_new(&g_map));
@@ -93,9 +96,9 @@ void test_core_oidmap__get_fails_with_nonexisting_key(void)
 void test_core_oidmap__setting_oid_persists(void)
 {
 	git_oid oids[] = {
-	    {{ 0x01 }},
-	    {{ 0x02 }},
-	    {{ 0x03 }}
+		GIT_OID_INIT(GIT_OID_SHA1, { 0x01 }),
+		GIT_OID_INIT(GIT_OID_SHA1, { 0x02 }),
+		GIT_OID_INIT(GIT_OID_SHA1, { 0x03 })
 	};
 
 	cl_git_pass(git_oidmap_set(g_map, &oids[0], "one"));
@@ -110,9 +113,9 @@ void test_core_oidmap__setting_oid_persists(void)
 void test_core_oidmap__setting_existing_key_updates(void)
 {
 	git_oid oids[] = {
-	    {{ 0x01 }},
-	    {{ 0x02 }},
-	    {{ 0x03 }}
+		GIT_OID_INIT(GIT_OID_SHA1, { 0x01 }),
+		GIT_OID_INIT(GIT_OID_SHA1, { 0x02 }),
+		GIT_OID_INIT(GIT_OID_SHA1, { 0x03 })
 	};
 
 	cl_git_pass(git_oidmap_set(g_map, &oids[0], "one"));
diff --git a/tests/libgit2/core/pool.c b/tests/libgit2/core/pool.c
index 5746e35b8..cf01cb9d1 100644
--- a/tests/libgit2/core/pool.c
+++ b/tests/libgit2/core/pool.c
@@ -7,7 +7,7 @@ static char to_hex[] = "0123456789abcdef";
 void test_core_pool__oid(void)
 {
 	git_pool p;
-	char oid_hex[GIT_OID_HEXSZ];
+	char oid_hex[GIT_OID_SHA1_HEXSIZE];
 	git_oid *oid;
 	int i, j;
 
@@ -22,12 +22,17 @@ void test_core_pool__oid(void)
 
 		for (j = 0; j < 8; j++)
 			oid_hex[j] = to_hex[(i >> (4 * j)) & 0x0f];
-		cl_git_pass(git_oid_fromstr(oid, oid_hex));
+		cl_git_pass(git_oid__fromstr(oid, oid_hex, GIT_OID_SHA1));
 	}
 
 #ifndef GIT_DEBUG_POOL
 	/* with fixed page size, allocation must end up with these values */
+
+# ifdef GIT_EXPERIMENTAL_SHA256
+	cl_assert_equal_i(sizeof(void *) == 8 ? 90 : 82, git_pool__open_pages(&p));
+# else
 	cl_assert_equal_i(sizeof(void *) == 8 ? 55 : 45, git_pool__open_pages(&p));
+# endif
 #endif
 	git_pool_clear(&p);
 }
diff --git a/tests/libgit2/diff/binary.c b/tests/libgit2/diff/binary.c
index 4e71f39c6..3bf39f34a 100644
--- a/tests/libgit2/diff/binary.c
+++ b/tests/libgit2/diff/binary.c
@@ -31,12 +31,12 @@ static void test_patch(
 	git_patch *patch;
 	git_buf actual = GIT_BUF_INIT;
 
-	cl_git_pass(git_oid_fromstr(&id_one, one));
+	cl_git_pass(git_oid__fromstr(&id_one, one, GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit_one, repo, &id_one));
 	cl_git_pass(git_commit_tree(&tree_one, commit_one));
 
 	if (two) {
-		cl_git_pass(git_oid_fromstr(&id_two, two));
+		cl_git_pass(git_oid__fromstr(&id_two, two, GIT_OID_SHA1));
 		cl_git_pass(git_commit_lookup(&commit_two, repo, &id_two));
 		cl_git_pass(git_commit_tree(&tree_two, commit_two));
 	} else {
@@ -100,7 +100,7 @@ void test_diff_binary__add(void)
 		"\n";
 
 	opts.flags = GIT_DIFF_SHOW_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("diff_format_email");
 	test_patch(
@@ -183,7 +183,7 @@ void test_diff_binary__delete(void)
 		"\n";
 
 	opts.flags = GIT_DIFF_SHOW_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("diff_format_email");
 	test_patch(
@@ -215,7 +215,7 @@ void test_diff_binary__delta(void)
 		"\n";
 
 	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("renames");
 	cl_git_pass(git_repository_index(&index, repo));
@@ -257,7 +257,7 @@ void test_diff_binary__delta_append(void)
 		"\n";
 
 	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("renames");
 	cl_git_pass(git_repository_index(&index, repo));
@@ -285,11 +285,11 @@ void test_diff_binary__empty_for_no_diff(void)
 	git_str actual = GIT_STR_INIT;
 
 	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("renames");
 
-	cl_git_pass(git_oid_fromstr(&id, "19dd32dfb1520a64e5bbaae8dce6ef423dfa2f13"));
+	cl_git_pass(git_oid__fromstr(&id, "19dd32dfb1520a64e5bbaae8dce6ef423dfa2f13", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, repo, &id));
 	cl_git_pass(git_commit_tree(&tree, commit));
 
@@ -323,7 +323,7 @@ void test_diff_binary__index_to_workdir(void)
 		"\n";
 
 	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("renames");
 	cl_git_pass(git_repository_index(&index, repo));
@@ -389,7 +389,7 @@ void test_diff_binary__print_patch_from_diff(void)
 		"\n";
 
 	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("renames");
 	cl_git_pass(git_repository_index(&index, repo));
@@ -501,7 +501,7 @@ void test_diff_binary__blob_to_blob(void)
 	struct diff_data diff_data = {0};
 
 	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 
 	repo = cl_git_sandbox_init("renames");
 	cl_git_pass(git_repository_index__weakptr(&index, repo));
@@ -510,8 +510,8 @@ void test_diff_binary__blob_to_blob(void)
 	cl_git_pass(git_index_add_bypath(index, "untimely.txt"));
 	cl_git_pass(git_index_write(index));
 
-	git_oid_fromstr(&old_id, "9a69d960ae94b060f56c2a8702545e2bb1abb935");
-	git_oid_fromstr(&new_id, "1111d4f11f4b35bf6759e0fb714fe09731ef0840");
+	git_oid__fromstr(&old_id, "9a69d960ae94b060f56c2a8702545e2bb1abb935", GIT_OID_SHA1);
+	git_oid__fromstr(&new_id, "1111d4f11f4b35bf6759e0fb714fe09731ef0840", GIT_OID_SHA1);
 
 	cl_git_pass(git_blob_lookup(&old_blob, repo, &old_id));
 	cl_git_pass(git_blob_lookup(&new_blob, repo, &new_id));
diff --git a/tests/libgit2/diff/blob.c b/tests/libgit2/diff/blob.c
index d2f42207d..cb7e48b8d 100644
--- a/tests/libgit2/diff/blob.c
+++ b/tests/libgit2/diff/blob.c
@@ -45,11 +45,11 @@ void test_diff_blob__initialize(void)
 	memset(&expected, 0, sizeof(expected));
 
 	/* tests/resources/attr/root_test4.txt */
-	cl_git_pass(git_oid_fromstrn(&oid, "a0f7217a", 8));
+	cl_git_pass(git_oid__fromstrn(&oid, "a0f7217a", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&d, g_repo, &oid, 8));
 
 	/* alien.png */
-	cl_git_pass(git_oid_fromstrn(&oid, "edf3dcee", 8));
+	cl_git_pass(git_oid__fromstrn(&oid, "edf3dcee", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&alien, g_repo, &oid, 8));
 }
 
@@ -86,10 +86,10 @@ void test_diff_blob__patch_with_freed_blobs(void)
 	git_buf buf = GIT_BUF_INIT;
 
 	/* tests/resources/attr/root_test1 */
-	cl_git_pass(git_oid_fromstrn(&a_oid, "45141a79", 8));
+	cl_git_pass(git_oid__fromstrn(&a_oid, "45141a79", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&a, g_repo, &a_oid, 4));
 	/* tests/resources/attr/root_test2 */
-	cl_git_pass(git_oid_fromstrn(&b_oid, "4d713dc4", 8));
+	cl_git_pass(git_oid__fromstrn(&b_oid, "4d713dc4", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&b, g_repo, &b_oid, 4));
 
 	cl_git_pass(git_patch_from_blobs(&p, a, NULL, b, NULL, NULL));
@@ -110,15 +110,15 @@ void test_diff_blob__can_compare_text_blobs(void)
 	git_oid a_oid, b_oid, c_oid;
 
 	/* tests/resources/attr/root_test1 */
-	cl_git_pass(git_oid_fromstrn(&a_oid, "45141a79", 8));
+	cl_git_pass(git_oid__fromstrn(&a_oid, "45141a79", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&a, g_repo, &a_oid, 4));
 
 	/* tests/resources/attr/root_test2 */
-	cl_git_pass(git_oid_fromstrn(&b_oid, "4d713dc4", 8));
+	cl_git_pass(git_oid__fromstrn(&b_oid, "4d713dc4", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&b, g_repo, &b_oid, 4));
 
 	/* tests/resources/attr/root_test3 */
-	cl_git_pass(git_oid_fromstrn(&c_oid, "c96bbb2c2557a832", 16));
+	cl_git_pass(git_oid__fromstrn(&c_oid, "c96bbb2c2557a832", 16, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&c, g_repo, &c_oid, 16));
 
 	/* Doing the equivalent of a `git diff -U1` on these files */
@@ -201,15 +201,15 @@ void test_diff_blob__can_compare_text_blobs_with_patch(void)
 	git_patch *p;
 
 	/* tests/resources/attr/root_test1 */
-	cl_git_pass(git_oid_fromstrn(&a_oid, "45141a79", 8));
+	cl_git_pass(git_oid__fromstrn(&a_oid, "45141a79", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&a, g_repo, &a_oid, 8));
 
 	/* tests/resources/attr/root_test2 */
-	cl_git_pass(git_oid_fromstrn(&b_oid, "4d713dc4", 8));
+	cl_git_pass(git_oid__fromstrn(&b_oid, "4d713dc4", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&b, g_repo, &b_oid, 8));
 
 	/* tests/resources/attr/root_test3 */
-	cl_git_pass(git_oid_fromstrn(&c_oid, "c96bbb2c2557a832", 16));
+	cl_git_pass(git_oid__fromstrn(&c_oid, "c96bbb2c2557a832", 16, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&c, g_repo, &c_oid, 16));
 
 	/* Doing the equivalent of a `git diff -U1` on these files */
@@ -475,7 +475,7 @@ void test_diff_blob__can_compare_two_binary_blobs(void)
 	git_oid h_oid;
 
 	/* heart.png */
-	cl_git_pass(git_oid_fromstrn(&h_oid, "de863bff", 8));
+	cl_git_pass(git_oid__fromstrn(&h_oid, "de863bff", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&heart, g_repo, &h_oid, 8));
 
 	cl_git_pass(git_diff_blobs(
@@ -543,7 +543,7 @@ void test_diff_blob__comparing_two_text_blobs_honors_interhunkcontext(void)
 	opts.context_lines = 3;
 
 	/* tests/resources/attr/root_test1 from commit f5b0af1 */
-	cl_git_pass(git_oid_fromstrn(&old_d_oid, "fe773770", 8));
+	cl_git_pass(git_oid__fromstrn(&old_d_oid, "fe773770", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&old_d, g_repo, &old_d_oid, 8));
 
 	/* Test with default inter-hunk-context (not set) => default is 0 */
@@ -652,7 +652,7 @@ void test_diff_blob__can_compare_blob_to_buffer(void)
 	const char *b_content = "Hello from the root\n\nSome additional lines\n\nDown here below\n\n";
 
 	/* tests/resources/attr/root_test1 */
-	cl_git_pass(git_oid_fromstrn(&a_oid, "45141a79", 8));
+	cl_git_pass(git_oid__fromstrn(&a_oid, "45141a79", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&a, g_repo, &a_oid, 8));
 
 	/* diff from blob a to content of b */
@@ -694,7 +694,7 @@ void test_diff_blob__can_compare_blob_to_buffer_with_patch(void)
 	size_t tc, ta, td;
 
 	/* tests/resources/attr/root_test1 */
-	cl_git_pass(git_oid_fromstrn(&a_oid, "45141a79", 8));
+	cl_git_pass(git_oid__fromstrn(&a_oid, "45141a79", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&a, g_repo, &a_oid, 8));
 
 	/* diff from blob a to content of b */
@@ -773,10 +773,10 @@ void test_diff_blob__binary_data_comparisons(void)
 
 	opts.flags |= GIT_DIFF_INCLUDE_UNMODIFIED;
 
-	cl_git_pass(git_oid_fromstrn(&oid, "45141a79", 8));
+	cl_git_pass(git_oid__fromstrn(&oid, "45141a79", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&nonbin, g_repo, &oid, 8));
 
-	cl_git_pass(git_oid_fromstrn(&oid, "b435cd56", 8));
+	cl_git_pass(git_oid__fromstrn(&oid, "b435cd56", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&bin, g_repo, &oid, 8));
 
 	/* non-binary to reference content */
@@ -879,11 +879,11 @@ void test_diff_blob__using_path_and_attributes(void)
 	opts.context_lines = 0;
 	opts.flags |= GIT_DIFF_INCLUDE_UNMODIFIED;
 
-	cl_git_pass(git_oid_fromstrn(&oid, "45141a79", 8));
+	cl_git_pass(git_oid__fromstrn(&oid, "45141a79", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&nonbin, g_repo, &oid, 8));
 	/* 20b: "Hello from the root\n" */
 
-	cl_git_pass(git_oid_fromstrn(&oid, "b435cd56", 8));
+	cl_git_pass(git_oid__fromstrn(&oid, "b435cd56", 8, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup_prefix(&bin, g_repo, &oid, 8));
 	/* 33b: "0123456789\n\x01\x02\x03\x04\x05\x06\x07\x08\x09\n0123456789\n" */
 
diff --git a/tests/libgit2/diff/diff_helpers.c b/tests/libgit2/diff/diff_helpers.c
index e9900339f..341b0a448 100644
--- a/tests/libgit2/diff/diff_helpers.c
+++ b/tests/libgit2/diff/diff_helpers.c
@@ -11,7 +11,7 @@ git_tree *resolve_commit_oid_to_tree(
 	git_object *obj = NULL;
 	git_tree *tree = NULL;
 
-	if (git_oid_fromstrn(&oid, partial_oid, len) == 0)
+	if (git_oid__fromstrn(&oid, partial_oid, len, GIT_OID_SHA1) == 0)
 		cl_git_pass(git_object_lookup_prefix(&obj, repo, &oid, len, GIT_OBJECT_ANY));
 
 	cl_git_pass(git_object_peel((git_object **) &tree, obj, GIT_OBJECT_TREE));
diff --git a/tests/libgit2/diff/format_email.c b/tests/libgit2/diff/format_email.c
index 612804c42..2726edb0d 100644
--- a/tests/libgit2/diff/format_email.c
+++ b/tests/libgit2/diff/format_email.c
@@ -28,7 +28,7 @@ static void assert_email_match(
 	git_diff *diff = NULL;
 	git_buf buf = GIT_BUF_INIT;
 
-	git_oid_fromstr(&oid, oidstr);
+	git_oid__fromstr(&oid, oidstr, GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 
@@ -228,7 +228,7 @@ void test_diff_format_email__multiple(void)
 	"\n";
 
 
-	git_oid_fromstr(&oid, "10808fe9c9be5a190c0ba68d1a002233fb363508");
+	git_oid__fromstr(&oid, "10808fe9c9be5a190c0ba68d1a002233fb363508", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 
 	opts.id = git_commit_id(commit);
@@ -245,7 +245,7 @@ void test_diff_format_email__multiple(void)
 	diff = NULL;
 	commit = NULL;
 
-	git_oid_fromstr(&oid, "873806f6f27e631eb0b23e4b56bea2bfac14a373");
+	git_oid__fromstr(&oid, "873806f6f27e631eb0b23e4b56bea2bfac14a373", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 
 	opts.id = git_commit_id(commit);
@@ -324,7 +324,7 @@ void test_diff_format_email__invalid_no(void)
 	git_diff_format_email_options opts = GIT_DIFF_FORMAT_EMAIL_OPTIONS_INIT;
 	git_buf buf = GIT_BUF_INIT;
 
-	git_oid_fromstr(&oid, "9264b96c6d104d0e07ae33d3007b6a48246c6f92");
+	git_oid__fromstr(&oid, "9264b96c6d104d0e07ae33d3007b6a48246c6f92", GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 
diff --git a/tests/libgit2/diff/index.c b/tests/libgit2/diff/index.c
index b616a372b..5773b748e 100644
--- a/tests/libgit2/diff/index.c
+++ b/tests/libgit2/diff/index.c
@@ -185,9 +185,9 @@ static void do_conflicted_diff(diff_expects *exp, unsigned long flags)
 	ancestor.path = ours.path = theirs.path = "staged_changes";
 	ancestor.mode = ours.mode = theirs.mode = GIT_FILEMODE_BLOB;
 
-	git_oid_fromstr(&ancestor.id, "d427e0b2e138501a3d15cc376077a3631e15bd46");
-	git_oid_fromstr(&ours.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf");
-	git_oid_fromstr(&theirs.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863");
+	git_oid__fromstr(&ancestor.id, "d427e0b2e138501a3d15cc376077a3631e15bd46", GIT_OID_SHA1);
+	git_oid__fromstr(&ours.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf", GIT_OID_SHA1);
+	git_oid__fromstr(&theirs.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863", GIT_OID_SHA1);
 
 	cl_git_pass(git_index_conflict_add(index, &ancestor, &ours, &theirs));
 	cl_git_pass(git_diff_tree_to_index(&diff, g_repo, a, index, &opts));
@@ -255,7 +255,7 @@ void test_diff_index__not_in_head_conflicted(void)
 
 	theirs.path = "file_not_in_head";
 	theirs.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&theirs.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863");
+	git_oid__fromstr(&theirs.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863", GIT_OID_SHA1);
 	cl_git_pass(git_index_conflict_add(index, NULL, NULL, &theirs));
 
 	cl_git_pass(git_diff_tree_to_index(&diff, g_repo, a, index, NULL));
diff --git a/tests/libgit2/diff/parse.c b/tests/libgit2/diff/parse.c
index 9c3f798e4..cae843cc8 100644
--- a/tests/libgit2/diff/parse.c
+++ b/tests/libgit2/diff/parse.c
@@ -151,7 +151,7 @@ static void test_tree_to_tree_computed_to_parsed(
 
 	repo = cl_git_sandbox_init(sandbox);
 
-	opts.id_abbrev = GIT_OID_HEXSZ;
+	opts.id_abbrev = GIT_OID_SHA1_HEXSIZE;
 	opts.flags = GIT_DIFF_SHOW_BINARY | diff_flags;
 	findopts.flags = find_flags;
 
diff --git a/tests/libgit2/diff/patchid.c b/tests/libgit2/diff/patchid.c
index 621a720f7..1cc368e21 100644
--- a/tests/libgit2/diff/patchid.c
+++ b/tests/libgit2/diff/patchid.c
@@ -6,7 +6,7 @@ static void verify_patch_id(const char *diff_content, const char *expected_id)
 	git_oid expected_oid, actual_oid;
 	git_diff *diff;
 
-	cl_git_pass(git_oid_fromstr(&expected_oid, expected_id));
+	cl_git_pass(git_oid__fromstr(&expected_oid, expected_id, GIT_OID_SHA1));
 	cl_git_pass(git_diff_from_buffer(&diff, diff_content, strlen(diff_content)));
 	cl_git_pass(git_diff_patchid(&actual_oid, diff, NULL));
 
diff --git a/tests/libgit2/diff/rename.c b/tests/libgit2/diff/rename.c
index 30e9ea432..9d4439462 100644
--- a/tests/libgit2/diff/rename.c
+++ b/tests/libgit2/diff/rename.c
@@ -574,7 +574,7 @@ void test_diff_rename__working_directory_changes(void)
 
 	/* again with exact match blob */
 
-	cl_git_pass(git_oid_fromstr(&id, blobsha));
+	cl_git_pass(git_oid__fromstr(&id, blobsha, GIT_OID_SHA1));
 	cl_git_pass(git_blob_lookup(&blob, g_repo, &id));
 	cl_git_pass(git_str_set(
 		&content, git_blob_rawcontent(blob), (size_t)git_blob_rawsize(blob)));
diff --git a/tests/libgit2/diff/stats.c b/tests/libgit2/diff/stats.c
index f69dba9b3..b076ad5a9 100644
--- a/tests/libgit2/diff/stats.c
+++ b/tests/libgit2/diff/stats.c
@@ -26,7 +26,7 @@ static void diff_stats_from_commit_oid(
 	git_commit *commit;
 	git_diff *diff;
 
-	git_oid_fromstr(&oid, oidstr);
+	git_oid__fromstr(&oid, oidstr, GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
 	cl_git_pass(git_diff__commit(&diff, _repo, commit, NULL));
 	if (rename)
diff --git a/tests/libgit2/diff/workdir.c b/tests/libgit2/diff/workdir.c
index 20e000906..8ccde41ff 100644
--- a/tests/libgit2/diff/workdir.c
+++ b/tests/libgit2/diff/workdir.c
@@ -86,11 +86,11 @@ void test_diff_workdir__to_index_with_conflicts(void)
 	/* Adding an entry that represents a rename gets two files in conflict */
 	our_entry.path = "subdir/modified_file";
 	our_entry.mode = 0100644;
-	git_oid_fromstr(&our_entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf");
+	git_oid__fromstr(&our_entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf", GIT_OID_SHA1);
 
 	their_entry.path = "subdir/rename_conflict";
 	their_entry.mode = 0100644;
-	git_oid_fromstr(&their_entry.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863");
+	git_oid__fromstr(&their_entry.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863", GIT_OID_SHA1);
 
 	cl_git_pass(git_repository_index(&index, g_repo));
 	cl_git_pass(git_index_conflict_add(index, NULL, &our_entry, &their_entry));
@@ -1979,9 +1979,9 @@ void test_diff_workdir__to_index_conflicted(void) {
 
 	ancestor.path = ours.path = theirs.path = "_file";
 	ancestor.mode = ours.mode = theirs.mode = 0100644;
-	git_oid_fromstr(&ancestor.id, "d427e0b2e138501a3d15cc376077a3631e15bd46");
-	git_oid_fromstr(&ours.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf");
-	git_oid_fromstr(&theirs.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863");
+	git_oid__fromstr(&ancestor.id, "d427e0b2e138501a3d15cc376077a3631e15bd46", GIT_OID_SHA1);
+	git_oid__fromstr(&ours.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf", GIT_OID_SHA1);
+	git_oid__fromstr(&theirs.id, "2bd0a343aeef7a2cf0d158478966a6e587ff3863", GIT_OID_SHA1);
 	cl_git_pass(git_index_conflict_add(index, &ancestor, &ours, &theirs));
 
 	cl_git_pass(git_diff_tree_to_index(&diff1, g_repo, a, index, NULL));
diff --git a/tests/libgit2/email/create.c b/tests/libgit2/email/create.c
index 27a665582..cf40ff552 100644
--- a/tests/libgit2/email/create.c
+++ b/tests/libgit2/email/create.c
@@ -24,7 +24,7 @@ static void email_for_commit(
 	git_commit *commit = NULL;
 	git_diff *diff = NULL;
 
-	git_oid_fromstr(&oid, commit_id);
+	git_oid__fromstr(&oid, commit_id, GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 
@@ -323,7 +323,7 @@ void test_email_create__custom_summary_and_body(void)
 
 	opts.subject_prefix = "PPPPPATCH";
 
-	git_oid_fromstr(&oid, "627e7e12d87e07a83fad5b6bfa25e86ead4a5270");
+	git_oid__fromstr(&oid, "627e7e12d87e07a83fad5b6bfa25e86ead4a5270", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
 	cl_git_pass(git_email_create_from_diff(&buf, diff, 2, 4, &oid, summary, body, git_commit_author(commit), &opts));
diff --git a/tests/libgit2/email/create.c.bak b/tests/libgit2/email/create.c.bak
index 3bb95a6f6..cbb140bd2 100644
--- a/tests/libgit2/email/create.c.bak
+++ b/tests/libgit2/email/create.c.bak
@@ -25,7 +25,7 @@ static void email_for_commit(
 	git_commit *commit = NULL;
 	git_diff *diff = NULL;
 
-	git_oid_fromstr(&oid, commit_id);
+	git_oid_fromstr(&oid, commit_id, GIT_OID_SHA1);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 
@@ -156,7 +156,7 @@ void test_email_create__custom_summary_and_body(void)
 
 	opts.subject_prefix = "PPPPPATCH";
 
-	git_oid_fromstr(&oid, "627e7e12d87e07a83fad5b6bfa25e86ead4a5270");
+	git_oid_fromstr(&oid, "627e7e12d87e07a83fad5b6bfa25e86ead4a5270", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
 	cl_git_pass(git_email_create_from_diff(&buf, diff, 2, 4, &oid, summary, body, git_commit_author(commit), &opts));
diff --git a/tests/libgit2/fetch/local.c b/tests/libgit2/fetch/local.c
index 20bd7adf4..5d2417f1c 100644
--- a/tests/libgit2/fetch/local.c
+++ b/tests/libgit2/fetch/local.c
@@ -26,7 +26,7 @@ void test_fetch_local__defaults(void)
 		cl_fixture("testrepo.git")));
 	cl_git_pass(git_remote_fetch(remote, NULL, NULL, NULL));
 
-	git_oid_fromstr(&expected_id, "258f0e2a959a364e40ed6603d5d44fbb24765b10");
+	git_oid__fromstr(&expected_id, "258f0e2a959a364e40ed6603d5d44fbb24765b10", GIT_OID_SHA1);
 
 	cl_git_pass(git_revparse_single(&obj, repo, "refs/remotes/test/haacked"));
 	cl_assert_equal_oid(&expected_id, git_object_id(obj));
@@ -47,7 +47,7 @@ void test_fetch_local__reachable_commit(void)
 	refspecs.strings = &refspec;
 	refspecs.count = 1;
 
-	git_oid_fromstr(&expected_id, "5b5b025afb0b4c913b4c338a42934a3863bf3644");
+	git_oid__fromstr(&expected_id, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1);
 
 	cl_git_pass(git_remote_create(&remote, repo, "test",
 		cl_fixture("testrepo.git")));
diff --git a/tests/libgit2/fetchhead/nonetwork.c b/tests/libgit2/fetchhead/nonetwork.c
index aadcc7880..2519d895e 100644
--- a/tests/libgit2/fetchhead/nonetwork.c
+++ b/tests/libgit2/fetchhead/nonetwork.c
@@ -29,43 +29,49 @@ static void populate_fetchhead(git_vector *out, git_repository *repo)
 	git_fetchhead_ref *fetchhead_ref;
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"49322bb17d3acc9146f98c97d078513228bbf3c0"));
+	cl_git_pass(git_oid__fromstr(&oid,
+		"49322bb17d3acc9146f98c97d078513228bbf3c0",
+		GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&fetchhead_ref, &oid, 1,
 		"refs/heads/master",
 		"https://github.com/libgit2/TestGitRepository"));
 	cl_git_pass(git_vector_insert(out, fetchhead_ref));
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"0966a434eb1a025db6b71485ab63a3bfbea520b6"));
+	cl_git_pass(git_oid__fromstr(&oid,
+		"0966a434eb1a025db6b71485ab63a3bfbea520b6",
+		GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&fetchhead_ref, &oid, 0,
 		"refs/heads/first-merge",
 		"https://github.com/libgit2/TestGitRepository"));
 	cl_git_pass(git_vector_insert(out, fetchhead_ref));
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"42e4e7c5e507e113ebbb7801b16b52cf867b7ce1"));
+	cl_git_pass(git_oid__fromstr(&oid,
+		"42e4e7c5e507e113ebbb7801b16b52cf867b7ce1",
+		GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&fetchhead_ref, &oid, 0,
 		"refs/heads/no-parent",
 		"https://github.com/libgit2/TestGitRepository"));
 	cl_git_pass(git_vector_insert(out, fetchhead_ref));
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"d96c4e80345534eccee5ac7b07fc7603b56124cb"));
+	cl_git_pass(git_oid__fromstr(&oid,
+		"d96c4e80345534eccee5ac7b07fc7603b56124cb",
+		GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&fetchhead_ref, &oid, 0,
 		"refs/tags/annotated_tag",
 		"https://github.com/libgit2/TestGitRepository"));
 	cl_git_pass(git_vector_insert(out, fetchhead_ref));
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"55a1a760df4b86a02094a904dfa511deb5655905"));
+	cl_git_pass(git_oid__fromstr(&oid,
+		"55a1a760df4b86a02094a904dfa511deb5655905",
+		GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&fetchhead_ref, &oid, 0,
 		"refs/tags/blob",
 		"https://github.com/libgit2/TestGitRepository"));
 	cl_git_pass(git_vector_insert(out, fetchhead_ref));
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"8f50ba15d49353813cc6e20298002c0d17b0a9ee"));
+	cl_git_pass(git_oid__fromstr(&oid,
+		"8f50ba15d49353813cc6e20298002c0d17b0a9ee",
+		GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&fetchhead_ref, &oid, 0,
 		"refs/tags/commit_tree",
 		"https://github.com/libgit2/TestGitRepository"));
@@ -170,7 +176,7 @@ static int read_old_style_cb(const char *name, const char *url,
 
 	GIT_UNUSED(payload);
 
-	git_oid_fromstr(&expected, "49322bb17d3acc9146f98c97d078513228bbf3c0");
+	git_oid__fromstr(&expected, "49322bb17d3acc9146f98c97d078513228bbf3c0", GIT_OID_SHA1);
 
 	cl_assert(name == NULL);
 	cl_assert(url == NULL);
@@ -197,7 +203,7 @@ static int read_type_missing(const char *ref_name, const char *remote_url,
 
 	GIT_UNUSED(payload);
 
-	git_oid_fromstr(&expected, "49322bb17d3acc9146f98c97d078513228bbf3c0");
+	git_oid__fromstr(&expected, "49322bb17d3acc9146f98c97d078513228bbf3c0", GIT_OID_SHA1);
 
 	cl_assert_equal_s("name", ref_name);
 	cl_assert_equal_s("remote_url", remote_url);
@@ -224,7 +230,7 @@ static int read_name_missing(const char *ref_name, const char *remote_url,
 
 	GIT_UNUSED(payload);
 
-	git_oid_fromstr(&expected, "49322bb17d3acc9146f98c97d078513228bbf3c0");
+	git_oid__fromstr(&expected, "49322bb17d3acc9146f98c97d078513228bbf3c0", GIT_OID_SHA1);
 
 	cl_assert(ref_name == NULL);
 	cl_assert_equal_s("remote_url", remote_url);
@@ -528,13 +534,13 @@ void test_fetchhead_nonetwork__credentials_are_stripped(void)
 	git_fetchhead_ref *ref;
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, "49322bb17d3acc9146f98c97d078513228bbf3c0"));
+	cl_git_pass(git_oid__fromstr(&oid, "49322bb17d3acc9146f98c97d078513228bbf3c0", GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&ref, &oid, 0,
 		"refs/tags/commit_tree", "http://foo:bar@github.com/libgit2/TestGitRepository"));
 	cl_assert_equal_s(ref->remote_url, "http://github.com/libgit2/TestGitRepository");
 	git_fetchhead_ref_free(ref);
 
-	cl_git_pass(git_oid_fromstr(&oid, "49322bb17d3acc9146f98c97d078513228bbf3c0"));
+	cl_git_pass(git_oid__fromstr(&oid, "49322bb17d3acc9146f98c97d078513228bbf3c0", GIT_OID_SHA1));
 	cl_git_pass(git_fetchhead_ref_create(&ref, &oid, 0,
 		"refs/tags/commit_tree", "https://foo:bar@github.com/libgit2/TestGitRepository"));
 	cl_assert_equal_s(ref->remote_url, "https://github.com/libgit2/TestGitRepository");
diff --git a/tests/libgit2/filter/bare.c b/tests/libgit2/filter/bare.c
index 8402638ce..f53cfcb49 100644
--- a/tests/libgit2/filter/bare.c
+++ b/tests/libgit2/filter/bare.c
@@ -140,7 +140,7 @@ void test_filter_bare__from_specific_commit_one(void)
 
 	opts.flags |= GIT_BLOB_FILTER_NO_SYSTEM_ATTRIBUTES;
 	opts.flags |= GIT_BLOB_FILTER_ATTRIBUTES_FROM_COMMIT;
-	cl_git_pass(git_oid_fromstr(&opts.attr_commit_id, "b8986fec0f7bde90f78ac72706e782d82f24f2f0"));
+	cl_git_pass(git_oid__fromstr(&opts.attr_commit_id, "b8986fec0f7bde90f78ac72706e782d82f24f2f0", GIT_OID_SHA1));
 
 	cl_git_pass(git_revparse_single(
 		(git_object **)&blob, g_repo, "055c872")); /* ident */
@@ -165,7 +165,7 @@ void test_filter_bare__from_specific_commit_with_no_attributes_file(void)
 
 	opts.flags |= GIT_BLOB_FILTER_NO_SYSTEM_ATTRIBUTES;
 	opts.flags |= GIT_BLOB_FILTER_ATTRIBUTES_FROM_COMMIT;
-	cl_git_pass(git_oid_fromstr(&opts.attr_commit_id, "5afb6a14a864e30787857dd92af837e8cdd2cb1b"));
+	cl_git_pass(git_oid__fromstr(&opts.attr_commit_id, "5afb6a14a864e30787857dd92af837e8cdd2cb1b", GIT_OID_SHA1));
 
 	cl_git_pass(git_revparse_single(
 		(git_object **)&blob, g_repo, "799770d")); /* all-lf */
diff --git a/tests/libgit2/graph/ahead_behind.c b/tests/libgit2/graph/ahead_behind.c
index 77d7768af..dd828c5f3 100644
--- a/tests/libgit2/graph/ahead_behind.c
+++ b/tests/libgit2/graph/ahead_behind.c
@@ -10,7 +10,7 @@ void test_graph_ahead_behind__initialize(void)
 	git_oid oid;
 	cl_git_pass(git_repository_open(&_repo, cl_fixture("testrepo.git")));
 
-	cl_git_pass(git_oid_fromstr(&oid, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
+	cl_git_pass(git_oid__fromstr(&oid, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
 }
 
@@ -29,8 +29,8 @@ void test_graph_ahead_behind__returns_correct_result(void)
 	git_oid oid2;
 	git_commit *other;
 
-	cl_git_pass(git_oid_fromstr(&oid, "e90810b8df3e80c413d903f631643c716887138d"));
-	cl_git_pass(git_oid_fromstr(&oid2, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
+	cl_git_pass(git_oid__fromstr(&oid, "e90810b8df3e80c413d903f631643c716887138d", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&oid2, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
 	
 	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &oid, &oid2));
 	cl_assert_equal_sz(2, ahead);
diff --git a/tests/libgit2/graph/commitgraph.c b/tests/libgit2/graph/commitgraph.c
index 7607c35a3..e2452000d 100644
--- a/tests/libgit2/graph/commitgraph.c
+++ b/tests/libgit2/graph/commitgraph.c
@@ -19,28 +19,28 @@ void test_graph_commitgraph__parse(void)
 	cl_git_pass(git_commit_graph_file_open(&file, git_str_cstr(&commit_graph_path)));
 	cl_assert_equal_i(git_commit_graph_file_needs_refresh(file, git_str_cstr(&commit_graph_path)), 0);
 
-	cl_git_pass(git_oid_fromstr(&id, "5001298e0c09ad9c34e4249bc5801c75e9754fa5"));
-	cl_git_pass(git_commit_graph_entry_find(&e, file, &id, GIT_OID_HEXSZ));
+	cl_git_pass(git_oid__fromstr(&id, "5001298e0c09ad9c34e4249bc5801c75e9754fa5", GIT_OID_SHA1));
+	cl_git_pass(git_commit_graph_entry_find(&e, file, &id, GIT_OID_SHA1_HEXSIZE));
 	cl_assert_equal_oid(&e.sha1, &id);
-	cl_git_pass(git_oid_fromstr(&id, "418382dff1ffb8bdfba833f4d8bbcde58b1e7f47"));
+	cl_git_pass(git_oid__fromstr(&id, "418382dff1ffb8bdfba833f4d8bbcde58b1e7f47", GIT_OID_SHA1));
 	cl_assert_equal_oid(&e.tree_oid, &id);
 	cl_assert_equal_i(e.generation, 1);
 	cl_assert_equal_i(e.commit_time, UINT64_C(1273610423));
 	cl_assert_equal_i(e.parent_count, 0);
 
-	cl_git_pass(git_oid_fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
-	cl_git_pass(git_commit_graph_entry_find(&e, file, &id, GIT_OID_HEXSZ));
+	cl_git_pass(git_oid__fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
+	cl_git_pass(git_commit_graph_entry_find(&e, file, &id, GIT_OID_SHA1_HEXSIZE));
 	cl_assert_equal_oid(&e.sha1, &id);
 	cl_assert_equal_i(e.generation, 5);
 	cl_assert_equal_i(e.commit_time, UINT64_C(1274813907));
 	cl_assert_equal_i(e.parent_count, 2);
 
-	cl_git_pass(git_oid_fromstr(&id, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
+	cl_git_pass(git_oid__fromstr(&id, "9fd738e8f7967c078dceed8190330fc8648ee56a", GIT_OID_SHA1));
 	cl_git_pass(git_commit_graph_entry_parent(&parent, file, &e, 0));
 	cl_assert_equal_oid(&parent.sha1, &id);
 	cl_assert_equal_i(parent.generation, 4);
 
-	cl_git_pass(git_oid_fromstr(&id, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
+	cl_git_pass(git_oid__fromstr(&id, "c47800c7266a2be04c571c04d5a6614691ea99bd", GIT_OID_SHA1));
 	cl_git_pass(git_commit_graph_entry_parent(&parent, file, &e, 1));
 	cl_assert_equal_oid(&parent.sha1, &id);
 	cl_assert_equal_i(parent.generation, 3);
@@ -62,26 +62,26 @@ void test_graph_commitgraph__parse_octopus_merge(void)
 	cl_git_pass(git_str_joinpath(&commit_graph_path, git_repository_path(repo), "objects/info/commit-graph"));
 	cl_git_pass(git_commit_graph_file_open(&file, git_str_cstr(&commit_graph_path)));
 
-	cl_git_pass(git_oid_fromstr(&id, "d71c24b3b113fd1d1909998c5bfe33b86a65ee03"));
-	cl_git_pass(git_commit_graph_entry_find(&e, file, &id, GIT_OID_HEXSZ));
+	cl_git_pass(git_oid__fromstr(&id, "d71c24b3b113fd1d1909998c5bfe33b86a65ee03", GIT_OID_SHA1));
+	cl_git_pass(git_commit_graph_entry_find(&e, file, &id, GIT_OID_SHA1_HEXSIZE));
 	cl_assert_equal_oid(&e.sha1, &id);
-	cl_git_pass(git_oid_fromstr(&id, "348f16ffaeb73f319a75cec5b16a0a47d2d5e27c"));
+	cl_git_pass(git_oid__fromstr(&id, "348f16ffaeb73f319a75cec5b16a0a47d2d5e27c", GIT_OID_SHA1));
 	cl_assert_equal_oid(&e.tree_oid, &id);
 	cl_assert_equal_i(e.generation, 7);
 	cl_assert_equal_i(e.commit_time, UINT64_C(1447083009));
 	cl_assert_equal_i(e.parent_count, 3);
 
-	cl_git_pass(git_oid_fromstr(&id, "ad2ace9e15f66b3d1138922e6ffdc3ea3f967fa6"));
+	cl_git_pass(git_oid__fromstr(&id, "ad2ace9e15f66b3d1138922e6ffdc3ea3f967fa6", GIT_OID_SHA1));
 	cl_git_pass(git_commit_graph_entry_parent(&parent, file, &e, 0));
 	cl_assert_equal_oid(&parent.sha1, &id);
 	cl_assert_equal_i(parent.generation, 6);
 
-	cl_git_pass(git_oid_fromstr(&id, "483065df53c0f4a02cdc6b2910b05d388fc17ffb"));
+	cl_git_pass(git_oid__fromstr(&id, "483065df53c0f4a02cdc6b2910b05d388fc17ffb", GIT_OID_SHA1));
 	cl_git_pass(git_commit_graph_entry_parent(&parent, file, &e, 1));
 	cl_assert_equal_oid(&parent.sha1, &id);
 	cl_assert_equal_i(parent.generation, 2);
 
-	cl_git_pass(git_oid_fromstr(&id, "815b5a1c80ca749d705c7aa0cb294a00cbedd340"));
+	cl_git_pass(git_oid__fromstr(&id, "815b5a1c80ca749d705c7aa0cb294a00cbedd340", GIT_OID_SHA1));
 	cl_git_pass(git_commit_graph_entry_parent(&parent, file, &e, 2));
 	cl_assert_equal_oid(&parent.sha1, &id);
 	cl_assert_equal_i(parent.generation, 6);
diff --git a/tests/libgit2/graph/descendant_of.c b/tests/libgit2/graph/descendant_of.c
index 8e9952a09..b6dffae06 100644
--- a/tests/libgit2/graph/descendant_of.c
+++ b/tests/libgit2/graph/descendant_of.c
@@ -9,7 +9,7 @@ void test_graph_descendant_of__initialize(void)
 
 	cl_git_pass(git_repository_open(&_repo, cl_fixture("testrepo.git")));
 
-	git_oid_fromstr(&oid, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+	git_oid__fromstr(&oid, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
 }
 
@@ -50,6 +50,6 @@ void test_graph_descendant_of__nopath(void)
 {
 	git_oid oid;
 
-	git_oid_fromstr(&oid, "e90810b8df3e80c413d903f631643c716887138d");
+	git_oid__fromstr(&oid, "e90810b8df3e80c413d903f631643c716887138d", GIT_OID_SHA1);
 	cl_assert_equal_i(0, git_graph_descendant_of(_repo, git_commit_id(commit), &oid));
 }
diff --git a/tests/libgit2/graph/reachable_from_any.c b/tests/libgit2/graph/reachable_from_any.c
index 9693d7d67..8e1c23874 100644
--- a/tests/libgit2/graph/reachable_from_any.c
+++ b/tests/libgit2/graph/reachable_from_any.c
@@ -17,7 +17,7 @@ void test_graph_reachable_from_any__initialize(void)
 
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
 
-	git_oid_fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707");
+	git_oid__fromstr(&oid, "539bd011c4822c560c1d17cab095006b7a10f707", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
diff --git a/tests/libgit2/index/add.c b/tests/libgit2/index/add.c
index f101ea266..b0c3bd2b7 100644
--- a/tests/libgit2/index/add.c
+++ b/tests/libgit2/index/add.c
@@ -28,7 +28,7 @@ static void test_add_entry(
 {
 	git_index_entry entry = {{0}};
 
-	cl_git_pass(git_oid_fromstr(&entry.id, idstr));
+	cl_git_pass(git_oid__fromstr(&entry.id, idstr, GIT_OID_SHA1));
 
 	entry.path = mode == GIT_FILEMODE_TREE ? "test_folder" : "test_file";
 	entry.mode = mode;
diff --git a/tests/libgit2/index/bypath.c b/tests/libgit2/index/bypath.c
index b32a0a789..15c11af5f 100644
--- a/tests/libgit2/index/bypath.c
+++ b/tests/libgit2/index/bypath.c
@@ -131,7 +131,7 @@ void test_index_bypath__add_honors_existing_case_2(void)
 		clar__skip();
 
 	dummy.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&dummy.id, "f990a25a74d1a8281ce2ab018ea8df66795cd60b"));
+	cl_git_pass(git_oid__fromstr(&dummy.id, "f990a25a74d1a8281ce2ab018ea8df66795cd60b", GIT_OID_SHA1));
 
 	/* note that `git_index_add` does no checking to canonical directories */
 	dummy.path = "Just_a_dir/file0.txt";
@@ -187,7 +187,7 @@ void test_index_bypath__add_honors_existing_case_3(void)
 		clar__skip();
 
 	dummy.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&dummy.id, "f990a25a74d1a8281ce2ab018ea8df66795cd60b"));
+	cl_git_pass(git_oid__fromstr(&dummy.id, "f990a25a74d1a8281ce2ab018ea8df66795cd60b", GIT_OID_SHA1));
 
 	dummy.path = "just_a_dir/filea.txt";
 	cl_git_pass(git_index_add(g_idx, &dummy));
@@ -218,7 +218,7 @@ void test_index_bypath__add_honors_existing_case_4(void)
 		clar__skip();
 
 	dummy.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&dummy.id, "f990a25a74d1a8281ce2ab018ea8df66795cd60b"));
+	cl_git_pass(git_oid__fromstr(&dummy.id, "f990a25a74d1a8281ce2ab018ea8df66795cd60b", GIT_OID_SHA1));
 
 	dummy.path = "just_a_dir/a/b/c/d/e/file1.txt";
 	cl_git_pass(git_index_add(g_idx, &dummy));
diff --git a/tests/libgit2/index/cache.c b/tests/libgit2/index/cache.c
index 56885aff7..7576331b0 100644
--- a/tests/libgit2/index/cache.c
+++ b/tests/libgit2/index/cache.c
@@ -26,7 +26,7 @@ void test_index_cache__write_extension_at_root(void)
 
 	cl_git_pass(git_index_open(&index, index_file));
 	cl_assert(index->tree == NULL);
-	cl_git_pass(git_oid_fromstr(&id, tree_id_str));
+	cl_git_pass(git_oid__fromstr(&id, tree_id_str, GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 	cl_git_pass(git_index_read_tree(index, tree));
 	git_tree_free(tree);
@@ -58,7 +58,7 @@ void test_index_cache__write_extension_invalidated_root(void)
 
 	cl_git_pass(git_index_open(&index, index_file));
 	cl_assert(index->tree == NULL);
-	cl_git_pass(git_oid_fromstr(&id, tree_id_str));
+	cl_git_pass(git_oid__fromstr(&id, tree_id_str, GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 	cl_git_pass(git_index_read_tree(index, tree));
 	git_tree_free(tree);
@@ -98,7 +98,7 @@ void test_index_cache__read_tree_no_children(void)
 
 	cl_git_pass(git_index_new(&index));
 	cl_assert(index->tree == NULL);
-	cl_git_pass(git_oid_fromstr(&id, "45dd856fdd4d89b884c340ba0e047752d9b085d6"));
+	cl_git_pass(git_oid__fromstr(&id, "45dd856fdd4d89b884c340ba0e047752d9b085d6", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 	cl_git_pass(git_index_read_tree(index, tree));
 	git_tree_free(tree);
@@ -111,7 +111,7 @@ void test_index_cache__read_tree_no_children(void)
 	memset(&entry, 0x0, sizeof(git_index_entry));
 	entry.path = "new.txt";
 	entry.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&entry.id, "d4bcc68acd4410bf836a39f20afb2c2ece09584e");
+	git_oid__fromstr(&entry.id, "d4bcc68acd4410bf836a39f20afb2c2ece09584e", GIT_OID_SHA1);
 
 	cl_git_pass(git_index_add(index, &entry));
 	cl_assert_equal_i(-1, index->tree->entry_count);
@@ -132,7 +132,7 @@ void test_index_cache__two_levels(void)
 
 	memset(&entry, 0x0, sizeof(entry));
 	entry.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&entry.id, "a8233120f6ad708f843d861ce2b7228ec4e3dec6"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "a8233120f6ad708f843d861ce2b7228ec4e3dec6", GIT_OID_SHA1));
 	entry.path = "top-level.txt";
 	cl_git_pass(git_index_add(index, &entry));
 
@@ -156,7 +156,7 @@ void test_index_cache__two_levels(void)
 	cl_assert(git_tree_cache_get(index->tree, "subdir"));
 
 	entry.path = "top-level.txt";
-	cl_git_pass(git_oid_fromstr(&entry.id, "3697d64be941a53d4ae8f6a271e4e3fa56b022cc"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "3697d64be941a53d4ae8f6a271e4e3fa56b022cc", GIT_OID_SHA1));
 	cl_git_pass(git_index_add(index, &entry));
 
 	/* writ out the index after we invalidate the root */
@@ -191,7 +191,7 @@ void test_index_cache__read_tree_children(void)
 	memset(&entry, 0x0, sizeof(git_index_entry));
 	entry.path = "top-level";
 	entry.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf");
+	git_oid__fromstr(&entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf", GIT_OID_SHA1);
 	cl_git_pass(git_index_add(index, &entry));
 
 
@@ -217,7 +217,7 @@ void test_index_cache__read_tree_children(void)
 
 	/* override with a slightly different id, also dummy */
 	entry.path = "subdir/some-file";
-	git_oid_fromstr(&entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf");
+	git_oid__fromstr(&entry.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf", GIT_OID_SHA1);
 	cl_git_pass(git_index_add(index, &entry));
 
 	cl_assert_equal_i(-1, index->tree->entry_count);
diff --git a/tests/libgit2/index/conflicts.c b/tests/libgit2/index/conflicts.c
index 41d0e219c..353886f7b 100644
--- a/tests/libgit2/index/conflicts.c
+++ b/tests/libgit2/index/conflicts.c
@@ -37,17 +37,17 @@ void test_index_conflicts__add(void)
 	ancestor_entry.path = "test-one.txt";
 	ancestor_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 1);
-	git_oid_fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 
 	our_entry.path = "test-one.txt";
 	our_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&our_entry, 2);
-	git_oid_fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID);
+	git_oid__fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 
 	their_entry.path = "test-one.txt";
 	their_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 2);
-	git_oid_fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID);
+	git_oid__fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_conflict_add(repo_index, &ancestor_entry, &our_entry, &their_entry));
 
@@ -68,17 +68,17 @@ void test_index_conflicts__add_fixes_incorrect_stage(void)
 	ancestor_entry.path = "test-one.txt";
 	ancestor_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 3);
-	git_oid_fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 
 	our_entry.path = "test-one.txt";
 	our_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&our_entry, 1);
-	git_oid_fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID);
+	git_oid__fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 
 	their_entry.path = "test-one.txt";
 	their_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&their_entry, 2);
-	git_oid_fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID);
+	git_oid__fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_conflict_add(repo_index, &ancestor_entry, &our_entry, &their_entry));
 
@@ -111,17 +111,17 @@ void test_index_conflicts__add_detects_invalid_filemode(void)
 		ancestor_entry.path = "test-one.txt";
 		ancestor_entry.mode = 0100644;
 		GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 3);
-		git_oid_fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID);
+		git_oid__fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 
 		our_entry.path = "test-one.txt";
 		our_entry.mode = 0100644;
 		GIT_INDEX_ENTRY_STAGE_SET(&our_entry, 1);
-		git_oid_fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID);
+		git_oid__fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 
 		their_entry.path = "test-one.txt";
 		their_entry.mode = 0100644;
 		GIT_INDEX_ENTRY_STAGE_SET(&their_entry, 2);
-		git_oid_fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID);
+		git_oid__fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 
 		/* Corrupt the conflict entry's mode */
 		conflict_entry[i]->mode = 027431745;
@@ -151,17 +151,17 @@ void test_index_conflicts__add_removes_stage_zero(void)
 	ancestor_entry.path = "test-one.txt";
 	ancestor_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 3);
-	git_oid_fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 
 	our_entry.path = "test-one.txt";
 	our_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&our_entry, 1);
-	git_oid_fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID);
+	git_oid__fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 
 	their_entry.path = "test-one.txt";
 	their_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&their_entry, 2);
-	git_oid_fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID);
+	git_oid__fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_conflict_add(repo_index, &ancestor_entry, &our_entry, &their_entry));
 
@@ -189,13 +189,13 @@ void test_index_conflicts__get(void)
 
 	cl_assert_equal_s("conflicts-one.txt", conflict_entry[0]->path);
 
-	git_oid_fromstr(&oid, CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[0]->id);
 
-	git_oid_fromstr(&oid, CONFLICTS_ONE_OUR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[1]->id);
 
-	git_oid_fromstr(&oid, CONFLICTS_ONE_THEIR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[2]->id);
 
 	cl_git_pass(git_index_conflict_get(&conflict_entry[0], &conflict_entry[1],
@@ -203,13 +203,13 @@ void test_index_conflicts__get(void)
 
 	cl_assert_equal_s("conflicts-two.txt", conflict_entry[0]->path);
 
-	git_oid_fromstr(&oid, CONFLICTS_TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[0]->id);
 
-	git_oid_fromstr(&oid, CONFLICTS_TWO_OUR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[1]->id);
 
-	git_oid_fromstr(&oid, CONFLICTS_TWO_THEIR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[2]->id);
 }
 
@@ -223,29 +223,29 @@ void test_index_conflicts__iterate(void)
 
 	cl_git_pass(git_index_conflict_next(&conflict_entry[0], &conflict_entry[1], &conflict_entry[2], iterator));
 
-	git_oid_fromstr(&oid, CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[0]->id);
 	cl_assert(git__strcmp(conflict_entry[0]->path, "conflicts-one.txt") == 0);
 
-	git_oid_fromstr(&oid, CONFLICTS_ONE_OUR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[1]->id);
 	cl_assert(git__strcmp(conflict_entry[0]->path, "conflicts-one.txt") == 0);
 
-	git_oid_fromstr(&oid, CONFLICTS_ONE_THEIR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[2]->id);
 	cl_assert(git__strcmp(conflict_entry[0]->path, "conflicts-one.txt") == 0);
 
 	cl_git_pass(git_index_conflict_next(&conflict_entry[0], &conflict_entry[1], &conflict_entry[2], iterator));
 
-	git_oid_fromstr(&oid, CONFLICTS_TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[0]->id);
 	cl_assert(git__strcmp(conflict_entry[0]->path, "conflicts-two.txt") == 0);
 
-	git_oid_fromstr(&oid, CONFLICTS_TWO_OUR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[1]->id);
 	cl_assert(git__strcmp(conflict_entry[0]->path, "conflicts-two.txt") == 0);
 
-	git_oid_fromstr(&oid, CONFLICTS_TWO_THEIR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[2]->id);
 	cl_assert(git__strcmp(conflict_entry[0]->path, "conflicts-two.txt") == 0);
 
@@ -357,7 +357,7 @@ void test_index_conflicts__partial(void)
 	ancestor_entry.path = "test-one.txt";
 	ancestor_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 1);
-	git_oid_fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_conflict_add(repo_index, &ancestor_entry, NULL, NULL));
 	cl_assert(git_index_entrycount(repo_index) == 9);
@@ -387,17 +387,17 @@ void test_index_conflicts__case_matters(void)
 
 	ancestor_entry.path = upper_case;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, GIT_INDEX_STAGE_ANCESTOR);
-	git_oid_fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&ancestor_entry.id, CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 	ancestor_entry.mode = GIT_FILEMODE_BLOB;
 
 	our_entry.path = upper_case;
 	GIT_INDEX_ENTRY_STAGE_SET(&our_entry, GIT_INDEX_STAGE_OURS);
-	git_oid_fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID);
+	git_oid__fromstr(&our_entry.id, CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 	our_entry.mode = GIT_FILEMODE_BLOB;
 
 	their_entry.path = upper_case;
 	GIT_INDEX_ENTRY_STAGE_SET(&their_entry, GIT_INDEX_STAGE_THEIRS);
-	git_oid_fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID);
+	git_oid__fromstr(&their_entry.id, CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 	their_entry.mode = GIT_FILEMODE_BLOB;
 
 	cl_git_pass(git_index_conflict_add(repo_index,
@@ -405,17 +405,17 @@ void test_index_conflicts__case_matters(void)
 
 	ancestor_entry.path = mixed_case;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, GIT_INDEX_STAGE_ANCESTOR);
-	git_oid_fromstr(&ancestor_entry.id, CONFLICTS_TWO_ANCESTOR_OID);
+	git_oid__fromstr(&ancestor_entry.id, CONFLICTS_TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	ancestor_entry.mode = GIT_FILEMODE_BLOB;
 
 	our_entry.path = mixed_case;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, GIT_INDEX_STAGE_ANCESTOR);
-	git_oid_fromstr(&our_entry.id, CONFLICTS_TWO_OUR_OID);
+	git_oid__fromstr(&our_entry.id, CONFLICTS_TWO_OUR_OID, GIT_OID_SHA1);
 	ancestor_entry.mode = GIT_FILEMODE_BLOB;
 
 	their_entry.path = mixed_case;
 	GIT_INDEX_ENTRY_STAGE_SET(&their_entry, GIT_INDEX_STAGE_THEIRS);
-	git_oid_fromstr(&their_entry.id, CONFLICTS_TWO_THEIR_OID);
+	git_oid__fromstr(&their_entry.id, CONFLICTS_TWO_THEIR_OID, GIT_OID_SHA1);
 	their_entry.mode = GIT_FILEMODE_BLOB;
 
 	cl_git_pass(git_index_conflict_add(repo_index,
@@ -434,29 +434,29 @@ void test_index_conflicts__case_matters(void)
 		correct_case = upper_case;
 
 	cl_assert_equal_s(correct_case, conflict_entry[0]->path);
-	git_oid_fromstr(&oid, ignorecase ? CONFLICTS_TWO_ANCESTOR_OID : CONFLICTS_ONE_ANCESTOR_OID);
+	git_oid__fromstr(&oid, ignorecase ? CONFLICTS_TWO_ANCESTOR_OID : CONFLICTS_ONE_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[0]->id);
 
 	cl_assert_equal_s(correct_case, conflict_entry[1]->path);
-	git_oid_fromstr(&oid, ignorecase ? CONFLICTS_TWO_OUR_OID : CONFLICTS_ONE_OUR_OID);
+	git_oid__fromstr(&oid, ignorecase ? CONFLICTS_TWO_OUR_OID : CONFLICTS_ONE_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[1]->id);
 
 	cl_assert_equal_s(correct_case, conflict_entry[2]->path);
-	git_oid_fromstr(&oid, ignorecase ? CONFLICTS_TWO_THEIR_OID : CONFLICTS_ONE_THEIR_OID);
+	git_oid__fromstr(&oid, ignorecase ? CONFLICTS_TWO_THEIR_OID : CONFLICTS_ONE_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[2]->id);
 
 	cl_git_pass(git_index_conflict_get(&conflict_entry[0], &conflict_entry[1],
 		&conflict_entry[2], repo_index, mixed_case));
 
 	cl_assert_equal_s(mixed_case, conflict_entry[0]->path);
-	git_oid_fromstr(&oid, CONFLICTS_TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[0]->id);
 
 	cl_assert_equal_s(mixed_case, conflict_entry[1]->path);
-	git_oid_fromstr(&oid, CONFLICTS_TWO_OUR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[1]->id);
 
 	cl_assert_equal_s(mixed_case, conflict_entry[2]->path);
-	git_oid_fromstr(&oid, CONFLICTS_TWO_THEIR_OID);
+	git_oid__fromstr(&oid, CONFLICTS_TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&oid, &conflict_entry[2]->id);
 }
diff --git a/tests/libgit2/index/crlf.c b/tests/libgit2/index/crlf.c
index 7520c23a3..666ac1a0c 100644
--- a/tests/libgit2/index/crlf.c
+++ b/tests/libgit2/index/crlf.c
@@ -243,8 +243,9 @@ void test_index_crlf__autocrlf_false_no_attrs(void)
 	cl_git_pass(git_index_add_bypath(g_index, "newfile.txt"));
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		(GIT_EOL_NATIVE == GIT_EOL_CRLF) ? FILE_OID_CRLF : FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid,
+		(GIT_EOL_NATIVE == GIT_EOL_CRLF) ? FILE_OID_CRLF : FILE_OID_LF,
+		GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 }
 
@@ -261,7 +262,7 @@ void test_index_crlf__autocrlf_true_no_attrs(void)
 	cl_git_pass(git_index_add_bypath(g_index, "newfile.txt"));
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 
-	cl_git_pass(git_oid_fromstr(&oid, FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid, FILE_OID_LF, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 }
 
@@ -278,7 +279,7 @@ void test_index_crlf__autocrlf_input_no_attrs(void)
 	cl_git_pass(git_index_add_bypath(g_index, "newfile.txt"));
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 
-	cl_git_pass(git_oid_fromstr(&oid, FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid, FILE_OID_LF, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 }
 
@@ -297,7 +298,7 @@ void test_index_crlf__autocrlf_false_text_auto_attr(void)
 	cl_git_pass(git_index_add_bypath(g_index, "newfile.txt"));
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 
-	cl_git_pass(git_oid_fromstr(&oid, FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid, FILE_OID_LF, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 }
 
@@ -316,7 +317,7 @@ void test_index_crlf__autocrlf_true_text_auto_attr(void)
 	cl_git_pass(git_index_add_bypath(g_index, "newfile.txt"));
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 
-	cl_git_pass(git_oid_fromstr(&oid, FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid, FILE_OID_LF, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 }
 
@@ -335,7 +336,7 @@ void test_index_crlf__autocrlf_input_text_auto_attr(void)
 	cl_git_pass(git_index_add_bypath(g_index, "newfile.txt"));
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 
-	cl_git_pass(git_oid_fromstr(&oid, FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid, FILE_OID_LF, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 }
 
@@ -355,7 +356,7 @@ void test_index_crlf__safecrlf_true_autocrlf_input_text_auto_attr(void)
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 	cl_assert(entry);
 
-	cl_git_pass(git_oid_fromstr(&oid, FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid, FILE_OID_LF, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 
 	cl_git_mkfile("./crlf/newfile2.txt", FILE_CONTENTS_CRLF);
@@ -376,7 +377,7 @@ void test_index_crlf__safecrlf_true_autocrlf_input_text__no_attr(void)
 	entry = git_index_get_bypath(g_index, "newfile.txt", 0);
 	cl_assert(entry);
 
-	cl_git_pass(git_oid_fromstr(&oid, FILE_OID_LF));
+	cl_git_pass(git_oid__fromstr(&oid, FILE_OID_LF, GIT_OID_SHA1));
 	cl_assert_equal_oid(&oid, &entry->id);
 
 	cl_git_mkfile("./crlf/newfile2.txt", FILE_CONTENTS_CRLF);
diff --git a/tests/libgit2/index/names.c b/tests/libgit2/index/names.c
index 369318b03..2a41100aa 100644
--- a/tests/libgit2/index/names.c
+++ b/tests/libgit2/index/names.c
@@ -42,21 +42,21 @@ static void index_add_conflicts(void)
 		entry.path = conflict[0];
 		entry.mode = GIT_FILEMODE_BLOB;
 		GIT_INDEX_ENTRY_STAGE_SET(&entry, GIT_INDEX_STAGE_ANCESTOR);
-		git_oid_fromstr(&entry.id, "1f85ca51b8e0aac893a621b61a9c2661d6aa6d81");
+		git_oid__fromstr(&entry.id, "1f85ca51b8e0aac893a621b61a9c2661d6aa6d81", GIT_OID_SHA1);
 		cl_git_pass(git_index_add(repo_index, &entry));
 
 		/* ours */
 		entry.path = conflict[1];
 		entry.mode = GIT_FILEMODE_BLOB;
 		GIT_INDEX_ENTRY_STAGE_SET(&entry, GIT_INDEX_STAGE_OURS);
-		git_oid_fromstr(&entry.id, "1f85ca51b8e0aac893a621b61a9c2661d6aa6d81");
+		git_oid__fromstr(&entry.id, "1f85ca51b8e0aac893a621b61a9c2661d6aa6d81", GIT_OID_SHA1);
 		cl_git_pass(git_index_add(repo_index, &entry));
 
 		/* theirs */
 		entry.path = conflict[2];
 		entry.mode = GIT_FILEMODE_BLOB;
 		GIT_INDEX_ENTRY_STAGE_SET(&entry, GIT_INDEX_STAGE_THEIRS);
-		git_oid_fromstr(&entry.id, "1f85ca51b8e0aac893a621b61a9c2661d6aa6d81");
+		git_oid__fromstr(&entry.id, "1f85ca51b8e0aac893a621b61a9c2661d6aa6d81", GIT_OID_SHA1);
 		cl_git_pass(git_index_add(repo_index, &entry));
 	}
 }
diff --git a/tests/libgit2/index/read_index.c b/tests/libgit2/index/read_index.c
index 836c12b0e..ac03cf177 100644
--- a/tests/libgit2/index/read_index.c
+++ b/tests/libgit2/index/read_index.c
@@ -49,7 +49,7 @@ void test_index_read_index__maintains_stat_cache(void)
 	/* add a new entry that will not have stat data */
 	memset(&new_entry, 0, sizeof(git_index_entry));
 	new_entry.path = "Hello";
-	git_oid_fromstr(&new_entry.id, "0123456789012345678901234567890123456789");
+	git_oid__fromstr(&new_entry.id, "0123456789012345678901234567890123456789", GIT_OID_SHA1);
 	new_entry.file_size = 1234;
 	new_entry.mode = 0100644;
 	cl_git_pass(git_index_add(new_index, &new_entry));
@@ -79,7 +79,7 @@ static bool roundtrip_with_read_index(const char *tree_idstr)
 	git_tree *tree;
 	git_index *tree_index;
 
-	cl_git_pass(git_oid_fromstr(&tree_id, tree_idstr));
+	cl_git_pass(git_oid__fromstr(&tree_id, tree_idstr, GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, _repo, &tree_id));
 	cl_git_pass(git_index_new(&tree_index));
 	cl_git_pass(git_index_read_tree(tree_index, tree));
@@ -111,7 +111,7 @@ void test_index_read_index__read_and_writes(void)
 	git_tree *tree;
 	git_index *tree_index, *new_index;
 
-	cl_git_pass(git_oid_fromstr(&tree_id, "ae90f12eea699729ed24555e40b9fd669da12a12"));
+	cl_git_pass(git_oid__fromstr(&tree_id, "ae90f12eea699729ed24555e40b9fd669da12a12", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, _repo, &tree_id));
 	cl_git_pass(git_index_new(&tree_index));
 	cl_git_pass(git_index_read_tree(tree_index, tree));
@@ -148,17 +148,17 @@ static void add_conflicts(git_index *index, const char *filename)
 	ancestor_entry.path = filename;
 	ancestor_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 1);
-	git_oid_fromstr(&ancestor_entry.id, ancestor_ids[conflict_idx]);
+	git_oid__fromstr(&ancestor_entry.id, ancestor_ids[conflict_idx], GIT_OID_SHA1);
 
 	our_entry.path = filename;
 	our_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&our_entry, 2);
-	git_oid_fromstr(&our_entry.id, our_ids[conflict_idx]);
+	git_oid__fromstr(&our_entry.id, our_ids[conflict_idx], GIT_OID_SHA1);
 
 	their_entry.path = filename;
 	their_entry.mode = 0100644;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 2);
-	git_oid_fromstr(&their_entry.id, their_ids[conflict_idx]);
+	git_oid__fromstr(&their_entry.id, their_ids[conflict_idx], GIT_OID_SHA1);
 
 	cl_git_pass(git_index_conflict_add(index, &ancestor_entry,
 		&our_entry, &their_entry));
@@ -172,7 +172,7 @@ void test_index_read_index__handles_conflicts(void)
 	git_index_conflict_iterator *conflict_iterator;
 	const git_index_entry *ancestor, *ours, *theirs;
 
-	cl_git_pass(git_oid_fromstr(&tree_id, "ae90f12eea699729ed24555e40b9fd669da12a12"));
+	cl_git_pass(git_oid__fromstr(&tree_id, "ae90f12eea699729ed24555e40b9fd669da12a12", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, _repo, &tree_id));
 	cl_git_pass(git_index_new(&index));
 	cl_git_pass(git_index_new(&new_index));
diff --git a/tests/libgit2/index/rename.c b/tests/libgit2/index/rename.c
index 86eaf0053..9b132cb61 100644
--- a/tests/libgit2/index/rename.c
+++ b/tests/libgit2/index/rename.c
@@ -22,7 +22,7 @@ void test_index_rename__single_file(void)
 	cl_git_pass(git_index_add_bypath(index, "lame.name.txt"));
 	cl_assert(git_index_entrycount(index) == 1);
 
-	cl_git_pass(git_oid_fromstr(&expected, "d4fa8600b4f37d7516bef4816ae2c64dbf029e3a"));
+	cl_git_pass(git_oid__fromstr(&expected, "d4fa8600b4f37d7516bef4816ae2c64dbf029e3a", GIT_OID_SHA1));
 
 	cl_assert(!git_index_find(&position, index, "lame.name.txt"));
 
diff --git a/tests/libgit2/index/reuc.c b/tests/libgit2/index/reuc.c
index 1f95c4136..7d8766c57 100644
--- a/tests/libgit2/index/reuc.c
+++ b/tests/libgit2/index/reuc.c
@@ -38,9 +38,9 @@ void test_index_reuc__add(void)
 	git_oid ancestor_oid, our_oid, their_oid;
 	const git_index_reuc_entry *reuc;
 
-	git_oid_fromstr(&ancestor_oid, ONE_ANCESTOR_OID);
-	git_oid_fromstr(&our_oid, ONE_OUR_OID);
-	git_oid_fromstr(&their_oid, ONE_THEIR_OID);
+	git_oid__fromstr(&ancestor_oid, ONE_ANCESTOR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&our_oid, ONE_OUR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&their_oid, ONE_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_reuc_add(repo_index, "newfile.txt",
 		0100644, &ancestor_oid,
@@ -66,8 +66,8 @@ void test_index_reuc__add_no_ancestor(void)
 	const git_index_reuc_entry *reuc;
 
 	memset(&ancestor_oid, 0x0, sizeof(git_oid));
-	git_oid_fromstr(&our_oid, ONE_OUR_OID);
-	git_oid_fromstr(&their_oid, ONE_THEIR_OID);
+	git_oid__fromstr(&our_oid, ONE_OUR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&their_oid, ONE_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_reuc_add(repo_index, "newfile.txt",
 		0, NULL,
@@ -100,11 +100,11 @@ void test_index_reuc__read_bypath(void)
 	cl_assert(reuc->mode[0] == 0100644);
 	cl_assert(reuc->mode[1] == 0100644);
 	cl_assert(reuc->mode[2] == 0100644);
-	git_oid_fromstr(&oid, TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[0], &oid);
-	git_oid_fromstr(&oid, TWO_OUR_OID);
+	git_oid__fromstr(&oid, TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[1], &oid);
-	git_oid_fromstr(&oid, TWO_THEIR_OID);
+	git_oid__fromstr(&oid, TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[2], &oid);
 
 	cl_assert(reuc = git_index_reuc_get_bypath(repo_index, "one.txt"));
@@ -113,11 +113,11 @@ void test_index_reuc__read_bypath(void)
 	cl_assert(reuc->mode[0] == 0100644);
 	cl_assert(reuc->mode[1] == 0100644);
 	cl_assert(reuc->mode[2] == 0100644);
-	git_oid_fromstr(&oid, ONE_ANCESTOR_OID);
+	git_oid__fromstr(&oid, ONE_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[0], &oid);
-	git_oid_fromstr(&oid, ONE_OUR_OID);
+	git_oid__fromstr(&oid, ONE_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[1], &oid);
-	git_oid_fromstr(&oid, ONE_THEIR_OID);
+	git_oid__fromstr(&oid, ONE_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[2], &oid);
 }
 
@@ -145,11 +145,11 @@ void test_index_reuc__ignore_case(void)
 	cl_assert(reuc->mode[0] == 0100644);
 	cl_assert(reuc->mode[1] == 0100644);
 	cl_assert(reuc->mode[2] == 0100644);
-	git_oid_fromstr(&oid, TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[0], &oid);
-	git_oid_fromstr(&oid, TWO_OUR_OID);
+	git_oid__fromstr(&oid, TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[1], &oid);
-	git_oid_fromstr(&oid, TWO_THEIR_OID);
+	git_oid__fromstr(&oid, TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[2], &oid);
 }
 
@@ -166,11 +166,11 @@ void test_index_reuc__read_byindex(void)
 	cl_assert(reuc->mode[0] == 0100644);
 	cl_assert(reuc->mode[1] == 0100644);
 	cl_assert(reuc->mode[2] == 0100644);
-	git_oid_fromstr(&oid, ONE_ANCESTOR_OID);
+	git_oid__fromstr(&oid, ONE_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[0], &oid);
-	git_oid_fromstr(&oid, ONE_OUR_OID);
+	git_oid__fromstr(&oid, ONE_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[1], &oid);
-	git_oid_fromstr(&oid, ONE_THEIR_OID);
+	git_oid__fromstr(&oid, ONE_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[2], &oid);
 
 	cl_assert(reuc = git_index_reuc_get_byindex(repo_index, 1));
@@ -179,11 +179,11 @@ void test_index_reuc__read_byindex(void)
 	cl_assert(reuc->mode[0] == 0100644);
 	cl_assert(reuc->mode[1] == 0100644);
 	cl_assert(reuc->mode[2] == 0100644);
-	git_oid_fromstr(&oid, TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[0], &oid);
-	git_oid_fromstr(&oid, TWO_OUR_OID);
+	git_oid__fromstr(&oid, TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[1], &oid);
-	git_oid_fromstr(&oid, TWO_THEIR_OID);
+	git_oid__fromstr(&oid, TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[2], &oid);
 }
 
@@ -200,9 +200,9 @@ void test_index_reuc__updates_existing(void)
 	index_caps |= GIT_INDEX_CAPABILITY_IGNORE_CASE;
 	cl_git_pass(git_index_set_caps(repo_index, index_caps));
 
-	git_oid_fromstr(&ancestor_oid, TWO_ANCESTOR_OID);
-	git_oid_fromstr(&our_oid, TWO_OUR_OID);
-	git_oid_fromstr(&their_oid, TWO_THEIR_OID);
+	git_oid__fromstr(&ancestor_oid, TWO_ANCESTOR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&our_oid, TWO_OUR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&their_oid, TWO_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_reuc_add(repo_index, "two.txt",
 		0100644, &ancestor_oid,
@@ -219,11 +219,11 @@ void test_index_reuc__updates_existing(void)
 	cl_assert(reuc = git_index_reuc_get_byindex(repo_index, 0));
 
 	cl_assert_equal_s("TWO.txt", reuc->path);
-	git_oid_fromstr(&oid, TWO_OUR_OID);
+	git_oid__fromstr(&oid, TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[0], &oid);
-	git_oid_fromstr(&oid, TWO_THEIR_OID);
+	git_oid__fromstr(&oid, TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[1], &oid);
-	git_oid_fromstr(&oid, TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[2], &oid);
 }
 
@@ -245,11 +245,11 @@ void test_index_reuc__remove(void)
 	cl_assert(reuc->mode[0] == 0100644);
 	cl_assert(reuc->mode[1] == 0100644);
 	cl_assert(reuc->mode[2] == 0100644);
-	git_oid_fromstr(&oid, TWO_ANCESTOR_OID);
+	git_oid__fromstr(&oid, TWO_ANCESTOR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[0], &oid);
-	git_oid_fromstr(&oid, TWO_OUR_OID);
+	git_oid__fromstr(&oid, TWO_OUR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[1], &oid);
-	git_oid_fromstr(&oid, TWO_THEIR_OID);
+	git_oid__fromstr(&oid, TWO_THEIR_OID, GIT_OID_SHA1);
 	cl_assert_equal_oid(&reuc->oid[2], &oid);
 }
 
@@ -261,18 +261,18 @@ void test_index_reuc__write(void)
 	git_index_clear(repo_index);
 
 	/* Write out of order to ensure sorting is correct */
-	git_oid_fromstr(&ancestor_oid, TWO_ANCESTOR_OID);
-	git_oid_fromstr(&our_oid, TWO_OUR_OID);
-	git_oid_fromstr(&their_oid, TWO_THEIR_OID);
+	git_oid__fromstr(&ancestor_oid, TWO_ANCESTOR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&our_oid, TWO_OUR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&their_oid, TWO_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_reuc_add(repo_index, "two.txt",
 		0100644, &ancestor_oid,
 		0100644, &our_oid,
 		0100644, &their_oid));
 
-	git_oid_fromstr(&ancestor_oid, ONE_ANCESTOR_OID);
-	git_oid_fromstr(&our_oid, ONE_OUR_OID);
-	git_oid_fromstr(&their_oid, ONE_THEIR_OID);
+	git_oid__fromstr(&ancestor_oid, ONE_ANCESTOR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&our_oid, ONE_OUR_OID, GIT_OID_SHA1);
+	git_oid__fromstr(&their_oid, ONE_THEIR_OID, GIT_OID_SHA1);
 
 	cl_git_pass(git_index_reuc_add(repo_index, "one.txt",
 		0100644, &ancestor_oid,
diff --git a/tests/libgit2/index/tests.c b/tests/libgit2/index/tests.c
index 205d12e5b..da3ff6dd7 100644
--- a/tests/libgit2/index/tests.c
+++ b/tests/libgit2/index/tests.c
@@ -259,7 +259,7 @@ void test_index_tests__add(void)
 	 * This has been generated by executing the following
 	 * $ echo "hey there" | git hash-object --stdin
 	 */
-	cl_git_pass(git_oid_fromstr(&id1, "a8233120f6ad708f843d861ce2b7228ec4e3dec6"));
+	cl_git_pass(git_oid__fromstr(&id1, "a8233120f6ad708f843d861ce2b7228ec4e3dec6", GIT_OID_SHA1));
 
 	/* Add the new file to the index */
 	cl_git_pass(git_index_add_bypath(index, "test.txt"));
@@ -304,7 +304,7 @@ void test_index_tests__add_frombuffer(void)
 	 * This has been generated by executing the following
 	 * $ echo "hey there" | git hash-object --stdin
 	 */
-	cl_git_pass(git_oid_fromstr(&id1, "a8233120f6ad708f843d861ce2b7228ec4e3dec6"));
+	cl_git_pass(git_oid__fromstr(&id1, "a8233120f6ad708f843d861ce2b7228ec4e3dec6", GIT_OID_SHA1));
 
 	/* Add the new file to the index */
 	memset(&entry, 0x0, sizeof(git_index_entry));
@@ -447,7 +447,7 @@ void test_index_tests__add_frombuffer_reset_entry(void)
 	 * This has been generated by executing the following
 	 * $ echo "hey there" | git hash-object --stdin
 	 */
-	cl_git_pass(git_oid_fromstr(&id1, "a8233120f6ad708f843d861ce2b7228ec4e3dec6"));
+	cl_git_pass(git_oid__fromstr(&id1, "a8233120f6ad708f843d861ce2b7228ec4e3dec6", GIT_OID_SHA1));
 
 	cl_git_pass(git_index_add_bypath(index, "test.txt"));
 
@@ -511,7 +511,7 @@ void test_index_tests__add_issue_1397(void)
 	 * This has been generated by executing the following
 	 * $ git hash-object crlf_file.txt
 	 */
-	cl_git_pass(git_oid_fromstr(&id1, "8312e0889a9cbab77c732b6bc39b51a683e3a318"));
+	cl_git_pass(git_oid__fromstr(&id1, "8312e0889a9cbab77c732b6bc39b51a683e3a318", GIT_OID_SHA1));
 
 	/* Make sure the initial SHA-1 is correct */
 	cl_assert((entry = git_index_get_bypath(index, "crlf_file.txt", 0)) != NULL);
@@ -600,7 +600,7 @@ static void assert_add_fails(git_repository *repo, const char *fn)
 
 	entry.path = fn;
 	entry.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&entry.id, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", GIT_OID_SHA1));
 
 	cl_git_fail(git_index_add(index, &entry));
 
@@ -705,7 +705,7 @@ void test_index_tests__write_tree_invalid_unowned_index(void)
 
 	cl_git_pass(git_index_new(&idx));
 
-	cl_git_pass(git_oid_fromstr(&entry.id, "8312e0a89a9cbab77c732b6bc39b51a783e3a318"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "8312e0a89a9cbab77c732b6bc39b51a783e3a318", GIT_OID_SHA1));
 	entry.path = "foo";
 	entry.mode = GIT_FILEMODE_BLOB;
 	cl_git_pass(git_index_add(idx, &entry));
@@ -1147,12 +1147,12 @@ void test_index_tests__can_modify_while_iterating(void)
 	 * ensure that our iterator is backed by a snapshot and thus returns
 	 * the number of entries from when the iterator was created.
 	 */
-	cl_git_pass(git_oid_fromstr(&new_entry.id, "8312e0a89a9cbab77c732b6bc39b51a783e3a318"));
+	cl_git_pass(git_oid__fromstr(&new_entry.id, "8312e0a89a9cbab77c732b6bc39b51a783e3a318", GIT_OID_SHA1));
 	new_entry.path = "newfile";
 	new_entry.mode = GIT_FILEMODE_BLOB;
 	cl_git_pass(git_index_add(index, &new_entry));
 
-	cl_git_pass(git_oid_fromstr(&new_entry.id, "4141414141414141414141414141414141414141"));
+	cl_git_pass(git_oid__fromstr(&new_entry.id, "4141414141414141414141414141414141414141", GIT_OID_SHA1));
 	new_entry.path = "Makefile";
 	new_entry.mode = GIT_FILEMODE_BLOB;
 	cl_git_pass(git_index_add(index, &new_entry));
diff --git a/tests/libgit2/iterator/index.c b/tests/libgit2/iterator/index.c
index 7218b4f75..a0083479d 100644
--- a/tests/libgit2/iterator/index.c
+++ b/tests/libgit2/iterator/index.c
@@ -52,7 +52,7 @@ static void index_iterator_test(
 
 		if (expected_oids != NULL) {
 			git_oid oid;
-			cl_git_pass(git_oid_fromstr(&oid, expected_oids[count]));
+			cl_git_pass(git_oid__fromstr(&oid, expected_oids[count], GIT_OID_SHA1));
 			cl_assert_equal_oid(&oid, &entry->id);
 		}
 
@@ -999,7 +999,7 @@ static void create_paths(git_index *index, const char *root, int depth)
 			memset(&entry, 0, sizeof(git_index_entry));
 			entry.path = fullpath.ptr;
 			entry.mode = GIT_FILEMODE_BLOB;
-			git_oid_fromstr(&entry.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6");
+			git_oid__fromstr(&entry.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6", GIT_OID_SHA1);
 
 			cl_git_pass(git_index_add(index, &entry));
 		} else if (depth > 0) {
@@ -1296,17 +1296,17 @@ static void add_conflict(
 
 	ancestor.path = ancestor_path;
 	ancestor.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&ancestor.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6");
+	git_oid__fromstr(&ancestor.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6", GIT_OID_SHA1);
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor, 1);
 
 	ours.path = our_path;
 	ours.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&ours.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6");
+	git_oid__fromstr(&ours.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6", GIT_OID_SHA1);
 	GIT_INDEX_ENTRY_STAGE_SET(&ours, 2);
 
 	theirs.path = their_path;
 	theirs.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&theirs.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6");
+	git_oid__fromstr(&theirs.id, "d44e18fb93b7107b5cd1b95d601591d77869a1b6", GIT_OID_SHA1);
 	GIT_INDEX_ENTRY_STAGE_SET(&theirs, 3);
 
 	cl_git_pass(git_index_conflict_add(index, &ancestor, &ours, &theirs));
diff --git a/tests/libgit2/iterator/tree.c b/tests/libgit2/iterator/tree.c
index 06a920a18..7dfee28be 100644
--- a/tests/libgit2/iterator/tree.c
+++ b/tests/libgit2/iterator/tree.c
@@ -675,7 +675,7 @@ void test_iterator_tree__case_conflicts_0(void)
 
 	g_repo = cl_git_sandbox_init("icase");
 
-	cl_git_pass(git_oid_fromstr(&blob_id, blob_sha)); /* lookup blob */
+	cl_git_pass(git_oid__fromstr(&blob_id, blob_sha, GIT_OID_SHA1)); /* lookup blob */
 
 	/* create tree with: A/1.file, A/3.file, a/2.file, a/4.file */
 	build_test_tree(
@@ -729,7 +729,7 @@ void test_iterator_tree__case_conflicts_1(void)
 
 	g_repo = cl_git_sandbox_init("icase");
 
-	cl_git_pass(git_oid_fromstr(&blob_id, blob_sha)); /* lookup blob */
+	cl_git_pass(git_oid__fromstr(&blob_id, blob_sha, GIT_OID_SHA1)); /* lookup blob */
 
 	/* create: A/a A/b/1 A/c a/a a/b a/C */
 	build_test_tree(&Ab_id, g_repo, "b|1|", &blob_id);
@@ -798,7 +798,7 @@ void test_iterator_tree__case_conflicts_2(void)
 
 	g_repo = cl_git_sandbox_init("icase");
 
-	cl_git_pass(git_oid_fromstr(&blob_id, blob_sha)); /* lookup blob */
+	cl_git_pass(git_oid__fromstr(&blob_id, blob_sha, GIT_OID_SHA1)); /* lookup blob */
 
 	build_test_tree(&d1, g_repo, "b|16|,b|foo|", &blob_id, &blob_id);
 	build_test_tree(&d2, g_repo, "b|15|,b|FOO|", &blob_id, &blob_id);
diff --git a/tests/libgit2/iterator/workdir.c b/tests/libgit2/iterator/workdir.c
index 86b847cab..7634997e1 100644
--- a/tests/libgit2/iterator/workdir.c
+++ b/tests/libgit2/iterator/workdir.c
@@ -1481,7 +1481,7 @@ void test_iterator_workdir__hash_when_requested(void)
 	git_iterator *iter;
 	const git_index_entry *entry;
 	git_iterator_options iter_opts = GIT_ITERATOR_OPTIONS_INIT;
-	git_oid expected_id = {{0}};
+	git_oid expected_id = GIT_OID_SHA1_ZERO;
 	size_t i;
 
 	struct merge_index_entry expected[] = {
@@ -1514,7 +1514,7 @@ void test_iterator_workdir__hash_when_requested(void)
 	for (i = 0; i < sizeof(expected) / sizeof(struct merge_index_entry); i++) {
 		cl_git_pass(git_iterator_advance(&entry, iter));
 
-		cl_git_pass(git_oid_fromstr(&expected_id, expected[i].oid_str));
+		cl_git_pass(git_oid__fromstr(&expected_id, expected[i].oid_str, GIT_OID_SHA1));
 		cl_assert_equal_oid(&expected_id, &entry->id);
 		cl_assert_equal_s(expected[i].path, entry->path);
 	}
diff --git a/tests/libgit2/merge/driver.c b/tests/libgit2/merge/driver.c
index b7d320cbb..fd73c3770 100644
--- a/tests/libgit2/merge/driver.c
+++ b/tests/libgit2/merge/driver.c
@@ -22,7 +22,7 @@ void test_merge_driver__initialize(void)
     repo = cl_git_sandbox_init(TEST_REPO_PATH);
     git_repository_index(&repo_index, repo);
 
-	git_oid_fromstr(&automergeable_id, AUTOMERGEABLE_IDSTR);
+	git_oid__fromstr(&automergeable_id, AUTOMERGEABLE_IDSTR, GIT_OID_SHA1);
 
     /* Ensure that the user's merge.conflictstyle doesn't interfere */
     cl_git_pass(git_repository_config(&cfg, repo));
@@ -145,7 +145,7 @@ static void merge_branch(void)
 	git_oid their_id;
 	git_annotated_commit *their_head;
 
-	cl_git_pass(git_oid_fromstr(&their_id, BRANCH_ID));
+	cl_git_pass(git_oid__fromstr(&their_id, BRANCH_ID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_head, repo, &their_id));
 
 	cl_git_pass(git_merge(repo, (const git_annotated_commit **)&their_head,
@@ -299,7 +299,7 @@ void test_merge_driver__default_can_be_specified(void)
 
 	merge_opts.default_driver = "custom";
 
-	cl_git_pass(git_oid_fromstr(&their_id, BRANCH_ID));
+	cl_git_pass(git_oid__fromstr(&their_id, BRANCH_ID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_head, repo, &their_id));
 
 	cl_git_pass(git_merge(repo, (const git_annotated_commit **)&their_head,
diff --git a/tests/libgit2/merge/files.c b/tests/libgit2/merge/files.c
index 6296f3b7b..6c1c2e13f 100644
--- a/tests/libgit2/merge/files.c
+++ b/tests/libgit2/merge/files.c
@@ -149,15 +149,15 @@ void test_merge_files__automerge_from_index(void)
 	git_merge_file_result result = {0};
 	git_index_entry ancestor, ours, theirs;
 
-	git_oid_fromstr(&ancestor.id, "6212c31dab5e482247d7977e4f0dd3601decf13b");
+	git_oid__fromstr(&ancestor.id, "6212c31dab5e482247d7977e4f0dd3601decf13b", GIT_OID_SHA1);
 	ancestor.path = "automergeable.txt";
 	ancestor.mode = 0100644;
 
-	git_oid_fromstr(&ours.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf");
+	git_oid__fromstr(&ours.id, "ee3fa1b8c00aff7fe02065fdb50864bb0d932ccf", GIT_OID_SHA1);
 	ours.path = "automergeable.txt";
 	ours.mode = 0100755;
 
-	git_oid_fromstr(&theirs.id, "058541fc37114bfc1dddf6bd6bffc7fae5c2e6fe");
+	git_oid__fromstr(&theirs.id, "058541fc37114bfc1dddf6bd6bffc7fae5c2e6fe", GIT_OID_SHA1);
 	theirs.path = "newname.txt";
 	theirs.mode = 0100644;
 
diff --git a/tests/libgit2/merge/merge_helpers.c b/tests/libgit2/merge/merge_helpers.c
index ce3cd229b..1406987e5 100644
--- a/tests/libgit2/merge/merge_helpers.c
+++ b/tests/libgit2/merge/merge_helpers.c
@@ -165,7 +165,7 @@ static int index_entry_eq_merge_index_entry(const struct merge_index_entry *expe
 	bool test_oid;
 
 	if (strlen(expected->oid_str) != 0) {
-		cl_git_pass(git_oid_fromstr(&expected_oid, expected->oid_str));
+		cl_git_pass(git_oid__fromstr(&expected_oid, expected->oid_str, GIT_OID_SHA1));
 		test_oid = 1;
 	} else
 		test_oid = 0;
@@ -304,21 +304,21 @@ int merge_test_reuc(git_index *index, const struct merge_reuc_entry expected[],
 			return 0;
 
 		if (expected[i].ancestor_mode > 0) {
-			cl_git_pass(git_oid_fromstr(&expected_oid, expected[i].ancestor_oid_str));
+			cl_git_pass(git_oid__fromstr(&expected_oid, expected[i].ancestor_oid_str, GIT_OID_SHA1));
 
 			if (git_oid_cmp(&reuc_entry->oid[0], &expected_oid) != 0)
 				return 0;
 		}
 
 		if (expected[i].our_mode > 0) {
-			cl_git_pass(git_oid_fromstr(&expected_oid, expected[i].our_oid_str));
+			cl_git_pass(git_oid__fromstr(&expected_oid, expected[i].our_oid_str, GIT_OID_SHA1));
 
 			if (git_oid_cmp(&reuc_entry->oid[1], &expected_oid) != 0)
 				return 0;
 		}
 
 		if (expected[i].their_mode > 0) {
-			cl_git_pass(git_oid_fromstr(&expected_oid, expected[i].their_oid_str));
+			cl_git_pass(git_oid__fromstr(&expected_oid, expected[i].their_oid_str, GIT_OID_SHA1));
 
 			if (git_oid_cmp(&reuc_entry->oid[2], &expected_oid) != 0)
 				return 0;
@@ -353,7 +353,7 @@ int merge_test_workdir(git_repository *repo, const struct merge_index_entry expe
 
 	for (i = 0; i < expected_len; i++) {
 		git_blob_create_from_workdir(&actual_oid, repo, expected[i].path);
-		git_oid_fromstr(&expected_oid, expected[i].oid_str);
+		git_oid__fromstr(&expected_oid, expected[i].oid_str, GIT_OID_SHA1);
 
 		if (git_oid_cmp(&actual_oid, &expected_oid) != 0)
 			return 0;
diff --git a/tests/libgit2/merge/merge_helpers.h b/tests/libgit2/merge/merge_helpers.h
index 339812ba5..72c6e61f7 100644
--- a/tests/libgit2/merge/merge_helpers.h
+++ b/tests/libgit2/merge/merge_helpers.h
@@ -6,7 +6,7 @@
 
 struct merge_index_entry {
 	uint16_t mode;
-	char oid_str[GIT_OID_HEXSZ+1];
+	char oid_str[GIT_OID_SHA1_HEXSIZE+1];
 	int stage;
 	char path[128];
 };
@@ -27,9 +27,9 @@ struct merge_reuc_entry {
 	unsigned int ancestor_mode;
 	unsigned int our_mode;
 	unsigned int their_mode;
-	char ancestor_oid_str[GIT_OID_HEXSZ+1];
-	char our_oid_str[GIT_OID_HEXSZ+1];
-	char their_oid_str[GIT_OID_HEXSZ+1];
+	char ancestor_oid_str[GIT_OID_SHA1_HEXSIZE+1];
+	char our_oid_str[GIT_OID_SHA1_HEXSIZE+1];
+	char their_oid_str[GIT_OID_SHA1_HEXSIZE+1];
 };
 
 struct merge_index_conflict_data {
diff --git a/tests/libgit2/merge/trees/renames.c b/tests/libgit2/merge/trees/renames.c
index 26f6d3306..a27945ee0 100644
--- a/tests/libgit2/merge/trees/renames.c
+++ b/tests/libgit2/merge/trees/renames.c
@@ -286,7 +286,7 @@ void test_merge_trees_renames__cache_recomputation(void)
 	void *data;
 	size_t i;
 
-	cl_git_pass(git_oid_fromstr(&blob, "a2d8d1824c68541cca94ffb90f79291eba495921"));
+	cl_git_pass(git_oid__fromstr(&blob, "a2d8d1824c68541cca94ffb90f79291eba495921", GIT_OID_SHA1));
 
 	/*
 	 * Create a 50MB blob that consists of NUL bytes only. It is important
diff --git a/tests/libgit2/merge/trees/treediff.c b/tests/libgit2/merge/trees/treediff.c
index cd2cf7827..094018d3c 100644
--- a/tests/libgit2/merge/trees/treediff.c
+++ b/tests/libgit2/merge/trees/treediff.c
@@ -61,9 +61,9 @@ static void test_find_differences(
 	opts.metric->similarity = git_diff_find_similar__calc_similarity;
 	opts.metric->payload = (void *)GIT_HASHSIG_SMART_WHITESPACE;
 
-	cl_git_pass(git_oid_fromstr(&ancestor_oid, ancestor_oidstr));
-	cl_git_pass(git_oid_fromstr(&ours_oid, ours_oidstr));
-	cl_git_pass(git_oid_fromstr(&theirs_oid, theirs_oidstr));
+	cl_git_pass(git_oid__fromstr(&ancestor_oid, ancestor_oidstr, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&ours_oid, ours_oidstr, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&theirs_oid, theirs_oidstr, GIT_OID_SHA1));
 
 	cl_git_pass(git_tree_lookup(&ancestor_tree, repo, &ancestor_oid));
 	cl_git_pass(git_tree_lookup(&ours_tree, repo, &ours_oid));
diff --git a/tests/libgit2/merge/trees/trivial.c b/tests/libgit2/merge/trees/trivial.c
index dce392c86..287a53cfe 100644
--- a/tests/libgit2/merge/trees/trivial.c
+++ b/tests/libgit2/merge/trees/trivial.c
@@ -258,7 +258,7 @@ void test_merge_trees_trivial__13(void)
 	cl_git_pass(merge_trivial(&result, "trivial-13", "trivial-13-branch"));
 
 	cl_assert(entry = git_index_get_bypath(result, "modified-in-13.txt", 0));
-	cl_git_pass(git_oid_fromstr(&expected_oid, "1cff9ec6a47a537380dedfdd17c9e76d74259a2b"));
+	cl_git_pass(git_oid__fromstr(&expected_oid, "1cff9ec6a47a537380dedfdd17c9e76d74259a2b", GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected_oid, &entry->id);
 
 	cl_assert(git_index_reuc_entrycount(result) == 0);
@@ -277,7 +277,7 @@ void test_merge_trees_trivial__14(void)
 	cl_git_pass(merge_trivial(&result, "trivial-14", "trivial-14-branch"));
 
 	cl_assert(entry = git_index_get_bypath(result, "modified-in-14-branch.txt", 0));
-	cl_git_pass(git_oid_fromstr(&expected_oid, "26153a3ff3649b6c2bb652d3f06878c6e0a172f9"));
+	cl_git_pass(git_oid__fromstr(&expected_oid, "26153a3ff3649b6c2bb652d3f06878c6e0a172f9", GIT_OID_SHA1));
 	cl_assert(git_oid_cmp(&entry->id, &expected_oid) == 0);
 
 	cl_assert(git_index_reuc_entrycount(result) == 0);
diff --git a/tests/libgit2/merge/workdir/dirty.c b/tests/libgit2/merge/workdir/dirty.c
index b9c2ad033..36b42a103 100644
--- a/tests/libgit2/merge/workdir/dirty.c
+++ b/tests/libgit2/merge/workdir/dirty.c
@@ -94,7 +94,7 @@ static int merge_branch(void)
 	git_checkout_options checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
 	int error;
 
-	cl_git_pass(git_oid_fromstr(&their_oids[0], MERGE_BRANCH_OID));
+	cl_git_pass(git_oid__fromstr(&their_oids[0], MERGE_BRANCH_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_head, repo, &their_oids[0]));
 
 	checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE;
diff --git a/tests/libgit2/merge/workdir/setup.c b/tests/libgit2/merge/workdir/setup.c
index 3db2d074f..98ccdf700 100644
--- a/tests/libgit2/merge/workdir/setup.c
+++ b/tests/libgit2/merge/workdir/setup.c
@@ -78,7 +78,7 @@ void test_merge_workdir_setup__one_branch(void)
 	git_reference *octo1_ref;
 	git_annotated_commit *our_head, *their_heads[1];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -104,10 +104,10 @@ void test_merge_workdir_setup__one_oid(void)
 	git_oid octo1_oid;
 	git_annotated_commit *our_head, *their_heads[1];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &octo1_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 1));
@@ -129,7 +129,7 @@ void test_merge_workdir_setup__two_branches(void)
 	git_reference *octo2_ref;
 	git_annotated_commit *our_head, *their_heads[2];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -162,7 +162,7 @@ void test_merge_workdir_setup__three_branches(void)
 	git_reference *octo3_ref;
 	git_annotated_commit *our_head, *their_heads[3];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -200,16 +200,16 @@ void test_merge_workdir_setup__three_oids(void)
 	git_oid octo3_oid;
 	git_annotated_commit *our_head, *their_heads[3];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &octo1_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo2_oid, OCTO2_OID));
+	cl_git_pass(git_oid__fromstr(&octo2_oid, OCTO2_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[1], repo, &octo2_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo3_oid, OCTO3_OID));
+	cl_git_pass(git_oid__fromstr(&octo3_oid, OCTO3_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[2], repo, &octo3_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 3));
@@ -233,13 +233,13 @@ void test_merge_workdir_setup__branches_and_oids_1(void)
 	git_oid octo2_oid;
 	git_annotated_commit *our_head, *their_heads[2];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
 	cl_git_pass(git_annotated_commit_from_ref(&their_heads[0], repo, octo1_ref));
 
-	cl_git_pass(git_oid_fromstr(&octo2_oid, OCTO2_OID));
+	cl_git_pass(git_oid__fromstr(&octo2_oid, OCTO2_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[1], repo, &octo2_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 2));
@@ -266,19 +266,19 @@ void test_merge_workdir_setup__branches_and_oids_2(void)
 	git_oid octo4_oid;
 	git_annotated_commit *our_head, *their_heads[4];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
 	cl_git_pass(git_annotated_commit_from_ref(&their_heads[0], repo, octo1_ref));
 
-	cl_git_pass(git_oid_fromstr(&octo2_oid, OCTO2_OID));
+	cl_git_pass(git_oid__fromstr(&octo2_oid, OCTO2_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[1], repo, &octo2_oid));
 
 	cl_git_pass(git_reference_lookup(&octo3_ref, repo, GIT_REFS_HEADS_DIR OCTO3_BRANCH));
 	cl_git_pass(git_annotated_commit_from_ref(&their_heads[2], repo, octo3_ref));
 
-	cl_git_pass(git_oid_fromstr(&octo4_oid, OCTO4_OID));
+	cl_git_pass(git_oid__fromstr(&octo4_oid, OCTO4_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[3], repo, &octo4_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 4));
@@ -308,16 +308,16 @@ void test_merge_workdir_setup__branches_and_oids_3(void)
 	git_reference *octo4_ref;
 	git_annotated_commit *our_head, *their_heads[4];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &octo1_oid));
 
 	cl_git_pass(git_reference_lookup(&octo2_ref, repo, GIT_REFS_HEADS_DIR OCTO2_BRANCH));
 	cl_git_pass(git_annotated_commit_from_ref(&their_heads[1], repo, octo2_ref));
 
-	cl_git_pass(git_oid_fromstr(&octo3_oid, OCTO3_OID));
+	cl_git_pass(git_oid__fromstr(&octo3_oid, OCTO3_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[2], repo, &octo3_oid));
 
 	cl_git_pass(git_reference_lookup(&octo4_ref, repo, GIT_REFS_HEADS_DIR OCTO4_BRANCH));
@@ -351,16 +351,16 @@ void test_merge_workdir_setup__branches_and_oids_4(void)
 	git_reference *octo5_ref;
 	git_annotated_commit *our_head, *their_heads[5];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &octo1_oid));
 
 	cl_git_pass(git_reference_lookup(&octo2_ref, repo, GIT_REFS_HEADS_DIR OCTO2_BRANCH));
 	cl_git_pass(git_annotated_commit_from_ref(&their_heads[1], repo, octo2_ref));
 
-	cl_git_pass(git_oid_fromstr(&octo3_oid, OCTO3_OID));
+	cl_git_pass(git_oid__fromstr(&octo3_oid, OCTO3_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[2], repo, &octo3_oid));
 
 	cl_git_pass(git_reference_lookup(&octo4_ref, repo, GIT_REFS_HEADS_DIR OCTO4_BRANCH));
@@ -397,7 +397,7 @@ void test_merge_workdir_setup__three_same_branches(void)
 	git_reference *octo1_3_ref;
 	git_annotated_commit *our_head, *their_heads[3];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -435,16 +435,16 @@ void test_merge_workdir_setup__three_same_oids(void)
 	git_oid octo1_3_oid;
 	git_annotated_commit *our_head, *their_heads[3];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &octo1_1_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_2_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_2_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[1], repo, &octo1_2_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_3_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_3_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[2], repo, &octo1_3_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 3));
@@ -512,7 +512,7 @@ void test_merge_workdir_setup__remote_tracking_one_branch(void)
 
 	cl_git_pass(create_remote_tracking_branch(OCTO1_BRANCH, OCTO1_OID));
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_REMOTES_DIR "origin/" OCTO1_BRANCH));
@@ -542,7 +542,7 @@ void test_merge_workdir_setup__remote_tracking_two_branches(void)
 	cl_git_pass(create_remote_tracking_branch(OCTO1_BRANCH, OCTO1_OID));
 	cl_git_pass(create_remote_tracking_branch(OCTO2_BRANCH, OCTO2_OID));
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_REMOTES_DIR "origin/" OCTO1_BRANCH));
@@ -579,7 +579,7 @@ void test_merge_workdir_setup__remote_tracking_three_branches(void)
 	cl_git_pass(create_remote_tracking_branch(OCTO2_BRANCH, OCTO2_OID));
 	cl_git_pass(create_remote_tracking_branch(OCTO3_BRANCH, OCTO3_OID));
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_REMOTES_DIR "origin/" OCTO1_BRANCH));
@@ -618,7 +618,7 @@ void test_merge_workdir_setup__normal_branch_and_remote_tracking_branch(void)
 
 	cl_git_pass(create_remote_tracking_branch(OCTO2_BRANCH, OCTO2_OID));
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -652,7 +652,7 @@ void test_merge_workdir_setup__remote_tracking_branch_and_normal_branch(void)
 
 	cl_git_pass(create_remote_tracking_branch(OCTO1_BRANCH, OCTO1_OID));
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_REMOTES_DIR "origin/" OCTO1_BRANCH));
@@ -689,7 +689,7 @@ void test_merge_workdir_setup__two_remote_tracking_branch_and_two_normal_branche
 	cl_git_pass(create_remote_tracking_branch(OCTO2_BRANCH, OCTO2_OID));
 	cl_git_pass(create_remote_tracking_branch(OCTO4_BRANCH, OCTO4_OID));
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -730,10 +730,10 @@ void test_merge_workdir_setup__pull_one(void)
 	git_oid octo1_1_oid;
 	git_annotated_commit *our_head, *their_heads[1];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[0], repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH, "http://remote.url/repo.git", &octo1_1_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 1));
@@ -755,13 +755,13 @@ void test_merge_workdir_setup__pull_two(void)
 	git_oid octo2_oid;
 	git_annotated_commit *our_head, *their_heads[2];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[0], repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH, "http://remote.url/repo.git", &octo1_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo2_oid, OCTO2_OID));
+	cl_git_pass(git_oid__fromstr(&octo2_oid, OCTO2_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[1], repo, GIT_REFS_HEADS_DIR OCTO2_BRANCH, "http://remote.url/repo.git", &octo2_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 2));
@@ -785,16 +785,16 @@ void test_merge_workdir_setup__pull_three(void)
 	git_oid octo3_oid;
 	git_annotated_commit *our_head, *their_heads[3];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[0], repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH, "http://remote.url/repo.git", &octo1_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo2_oid, OCTO2_OID));
+	cl_git_pass(git_oid__fromstr(&octo2_oid, OCTO2_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[1], repo, GIT_REFS_HEADS_DIR OCTO2_BRANCH, "http://remote.url/repo.git", &octo2_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo3_oid, OCTO3_OID));
+	cl_git_pass(git_oid__fromstr(&octo3_oid, OCTO3_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[2], repo, GIT_REFS_HEADS_DIR OCTO3_BRANCH, "http://remote.url/repo.git", &octo3_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 3));
@@ -818,16 +818,16 @@ void test_merge_workdir_setup__three_remotes(void)
 	git_oid octo3_oid;
 	git_annotated_commit *our_head, *their_heads[3];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[0], repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH, "http://remote.first/repo.git", &octo1_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo2_oid, OCTO2_OID));
+	cl_git_pass(git_oid__fromstr(&octo2_oid, OCTO2_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[1], repo, GIT_REFS_HEADS_DIR OCTO2_BRANCH, "http://remote.second/repo.git", &octo2_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo3_oid, OCTO3_OID));
+	cl_git_pass(git_oid__fromstr(&octo3_oid, OCTO3_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[2], repo, GIT_REFS_HEADS_DIR OCTO3_BRANCH, "http://remote.third/repo.git", &octo3_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 3));
@@ -852,19 +852,19 @@ void test_merge_workdir_setup__two_remotes(void)
 	git_oid octo4_oid;
 	git_annotated_commit *our_head, *their_heads[4];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo1_oid, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&octo1_oid, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[0], repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH, "http://remote.first/repo.git", &octo1_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo2_oid, OCTO2_OID));
+	cl_git_pass(git_oid__fromstr(&octo2_oid, OCTO2_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[1], repo, GIT_REFS_HEADS_DIR OCTO2_BRANCH, "http://remote.second/repo.git", &octo2_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo3_oid, OCTO3_OID));
+	cl_git_pass(git_oid__fromstr(&octo3_oid, OCTO3_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[2], repo, GIT_REFS_HEADS_DIR OCTO3_BRANCH, "http://remote.first/repo.git", &octo3_oid));
 
-	cl_git_pass(git_oid_fromstr(&octo4_oid, OCTO4_OID));
+	cl_git_pass(git_oid__fromstr(&octo4_oid, OCTO4_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&their_heads[3], repo, GIT_REFS_HEADS_DIR OCTO4_BRANCH, "http://remote.second/repo.git", &octo4_oid));
 
 	cl_git_pass(git_merge__setup(repo, our_head, (const git_annotated_commit **)their_heads, 4));
@@ -888,7 +888,7 @@ void test_merge_workdir_setup__id_from_head(void)
 	git_reference *ref;
 	git_annotated_commit *heads[3];
 
-	cl_git_pass(git_oid_fromstr(&expected_id, OCTO1_OID));
+	cl_git_pass(git_oid__fromstr(&expected_id, OCTO1_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_from_fetchhead(&heads[0], repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH, "http://remote.url/repo.git", &expected_id));
 	id = git_annotated_commit_id(heads[0]);
 	cl_assert_equal_i(1, git_oid_equal(id, &expected_id));
@@ -920,7 +920,7 @@ static int annotated_commit_foreach_cb(const git_oid *oid, void *payload)
 	git_oid expected_oid;
 	struct annotated_commit_cb_data *cb_data = payload;
 
-	git_oid_fromstr(&expected_oid, cb_data->oid_str[cb_data->i]);
+	git_oid__fromstr(&expected_oid, cb_data->oid_str[cb_data->i], GIT_OID_SHA1);
 	cl_assert(git_oid_cmp(&expected_oid, oid) == 0);
 	cb_data->i++;
 	return 0;
@@ -998,7 +998,7 @@ void test_merge_workdir_setup__retained_after_success(void)
 	git_reference *octo1_ref;
 	git_annotated_commit *our_head, *their_heads[1];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -1025,7 +1025,7 @@ void test_merge_workdir_setup__removed_after_failure(void)
 	git_reference *octo1_ref;
 	git_annotated_commit *our_head, *their_heads[1];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -1052,7 +1052,7 @@ void test_merge_workdir_setup__unlocked_after_success(void)
 	git_reference *octo1_ref;
 	git_annotated_commit *our_head, *their_heads[1];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
@@ -1075,7 +1075,7 @@ void test_merge_workdir_setup__unlocked_after_conflict(void)
 	git_reference *octo1_ref;
 	git_annotated_commit *our_head, *their_heads[1];
 
-	cl_git_pass(git_oid_fromstr(&our_oid, ORIG_HEAD));
+	cl_git_pass(git_oid__fromstr(&our_oid, ORIG_HEAD, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&our_head, repo, &our_oid));
 
 	cl_git_pass(git_reference_lookup(&octo1_ref, repo, GIT_REFS_HEADS_DIR OCTO1_BRANCH));
diff --git a/tests/libgit2/merge/workdir/simple.c b/tests/libgit2/merge/workdir/simple.c
index b9d3fc24c..e9cffeea8 100644
--- a/tests/libgit2/merge/workdir/simple.c
+++ b/tests/libgit2/merge/workdir/simple.c
@@ -99,7 +99,7 @@ static void merge_simple_branch(int merge_file_favor, int addl_checkout_strategy
 	git_merge_options merge_opts = GIT_MERGE_OPTIONS_INIT;
 	git_checkout_options checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
 
-	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_SIMPLE_OID));
+	cl_git_pass(git_oid__fromstr(&their_oids[0], THEIRS_SIMPLE_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &their_oids[0]));
 
 	merge_opts.file_favor = merge_file_favor;
@@ -180,14 +180,14 @@ void test_merge_workdir_simple__index_reload(void)
 	cl_git_pass(git_index_read(repo_index, 0));
 
 	entry.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&entry.id, "11deab00b2d3a6f5a3073988ac050c2d7b6655e2"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "11deab00b2d3a6f5a3073988ac050c2d7b6655e2", GIT_OID_SHA1));
 	entry.path = "automergeable.txt";
 	cl_git_pass(git_index_add(repo_index, &entry));
 
 	cl_git_pass(git_index_add_bypath(tmp_index, "automergeable.txt"));
 	cl_git_pass(git_index_write(tmp_index));
 
-	cl_git_pass(git_oid_fromstr(&their_oid, THEIRS_SIMPLE_OID));
+	cl_git_pass(git_oid__fromstr(&their_oid, THEIRS_SIMPLE_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &their_oid));
 	cl_git_pass(git_merge(repo, (const git_annotated_commit **)their_heads, 1, NULL, NULL));
 
@@ -669,7 +669,7 @@ void test_merge_workdir_simple__directory_file(void)
 	cl_git_pass(git_commit_lookup(&head_commit, repo, &head_commit_id));
 	cl_git_pass(git_reset(repo, (git_object *)head_commit, GIT_RESET_HARD, NULL));
 
-	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_DIRECTORY_FILE));
+	cl_git_pass(git_oid__fromstr(&their_oids[0], THEIRS_DIRECTORY_FILE, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &their_oids[0]));
 
 	merge_opts.file_favor = 0;
@@ -700,7 +700,7 @@ void test_merge_workdir_simple__unrelated(void)
 		{ 0100644, "c8f06f2e3bb2964174677e91f0abead0e43c9e5d", 0, "unchanged.txt" },
 	};
 
-	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_UNRELATED_PARENT));
+	cl_git_pass(git_oid__fromstr(&their_oids[0], THEIRS_UNRELATED_PARENT, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &their_oids[0]));
 
 	merge_opts.file_favor = 0;
@@ -731,7 +731,7 @@ void test_merge_workdir_simple__unrelated_with_conflicts(void)
 		{ 0100644, "c8f06f2e3bb2964174677e91f0abead0e43c9e5d", 0, "unchanged.txt" },
 	};
 
-	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_UNRELATED_OID));
+	cl_git_pass(git_oid__fromstr(&their_oids[0], THEIRS_UNRELATED_OID, GIT_OID_SHA1));
 	cl_git_pass(git_annotated_commit_lookup(&their_heads[0], repo, &their_oids[0]));
 
 	merge_opts.file_favor = 0;
@@ -755,8 +755,8 @@ void test_merge_workdir_simple__binary(void)
 		{ 0100644, "836b8b82b26cab22eaaed8820877c76d6c8bca19", 3, "binary" },
 	};
 
-	cl_git_pass(git_oid_fromstr(&our_oid, "cc338e4710c9b257106b8d16d82f86458d5beaf1"));
-	cl_git_pass(git_oid_fromstr(&their_oid, "ad01aebfdf2ac13145efafe3f9fcf798882f1730"));
+	cl_git_pass(git_oid__fromstr(&our_oid, "cc338e4710c9b257106b8d16d82f86458d5beaf1", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&their_oid, "ad01aebfdf2ac13145efafe3f9fcf798882f1730", GIT_OID_SHA1));
 
 	cl_git_pass(git_commit_lookup(&our_commit, repo, &our_oid));
 	cl_git_pass(git_reset(repo, (git_object *)our_commit, GIT_RESET_HARD, NULL));
@@ -770,7 +770,7 @@ void test_merge_workdir_simple__binary(void)
 	cl_git_pass(git_index_add_bypath(repo_index, "binary"));
 	cl_assert((binary_entry = git_index_get_bypath(repo_index, "binary", 0)) != NULL);
 
-	cl_git_pass(git_oid_fromstr(&our_file_oid, "23ed141a6ae1e798b2f721afedbe947c119111ba"));
+	cl_git_pass(git_oid__fromstr(&our_file_oid, "23ed141a6ae1e798b2f721afedbe947c119111ba", GIT_OID_SHA1));
 	cl_assert(git_oid_cmp(&binary_entry->id, &our_file_oid) == 0);
 
 	git_annotated_commit_free(their_head);
diff --git a/tests/libgit2/merge/workdir/trivial.c b/tests/libgit2/merge/workdir/trivial.c
index fe8374851..364182c89 100644
--- a/tests/libgit2/merge/workdir/trivial.c
+++ b/tests/libgit2/merge/workdir/trivial.c
@@ -222,7 +222,7 @@ void test_merge_workdir_trivial__13(void)
 	cl_git_pass(merge_trivial("trivial-13", "trivial-13-branch"));
 
 	cl_assert(entry = git_index_get_bypath(repo_index, "modified-in-13.txt", 0));
-	cl_git_pass(git_oid_fromstr(&expected_oid, "1cff9ec6a47a537380dedfdd17c9e76d74259a2b"));
+	cl_git_pass(git_oid__fromstr(&expected_oid, "1cff9ec6a47a537380dedfdd17c9e76d74259a2b", GIT_OID_SHA1));
 	cl_assert(git_oid_cmp(&entry->id, &expected_oid) == 0);
 
 	cl_assert(git_index_reuc_entrycount(repo_index) == 0);
@@ -238,7 +238,7 @@ void test_merge_workdir_trivial__14(void)
 	cl_git_pass(merge_trivial("trivial-14", "trivial-14-branch"));
 
 	cl_assert(entry = git_index_get_bypath(repo_index, "modified-in-14-branch.txt", 0));
-	cl_git_pass(git_oid_fromstr(&expected_oid, "26153a3ff3649b6c2bb652d3f06878c6e0a172f9"));
+	cl_git_pass(git_oid__fromstr(&expected_oid, "26153a3ff3649b6c2bb652d3f06878c6e0a172f9", GIT_OID_SHA1));
 	cl_assert(git_oid_cmp(&entry->id, &expected_oid) == 0);
 
 	cl_assert(git_index_reuc_entrycount(repo_index) == 0);
diff --git a/tests/libgit2/network/remote/push.c b/tests/libgit2/network/remote/push.c
index 3905debdf..16588a292 100644
--- a/tests/libgit2/network/remote/push.c
+++ b/tests/libgit2/network/remote/push.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include "git2/sys/commit.h"
+#include "oid.h"
 
 static git_remote *_remote;
 static git_repository *_repo, *_dummy;
@@ -57,7 +58,7 @@ void test_network_remote_push__delete_notification(void)
 
 	expected.src_refname = "";
 	expected.dst_refname = "refs/heads/master";
-	memset(&expected.dst, 0, sizeof(git_oid));
+	git_oid_clear(&expected.dst, GIT_OID_SHA1);
 	git_oid_cpy(&expected.src, git_reference_target(ref));
 
 	opts.callbacks.push_negotiation = negotiation_cb;
@@ -102,7 +103,7 @@ void test_network_remote_push__create_notification(void)
 	expected.src_refname = "refs/heads/empty-tree";
 	expected.dst_refname = "refs/heads/empty-tree";
 	git_oid_cpy(&expected.dst, git_reference_target(ref));
-	memset(&expected.src, 0, sizeof(git_oid));
+	git_oid_clear(&expected.src, GIT_OID_SHA1);
 
 	opts.callbacks.push_negotiation = negotiation_cb;
 	opts.callbacks.payload = &expected;
diff --git a/tests/libgit2/network/remote/rename.c b/tests/libgit2/network/remote/rename.c
index 1fd2affba..b071f9cef 100644
--- a/tests/libgit2/network/remote/rename.c
+++ b/tests/libgit2/network/remote/rename.c
@@ -164,13 +164,13 @@ void test_network_remote_rename__renaming_a_remote_moves_the_underlying_referenc
 void test_network_remote_rename__overwrite_ref_in_target(void)
 {
 	git_oid id;
-	char idstr[GIT_OID_HEXSZ + 1] = {0};
+	char idstr[GIT_OID_SHA1_HEXSIZE + 1] = {0};
 	git_reference *ref;
 	git_branch_t btype;
 	git_branch_iterator *iter;
 	git_strarray problems = {0};
 
-	cl_git_pass(git_oid_fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
+	cl_git_pass(git_oid__fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
 	cl_git_pass(git_reference_create(&ref, _repo, "refs/remotes/renamed/master", &id, 1, NULL));
 	git_reference_free(ref);
 
@@ -206,7 +206,7 @@ void test_network_remote_rename__symref_head(void)
 	git_branch_t btype;
 	git_branch_iterator *iter;
 	git_strarray problems = {0};
-	char idstr[GIT_OID_HEXSZ + 1] = {0};
+	char idstr[GIT_OID_SHA1_HEXSIZE + 1] = {0};
 	git_vector refs;
 
 	cl_git_pass(git_reference_symbolic_create(&ref, _repo, "refs/remotes/test/HEAD", "refs/remotes/test/master", 0, NULL));
diff --git a/tests/libgit2/notes/notes.c b/tests/libgit2/notes/notes.c
index a36cddb8a..06c440955 100644
--- a/tests/libgit2/notes/notes.c
+++ b/tests/libgit2/notes/notes.c
@@ -33,7 +33,7 @@ static void create_note(git_oid *note_oid, const char *canonical_namespace, cons
 {
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, target_sha));
+	cl_git_pass(git_oid__fromstr(&oid, target_sha, GIT_OID_SHA1));
 	cl_git_pass(git_note_create(note_oid, _repo, canonical_namespace, _sig, _sig, &oid, message, 0));
 }
 
@@ -60,10 +60,10 @@ static int note_list_cb(
 
 	cl_assert(*count < EXPECTATIONS_COUNT);
 
-	cl_git_pass(git_oid_fromstr(&expected_note_oid, list_expectations[*count].note_sha));
+	cl_git_pass(git_oid__fromstr(&expected_note_oid, list_expectations[*count].note_sha, GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected_note_oid, blob_id);
 
-	cl_git_pass(git_oid_fromstr(&expected_target_oid, list_expectations[*count].annotated_object_sha));
+	cl_git_pass(git_oid__fromstr(&expected_target_oid, list_expectations[*count].annotated_object_sha, GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected_target_oid, annotated_obj_id);
 
 	(*count)++;
@@ -85,12 +85,12 @@ static int note_list_create_cb(
 	size_t i;
 
 	for (i = 0; notes[i].note_oid != NULL; i++) {
-		cl_git_pass(git_oid_fromstr(&expected_note_oid, notes[i].note_oid));
+		cl_git_pass(git_oid__fromstr(&expected_note_oid, notes[i].note_oid, GIT_OID_SHA1));
 
 		if (git_oid_cmp(&expected_note_oid, blob_oid) != 0)
 			continue;
 
-		cl_git_pass(git_oid_fromstr(&expected_target_oid, notes[i].object_oid));
+		cl_git_pass(git_oid__fromstr(&expected_target_oid, notes[i].object_oid, GIT_OID_SHA1));
 
 		if (git_oid_cmp(&expected_target_oid, annotated_obj_id) != 0)
 			continue;
@@ -140,7 +140,7 @@ void test_notes_notes__can_create_a_note_from_commit(void)
 		{ NULL, NULL, 0 }
 	};
 
-	cl_git_pass(git_oid_fromstr(&oid, can_create_a_note_from_commit[0].object_oid));
+	cl_git_pass(git_oid__fromstr(&oid, can_create_a_note_from_commit[0].object_oid, GIT_OID_SHA1));
 
 	cl_git_pass(git_note_commit_create(&notes_commit_out, NULL, _repo, NULL, _sig, _sig, &oid, "I decorate 4a20\n", 1));
 
@@ -169,11 +169,11 @@ void test_notes_notes__can_create_a_note_from_commit_given_an_existing_commit(vo
 		{ NULL, NULL, 0 }
 	};
 
-	cl_git_pass(git_oid_fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045"));
+	cl_git_pass(git_oid__fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", GIT_OID_SHA1));
 
 	cl_git_pass(git_note_commit_create(&notes_commit_out, NULL, _repo, NULL, _sig, _sig, &oid, "I decorate 4a20\n", 0));
 
-	cl_git_pass(git_oid_fromstr(&oid, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
+	cl_git_pass(git_oid__fromstr(&oid, "9fd738e8f7967c078dceed8190330fc8648ee56a", GIT_OID_SHA1));
 
 	git_commit_lookup(&existing_notes_commit, _repo, &notes_commit_out);
 
@@ -274,7 +274,7 @@ void test_notes_notes__inserting_a_note_without_passing_a_namespace_uses_the_def
 	git_note *note, *default_namespace_note;
 	git_buf default_ref = GIT_BUF_INIT;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125", GIT_OID_SHA1));
 	cl_git_pass(git_note_default_ref(&default_ref, _repo));
 
 	create_note(&note_oid, NULL, "08b041783f40edfe12bb406c9c9a8a040177c125", "hello world\n");
@@ -295,7 +295,7 @@ void test_notes_notes__can_insert_a_note_with_a_custom_namespace(void)
 	git_oid note_oid, target_oid;
 	git_note *note;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125", GIT_OID_SHA1));
 
 	create_note(&note_oid, "refs/notes/some/namespace", "08b041783f40edfe12bb406c9c9a8a040177c125", "hello world on a custom namespace\n");
 
@@ -315,7 +315,7 @@ void test_notes_notes__creating_a_note_on_a_target_which_already_has_one_returns
 	int error;
 	git_oid note_oid, target_oid;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125", GIT_OID_SHA1));
 
 	create_note(&note_oid, NULL, "08b041783f40edfe12bb406c9c9a8a040177c125", "hello world\n");
 	error = git_note_create(&note_oid, _repo, NULL, _sig, _sig, &target_oid, "hello world\n", 0);
@@ -334,7 +334,7 @@ void test_notes_notes__creating_a_note_on_a_target_can_overwrite_existing_note(v
 	git_oid note_oid, target_oid;
 	git_note *note, *namespace_note;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125", GIT_OID_SHA1));
 
 	create_note(&note_oid, NULL, "08b041783f40edfe12bb406c9c9a8a040177c125", "hello old world\n");
 	cl_git_pass(git_note_create(&note_oid, _repo, NULL, _sig, _sig, &target_oid, "hello new world\n", 1));
@@ -381,7 +381,7 @@ void test_notes_notes__can_read_a_note(void)
 
 	create_note(&note_oid, "refs/notes/i-can-see-dead-notes", "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", "I decorate 4a20\n");
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", GIT_OID_SHA1));
 
 	cl_git_pass(git_note_read(&note, _repo, "refs/notes/i-can-see-dead-notes", &target_oid));
 
@@ -397,7 +397,7 @@ void test_notes_notes__can_read_a_note_from_a_commit(void)
 	git_commit *notes_commit;
 	git_note *note;
 
-	cl_git_pass(git_oid_fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045"));
+	cl_git_pass(git_oid__fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", GIT_OID_SHA1));
 	cl_git_pass(git_note_commit_create(&notes_commit_oid, NULL, _repo, NULL, _sig, _sig, &oid, "I decorate 4a20\n", 1));
 	cl_git_pass(git_commit_lookup(&notes_commit, _repo, &notes_commit_oid));
 	cl_assert(notes_commit);
@@ -416,7 +416,7 @@ void test_notes_notes__attempt_to_read_a_note_from_a_commit_with_no_note_fails(v
 	git_commit *notes_commit;
 	git_note *note;
 
-	cl_git_pass(git_oid_fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045"));
+	cl_git_pass(git_oid__fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", GIT_OID_SHA1));
 
 	cl_git_pass(git_note_commit_create(&notes_commit_oid, NULL, _repo, NULL, _sig, _sig, &oid, "I decorate 4a20\n", 1));
 
@@ -450,7 +450,7 @@ void test_notes_notes__can_insert_a_note_in_an_existing_fanout(void)
 	git_oid note_oid, target_oid;
 	git_note *_note;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "08b041783f40edfe12bb406c9c9a8a040177c125", GIT_OID_SHA1));
 
 	for (i = 0; i <  MESSAGES_COUNT; i++) {
 		cl_git_pass(git_note_create(&note_oid, _repo, "refs/notes/fanout", _sig, _sig, &target_oid, messages[i], 0));
@@ -470,10 +470,10 @@ void test_notes_notes__can_read_a_note_in_an_existing_fanout(void)
 	git_oid note_oid, target_oid;
 	git_note *note;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "8496071c1b46c854b31185ea97743be6a8774479"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "8496071c1b46c854b31185ea97743be6a8774479", GIT_OID_SHA1));
 	cl_git_pass(git_note_read(&note, _repo, "refs/notes/fanout", &target_oid));
 
-	cl_git_pass(git_oid_fromstr(&note_oid, "08b041783f40edfe12bb406c9c9a8a040177c125"));
+	cl_git_pass(git_oid__fromstr(&note_oid, "08b041783f40edfe12bb406c9c9a8a040177c125", GIT_OID_SHA1));
 	cl_assert_equal_oid(git_note_id(note), &note_oid);
 
 	git_note_free(note);
@@ -487,7 +487,7 @@ void test_notes_notes__can_remove_a_note(void)
 
 	create_note(&note_oid, "refs/notes/i-can-see-dead-notes", "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", "I decorate 4a20\n");
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", GIT_OID_SHA1));
 	cl_git_pass(git_note_remove(_repo, "refs/notes/i-can-see-dead-notes", _sig, _sig, &target_oid));
 
 	cl_git_fail(git_note_read(&note, _repo, "refs/notes/i-can-see-dead-notes", &target_oid));
@@ -501,7 +501,7 @@ void test_notes_notes__can_remove_a_note_from_commit(void)
 	git_commit *existing_notes_commit;
 	git_reference *ref;
 
-	cl_git_pass(git_oid_fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045"));
+	cl_git_pass(git_oid__fromstr(&oid, "4a202b346bb0fb0db7eff3cffeb3c70babbd2045", GIT_OID_SHA1));
 
 	cl_git_pass(git_note_commit_create(&notes_commit_oid, NULL, _repo, NULL, _sig, _sig, &oid, "I decorate 4a20\n", 0));
 
@@ -528,7 +528,7 @@ void test_notes_notes__can_remove_a_note_in_an_existing_fanout(void)
 	git_oid target_oid;
 	git_note *note;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "8496071c1b46c854b31185ea97743be6a8774479"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "8496071c1b46c854b31185ea97743be6a8774479", GIT_OID_SHA1));
 	cl_git_pass(git_note_remove(_repo, "refs/notes/fanout", _sig, _sig, &target_oid));
 
 	cl_git_fail(git_note_read(&note, _repo, "refs/notes/fanout", &target_oid));
@@ -539,7 +539,7 @@ void test_notes_notes__removing_a_note_which_doesnt_exists_returns_ENOTFOUND(voi
 	int error;
 	git_oid target_oid;
 
-	cl_git_pass(git_oid_fromstr(&target_oid, "8496071c1b46c854b31185ea97743be6a8774479"));
+	cl_git_pass(git_oid__fromstr(&target_oid, "8496071c1b46c854b31185ea97743be6a8774479", GIT_OID_SHA1));
 	cl_git_pass(git_note_remove(_repo, "refs/notes/fanout", _sig, _sig, &target_oid));
 
 	error = git_note_remove(_repo, "refs/notes/fanout", _sig, _sig, &target_oid);
@@ -628,8 +628,8 @@ void test_notes_notes__iterate_from_commit(void)
 	};
 	int i, err;
 
-	cl_git_pass(git_oid_fromstr(&(oids[0]), "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
-	cl_git_pass(git_oid_fromstr(&(oids[1]), "c47800c7266a2be04c571c04d5a6614691ea99bd"));
+	cl_git_pass(git_oid__fromstr(&(oids[0]), "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&(oids[1]), "c47800c7266a2be04c571c04d5a6614691ea99bd", GIT_OID_SHA1));
 
 	cl_git_pass(git_note_commit_create(&notes_commit_oids[0], NULL, _repo, NULL, _sig, _sig, &(oids[0]), note_message[0], 0));
 
diff --git a/tests/libgit2/notes/notesref.c b/tests/libgit2/notes/notesref.c
index 6ba324c76..8696ff66a 100644
--- a/tests/libgit2/notes/notesref.c
+++ b/tests/libgit2/notes/notesref.c
@@ -36,7 +36,7 @@ void test_notes_notesref__config_corenotesref(void)
 	git_buf default_ref = GIT_BUF_INIT;
 
 	cl_git_pass(git_signature_now(&_sig, "alice", "alice@example.com"));
-	cl_git_pass(git_oid_fromstr(&oid, "8496071c1b46c854b31185ea97743be6a8774479"));
+	cl_git_pass(git_oid__fromstr(&oid, "8496071c1b46c854b31185ea97743be6a8774479", GIT_OID_SHA1));
 
 	cl_git_pass(git_repository_config(&_cfg, _repo));
 
diff --git a/tests/libgit2/object/blob/fromstream.c b/tests/libgit2/object/blob/fromstream.c
index 60ff3991b..dad0b52e1 100644
--- a/tests/libgit2/object/blob/fromstream.c
+++ b/tests/libgit2/object/blob/fromstream.c
@@ -23,7 +23,7 @@ void test_object_blob_fromstream__multiple_write(void)
 	git_writestream *stream;
 	int i, howmany = 6;
 
-	cl_git_pass(git_oid_fromstr(&expected_id, "321cbdf08803c744082332332838df6bd160f8f9"));
+	cl_git_pass(git_oid__fromstr(&expected_id, "321cbdf08803c744082332332838df6bd160f8f9", GIT_OID_SHA1));
 
 	cl_git_fail_with(GIT_ENOTFOUND,
 			 git_object_lookup(&blob, repo, &expected_id, GIT_OBJECT_ANY));
@@ -64,7 +64,7 @@ static void assert_named_chunked_blob(const char *expected_sha, const char *fake
 	git_writestream *stream;
 	int i, howmany = 6;
 
-	cl_git_pass(git_oid_fromstr(&expected_id, expected_sha));
+	cl_git_pass(git_oid__fromstr(&expected_id, expected_sha, GIT_OID_SHA1));
 
 	cl_git_pass(git_blob_create_from_stream(&stream, repo, fake_name));
 
diff --git a/tests/libgit2/object/cache.c b/tests/libgit2/object/cache.c
index 08bf03648..bf8c6fb53 100644
--- a/tests/libgit2/object/cache.c
+++ b/tests/libgit2/object/cache.c
@@ -91,7 +91,7 @@ void test_object_cache__cache_counts(void)
 	for (i = 0; g_data[i].sha != NULL; ++i) {
 		int count = (int)git_cache_size(&g_repo->objects);
 
-		cl_git_pass(git_oid_fromstr(&oid, g_data[i].sha));
+		cl_git_pass(git_oid__fromstr(&oid, g_data[i].sha, GIT_OID_SHA1));
 
 		/* alternate between loading raw and parsed objects */
 		if ((i & 1) == 0) {
@@ -118,7 +118,7 @@ void test_object_cache__cache_counts(void)
 	for (i = 0; g_data[i].sha != NULL; ++i) {
 		int count = (int)git_cache_size(&g_repo->objects);
 
-		cl_git_pass(git_oid_fromstr(&oid, g_data[i].sha));
+		cl_git_pass(git_oid__fromstr(&oid, g_data[i].sha, GIT_OID_SHA1));
 		cl_git_pass(git_object_lookup(&obj, g_repo, &oid, GIT_OBJECT_ANY));
 		cl_assert(g_data[i].type == git_object_type(obj));
 		git_object_free(obj);
@@ -136,14 +136,14 @@ static void *cache_parsed(void *arg)
 	git_object *obj;
 
 	for (i = ((int *)arg)[1]; g_data[i].sha != NULL; i += 2) {
-		cl_git_pass(git_oid_fromstr(&oid, g_data[i].sha));
+		cl_git_pass(git_oid__fromstr(&oid, g_data[i].sha, GIT_OID_SHA1));
 		cl_git_pass(git_object_lookup(&obj, g_repo, &oid, GIT_OBJECT_ANY));
 		cl_assert(g_data[i].type == git_object_type(obj));
 		git_object_free(obj);
 	}
 
 	for (i = 0; i < ((int *)arg)[1]; i += 2) {
-		cl_git_pass(git_oid_fromstr(&oid, g_data[i].sha));
+		cl_git_pass(git_oid__fromstr(&oid, g_data[i].sha, GIT_OID_SHA1));
 		cl_git_pass(git_object_lookup(&obj, g_repo, &oid, GIT_OBJECT_ANY));
 		cl_assert(g_data[i].type == git_object_type(obj));
 		git_object_free(obj);
@@ -162,14 +162,14 @@ static void *cache_raw(void *arg)
 	cl_git_pass(git_repository_odb(&odb, g_repo));
 
 	for (i = ((int *)arg)[1]; g_data[i].sha != NULL; i += 2) {
-		cl_git_pass(git_oid_fromstr(&oid, g_data[i].sha));
+		cl_git_pass(git_oid__fromstr(&oid, g_data[i].sha, GIT_OID_SHA1));
 		cl_git_pass(git_odb_read(&odb_obj, odb, &oid));
 		cl_assert(g_data[i].type == git_odb_object_type(odb_obj));
 		git_odb_object_free(odb_obj);
 	}
 
 	for (i = 0; i < ((int *)arg)[1]; i += 2) {
-		cl_git_pass(git_oid_fromstr(&oid, g_data[i].sha));
+		cl_git_pass(git_oid__fromstr(&oid, g_data[i].sha, GIT_OID_SHA1));
 		cl_git_pass(git_odb_read(&odb_obj, odb, &oid));
 		cl_assert(g_data[i].type == git_odb_object_type(odb_obj));
 		git_odb_object_free(odb_obj);
@@ -234,7 +234,7 @@ static void *cache_quick(void *arg)
 	git_oid oid;
 	git_object *obj;
 
-	cl_git_pass(git_oid_fromstr(&oid, g_data[4].sha));
+	cl_git_pass(git_oid__fromstr(&oid, g_data[4].sha, GIT_OID_SHA1));
 	cl_git_pass(git_object_lookup(&obj, g_repo, &oid, GIT_OBJECT_ANY));
 	cl_assert(g_data[4].type == git_object_type(obj));
 	git_object_free(obj);
diff --git a/tests/libgit2/object/commit/commitstagedfile.c b/tests/libgit2/object/commit/commitstagedfile.c
index 7322a4e86..61f50b2af 100644
--- a/tests/libgit2/object/commit/commitstagedfile.c
+++ b/tests/libgit2/object/commit/commitstagedfile.c
@@ -64,9 +64,9 @@ void test_object_commit_commitstagedfile__generate_predictable_object_ids(void)
 	 * 100644 blob 9daeafb9864cf43055ae93beb0afd6c7d144bfa4    test.txt
 	 */
 
-	cl_git_pass(git_oid_fromstr(&expected_commit_oid, "1fe3126578fc4eca68c193e4a3a0a14a0704624d"));
-	cl_git_pass(git_oid_fromstr(&expected_tree_oid, "2b297e643c551e76cfa1f93810c50811382f9117"));
-	cl_git_pass(git_oid_fromstr(&expected_blob_oid, "9daeafb9864cf43055ae93beb0afd6c7d144bfa4"));
+	cl_git_pass(git_oid__fromstr(&expected_commit_oid, "1fe3126578fc4eca68c193e4a3a0a14a0704624d", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected_tree_oid, "2b297e643c551e76cfa1f93810c50811382f9117", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected_blob_oid, "9daeafb9864cf43055ae93beb0afd6c7d144bfa4", GIT_OID_SHA1));
 
 	/*
 	 * Add a new file to the index
diff --git a/tests/libgit2/object/commit/parse.c b/tests/libgit2/object/commit/parse.c
index 4ff1ad62a..28a3ccd85 100644
--- a/tests/libgit2/object/commit/parse.c
+++ b/tests/libgit2/object/commit/parse.c
@@ -51,7 +51,7 @@ static void assert_commit_parses(const char *data, size_t datalen,
 
 	if (expected_treeid) {
 		git_oid tree_oid;
-		cl_git_pass(git_oid_fromstr(&tree_oid, expected_treeid));
+		cl_git_pass(git_oid__fromstr(&tree_oid, expected_treeid, GIT_OID_SHA1));
 		cl_assert_equal_oid(&tree_oid, &commit->tree_id);
 	}
 
diff --git a/tests/libgit2/object/lookup.c b/tests/libgit2/object/lookup.c
index a7b1ceeb4..7ef1dbd1c 100644
--- a/tests/libgit2/object/lookup.c
+++ b/tests/libgit2/object/lookup.c
@@ -20,7 +20,7 @@ void test_object_lookup__lookup_wrong_type_returns_enotfound(void)
 	git_oid oid;
 	git_object *object;
 
-	cl_git_pass(git_oid_fromstr(&oid, commit));
+	cl_git_pass(git_oid__fromstr(&oid, commit, GIT_OID_SHA1));
 	cl_assert_equal_i(
 		GIT_ENOTFOUND, git_object_lookup(&object, g_repo, &oid, GIT_OBJECT_TAG));
 }
@@ -31,7 +31,7 @@ void test_object_lookup__lookup_nonexisting_returns_enotfound(void)
 	git_oid oid;
 	git_object *object;
 
-	cl_git_pass(git_oid_fromstr(&oid, unknown));
+	cl_git_pass(git_oid__fromstr(&oid, unknown, GIT_OID_SHA1));
 	cl_assert_equal_i(
 		GIT_ENOTFOUND, git_object_lookup(&object, g_repo, &oid, GIT_OBJECT_ANY));
 }
@@ -42,7 +42,7 @@ void test_object_lookup__lookup_wrong_type_by_abbreviated_id_returns_enotfound(v
 	git_oid oid;
 	git_object *object;
 
-	cl_git_pass(git_oid_fromstrn(&oid, commit, strlen(commit)));
+	cl_git_pass(git_oid__fromstrn(&oid, commit, strlen(commit), GIT_OID_SHA1));
 	cl_assert_equal_i(
 		GIT_ENOTFOUND, git_object_lookup_prefix(&object, g_repo, &oid, strlen(commit), GIT_OBJECT_TAG));
 }
@@ -53,7 +53,7 @@ void test_object_lookup__lookup_wrong_type_eventually_returns_enotfound(void)
 	git_oid oid;
 	git_object *object;
 
-	cl_git_pass(git_oid_fromstr(&oid, commit));
+	cl_git_pass(git_oid__fromstr(&oid, commit, GIT_OID_SHA1));
 
 	cl_git_pass(git_object_lookup(&object, g_repo, &oid, GIT_OBJECT_COMMIT));
 	git_object_free(object);
@@ -71,7 +71,7 @@ void test_object_lookup__lookup_corrupt_object_returns_error(void)
 	git_object *object;
 	size_t i;
 
-	cl_git_pass(git_oid_fromstr(&oid, commit));
+	cl_git_pass(git_oid__fromstr(&oid, commit, GIT_OID_SHA1));
 	cl_git_pass(git_str_joinpath(&path, git_repository_path(g_repo), file));
 	cl_git_pass(git_futils_readbuffer(&contents, path.ptr));
 
@@ -101,7 +101,7 @@ void test_object_lookup__lookup_object_with_wrong_hash_returns_error(void)
 	git_object *object;
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, commit));
+	cl_git_pass(git_oid__fromstr(&oid, commit, GIT_OID_SHA1));
 
 	/* Copy object to another location with wrong hash */
 	cl_git_pass(git_str_joinpath(&oldpath, git_repository_path(g_repo), oldloose));
diff --git a/tests/libgit2/object/peel.c b/tests/libgit2/object/peel.c
index 8be6e42d4..da3ef17e2 100644
--- a/tests/libgit2/object/peel.c
+++ b/tests/libgit2/object/peel.c
@@ -23,12 +23,12 @@ static void assert_peel(
 	git_object *obj;
 	git_object *peeled;
 
-	cl_git_pass(git_oid_fromstr(&oid, sha));
+	cl_git_pass(git_oid__fromstr(&oid, sha, GIT_OID_SHA1));
 	cl_git_pass(git_object_lookup(&obj, g_repo, &oid, GIT_OBJECT_ANY));
 
 	cl_git_pass(git_object_peel(&peeled, obj, requested_type));
 
-	cl_git_pass(git_oid_fromstr(&expected_oid, expected_sha));
+	cl_git_pass(git_oid__fromstr(&expected_oid, expected_sha, GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected_oid, git_object_id(peeled));
 
 	cl_assert_equal_i(expected_type, git_object_type(peeled));
@@ -43,7 +43,7 @@ static void assert_peel_error(int error, const char *sha, git_object_t requested
 	git_object *obj;
 	git_object *peeled;
 
-	cl_git_pass(git_oid_fromstr(&oid, sha));
+	cl_git_pass(git_oid__fromstr(&oid, sha, GIT_OID_SHA1));
 	cl_git_pass(git_object_lookup(&obj, g_repo, &oid, GIT_OBJECT_ANY));
 
 	cl_assert_equal_i(error, git_object_peel(&peeled, obj, requested_type));
diff --git a/tests/libgit2/object/raw/chars.c b/tests/libgit2/object/raw/chars.c
index cde0bdbf6..cb159e9ac 100644
--- a/tests/libgit2/object/raw/chars.c
+++ b/tests/libgit2/object/raw/chars.c
@@ -19,10 +19,10 @@ void test_object_raw_chars__find_invalid_chars_in_oid(void)
 		in[38] = (char)i;
 		if (git__fromhex(i) >= 0) {
 			exp[19] = (unsigned char)(git__fromhex(i) << 4);
-			cl_git_pass(git_oid_fromstr(&out, in));
-			cl_assert(memcmp(out.id, exp, sizeof(out.id)) == 0);
+			cl_git_pass(git_oid__fromstr(&out, in, GIT_OID_SHA1));
+			cl_assert(memcmp(out.id, exp, GIT_OID_SHA1_SIZE) == 0);
 		} else {
-			cl_git_fail(git_oid_fromstr(&out, in));
+			cl_git_fail(git_oid__fromstr(&out, in, GIT_OID_SHA1));
 		}
 	}
 }
@@ -36,6 +36,6 @@ void test_object_raw_chars__build_valid_oid_from_raw_bytes(void)
 		0xb7, 0x75, 0x21, 0x3c, 0x23,
 		0xa8, 0xbd, 0x74, 0xf5, 0xe0,
 	};
-	git_oid_fromraw(&out, exp);
-	cl_git_pass(memcmp(out.id, exp, sizeof(out.id)));
+	git_oid__fromraw(&out, exp, GIT_OID_SHA1);
+	cl_git_pass(memcmp(out.id, exp, GIT_OID_SHA1_SIZE));
 }
diff --git a/tests/libgit2/object/raw/compare.c b/tests/libgit2/object/raw/compare.c
index 56c016b72..9258eef41 100644
--- a/tests/libgit2/object/raw/compare.c
+++ b/tests/libgit2/object/raw/compare.c
@@ -13,9 +13,9 @@ void test_object_raw_compare__succeed_on_copy_oid(void)
 		0xa8, 0xbd, 0x74, 0xf5, 0xe0,
 	};
 	memset(&b, 0, sizeof(b));
-	git_oid_fromraw(&a, exp);
+	git_oid__fromraw(&a, exp, GIT_OID_SHA1);
 	git_oid_cpy(&b, &a);
-	cl_git_pass(memcmp(a.id, exp, sizeof(a.id)));
+	cl_git_pass(memcmp(a.id, exp, GIT_OID_SHA1_SIZE));
 }
 
 void test_object_raw_compare__succeed_on_oid_comparison_lesser(void)
@@ -33,8 +33,8 @@ void test_object_raw_compare__succeed_on_oid_comparison_lesser(void)
 		0xb7, 0x75, 0x21, 0x3c, 0x23,
 		0xa8, 0xbd, 0x74, 0xf5, 0xf0,
 	};
-	git_oid_fromraw(&a, a_in);
-	git_oid_fromraw(&b, b_in);
+	git_oid__fromraw(&a, a_in, GIT_OID_SHA1);
+	git_oid__fromraw(&b, b_in, GIT_OID_SHA1);
 	cl_assert(git_oid_cmp(&a, &b) < 0);
 }
 
@@ -47,8 +47,8 @@ void test_object_raw_compare__succeed_on_oid_comparison_equal(void)
 		0xb7, 0x75, 0x21, 0x3c, 0x23,
 		0xa8, 0xbd, 0x74, 0xf5, 0xe0,
 	};
-	git_oid_fromraw(&a, a_in);
-	git_oid_fromraw(&b, a_in);
+	git_oid__fromraw(&a, a_in, GIT_OID_SHA1);
+	git_oid__fromraw(&b, a_in, GIT_OID_SHA1);
 	cl_assert(git_oid_cmp(&a, &b) == 0);
 }
 
@@ -67,8 +67,8 @@ void test_object_raw_compare__succeed_on_oid_comparison_greater(void)
 		0xb7, 0x75, 0x21, 0x3c, 0x23,
 		0xa8, 0xbd, 0x74, 0xf5, 0xd0,
 	};
-	git_oid_fromraw(&a, a_in);
-	git_oid_fromraw(&b, b_in);
+	git_oid__fromraw(&a, a_in, GIT_OID_SHA1);
+	git_oid__fromraw(&b, b_in, GIT_OID_SHA1);
 	cl_assert(git_oid_cmp(&a, &b) > 0);
 }
 
@@ -76,17 +76,17 @@ void test_object_raw_compare__compare_fmt_oids(void)
 {
 	const char *exp = "16a0123456789abcdef4b775213c23a8bd74f5e0";
 	git_oid in;
-	char out[GIT_OID_HEXSZ + 1];
+	char out[GIT_OID_SHA1_HEXSIZE + 1];
 
-	cl_git_pass(git_oid_fromstr(&in, exp));
+	cl_git_pass(git_oid__fromstr(&in, exp, GIT_OID_SHA1));
 
 	/* Format doesn't touch the last byte */
-	out[GIT_OID_HEXSZ] = 'Z';
+	out[GIT_OID_SHA1_HEXSIZE] = 'Z';
 	git_oid_fmt(out, &in);
-	cl_assert(out[GIT_OID_HEXSZ] == 'Z');
+	cl_assert(out[GIT_OID_SHA1_HEXSIZE] == 'Z');
 
 	/* Format produced the right result */
-	out[GIT_OID_HEXSZ] = '\0';
+	out[GIT_OID_SHA1_HEXSIZE] = '\0';
 	cl_assert_equal_s(exp, out);
 }
 
@@ -96,7 +96,7 @@ void test_object_raw_compare__compare_static_oids(void)
 	git_oid in;
 	char *out;
 
-	cl_git_pass(git_oid_fromstr(&in, exp));
+	cl_git_pass(git_oid__fromstr(&in, exp, GIT_OID_SHA1));
 
 	out = git_oid_tostr_s(&in);
 	cl_assert(out);
@@ -108,16 +108,16 @@ void test_object_raw_compare__compare_pathfmt_oids(void)
 	const char *exp1 = "16a0123456789abcdef4b775213c23a8bd74f5e0";
 	const char *exp2 = "16/a0123456789abcdef4b775213c23a8bd74f5e0";
 	git_oid in;
-	char out[GIT_OID_HEXSZ + 2];
+	char out[GIT_OID_SHA1_HEXSIZE + 2];
 
-	cl_git_pass(git_oid_fromstr(&in, exp1));
+	cl_git_pass(git_oid__fromstr(&in, exp1, GIT_OID_SHA1));
 
 	/* Format doesn't touch the last byte */
-	out[GIT_OID_HEXSZ + 1] = 'Z';
+	out[GIT_OID_SHA1_HEXSIZE + 1] = 'Z';
 	git_oid_pathfmt(out, &in);
-	cl_assert(out[GIT_OID_HEXSZ + 1] == 'Z');
+	cl_assert(out[GIT_OID_SHA1_HEXSIZE + 1] == 'Z');
 
 	/* Format produced the right result */
-	out[GIT_OID_HEXSZ + 1] = '\0';
+	out[GIT_OID_SHA1_HEXSIZE + 1] = '\0';
 	cl_assert_equal_s(exp2, out);
 }
diff --git a/tests/libgit2/object/raw/convert.c b/tests/libgit2/object/raw/convert.c
index 40a01ae09..962476b97 100644
--- a/tests/libgit2/object/raw/convert.c
+++ b/tests/libgit2/object/raw/convert.c
@@ -7,11 +7,11 @@ void test_object_raw_convert__succeed_on_oid_to_string_conversion(void)
 {
 	const char *exp = "16a0123456789abcdef4b775213c23a8bd74f5e0";
 	git_oid in;
-	char out[GIT_OID_HEXSZ + 1];
+	char out[GIT_OID_SHA1_HEXSIZE + 1];
 	char *str;
 	int i;
 
-	cl_git_pass(git_oid_fromstr(&in, exp));
+	cl_git_pass(git_oid__fromstr(&in, exp, GIT_OID_SHA1));
 
 	/* NULL buffer pointer, returns static empty string */
 	str = git_oid_tostr(NULL, sizeof(out), &in);
@@ -29,7 +29,7 @@ void test_object_raw_convert__succeed_on_oid_to_string_conversion(void)
 	str = git_oid_tostr(out, 1, &in);
 	cl_assert(str && *str == '\0' && str == out);
 
-	for (i = 1; i < GIT_OID_HEXSZ; i++) {
+	for (i = 1; i < GIT_OID_SHA1_HEXSIZE; i++) {
 		out[i+1] = 'Z';
 		str = git_oid_tostr(out, i+1, &in);
 		/* returns out containing c-string */
@@ -44,7 +44,7 @@ void test_object_raw_convert__succeed_on_oid_to_string_conversion(void)
 
 	/* returns out as hex formatted c-string */
 	str = git_oid_tostr(out, sizeof(out), &in);
-	cl_assert(str && str == out && *(str+GIT_OID_HEXSZ) == '\0');
+	cl_assert(str && str == out && *(str+GIT_OID_SHA1_HEXSIZE) == '\0');
 	cl_assert_equal_s(exp, out);
 }
 
@@ -52,26 +52,26 @@ void test_object_raw_convert__succeed_on_oid_to_string_conversion_big(void)
 {
 	const char *exp = "16a0123456789abcdef4b775213c23a8bd74f5e0";
 	git_oid in;
-	char big[GIT_OID_HEXSZ + 1 + 3]; /* note + 4 => big buffer */
+	char big[GIT_OID_SHA1_HEXSIZE + 1 + 3]; /* note + 4 => big buffer */
 	char *str;
 
-	cl_git_pass(git_oid_fromstr(&in, exp));
+	cl_git_pass(git_oid__fromstr(&in, exp, GIT_OID_SHA1));
 
 	/* place some tail material */
-	big[GIT_OID_HEXSZ+0] = 'W'; /* should be '\0' afterwards */
-	big[GIT_OID_HEXSZ+1] = 'X'; /* should remain untouched   */
-	big[GIT_OID_HEXSZ+2] = 'Y'; /* ditto */
-	big[GIT_OID_HEXSZ+3] = 'Z'; /* ditto */
+	big[GIT_OID_SHA1_HEXSIZE+0] = 'W'; /* should be '\0' afterwards */
+	big[GIT_OID_SHA1_HEXSIZE+1] = 'X'; /* should remain untouched   */
+	big[GIT_OID_SHA1_HEXSIZE+2] = 'Y'; /* ditto */
+	big[GIT_OID_SHA1_HEXSIZE+3] = 'Z'; /* ditto */
 
 	/* returns big as hex formatted c-string */
 	str = git_oid_tostr(big, sizeof(big), &in);
-	cl_assert(str && str == big && *(str+GIT_OID_HEXSZ) == '\0');
+	cl_assert(str && str == big && *(str+GIT_OID_SHA1_HEXSIZE) == '\0');
 	cl_assert_equal_s(exp, big);
 
 	/* check tail material is untouched */
-	cl_assert(str && str == big && *(str+GIT_OID_HEXSZ+1) == 'X');
-	cl_assert(str && str == big && *(str+GIT_OID_HEXSZ+2) == 'Y');
-	cl_assert(str && str == big && *(str+GIT_OID_HEXSZ+3) == 'Z');
+	cl_assert(str && str == big && *(str+GIT_OID_SHA1_HEXSIZE+1) == 'X');
+	cl_assert(str && str == big && *(str+GIT_OID_SHA1_HEXSIZE+2) == 'Y');
+	cl_assert(str && str == big && *(str+GIT_OID_SHA1_HEXSIZE+3) == 'Z');
 }
 
 static void check_partial_oid(
@@ -86,14 +86,14 @@ void test_object_raw_convert__convert_oid_partially(void)
 {
 	const char *exp = "16a0123456789abcdef4b775213c23a8bd74f5e0";
 	git_oid in;
-	char big[GIT_OID_HEXSZ + 1 + 3]; /* note + 4 => big buffer */
+	char big[GIT_OID_SHA1_HEXSIZE + 1 + 3]; /* note + 4 => big buffer */
 
-	cl_git_pass(git_oid_fromstr(&in, exp));
+	cl_git_pass(git_oid__fromstr(&in, exp, GIT_OID_SHA1));
 
 	git_oid_nfmt(big, sizeof(big), &in);
 	cl_assert_equal_s(exp, big);
 
-	git_oid_nfmt(big, GIT_OID_HEXSZ + 1, &in);
+	git_oid_nfmt(big, GIT_OID_SHA1_HEXSIZE + 1, &in);
 	cl_assert_equal_s(exp, big);
 
 	check_partial_oid(big, 1, &in, "1");
@@ -102,11 +102,11 @@ void test_object_raw_convert__convert_oid_partially(void)
 	check_partial_oid(big, 4, &in, "16a0");
 	check_partial_oid(big, 5, &in, "16a01");
 
-	check_partial_oid(big, GIT_OID_HEXSZ, &in, exp);
+	check_partial_oid(big, GIT_OID_SHA1_HEXSIZE, &in, exp);
 	check_partial_oid(
-		big, GIT_OID_HEXSZ - 1, &in, "16a0123456789abcdef4b775213c23a8bd74f5e");
+		big, GIT_OID_SHA1_HEXSIZE - 1, &in, "16a0123456789abcdef4b775213c23a8bd74f5e");
 	check_partial_oid(
-		big, GIT_OID_HEXSZ - 2, &in, "16a0123456789abcdef4b775213c23a8bd74f5");
+		big, GIT_OID_SHA1_HEXSIZE - 2, &in, "16a0123456789abcdef4b775213c23a8bd74f5");
 	check_partial_oid(
-		big, GIT_OID_HEXSZ - 3, &in, "16a0123456789abcdef4b775213c23a8bd74f");
+		big, GIT_OID_SHA1_HEXSIZE - 3, &in, "16a0123456789abcdef4b775213c23a8bd74f");
 }
diff --git a/tests/libgit2/object/raw/fromstr.c b/tests/libgit2/object/raw/fromstr.c
index 8c11c105f..302d362d7 100644
--- a/tests/libgit2/object/raw/fromstr.c
+++ b/tests/libgit2/object/raw/fromstr.c
@@ -6,9 +6,9 @@
 void test_object_raw_fromstr__fail_on_invalid_oid_string(void)
 {
 	git_oid out;
-	cl_git_fail(git_oid_fromstr(&out, ""));
-	cl_git_fail(git_oid_fromstr(&out, "moo"));
-	cl_git_fail(git_oid_fromstr(&out, "16a67770b7d8d72317c4b775213c23a8bd74f5ez"));
+	cl_git_fail(git_oid__fromstr(&out, "", GIT_OID_SHA1));
+	cl_git_fail(git_oid__fromstr(&out, "moo", GIT_OID_SHA1));
+	cl_git_fail(git_oid__fromstr(&out, "16a67770b7d8d72317c4b775213c23a8bd74f5ez", GIT_OID_SHA1));
 }
 
 void test_object_raw_fromstr__succeed_on_valid_oid_string(void)
@@ -21,10 +21,9 @@ void test_object_raw_fromstr__succeed_on_valid_oid_string(void)
 		0xa8, 0xbd, 0x74, 0xf5, 0xe0,
 	};
 
-	cl_git_pass(git_oid_fromstr(&out, "16a67770b7d8d72317c4b775213c23a8bd74f5e0"));
-	cl_git_pass(memcmp(out.id, exp, sizeof(out.id)));
-
-	cl_git_pass(git_oid_fromstr(&out, "16A67770B7D8D72317C4b775213C23A8BD74F5E0"));
-	cl_git_pass(memcmp(out.id, exp, sizeof(out.id)));
+	cl_git_pass(git_oid__fromstr(&out, "16a67770b7d8d72317c4b775213c23a8bd74f5e0", GIT_OID_SHA1));
+	cl_git_pass(memcmp(out.id, exp, GIT_OID_SHA1_SIZE));
 
+	cl_git_pass(git_oid__fromstr(&out, "16A67770B7D8D72317C4b775213C23A8BD74F5E0", GIT_OID_SHA1));
+	cl_git_pass(memcmp(out.id, exp, GIT_OID_SHA1_SIZE));
 }
diff --git a/tests/libgit2/object/raw/hash.c b/tests/libgit2/object/raw/hash.c
index 8f22fe0ee..0df1afc3a 100644
--- a/tests/libgit2/object/raw/hash.c
+++ b/tests/libgit2/object/raw/hash.c
@@ -8,11 +8,11 @@
 
 static void hash_object_pass(git_oid *oid, git_rawobj *obj)
 {
-	cl_git_pass(git_odb_hash(oid, obj->data, obj->len, obj->type));
+	cl_git_pass(git_odb__hash(oid, obj->data, obj->len, obj->type, GIT_OID_SHA1));
 }
 static void hash_object_fail(git_oid *oid, git_rawobj *obj)
 {
-	cl_git_fail(git_odb_hash(oid, obj->data, obj->len, obj->type));
+	cl_git_fail(git_odb__hash(oid, obj->data, obj->len, obj->type, GIT_OID_SHA1));
 }
 
 static char *hello_id = "22596363b3de40b06f981fb85d82312e8c0ed511";
@@ -32,16 +32,16 @@ void test_object_raw_hash__hash_by_blocks(void)
 	/* should already be init'd */
 	cl_git_pass(git_hash_update(&ctx, hello_text, strlen(hello_text)));
 	cl_git_pass(git_hash_final(hash, &ctx));
-	cl_git_pass(git_oid_fromraw(&id2, hash));
-	cl_git_pass(git_oid_fromstr(&id1, hello_id));
+	cl_git_pass(git_oid__fromraw(&id2, hash, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&id1, hello_id, GIT_OID_SHA1));
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 
 	/* reinit should permit reuse */
 	cl_git_pass(git_hash_init(&ctx));
 	cl_git_pass(git_hash_update(&ctx, bye_text, strlen(bye_text)));
 	cl_git_pass(git_hash_final(hash, &ctx));
-	cl_git_pass(git_oid_fromraw(&id2, hash));
-	cl_git_pass(git_oid_fromstr(&id1, bye_id));
+	cl_git_pass(git_oid__fromraw(&id2, hash, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&id1, bye_id, GIT_OID_SHA1));
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 
 	git_hash_ctx_cleanup(&ctx);
@@ -52,9 +52,9 @@ void test_object_raw_hash__hash_buffer_in_single_call(void)
 	git_oid id1, id2;
 	unsigned char hash[GIT_HASH_SHA1_SIZE];
 
-	cl_git_pass(git_oid_fromstr(&id1, hello_id));
+	cl_git_pass(git_oid__fromstr(&id1, hello_id, GIT_OID_SHA1));
 	cl_git_pass(git_hash_buf(hash, hello_text, strlen(hello_text), GIT_HASH_ALGORITHM_SHA1));
-	cl_git_pass(git_oid_fromraw(&id2, hash));
+	cl_git_pass(git_oid__fromraw(&id2, hash, GIT_OID_SHA1));
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
 
@@ -62,15 +62,17 @@ void test_object_raw_hash__hash_vector(void)
 {
 	git_oid id1, id2;
 	git_str_vec vec[2];
+	unsigned char hash[GIT_HASH_SHA1_SIZE];
 
-	cl_git_pass(git_oid_fromstr(&id1, hello_id));
+	cl_git_pass(git_oid__fromstr(&id1, hello_id, GIT_OID_SHA1));
 
 	vec[0].data = hello_text;
 	vec[0].len  = 4;
 	vec[1].data = hello_text+4;
 	vec[1].len  = strlen(hello_text)-4;
 
-	git_hash_vec(id2.id, vec, 2, GIT_HASH_ALGORITHM_SHA1);
+	git_hash_vec(hash, vec, 2, GIT_HASH_ALGORITHM_SHA1);
+	git_oid__fromraw(&id2, hash, GIT_OID_SHA1);
 
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
@@ -79,7 +81,7 @@ void test_object_raw_hash__hash_junk_data(void)
 {
 	git_oid id, id_zero;
 
-	cl_git_pass(git_oid_fromstr(&id_zero, zero_id));
+	cl_git_pass(git_oid__fromstr(&id_zero, zero_id, GIT_OID_SHA1));
 
 	/* invalid types: */
 	junk_obj.data = some_data;
@@ -114,7 +116,7 @@ void test_object_raw_hash__hash_commit_object(void)
 {
 	git_oid id1, id2;
 
-	cl_git_pass(git_oid_fromstr(&id1, commit_id));
+	cl_git_pass(git_oid__fromstr(&id1, commit_id, GIT_OID_SHA1));
 	hash_object_pass(&id2, &commit_obj);
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
@@ -123,7 +125,7 @@ void test_object_raw_hash__hash_tree_object(void)
 {
 	git_oid id1, id2;
 
-	cl_git_pass(git_oid_fromstr(&id1, tree_id));
+	cl_git_pass(git_oid__fromstr(&id1, tree_id, GIT_OID_SHA1));
 	hash_object_pass(&id2, &tree_obj);
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
@@ -132,7 +134,7 @@ void test_object_raw_hash__hash_tag_object(void)
 {
 	git_oid id1, id2;
 
-	cl_git_pass(git_oid_fromstr(&id1, tag_id));
+	cl_git_pass(git_oid__fromstr(&id1, tag_id, GIT_OID_SHA1));
 	hash_object_pass(&id2, &tag_obj);
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
@@ -141,7 +143,7 @@ void test_object_raw_hash__hash_zero_length_object(void)
 {
 	git_oid id1, id2;
 
-	cl_git_pass(git_oid_fromstr(&id1, zero_id));
+	cl_git_pass(git_oid__fromstr(&id1, zero_id, GIT_OID_SHA1));
 	hash_object_pass(&id2, &zero_obj);
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
@@ -150,7 +152,7 @@ void test_object_raw_hash__hash_one_byte_object(void)
 {
 	git_oid id1, id2;
 
-	cl_git_pass(git_oid_fromstr(&id1, one_id));
+	cl_git_pass(git_oid__fromstr(&id1, one_id, GIT_OID_SHA1));
 	hash_object_pass(&id2, &one_obj);
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
@@ -159,7 +161,7 @@ void test_object_raw_hash__hash_two_byte_object(void)
 {
 	git_oid id1, id2;
 
-	cl_git_pass(git_oid_fromstr(&id1, two_id));
+	cl_git_pass(git_oid__fromstr(&id1, two_id, GIT_OID_SHA1));
 	hash_object_pass(&id2, &two_obj);
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
@@ -168,7 +170,7 @@ void test_object_raw_hash__hash_multi_byte_object(void)
 {
 	git_oid id1, id2;
 
-	cl_git_pass(git_oid_fromstr(&id1, some_id));
+	cl_git_pass(git_oid__fromstr(&id1, some_id, GIT_OID_SHA1));
 	hash_object_pass(&id2, &some_obj);
 	cl_assert(git_oid_cmp(&id1, &id2) == 0);
 }
diff --git a/tests/libgit2/object/raw/short.c b/tests/libgit2/object/raw/short.c
index cc2b5f62a..f867e6ba1 100644
--- a/tests/libgit2/object/raw/short.c
+++ b/tests/libgit2/object/raw/short.c
@@ -17,7 +17,7 @@ void test_object_raw_short__oid_shortener_no_duplicates(void)
 	git_oid_shorten_add(os, "16a0123456789abcdef4b775213c23a8bd74f5e0");
 	min_len = git_oid_shorten_add(os, "ce08fe4884650f067bd5703b6a59a8b3b3c99a09");
 
-	cl_assert(min_len == GIT_OID_HEXSZ + 1);
+	cl_assert(min_len == GIT_OID_SHA1_HEXSIZE + 1);
 
 	git_oid_shorten_free(os);
 }
@@ -36,11 +36,11 @@ static int insert_sequential_oids(
 		p_snprintf(numbuf, sizeof(numbuf), "%u", (unsigned int)i);
 		git_hash_buf(hashbuf, numbuf, strlen(numbuf), GIT_HASH_ALGORITHM_SHA1);
 
-		git_oid_fromraw(&oid, hashbuf);
+		git_oid__fromraw(&oid, hashbuf, GIT_OID_SHA1);
 
-		oids[i] = git__malloc(GIT_OID_HEXSZ + 1);
+		oids[i] = git__malloc(GIT_OID_SHA1_HEXSIZE + 1);
 		cl_assert(oids[i]);
-		git_oid_nfmt(oids[i], GIT_OID_HEXSZ + 1, &oid);
+		git_oid_nfmt(oids[i], GIT_OID_SHA1_HEXSIZE + 1, &oid);
 
 		min_len = git_oid_shorten_add(os, oids[i]);
 
diff --git a/tests/libgit2/object/raw/size.c b/tests/libgit2/object/raw/size.c
index 930c6de23..a45e1d272 100644
--- a/tests/libgit2/object/raw/size.c
+++ b/tests/libgit2/object/raw/size.c
@@ -6,8 +6,8 @@
 void test_object_raw_size__validate_oid_size(void)
 {
 	git_oid out;
-	cl_assert(20 == GIT_OID_RAWSZ);
-	cl_assert(40 == GIT_OID_HEXSZ);
-	cl_assert(sizeof(out) == GIT_OID_RAWSZ);
-	cl_assert(sizeof(out.id) == GIT_OID_RAWSZ);
+
+	cl_assert(20 == GIT_OID_SHA1_SIZE);
+	cl_assert(40 == GIT_OID_SHA1_HEXSIZE);
+	cl_assert(sizeof(out.id) == GIT_OID_MAX_SIZE);
 }
diff --git a/tests/libgit2/object/raw/write.c b/tests/libgit2/object/raw/write.c
index 40e05f357..346053df5 100644
--- a/tests/libgit2/object/raw/write.c
+++ b/tests/libgit2/object/raw/write.c
@@ -66,8 +66,8 @@ void test_body(object_data *d, git_rawobj *o)
    git_rawobj tmp;
 
    make_odb_dir();
-   cl_git_pass(git_odb_open(&db, odb_dir));
-   cl_git_pass(git_oid_fromstr(&id1, d->id));
+   cl_git_pass(git_odb__open(&db, odb_dir, NULL));
+   cl_git_pass(git_oid__fromstr(&id1, d->id, GIT_OID_SHA1));
 
    streaming_write(&id2, db, o);
    cl_assert(git_oid_cmp(&id1, &id2) == 0);
diff --git a/tests/libgit2/object/shortid.c b/tests/libgit2/object/shortid.c
index 9b673efeb..69fceeeda 100644
--- a/tests/libgit2/object/shortid.c
+++ b/tests/libgit2/object/shortid.c
@@ -19,28 +19,28 @@ void test_object_shortid__select(void)
 	git_object *obj;
 	git_buf shorty = {0};
 
-	git_oid_fromstr(&full, "ce013625030ba8dba906f756967f9e9ca394464a");
+	git_oid__fromstr(&full, "ce013625030ba8dba906f756967f9e9ca394464a", GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&obj, _repo, &full, GIT_OBJECT_ANY));
 	cl_git_pass(git_object_short_id(&shorty, obj));
 	cl_assert_equal_i(7, shorty.size);
 	cl_assert_equal_s("ce01362", shorty.ptr);
 	git_object_free(obj);
 
-	git_oid_fromstr(&full, "038d718da6a1ebbc6a7780a96ed75a70cc2ad6e2");
+	git_oid__fromstr(&full, "038d718da6a1ebbc6a7780a96ed75a70cc2ad6e2", GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&obj, _repo, &full, GIT_OBJECT_ANY));
 	cl_git_pass(git_object_short_id(&shorty, obj));
 	cl_assert_equal_i(7, shorty.size);
 	cl_assert_equal_s("038d718", shorty.ptr);
 	git_object_free(obj);
 
-	git_oid_fromstr(&full, "dea509d097ce692e167dfc6a48a7a280cc5e877e");
+	git_oid__fromstr(&full, "dea509d097ce692e167dfc6a48a7a280cc5e877e", GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&obj, _repo, &full, GIT_OBJECT_ANY));
 	cl_git_pass(git_object_short_id(&shorty, obj));
 	cl_assert_equal_i(9, shorty.size);
 	cl_assert_equal_s("dea509d09", shorty.ptr);
 	git_object_free(obj);
 
-	git_oid_fromstr(&full, "dea509d0b3cb8ee0650f6ca210bc83f4678851ba");
+	git_oid__fromstr(&full, "dea509d0b3cb8ee0650f6ca210bc83f4678851ba", GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&obj, _repo, &full, GIT_OBJECT_ANY));
 	cl_git_pass(git_object_short_id(&shorty, obj));
 	cl_assert_equal_i(9, shorty.size);
diff --git a/tests/libgit2/object/tag/parse.c b/tests/libgit2/object/tag/parse.c
index 2c0635ae4..92298b5ce 100644
--- a/tests/libgit2/object/tag/parse.c
+++ b/tests/libgit2/object/tag/parse.c
@@ -19,7 +19,7 @@ static void assert_tag_parses(const char *data, size_t datalen,
 
 	if (expected_oid) {
 		git_oid oid;
-		cl_git_pass(git_oid_fromstr(&oid, expected_oid));
+		cl_git_pass(git_oid__fromstr(&oid, expected_oid, GIT_OID_SHA1));
 		cl_assert_equal_oid(&oid, &tag->target);
 	}
 
diff --git a/tests/libgit2/object/tag/peel.c b/tests/libgit2/object/tag/peel.c
index 7456a8e17..db81c5aee 100644
--- a/tests/libgit2/object/tag/peel.c
+++ b/tests/libgit2/object/tag/peel.c
@@ -29,7 +29,7 @@ static void retrieve_tag_from_oid(git_tag **tag_out, git_repository *repo, const
 {
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, sha));
+	cl_git_pass(git_oid__fromstr(&oid, sha, GIT_OID_SHA1));
 	cl_git_pass(git_tag_lookup(tag_out, repo, &oid));
 }
 
diff --git a/tests/libgit2/object/tag/read.c b/tests/libgit2/object/tag/read.c
index 90ba58029..6270b567a 100644
--- a/tests/libgit2/object/tag/read.c
+++ b/tests/libgit2/object/tag/read.c
@@ -32,9 +32,9 @@ void test_object_tag_read__parse(void)
 	git_commit *commit;
 	git_oid id1, id2, id_commit;
 
-	git_oid_fromstr(&id1, tag1_id);
-	git_oid_fromstr(&id2, tag2_id);
-	git_oid_fromstr(&id_commit, tagged_commit);
+	git_oid__fromstr(&id1, tag1_id, GIT_OID_SHA1);
+	git_oid__fromstr(&id2, tag2_id, GIT_OID_SHA1);
+	git_oid__fromstr(&id_commit, tagged_commit, GIT_OID_SHA1);
 
 	cl_git_pass(git_tag_lookup(&tag1, g_repo, &id1));
 
@@ -67,8 +67,8 @@ void test_object_tag_read__parse_without_tagger(void)
 	/* TODO: This is a little messy */
 	cl_git_pass(git_repository_open(&bad_tag_repo, cl_fixture("bad_tag.git")));
 
-	git_oid_fromstr(&id, bad_tag_id);
-	git_oid_fromstr(&id_commit, badly_tagged_commit);
+	git_oid__fromstr(&id, bad_tag_id, GIT_OID_SHA1);
+	git_oid__fromstr(&id_commit, badly_tagged_commit, GIT_OID_SHA1);
 
 	cl_git_pass(git_tag_lookup(&bad_tag, bad_tag_repo, &id));
 	cl_assert(bad_tag != NULL);
@@ -99,8 +99,8 @@ void test_object_tag_read__parse_without_message(void)
 	/* TODO: This is a little messy */
 	cl_git_pass(git_repository_open(&short_tag_repo, cl_fixture("short_tag.git")));
 
-	git_oid_fromstr(&id, short_tag_id);
-	git_oid_fromstr(&id_commit, short_tagged_commit);
+	git_oid__fromstr(&id, short_tag_id, GIT_OID_SHA1);
+	git_oid__fromstr(&id_commit, short_tagged_commit, GIT_OID_SHA1);
 
 	cl_git_pass(git_tag_lookup(&short_tag, short_tag_repo, &id));
 	cl_assert(short_tag != NULL);
@@ -127,7 +127,7 @@ void test_object_tag_read__without_tagger_nor_message(void)
 
 	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
 
-	cl_git_pass(git_oid_fromstr(&id, taggerless));
+	cl_git_pass(git_oid__fromstr(&id, taggerless, GIT_OID_SHA1));
 
 	cl_git_pass(git_tag_lookup(&tag, repo, &id));
 
diff --git a/tests/libgit2/object/tag/write.c b/tests/libgit2/object/tag/write.c
index 064f328fd..79e01452a 100644
--- a/tests/libgit2/object/tag/write.c
+++ b/tests/libgit2/object/tag/write.c
@@ -30,7 +30,7 @@ void test_object_tag_write__basic(void)
 	git_reference *ref_tag;
 	git_object *target;
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 
 	/* create signature */
@@ -72,7 +72,7 @@ void test_object_tag_write__overwrite(void)
 	git_signature *tagger;
 	git_object *target;
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 
 	/* create signature */
@@ -99,7 +99,7 @@ void test_object_tag_write__replace(void)
 	git_reference *ref_tag;
 	git_object *target;
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 
 	cl_git_pass(git_reference_lookup(&ref_tag, g_repo, "refs/tags/e90810b"));
@@ -135,7 +135,7 @@ void test_object_tag_write__lightweight(void)
 	git_reference *ref_tag;
 	git_object *target;
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 
 	cl_git_pass(git_tag_create_lightweight(
@@ -163,7 +163,7 @@ void test_object_tag_write__lightweight_over_existing(void)
 	git_oid target_id, object_id, existing_object_id;
 	git_object *target;
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 
 	cl_assert_equal_i(GIT_EEXISTS, git_tag_create_lightweight(
@@ -173,7 +173,7 @@ void test_object_tag_write__lightweight_over_existing(void)
                                           target,
                                           0));
 
-	git_oid_fromstr(&existing_object_id, tag2_id);
+	git_oid__fromstr(&existing_object_id, tag2_id, GIT_OID_SHA1);
 	cl_assert(git_oid_cmp(&object_id, &existing_object_id) == 0);
 
 	git_object_free(target);
@@ -197,7 +197,7 @@ void test_object_tag_write__creating_with_an_invalid_name_returns_EINVALIDSPEC(v
 	git_signature *tagger;
 	git_object *target;
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 
 	cl_git_pass(git_signature_new(&tagger, tagger_name, tagger_email, 123456789, 60));
@@ -229,7 +229,7 @@ static void create_annotation(git_oid *tag_id, const char *name)
 
 	cl_git_pass(git_signature_new(&tagger, tagger_name, tagger_email, 123456789, 60));
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 
 	cl_git_pass(git_tag_annotation_create(tag_id, g_repo, name, target, tagger, "boom!"));
@@ -265,7 +265,7 @@ void test_object_tag_write__error_when_create_tag_with_invalid_name(void)
 	git_signature *tagger;
 	git_object *target;
 
-	git_oid_fromstr(&target_id, tagged_commit);
+	git_oid__fromstr(&target_id, tagged_commit, GIT_OID_SHA1);
 	cl_git_pass(git_object_lookup(&target, g_repo, &target_id, GIT_OBJECT_COMMIT));
 	cl_git_pass(git_signature_new(&tagger, tagger_name, tagger_email, 123456789, 60));
 
diff --git a/tests/libgit2/object/tree/attributes.c b/tests/libgit2/object/tree/attributes.c
index 8654dfa31..285d19804 100644
--- a/tests/libgit2/object/tree/attributes.c
+++ b/tests/libgit2/object/tree/attributes.c
@@ -21,7 +21,7 @@ void test_object_tree_attributes__ensure_correctness_of_attributes_on_insertion(
 	git_treebuilder *builder;
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, blob_oid));
+	cl_git_pass(git_oid__fromstr(&oid, blob_oid, GIT_OID_SHA1));
 
 	cl_git_pass(git_treebuilder_new(&builder, repo, NULL));
 
@@ -39,7 +39,7 @@ void test_object_tree_attributes__group_writable_tree_entries_created_with_an_an
 	const git_tree_entry *entry;
 
 
-	cl_git_pass(git_oid_fromstr(&tid, tree_oid));
+	cl_git_pass(git_oid__fromstr(&tid, tree_oid, GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, repo, &tid));
 
 	entry = git_tree_entry_byname(tree, "old_mode.txt");
@@ -56,7 +56,7 @@ void test_object_tree_attributes__treebuilder_reject_invalid_filemode(void)
 	git_oid bid;
 	const git_tree_entry *entry;
 
-	cl_git_pass(git_oid_fromstr(&bid, blob_oid));
+	cl_git_pass(git_oid__fromstr(&bid, blob_oid, GIT_OID_SHA1));
 	cl_git_pass(git_treebuilder_new(&builder, repo, NULL));
 
 	cl_git_fail(git_treebuilder_insert(
@@ -76,7 +76,7 @@ void test_object_tree_attributes__normalize_attributes_when_creating_a_tree_from
 	git_tree *tree;
 	const git_tree_entry *entry;
 
-	cl_git_pass(git_oid_fromstr(&tid, tree_oid));
+	cl_git_pass(git_oid__fromstr(&tid, tree_oid, GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, repo, &tid));
 
 	cl_git_pass(git_treebuilder_new(&builder, repo, tree));
@@ -107,7 +107,7 @@ void test_object_tree_attributes__normalize_600(void)
 	git_tree *tree;
 	const git_tree_entry *entry;
 
-	git_oid_fromstr(&id, "0810fb7818088ff5ac41ee49199b51473b1bd6c7");
+	git_oid__fromstr(&id, "0810fb7818088ff5ac41ee49199b51473b1bd6c7", GIT_OID_SHA1);
 	cl_git_pass(git_tree_lookup(&tree, repo, &id));
 
 	entry = git_tree_entry_byname(tree, "ListaTeste.xml");
diff --git a/tests/libgit2/object/tree/duplicateentries.c b/tests/libgit2/object/tree/duplicateentries.c
index c11ae0d3d..e9774cac3 100644
--- a/tests/libgit2/object/tree/duplicateentries.c
+++ b/tests/libgit2/object/tree/duplicateentries.c
@@ -45,7 +45,7 @@ static void tree_checker(
 	cl_assert_equal_i(1, (int)git_tree_entrycount(tree));
 	entry = git_tree_entry_byindex(tree, 0);
 
-	cl_git_pass(git_oid_fromstr(&oid, expected_sha));
+	cl_git_pass(git_oid__fromstr(&oid, expected_sha, GIT_OID_SHA1));
 
 	cl_assert_equal_i(0, git_oid_cmp(&oid, git_tree_entry_id(entry)));
 	cl_assert_equal_i(expected_filemode, git_tree_entry_filemode(entry));
@@ -70,15 +70,17 @@ static void two_blobs(git_treebuilder *bld)
 	git_oid oid;
 	const git_tree_entry *entry;
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"a8233120f6ad708f843d861ce2b7228ec4e3dec6"));	/* blob oid (README) */
+	cl_git_pass(git_oid__fromstr(&oid,
+		"a8233120f6ad708f843d861ce2b7228ec4e3dec6",
+		GIT_OID_SHA1));	/* blob oid (README) */
 
 	cl_git_pass(git_treebuilder_insert(
 		&entry,	bld, "duplicate", &oid,
 		GIT_FILEMODE_BLOB));
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"a71586c1dfe8a71c6cbf6c129f404c5642ff31bd"));	/* blob oid (new.txt) */
+	cl_git_pass(git_oid__fromstr(&oid,
+		"a71586c1dfe8a71c6cbf6c129f404c5642ff31bd",
+		GIT_OID_SHA1));	/* blob oid (new.txt) */
 
 	cl_git_pass(git_treebuilder_insert(
 		&entry,	bld, "duplicate", &oid,
@@ -90,15 +92,17 @@ static void one_blob_and_one_tree(git_treebuilder *bld)
 	git_oid oid;
 	const git_tree_entry *entry;
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"a8233120f6ad708f843d861ce2b7228ec4e3dec6"));	/* blob oid (README) */
+	cl_git_pass(git_oid__fromstr(&oid,
+		"a8233120f6ad708f843d861ce2b7228ec4e3dec6",
+		GIT_OID_SHA1));	/* blob oid (README) */
 
 	cl_git_pass(git_treebuilder_insert(
 		&entry,	bld, "duplicate", &oid,
 		GIT_FILEMODE_BLOB));
 
-	cl_git_pass(git_oid_fromstr(&oid,
-		"4e0883eeeeebc1fb1735161cea82f7cb5fab7e63"));	/* tree oid (a) */
+	cl_git_pass(git_oid__fromstr(&oid,
+		"4e0883eeeeebc1fb1735161cea82f7cb5fab7e63",
+		GIT_OID_SHA1));	/* tree oid (a) */
 
 	cl_git_pass(git_treebuilder_insert(
 		&entry,	bld, "duplicate", &oid,
@@ -127,17 +131,17 @@ static void add_fake_conflicts(git_index *index)
 	ancestor_entry.path = "duplicate";
 	ancestor_entry.mode = GIT_FILEMODE_BLOB;
 	GIT_INDEX_ENTRY_STAGE_SET(&ancestor_entry, 1);
-	git_oid_fromstr(&ancestor_entry.id, "a8233120f6ad708f843d861ce2b7228ec4e3dec6");
+	git_oid__fromstr(&ancestor_entry.id, "a8233120f6ad708f843d861ce2b7228ec4e3dec6", GIT_OID_SHA1);
 
 	our_entry.path = "duplicate";
 	our_entry.mode = GIT_FILEMODE_BLOB;
 	GIT_INDEX_ENTRY_STAGE_SET(&our_entry, 2);
-	git_oid_fromstr(&our_entry.id, "45b983be36b73c0788dc9cbcb76cbb80fc7bb057");
+	git_oid__fromstr(&our_entry.id, "45b983be36b73c0788dc9cbcb76cbb80fc7bb057", GIT_OID_SHA1);
 
 	their_entry.path = "duplicate";
 	their_entry.mode = GIT_FILEMODE_BLOB;
 	GIT_INDEX_ENTRY_STAGE_SET(&their_entry, 3);
-	git_oid_fromstr(&their_entry.id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd");
+	git_oid__fromstr(&their_entry.id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd", GIT_OID_SHA1);
 
 	cl_git_pass(git_index_conflict_add(index, &ancestor_entry, &our_entry, &their_entry));
 }
diff --git a/tests/libgit2/object/tree/frompath.c b/tests/libgit2/object/tree/frompath.c
index 86ca47e94..147e53e93 100644
--- a/tests/libgit2/object/tree/frompath.c
+++ b/tests/libgit2/object/tree/frompath.c
@@ -11,7 +11,7 @@ void test_object_tree_frompath__initialize(void)
 	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
 	cl_assert(repo != NULL);
 
-	cl_git_pass(git_oid_fromstr(&id, tree_with_subtrees_oid));
+	cl_git_pass(git_oid__fromstr(&id, tree_with_subtrees_oid, GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, repo, &id));
 	cl_assert(tree != NULL);
 }
diff --git a/tests/libgit2/object/tree/parse.c b/tests/libgit2/object/tree/parse.c
index 4e871dcfa..d6d6e5302 100644
--- a/tests/libgit2/object/tree/parse.c
+++ b/tests/libgit2/object/tree/parse.c
@@ -35,7 +35,7 @@ static void assert_tree_parses(const char *data, size_t datalen,
 		const git_tree_entry *entry;
 		git_oid oid;
 
-		cl_git_pass(git_oid_fromstr(&oid, expected->oid));
+		cl_git_pass(git_oid__fromstr(&oid, expected->oid, GIT_OID_SHA1));
 
 		cl_assert(entry = git_tree_entry_byname(tree, expected->filename));
 		cl_assert_equal_s(expected->filename, entry->filename);
diff --git a/tests/libgit2/object/tree/read.c b/tests/libgit2/object/tree/read.c
index 95a2e70fb..e18637f03 100644
--- a/tests/libgit2/object/tree/read.c
+++ b/tests/libgit2/object/tree/read.c
@@ -25,7 +25,7 @@ void test_object_tree_read__loaded(void)
 	git_oid id;
 	git_tree *tree;
 
-	git_oid_fromstr(&id, tree_oid);
+	git_oid__fromstr(&id, tree_oid, GIT_OID_SHA1);
 
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 
@@ -48,7 +48,7 @@ void test_object_tree_read__two(void)
 	const git_tree_entry *entry;
 	git_object *obj;
 
-	git_oid_fromstr(&id, tree_oid);
+	git_oid__fromstr(&id, tree_oid, GIT_OID_SHA1);
 
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 
diff --git a/tests/libgit2/object/tree/update.c b/tests/libgit2/object/tree/update.c
index 41b50f3e9..1861ac838 100644
--- a/tests/libgit2/object/tree/update.c
+++ b/tests/libgit2/object/tree/update.c
@@ -21,10 +21,10 @@ void test_object_tree_update__remove_blob(void)
 	const char *path = "README";
 
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_REMOVE, {{0}}, GIT_FILEMODE_BLOB /* ignored */, path},
+		{ GIT_TREE_UPDATE_REMOVE, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB /* ignored */, path},
 	};
 
-	cl_git_pass(git_oid_fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b"));
+	cl_git_pass(git_oid__fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
 
 	/* Create it with an index */
@@ -50,10 +50,10 @@ void test_object_tree_update__remove_blob_deeper(void)
 	const char *path = "subdir/README";
 
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_REMOVE, {{0}}, GIT_FILEMODE_BLOB /* ignored */, path},
+		{ GIT_TREE_UPDATE_REMOVE, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB /* ignored */, path},
 	};
 
-	cl_git_pass(git_oid_fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b"));
+	cl_git_pass(git_oid__fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
 
 	/* Create it with an index */
@@ -80,11 +80,11 @@ void test_object_tree_update__remove_all_entries(void)
 	const char *path2 = "subdir/subdir2/new.txt";
 
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_REMOVE, {{0}}, GIT_FILEMODE_BLOB /* ignored */, path1},
-		{ GIT_TREE_UPDATE_REMOVE, {{0}}, GIT_FILEMODE_BLOB /* ignored */, path2},
+		{ GIT_TREE_UPDATE_REMOVE, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB /* ignored */, path1},
+		{ GIT_TREE_UPDATE_REMOVE, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB /* ignored */, path2},
 	};
 
-	cl_git_pass(git_oid_fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b"));
+	cl_git_pass(git_oid__fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
 
 	/* Create it with an index */
@@ -112,10 +112,10 @@ void test_object_tree_update__replace_blob(void)
 	git_index_entry entry = { {0} };
 
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, path},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, path},
 	};
 
-	cl_git_pass(git_oid_fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b"));
+	cl_git_pass(git_oid__fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&base_tree, g_repo, &base_id));
 
 	/* Create it with an index */
@@ -123,7 +123,7 @@ void test_object_tree_update__replace_blob(void)
 	cl_git_pass(git_index_read_tree(idx, base_tree));
 
 	entry.path = path;
-	cl_git_pass(git_oid_fromstr(&entry.id, "fa49b077972391ad58037050f2a75f74e3671e92"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "fa49b077972391ad58037050f2a75f74e3671e92", GIT_OID_SHA1));
 	entry.mode = GIT_FILEMODE_BLOB;
 	cl_git_pass(git_index_add(idx, &entry));
 
@@ -131,7 +131,7 @@ void test_object_tree_update__replace_blob(void)
 	git_index_free(idx);
 
 	/* Perform the same operation via the tree updater */
-	cl_git_pass(git_oid_fromstr(&updates[0].id, "fa49b077972391ad58037050f2a75f74e3671e92"));
+	cl_git_pass(git_oid__fromstr(&updates[0].id, "fa49b077972391ad58037050f2a75f74e3671e92", GIT_OID_SHA1));
 	cl_git_pass(git_tree_create_updated(&tree_updater_id, g_repo, base_tree, 1, updates));
 
 	cl_assert_equal_oid(&tree_index_id, &tree_updater_id);
@@ -153,18 +153,18 @@ void test_object_tree_update__add_blobs(void)
 	};
 
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[0]},
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[1]},
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[2]},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, paths[0]},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, paths[1]},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, paths[2]},
 	};
 
-	cl_git_pass(git_oid_fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b"));
+	cl_git_pass(git_oid__fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b", GIT_OID_SHA1));
 
 	entry.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&entry.id, "fa49b077972391ad58037050f2a75f74e3671e92"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "fa49b077972391ad58037050f2a75f74e3671e92", GIT_OID_SHA1));
 
 	for (i = 0; i < 3; i++) {
-		cl_git_pass(git_oid_fromstr(&updates[i].id, "fa49b077972391ad58037050f2a75f74e3671e92"));
+		cl_git_pass(git_oid__fromstr(&updates[i].id, "fa49b077972391ad58037050f2a75f74e3671e92", GIT_OID_SHA1));
 	}
 
 	for (i = 0; i < 2; i++) {
@@ -210,18 +210,18 @@ void test_object_tree_update__add_blobs_unsorted(void)
 	};
 
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[0]},
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[1]},
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, paths[2]},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, paths[0]},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, paths[1]},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, paths[2]},
 	};
 
-	cl_git_pass(git_oid_fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b"));
+	cl_git_pass(git_oid__fromstr(&base_id, "c4dc1555e4d4fa0e0c9c3fc46734c7c35b3ce90b", GIT_OID_SHA1));
 
 	entry.mode = GIT_FILEMODE_BLOB;
-	cl_git_pass(git_oid_fromstr(&entry.id, "fa49b077972391ad58037050f2a75f74e3671e92"));
+	cl_git_pass(git_oid__fromstr(&entry.id, "fa49b077972391ad58037050f2a75f74e3671e92", GIT_OID_SHA1));
 
 	for (i = 0; i < 3; i++) {
-		cl_git_pass(git_oid_fromstr(&updates[i].id, "fa49b077972391ad58037050f2a75f74e3671e92"));
+		cl_git_pass(git_oid__fromstr(&updates[i].id, "fa49b077972391ad58037050f2a75f74e3671e92", GIT_OID_SHA1));
 	}
 
 	for (i = 0; i < 2; i++) {
@@ -258,12 +258,12 @@ void test_object_tree_update__add_conflict(void)
 	int i;
 	git_oid tree_updater_id;
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, "a/dir/blob"},
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, "a/dir"},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, "a/dir/blob"},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, "a/dir"},
 	};
 
 	for (i = 0; i < 2; i++) {
-		cl_git_pass(git_oid_fromstr(&updates[i].id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd"));
+		cl_git_pass(git_oid__fromstr(&updates[i].id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd", GIT_OID_SHA1));
 	}
 
 	cl_git_fail(git_tree_create_updated(&tree_updater_id, g_repo, NULL, 2, updates));
@@ -274,12 +274,12 @@ void test_object_tree_update__add_conflict2(void)
 	int i;
 	git_oid tree_updater_id;
 	git_tree_update updates[] = {
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_BLOB, "a/dir/blob"},
-		{ GIT_TREE_UPDATE_UPSERT, {{0}}, GIT_FILEMODE_TREE, "a/dir/blob"},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, "a/dir/blob"},
+		{ GIT_TREE_UPDATE_UPSERT, GIT_OID_SHA1_ZERO, GIT_FILEMODE_TREE, "a/dir/blob"},
 	};
 
 	for (i = 0; i < 2; i++) {
-		cl_git_pass(git_oid_fromstr(&updates[i].id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd"));
+		cl_git_pass(git_oid__fromstr(&updates[i].id, "a71586c1dfe8a71c6cbf6c129f404c5642ff31bd", GIT_OID_SHA1));
 	}
 
 	cl_git_fail(git_tree_create_updated(&tree_updater_id, g_repo, NULL, 2, updates));
@@ -290,11 +290,11 @@ void test_object_tree_update__remove_invalid_submodule(void)
 	git_tree *baseline;
 	git_oid updated_tree_id, baseline_id;
 	git_tree_update updates[] = {
-		{GIT_TREE_UPDATE_REMOVE, {{0}}, GIT_FILEMODE_BLOB, "submodule"},
+		{GIT_TREE_UPDATE_REMOVE, GIT_OID_SHA1_ZERO, GIT_FILEMODE_BLOB, "submodule"},
 	};
 
 	/* This tree contains a submodule with an all-zero commit for a submodule named 'submodule' */
-	cl_git_pass(git_oid_fromstr(&baseline_id, "396c7f1adb7925f51ba13a75f48252f44c5a14a2"));
+	cl_git_pass(git_oid__fromstr(&baseline_id, "396c7f1adb7925f51ba13a75f48252f44c5a14a2", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&baseline, g_repo, &baseline_id));
 	cl_git_pass(git_tree_create_updated(&updated_tree_id, g_repo, baseline, 1, updates));
 
diff --git a/tests/libgit2/object/tree/walk.c b/tests/libgit2/object/tree/walk.c
index d1fdaa3a0..573a27849 100644
--- a/tests/libgit2/object/tree/walk.c
+++ b/tests/libgit2/object/tree/walk.c
@@ -33,7 +33,7 @@ void test_object_tree_walk__0(void)
 	git_tree *tree;
 	int ct;
 
-	git_oid_fromstr(&id, tree_oid);
+	git_oid__fromstr(&id, tree_oid, GIT_OID_SHA1);
 
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 
@@ -77,7 +77,7 @@ void test_object_tree_walk__1(void)
 	git_tree *tree;
 	int ct;
 
-	git_oid_fromstr(&id, tree_oid);
+	git_oid__fromstr(&id, tree_oid, GIT_OID_SHA1);
 
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 
@@ -138,7 +138,7 @@ void test_object_tree_walk__2(void)
 	struct treewalk_skip_data data;
 
 	/* look up a deep tree */
-	git_oid_fromstr(&id, "ae90f12eea699729ed24555e40b9fd669da12a12");
+	git_oid__fromstr(&id, "ae90f12eea699729ed24555e40b9fd669da12a12", GIT_OID_SHA1);
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 
 	memset(&data, 0, sizeof(data));
diff --git a/tests/libgit2/object/tree/write.c b/tests/libgit2/object/tree/write.c
index a4ceb35b6..71a4c54f6 100644
--- a/tests/libgit2/object/tree/write.c
+++ b/tests/libgit2/object/tree/write.c
@@ -29,9 +29,9 @@ void test_object_tree_write__from_memory(void)
 	git_tree *tree;
 	git_oid id, bid, rid, id2;
 
-	git_oid_fromstr(&id, first_tree);
-	git_oid_fromstr(&id2, second_tree);
-	git_oid_fromstr(&bid, blob_oid);
+	git_oid__fromstr(&id, first_tree, GIT_OID_SHA1);
+	git_oid__fromstr(&id2, second_tree, GIT_OID_SHA1);
+	git_oid__fromstr(&bid, blob_oid, GIT_OID_SHA1);
 
 	/* create a second tree from first tree using `git_treebuilder_insert`
 	 * on REPOSITORY_FOLDER.
@@ -71,10 +71,10 @@ void test_object_tree_write__subtree(void)
 	git_oid id, bid, subtree_id, id2, id3;
 	git_oid id_hiearar;
 
-	git_oid_fromstr(&id, first_tree);
-	git_oid_fromstr(&id2, second_tree);
-	git_oid_fromstr(&id3, third_tree);
-	git_oid_fromstr(&bid, blob_oid);
+	git_oid__fromstr(&id, first_tree, GIT_OID_SHA1);
+	git_oid__fromstr(&id2, second_tree, GIT_OID_SHA1);
+	git_oid__fromstr(&id3, third_tree, GIT_OID_SHA1);
+	git_oid__fromstr(&bid, blob_oid, GIT_OID_SHA1);
 
 	/* create subtree */
 	cl_git_pass(git_treebuilder_new(&builder, g_repo, NULL));
@@ -135,8 +135,8 @@ void test_object_tree_write__sorted_subtrees(void)
 
 	git_oid bid, tid, tree_oid;
 
-	cl_git_pass(git_oid_fromstr(&bid, blob_oid));
-	cl_git_pass(git_oid_fromstr(&tid, first_tree));
+	cl_git_pass(git_oid__fromstr(&bid, blob_oid, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&tid, first_tree, GIT_OID_SHA1));
 
 	cl_git_pass(git_treebuilder_new(&builder, g_repo, NULL));
 
@@ -195,7 +195,7 @@ void test_object_tree_write__removing_and_re_adding_in_treebuilder(void)
 	git_oid entry_oid, tree_oid;
 	git_tree *tree;
 
-	cl_git_pass(git_oid_fromstr(&entry_oid, blob_oid));
+	cl_git_pass(git_oid__fromstr(&entry_oid, blob_oid, GIT_OID_SHA1));
 
 	cl_git_pass(git_treebuilder_new(&builder, g_repo, NULL));
 
@@ -286,7 +286,7 @@ void test_object_tree_write__filtering(void)
 	git_oid entry_oid, tree_oid;
 	git_tree *tree;
 
-	git_oid_fromstr(&entry_oid, blob_oid);
+	git_oid__fromstr(&entry_oid, blob_oid, GIT_OID_SHA1);
 
 	cl_git_pass(git_treebuilder_new(&builder, g_repo, NULL));
 
@@ -348,7 +348,7 @@ void test_object_tree_write__cruel_paths(void)
 	int count = 0, i, j;
 	git_tree_entry *te;
 
-	git_oid_fromstr(&bid, blob_oid);
+	git_oid__fromstr(&bid, blob_oid, GIT_OID_SHA1);
 
 	/* create tree */
 	cl_git_pass(git_treebuilder_new(&builder, g_repo, NULL));
@@ -411,7 +411,7 @@ void test_object_tree_write__protect_filesystems(void)
 	git_treebuilder *builder;
 	git_oid bid;
 
-	cl_git_pass(git_oid_fromstr(&bid, "fa49b077972391ad58037050f2a75f74e3671e92"));
+	cl_git_pass(git_oid__fromstr(&bid, "fa49b077972391ad58037050f2a75f74e3671e92", GIT_OID_SHA1));
 
 	/* Ensure that (by default) we can write objects with funny names on
 	 * platforms that are not affected.
@@ -460,12 +460,14 @@ static void test_invalid_objects(bool should_allow_invalid)
 		 "Expected function call to fail: " #expr), \
 		NULL, 1)
 
-	cl_git_pass(git_oid_fromstr(&valid_blob_id, blob_oid));
-	cl_git_pass(git_oid_fromstr(&invalid_blob_id,
-		"1234567890123456789012345678901234567890"));
-	cl_git_pass(git_oid_fromstr(&valid_tree_id, first_tree));
-	cl_git_pass(git_oid_fromstr(&invalid_tree_id,
-		"0000000000111111111122222222223333333333"));
+	cl_git_pass(git_oid__fromstr(&valid_blob_id, blob_oid, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&invalid_blob_id,
+		"1234567890123456789012345678901234567890",
+		GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&valid_tree_id, first_tree, GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&invalid_tree_id,
+		"0000000000111111111122222222223333333333",
+		GIT_OID_SHA1));
 
 	cl_git_pass(git_treebuilder_new(&builder, g_repo, NULL));
 
@@ -495,7 +497,7 @@ static void test_inserting_submodule(void)
 	git_treebuilder *bld;
 	git_oid sm_id;
 
-	cl_git_pass(git_oid_fromstr(&sm_id, "da39a3ee5e6b4b0d3255bfef95601890afd80709"));
+	cl_git_pass(git_oid__fromstr(&sm_id, "da39a3ee5e6b4b0d3255bfef95601890afd80709", GIT_OID_SHA1));
 	cl_git_pass(git_treebuilder_new(&bld, g_repo, NULL));
 	cl_git_pass(git_treebuilder_insert(NULL, bld, "sm", &sm_id, GIT_FILEMODE_COMMIT));
 	git_treebuilder_free(bld);
@@ -516,7 +518,7 @@ void test_object_tree_write__object_validity(void)
 void test_object_tree_write__invalid_null_oid(void)
 {
 	git_treebuilder *bld;
-	git_oid null_oid = {{0}};
+	git_oid null_oid = GIT_OID_SHA1_ZERO;
 
 	cl_git_pass(git_treebuilder_new(&bld, g_repo, NULL));
 	cl_git_fail(git_treebuilder_insert(NULL, bld, "null_oid_file", &null_oid, GIT_FILEMODE_BLOB));
diff --git a/tests/libgit2/odb/alternates.c b/tests/libgit2/odb/alternates.c
index 6c00fda2f..4d2da6b1f 100644
--- a/tests/libgit2/odb/alternates.c
+++ b/tests/libgit2/odb/alternates.c
@@ -52,7 +52,7 @@ void test_odb_alternates__chained(void)
 
 	/* Now load B and see if we can find an object from testrepo.git */
 	cl_git_pass(git_repository_open(&repo, paths[1]));
-	git_oid_fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
 	git_commit_free(commit);
 	git_repository_free(repo);
@@ -74,7 +74,7 @@ void test_odb_alternates__long_chain(void)
 
 	/* Now load the last one and see if we can find an object from testrepo.git */
 	cl_git_pass(git_repository_open(&repo, paths[ARRAY_SIZE(paths)-1]));
-	git_oid_fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 	cl_git_fail(git_commit_lookup(&commit, repo, &oid));
 	git_repository_free(repo);
 }
diff --git a/tests/libgit2/odb/backend/backend_helpers.c b/tests/libgit2/odb/backend/backend_helpers.c
index 542799242..c1a0070d6 100644
--- a/tests/libgit2/odb/backend/backend_helpers.c
+++ b/tests/libgit2/odb/backend/backend_helpers.c
@@ -9,7 +9,7 @@ static int search_object(const fake_object **out, fake_backend *fake, const git_
 	while (obj && obj->oid) {
 		git_oid current_oid;
 
-		git_oid_fromstr(&current_oid, obj->oid);
+		git_oid__fromstr(&current_oid, obj->oid, GIT_OID_SHA1);
 
 		if (git_oid_ncmp(&current_oid, oid, len) == 0) {
 			if (found)
@@ -34,7 +34,7 @@ static int fake_backend__exists(git_odb_backend *backend, const git_oid *oid)
 
 	fake->exists_calls++;
 
-	return search_object(NULL, fake, oid, GIT_OID_HEXSZ) == GIT_OK;
+	return search_object(NULL, fake, oid, GIT_OID_SHA1_HEXSIZE) == GIT_OK;
 }
 
 static int fake_backend__exists_prefix(
@@ -52,7 +52,7 @@ static int fake_backend__exists_prefix(
 		return error;
 
 	if (out)
-		git_oid_fromstr(out, obj->oid);
+		git_oid__fromstr(out, obj->oid, GIT_OID_SHA1);
 
 	return 0;
 }
@@ -69,7 +69,7 @@ static int fake_backend__read(
 
 	fake->read_calls++;
 
-	if ((error = search_object(&obj, fake, oid, GIT_OID_HEXSZ)) < 0)
+	if ((error = search_object(&obj, fake, oid, GIT_OID_SHA1_HEXSIZE)) < 0)
 		return error;
 
 	*len_p = strlen(obj->content);
@@ -91,7 +91,7 @@ static int fake_backend__read_header(
 
 	fake->read_header_calls++;
 
-	if ((error = search_object(&obj, fake, oid, GIT_OID_HEXSZ)) < 0)
+	if ((error = search_object(&obj, fake, oid, GIT_OID_SHA1_HEXSIZE)) < 0)
 		return error;
 
 	*len_p = strlen(obj->content);
@@ -115,7 +115,7 @@ static int fake_backend__read_prefix(
 	if ((error = search_object(&obj, fake, short_oid, len)) < 0)
 		return error;
 
-	git_oid_fromstr(out_oid, obj->oid);
+	git_oid__fromstr(out_oid, obj->oid, GIT_OID_SHA1);
 	*len_p = strlen(obj->content);
 	*buffer_p = git__strdup(obj->content);
 	*type_p = GIT_OBJECT_BLOB;
diff --git a/tests/libgit2/odb/backend/mempack.c b/tests/libgit2/odb/backend/mempack.c
index 2eeed51aa..eb8ab3cb0 100644
--- a/tests/libgit2/odb/backend/mempack.c
+++ b/tests/libgit2/odb/backend/mempack.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include "repository.h"
+#include "odb.h"
 #include "backend_helpers.h"
 #include "git2/sys/mempack.h"
 
@@ -13,7 +14,7 @@ void test_odb_backend_mempack__initialize(void)
 	git_odb_backend *backend;
 
 	cl_git_pass(git_mempack_new(&backend));
-	cl_git_pass(git_odb_new(&_odb));
+	cl_git_pass(git_odb__new(&_odb, NULL));
 	cl_git_pass(git_odb_add_backend(_odb, backend, 10));
 	cl_git_pass(git_repository_wrap_odb(&_repo, _odb));
 }
@@ -34,13 +35,13 @@ void test_odb_backend_mempack__write_succeeds(void)
 
 void test_odb_backend_mempack__read_of_missing_object_fails(void)
 {
-	cl_git_pass(git_oid_fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633"));
+	cl_git_pass(git_oid__fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633", GIT_OID_SHA1));
 	cl_git_fail_with(GIT_ENOTFOUND, git_odb_read(&_obj, _odb, &_oid));
 }
 
 void test_odb_backend_mempack__exists_of_missing_object_fails(void)
 {
-	cl_git_pass(git_oid_fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633"));
+	cl_git_pass(git_oid__fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633", GIT_OID_SHA1));
 	cl_assert(git_odb_exists(_odb, &_oid) == 0);
 }
 
diff --git a/tests/libgit2/odb/backend/multiple.c b/tests/libgit2/odb/backend/multiple.c
index 5f1eacd52..97588164d 100644
--- a/tests/libgit2/odb/backend/multiple.c
+++ b/tests/libgit2/odb/backend/multiple.c
@@ -24,7 +24,7 @@ void test_odb_backend_multiple__initialize(void)
 {
 	git_odb_backend *backend;
 
-	git_oid_fromstr(&_existing_oid, EXISTING_HASH);
+	git_oid__fromstr(&_existing_oid, EXISTING_HASH, GIT_OID_SHA1);
 
 	_obj = NULL;
 	_repo = cl_git_sandbox_init("testrepo.git");
diff --git a/tests/libgit2/odb/backend/nobackend.c b/tests/libgit2/odb/backend/nobackend.c
index 7484d423b..7d9394c6f 100644
--- a/tests/libgit2/odb/backend/nobackend.c
+++ b/tests/libgit2/odb/backend/nobackend.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include "repository.h"
+#include "odb.h"
 #include "git2/sys/repository.h"
 
 static git_repository *_repo;
@@ -12,7 +13,7 @@ void test_odb_backend_nobackend__initialize(void)
 
 	cl_git_pass(git_repository_new(&_repo));
 	cl_git_pass(git_config_new(&config));
-	cl_git_pass(git_odb_new(&odb));
+	cl_git_pass(git_odb__new(&odb, NULL));
 	cl_git_pass(git_refdb_new(&refdb, _repo));
 
 	git_repository_set_config(_repo, config);
diff --git a/tests/libgit2/odb/backend/nonrefreshing.c b/tests/libgit2/odb/backend/nonrefreshing.c
index 2db10efbc..5084eb7f7 100644
--- a/tests/libgit2/odb/backend/nonrefreshing.c
+++ b/tests/libgit2/odb/backend/nonrefreshing.c
@@ -33,8 +33,8 @@ static void setup_repository_and_backend(void)
 
 void test_odb_backend_nonrefreshing__initialize(void)
 {
-	git_oid_fromstr(&_nonexisting_oid, NONEXISTING_HASH);
-	git_oid_fromstr(&_existing_oid, EXISTING_HASH);
+	git_oid__fromstr(&_nonexisting_oid, NONEXISTING_HASH, GIT_OID_SHA1);
+	git_oid__fromstr(&_existing_oid, EXISTING_HASH, GIT_OID_SHA1);
 	setup_repository_and_backend();
 }
 
diff --git a/tests/libgit2/odb/backend/refreshing.c b/tests/libgit2/odb/backend/refreshing.c
index 9e49298a8..fcba748ee 100644
--- a/tests/libgit2/odb/backend/refreshing.c
+++ b/tests/libgit2/odb/backend/refreshing.c
@@ -33,8 +33,8 @@ static void setup_repository_and_backend(void)
 
 void test_odb_backend_refreshing__initialize(void)
 {
-	git_oid_fromstr(&_nonexisting_oid, NONEXISTING_HASH);
-	git_oid_fromstr(&_existing_oid, EXISTING_HASH);
+	git_oid__fromstr(&_nonexisting_oid, NONEXISTING_HASH, GIT_OID_SHA1);
+	git_oid__fromstr(&_existing_oid, EXISTING_HASH, GIT_OID_SHA1);
 	setup_repository_and_backend();
 }
 
diff --git a/tests/libgit2/odb/backend/simple.c b/tests/libgit2/odb/backend/simple.c
index 6c9293ac0..25dfd90a2 100644
--- a/tests/libgit2/odb/backend/simple.c
+++ b/tests/libgit2/odb/backend/simple.c
@@ -49,7 +49,7 @@ void test_odb_backend_simple__read_of_object_succeeds(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_git_pass(git_odb_read(&_obj, _odb, &_oid));
 
 	assert_object_contains(_obj, objs[0].content);
@@ -64,7 +64,7 @@ void test_odb_backend_simple__read_of_nonexisting_object_fails(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633"));
+	cl_git_pass(git_oid__fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633", GIT_OID_SHA1));
 	cl_git_fail_with(GIT_ENOTFOUND, git_odb_read(&_obj, _odb, &_oid));
 }
 
@@ -77,7 +77,7 @@ void test_odb_backend_simple__read_with_hash_mismatch_fails(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_git_fail_with(GIT_EMISMATCH, git_odb_read(&_obj, _odb, &_oid));
 }
 
@@ -89,7 +89,7 @@ void test_odb_backend_simple__read_with_hash_mismatch_succeeds_without_verificat
 	};
 
 	setup_backend(objs);
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 
 	cl_git_pass(git_libgit2_opts(GIT_OPT_ENABLE_STRICT_HASH_VERIFICATION, 0));
 	cl_git_pass(git_odb_read(&_obj, _odb, &_oid));
@@ -106,7 +106,7 @@ void test_odb_backend_simple__read_prefix_succeeds(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4632"));
+	cl_git_pass(git_oid__fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4632", GIT_OID_SHA1));
 	cl_git_pass(git_odb_read(&_obj, _odb, &_oid));
 
 	assert_object_contains(_obj, objs[0].content);
@@ -122,7 +122,7 @@ void test_odb_backend_simple__read_prefix_of_nonexisting_object_fails(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstrn(&_oid, hash, strlen(hash)));
+	cl_git_pass(git_oid__fromstrn(&_oid, hash, strlen(hash), GIT_OID_SHA1));
 	cl_git_fail_with(GIT_ENOTFOUND, git_odb_read(&_obj, _odb, &_oid));
 }
 
@@ -136,7 +136,7 @@ void test_odb_backend_simple__read_with_ambiguous_prefix_fails(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_git_fail_with(GIT_EAMBIGUOUS, git_odb_read_prefix(&_obj, _odb, &_oid, 7));
 }
 
@@ -150,7 +150,7 @@ void test_odb_backend_simple__read_with_highly_ambiguous_prefix(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_git_pass(git_libgit2_opts(GIT_OPT_ENABLE_STRICT_HASH_VERIFICATION, 0));
 	cl_git_fail_with(GIT_EAMBIGUOUS, git_odb_read_prefix(&_obj, _odb, &_oid, 39));
 	cl_git_pass(git_odb_read_prefix(&_obj, _odb, &_oid, 40));
@@ -166,7 +166,7 @@ void test_odb_backend_simple__exists_succeeds(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_assert(git_odb_exists(_odb, &_oid));
 }
 
@@ -179,7 +179,7 @@ void test_odb_backend_simple__exists_fails_for_nonexisting_object(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633"));
+	cl_git_pass(git_oid__fromstr(&_oid, "f6ea0495187600e7b2288c8ac19c5886383a4633", GIT_OID_SHA1));
 	cl_assert(git_odb_exists(_odb, &_oid) == 0);
 }
 
@@ -194,7 +194,7 @@ void test_odb_backend_simple__exists_prefix_succeeds(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_git_pass(git_odb_exists_prefix(&found, _odb, &_oid, 12));
 	cl_assert(git_oid_equal(&found, &_oid));
 }
@@ -209,7 +209,7 @@ void test_odb_backend_simple__exists_with_ambiguous_prefix_fails(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_git_fail_with(GIT_EAMBIGUOUS, git_odb_exists_prefix(NULL, _odb, &_oid, 7));
 }
 
@@ -224,7 +224,7 @@ void test_odb_backend_simple__exists_with_highly_ambiguous_prefix(void)
 
 	setup_backend(objs);
 
-	cl_git_pass(git_oid_fromstr(&_oid, objs[0].oid));
+	cl_git_pass(git_oid__fromstr(&_oid, objs[0].oid, GIT_OID_SHA1));
 	cl_git_pass(git_libgit2_opts(GIT_OPT_ENABLE_STRICT_HASH_VERIFICATION, 0));
 	cl_git_fail_with(GIT_EAMBIGUOUS, git_odb_exists_prefix(&found, _odb, &_oid, 39));
 	cl_git_pass(git_odb_exists_prefix(&found, _odb, &_oid, 40));
@@ -237,7 +237,7 @@ void test_odb_backend_simple__null_oid_is_ignored(void)
 		{ "0000000000000000000000000000000000000000", "null oid content" },
 		{ NULL, NULL }
 	};
-	git_oid null_oid = {{0}};
+	git_oid null_oid = GIT_OID_SHA1_ZERO;
 	git_odb_object *obj;
 
 	setup_backend(objs);
diff --git a/tests/libgit2/odb/emptyobjects.c b/tests/libgit2/odb/emptyobjects.c
index e3ec62d3f..e7cc668d1 100644
--- a/tests/libgit2/odb/emptyobjects.c
+++ b/tests/libgit2/odb/emptyobjects.c
@@ -24,7 +24,7 @@ void test_odb_emptyobjects__blob_notfound(void)
 	git_oid id, written_id;
 	git_blob *blob;
 
-	cl_git_pass(git_oid_fromstr(&id, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"));
+	cl_git_pass(git_oid__fromstr(&id, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", GIT_OID_SHA1));
 	cl_git_fail_with(GIT_ENOTFOUND, git_blob_lookup(&blob, g_repo, &id));
 
 	cl_git_pass(git_odb_write(&written_id, g_odb, "", 0, GIT_OBJECT_BLOB));
@@ -36,7 +36,7 @@ void test_odb_emptyobjects__read_tree(void)
 	git_oid id;
 	git_tree *tree;
 
-	cl_git_pass(git_oid_fromstr(&id, "4b825dc642cb6eb9a060e54bf8d69288fbee4904"));
+	cl_git_pass(git_oid__fromstr(&id, "4b825dc642cb6eb9a060e54bf8d69288fbee4904", GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, g_repo, &id));
 	cl_assert_equal_i(GIT_OBJECT_TREE, git_object_type((git_object *) tree));
 	cl_assert_equal_i(0, git_tree_entrycount(tree));
@@ -49,7 +49,7 @@ void test_odb_emptyobjects__read_tree_odb(void)
 	git_oid id;
 	git_odb_object *tree_odb;
 
-	cl_git_pass(git_oid_fromstr(&id, "4b825dc642cb6eb9a060e54bf8d69288fbee4904"));
+	cl_git_pass(git_oid__fromstr(&id, "4b825dc642cb6eb9a060e54bf8d69288fbee4904", GIT_OID_SHA1));
 	cl_git_pass(git_odb_read(&tree_odb, g_odb, &id));
 	cl_assert(git_odb_object_data(tree_odb));
 	cl_assert_equal_s("", git_odb_object_data(tree_odb));
diff --git a/tests/libgit2/odb/foreach.c b/tests/libgit2/odb/foreach.c
index c2a448363..165a511a0 100644
--- a/tests/libgit2/odb/foreach.c
+++ b/tests/libgit2/odb/foreach.c
@@ -51,7 +51,7 @@ void test_odb_foreach__one_pack(void)
 	git_odb_backend *backend = NULL;
 	int nobj = 0;
 
-	cl_git_pass(git_odb_new(&_odb));
+	cl_git_pass(git_odb__new(&_odb, NULL));
 	cl_git_pass(git_odb_backend_one_pack(&backend, cl_fixture("testrepo.git/objects/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.idx")));
 	cl_git_pass(git_odb_add_backend(_odb, backend, 1));
 	_repo = NULL;
diff --git a/tests/libgit2/odb/freshen.c b/tests/libgit2/odb/freshen.c
index 2396e3774..e337c82b7 100644
--- a/tests/libgit2/odb/freshen.c
+++ b/tests/libgit2/odb/freshen.c
@@ -43,7 +43,7 @@ void test_odb_freshen__loose_blob(void)
 	git_oid expected_id, id;
 	struct stat before, after;
 
-	cl_git_pass(git_oid_fromstr(&expected_id, LOOSE_BLOB_ID));
+	cl_git_pass(git_oid__fromstr(&expected_id, LOOSE_BLOB_ID, GIT_OID_SHA1));
 	set_time_wayback(&before, LOOSE_BLOB_FN);
 
 	/* make sure we freshen a blob */
@@ -64,7 +64,7 @@ void test_odb_freshen__readonly_object(void)
 	git_oid expected_id, id;
 	struct stat before, after;
 
-	cl_git_pass(git_oid_fromstr(&expected_id, UNIQUE_BLOB_ID));
+	cl_git_pass(git_oid__fromstr(&expected_id, UNIQUE_BLOB_ID, GIT_OID_SHA1));
 
 	cl_git_pass(git_blob_create_from_buffer(&id, repo, UNIQUE_STR, CONST_STRLEN(UNIQUE_STR)));
 	cl_assert_equal_oid(&expected_id, &id);
@@ -89,7 +89,7 @@ void test_odb_freshen__loose_tree(void)
 	git_tree *tree;
 	struct stat before, after;
 
-	cl_git_pass(git_oid_fromstr(&expected_id, LOOSE_TREE_ID));
+	cl_git_pass(git_oid__fromstr(&expected_id, LOOSE_TREE_ID, GIT_OID_SHA1));
 	set_time_wayback(&before, LOOSE_TREE_FN);
 
 	cl_git_pass(git_tree_lookup(&tree, repo, &expected_id));
@@ -113,11 +113,11 @@ void test_odb_freshen__tree_during_commit(void)
 	git_signature *signature;
 	struct stat before, after;
 
-	cl_git_pass(git_oid_fromstr(&tree_id, LOOSE_TREE_ID));
+	cl_git_pass(git_oid__fromstr(&tree_id, LOOSE_TREE_ID, GIT_OID_SHA1));
 	cl_git_pass(git_tree_lookup(&tree, repo, &tree_id));
 	set_time_wayback(&before, LOOSE_TREE_FN);
 
-	cl_git_pass(git_oid_fromstr(&parent_id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
+	cl_git_pass(git_oid__fromstr(&parent_id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&parent, repo, &parent_id));
 
 	cl_git_pass(git_signature_new(&signature,
@@ -147,7 +147,7 @@ void test_odb_freshen__packed_object(void)
 	struct stat before, after;
 	struct p_timeval old_times[2];
 
-	cl_git_pass(git_oid_fromstr(&expected_id, PACKED_ID));
+	cl_git_pass(git_oid__fromstr(&expected_id, PACKED_ID, GIT_OID_SHA1));
 
 	old_times[0].tv_sec = 1234567890;
 	old_times[0].tv_usec = 0;
diff --git a/tests/libgit2/odb/largefiles.c b/tests/libgit2/odb/largefiles.c
index acc786ee4..2ec48102b 100644
--- a/tests/libgit2/odb/largefiles.c
+++ b/tests/libgit2/odb/largefiles.c
@@ -57,7 +57,7 @@ void test_odb_largefiles__write_from_memory(void)
 	for (i = 0; i < (3041*126103); i++)
 		cl_git_pass(git_str_puts(&buf, "Hello, world.\n"));
 
-	git_oid_fromstr(&expected, "3fb56989cca483b21ba7cb0a6edb229d10e1c26c");
+	git_oid__fromstr(&expected, "3fb56989cca483b21ba7cb0a6edb229d10e1c26c", GIT_OID_SHA1);
 	cl_git_pass(git_odb_write(&oid, odb, buf.ptr, buf.size, GIT_OBJECT_BLOB));
 
 	cl_assert_equal_oid(&expected, &oid);
@@ -75,7 +75,7 @@ void test_odb_largefiles__streamwrite(void)
 		!cl_is_env_set("GITTEST_SLOW"))
 		cl_skip();
 
-	git_oid_fromstr(&expected, "3fb56989cca483b21ba7cb0a6edb229d10e1c26c");
+	git_oid__fromstr(&expected, "3fb56989cca483b21ba7cb0a6edb229d10e1c26c", GIT_OID_SHA1);
 	writefile(&oid);
 
 	cl_assert_equal_oid(&expected, &oid);
diff --git a/tests/libgit2/odb/loose.c b/tests/libgit2/odb/loose.c
index fe013a78c..e79525478 100644
--- a/tests/libgit2/odb/loose.c
+++ b/tests/libgit2/odb/loose.c
@@ -34,24 +34,27 @@ static void cmp_objects(git_rawobj *o, object_data *d)
 
 static void test_read_object(object_data *data)
 {
-    git_oid id;
-    git_odb_object *obj;
+	git_oid id;
+	git_odb_object *obj;
 	git_odb *odb;
 	git_rawobj tmp;
+	git_odb_options opts = GIT_ODB_OPTIONS_INIT;
+
+	opts.oid_type = data->id_type;
 
-    write_object_files(data);
+	write_object_files(data);
 
-    cl_git_pass(git_odb_open(&odb, "test-objects"));
-    cl_git_pass(git_oid_fromstr(&id, data->id));
-    cl_git_pass(git_odb_read(&obj, odb, &id));
+	cl_git_pass(git_odb__open(&odb, "test-objects", &opts));
+	cl_git_pass(git_oid__fromstr(&id, data->id, data->id_type));
+	cl_git_pass(git_odb_read(&obj, odb, &id));
 
 	tmp.data = obj->buffer;
 	tmp.len = obj->cached.size;
 	tmp.type = obj->cached.type;
 
-    cmp_objects(&tmp, data);
+	cmp_objects(&tmp, data);
 
-    git_odb_object_free(obj);
+	git_odb_object_free(obj);
 	git_odb_free(odb);
 }
 
@@ -61,11 +64,14 @@ static void test_read_header(object_data *data)
 	git_odb *odb;
 	size_t len;
 	git_object_t type;
+	git_odb_options opts = GIT_ODB_OPTIONS_INIT;
+
+	opts.oid_type = data->id_type;
 
 	write_object_files(data);
 
-	cl_git_pass(git_odb_open(&odb, "test-objects"));
-	cl_git_pass(git_oid_fromstr(&id, data->id));
+	cl_git_pass(git_odb__open(&odb, "test-objects", &opts));
+	cl_git_pass(git_oid__fromstr(&id, data->id, data->id_type));
 	cl_git_pass(git_odb_read_header(&len, &type, odb, &id));
 
 	cl_assert_equal_sz(data->dlen, len);
@@ -83,11 +89,14 @@ static void test_readstream_object(object_data *data, size_t blocksize)
 	char buf[2048], *ptr = buf;
 	size_t remain;
 	int ret;
+	git_odb_options opts = GIT_ODB_OPTIONS_INIT;
+
+	opts.oid_type = data->id_type;
 
 	write_object_files(data);
 
-	cl_git_pass(git_odb_open(&odb, "test-objects"));
-	cl_git_pass(git_oid_fromstr(&id, data->id));
+	cl_git_pass(git_odb__open(&odb, "test-objects", &opts));
+	cl_git_pass(git_oid__fromstr(&id, data->id, data->id_type));
 	cl_git_pass(git_odb_open_rstream(&stream, &tmp.len, &tmp.type, odb, &id));
 
 	remain = tmp.len;
@@ -124,32 +133,62 @@ void test_odb_loose__cleanup(void)
 	cl_fixture_cleanup("test-objects");
 }
 
-void test_odb_loose__exists(void)
+void test_odb_loose__exists_sha1(void)
 {
 	git_oid id, id2;
 	git_odb *odb;
 
 	write_object_files(&one);
-	cl_git_pass(git_odb_open(&odb, "test-objects"));
+	cl_git_pass(git_odb__open(&odb, "test-objects", NULL));
 
-	cl_git_pass(git_oid_fromstr(&id, one.id));
+	cl_git_pass(git_oid__fromstr(&id, one.id, GIT_OID_SHA1));
 	cl_assert(git_odb_exists(odb, &id));
 
-	cl_git_pass(git_oid_fromstrp(&id, "8b137891"));
+	cl_git_pass(git_oid__fromstrp(&id, "8b137891", GIT_OID_SHA1));
 	cl_git_pass(git_odb_exists_prefix(&id2, odb, &id, 8));
 	cl_assert_equal_i(0, git_oid_streq(&id2, one.id));
 
 	/* Test for a missing object */
-	cl_git_pass(git_oid_fromstr(&id, "8b137891791fe96927ad78e64b0aad7bded08baa"));
+	cl_git_pass(git_oid__fromstr(&id, "8b137891791fe96927ad78e64b0aad7bded08baa", GIT_OID_SHA1));
 	cl_assert(!git_odb_exists(odb, &id));
 
-	cl_git_pass(git_oid_fromstrp(&id, "8b13789a"));
+	cl_git_pass(git_oid__fromstrp(&id, "8b13789a", GIT_OID_SHA1));
 	cl_assert_equal_i(GIT_ENOTFOUND, git_odb_exists_prefix(&id2, odb, &id, 8));
 
 	git_odb_free(odb);
 }
 
-void test_odb_loose__simple_reads(void)
+void test_odb_loose__exists_sha256(void)
+{
+#ifdef GIT_EXPERIMENTAL_SHA256
+	git_oid id, id2;
+	git_odb *odb;
+	git_odb_options odb_opts = GIT_ODB_OPTIONS_INIT;
+
+	odb_opts.oid_type = GIT_OID_SHA256;
+
+	write_object_files(&one_sha256);
+	cl_git_pass(git_odb__open(&odb, "test-objects", &odb_opts));
+
+	cl_git_pass(git_oid__fromstr(&id, one_sha256.id, GIT_OID_SHA256));
+	cl_assert(git_odb_exists(odb, &id));
+
+	cl_git_pass(git_oid__fromstrp(&id, "4c0d52d1", GIT_OID_SHA256));
+	cl_git_pass(git_odb_exists_prefix(&id2, odb, &id, 8));
+	cl_assert_equal_i(0, git_oid_streq(&id2, one_sha256.id));
+
+	/* Test for a missing object */
+	cl_git_pass(git_oid__fromstr(&id, "4c0d52d180c61d01ce1a91dec5ee58f0cbe65fd59433aea803ab927965493faa", GIT_OID_SHA256));
+	cl_assert(!git_odb_exists(odb, &id));
+
+	cl_git_pass(git_oid__fromstrp(&id, "4c0d52da", GIT_OID_SHA256));
+	cl_assert_equal_i(GIT_ENOTFOUND, git_odb_exists_prefix(&id2, odb, &id, 8));
+
+	git_odb_free(odb);
+#endif
+}
+
+void test_odb_loose__simple_reads_sha1(void)
 {
 	test_read_object(&commit);
 	test_read_object(&tree);
@@ -160,7 +199,20 @@ void test_odb_loose__simple_reads(void)
 	test_read_object(&some);
 }
 
-void test_odb_loose__streaming_reads(void)
+void test_odb_loose__simple_reads_sha256(void)
+{
+#ifdef GIT_EXPERIMENTAL_SHA256
+	test_read_object(&commit_sha256);
+	test_read_object(&tree_sha256);
+	test_read_object(&tag_sha256);
+	test_read_object(&zero_sha256);
+	test_read_object(&one_sha256);
+	test_read_object(&two_sha256);
+	test_read_object(&some_sha256);
+#endif
+}
+
+void test_odb_loose__streaming_reads_sha1(void)
 {
 	size_t blocksizes[] = { 1, 2, 4, 16, 99, 1024, 123456789 };
 	size_t i;
@@ -176,7 +228,25 @@ void test_odb_loose__streaming_reads(void)
 	}
 }
 
-void test_odb_loose__read_header(void)
+void test_odb_loose__streaming_reads_sha256(void)
+{
+#ifdef GIT_EXPERIMENTAL_SHA256
+	size_t blocksizes[] = { 1, 2, 4, 16, 99, 1024, 123456789 };
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(blocksizes); i++) {
+		test_readstream_object(&commit_sha256, blocksizes[i]);
+		test_readstream_object(&tree_sha256, blocksizes[i]);
+		test_readstream_object(&tag_sha256, blocksizes[i]);
+		test_readstream_object(&zero_sha256, blocksizes[i]);
+		test_readstream_object(&one_sha256, blocksizes[i]);
+		test_readstream_object(&two_sha256, blocksizes[i]);
+		test_readstream_object(&some_sha256, blocksizes[i]);
+	}
+#endif
+}
+
+void test_odb_loose__read_header_sha1(void)
 {
 	test_read_header(&commit);
 	test_read_header(&tree);
@@ -187,6 +257,19 @@ void test_odb_loose__read_header(void)
 	test_read_header(&some);
 }
 
+void test_odb_loose__read_header_sha256(void)
+{
+#ifdef GIT_EXPERIMENTAL_SHA256
+	test_read_header(&commit_sha256);
+	test_read_header(&tree_sha256);
+	test_read_header(&tag_sha256);
+	test_read_header(&zero_sha256);
+	test_read_header(&one_sha256);
+	test_read_header(&two_sha256);
+	test_read_header(&some_sha256);
+#endif
+}
+
 static void test_write_object_permission(
 	mode_t dir_mode, mode_t file_mode,
 	mode_t expected_dir_mode, mode_t expected_file_mode)
@@ -196,6 +279,7 @@ static void test_write_object_permission(
 	git_oid oid;
 	struct stat statbuf;
 	mode_t mask, os_mask;
+	git_odb_backend_loose_options opts = GIT_ODB_BACKEND_LOOSE_OPTIONS_INIT;
 
 	/* Windows does not return group/user bits from stat,
 	* files are never executable.
@@ -209,8 +293,11 @@ static void test_write_object_permission(
 	mask = p_umask(0);
 	p_umask(mask);
 
-	cl_git_pass(git_odb_new(&odb));
-	cl_git_pass(git_odb_backend_loose(&backend, "test-objects", -1, 0, dir_mode, file_mode));
+	opts.dir_mode = dir_mode;
+	opts.file_mode = file_mode;
+
+	cl_git_pass(git_odb__new(&odb, NULL));
+	cl_git_pass(git_odb__backend_loose(&backend, "test-objects", &opts));
 	cl_git_pass(git_odb_add_backend(odb, backend, 1));
 	cl_git_pass(git_odb_write(&oid, odb, "Test data\n", 10, GIT_OBJECT_BLOB));
 
@@ -243,9 +330,16 @@ static void write_object_to_loose_odb(int fsync)
 	git_odb *odb;
 	git_odb_backend *backend;
 	git_oid oid;
+	git_odb_backend_loose_options opts = GIT_ODB_BACKEND_LOOSE_OPTIONS_INIT;
+
+	if (fsync)
+		opts.flags |= GIT_ODB_BACKEND_LOOSE_FSYNC;
+
+	opts.dir_mode = 0777;
+	opts.file_mode = 0666;
 
-	cl_git_pass(git_odb_new(&odb));
-	cl_git_pass(git_odb_backend_loose(&backend, "test-objects", -1, fsync, 0777, 0666));
+	cl_git_pass(git_odb__new(&odb, NULL));
+	cl_git_pass(git_odb__backend_loose(&backend, "test-objects", &opts));
 	cl_git_pass(git_odb_add_backend(odb, backend, 1));
 	cl_git_pass(git_odb_write(&oid, odb, "Test data\n", 10, GIT_OBJECT_BLOB));
 	git_odb_free(odb);
diff --git a/tests/libgit2/odb/loose_data.h b/tests/libgit2/odb/loose_data.h
index c10c9bc7f..1a830740d 100644
--- a/tests/libgit2/odb/loose_data.h
+++ b/tests/libgit2/odb/loose_data.h
@@ -1,7 +1,8 @@
 typedef struct object_data {
     unsigned char *bytes;  /* (compressed) bytes stored in object store */
     size_t        blen;    /* length of data in object store            */
-    char          *id;     /* object id (sha1)                          */
+    char          *id;     /* object id (hex chars)                     */
+    git_oid_t     id_type; /* type of object id (sha1 or sha256)        */
     char          *type;   /* object type                               */
     char          *dir;    /* object store (fan-out) directory name     */
     char          *file;   /* object store filename                     */
@@ -9,7 +10,10 @@ typedef struct object_data {
     size_t        dlen;    /* length of (uncompressed) object data      */
 } object_data;
 
-/* one == 8b137891791fe96927ad78e64b0aad7bded08bdc */
+/*
+ * one == 8b137891791fe96927ad78e64b0aad7bded08bdc (sha1)
+ * 4c0d52d180c61d01ce1a91dec5ee58f0cbe65fd59433aea803ab927965493fd7 (sha256)
+ */
 static unsigned char one_bytes[] = {
     0x31, 0x78, 0x9c, 0xe3, 0x02, 0x00, 0x00, 0x0b,
     0x00, 0x0b,
@@ -23,6 +27,7 @@ static object_data one = {
     one_bytes,
     sizeof(one_bytes),
     "8b137891791fe96927ad78e64b0aad7bded08bdc",
+    GIT_OID_SHA1,
     "blob",
     "test-objects/8b",
     "test-objects/8b/137891791fe96927ad78e64b0aad7bded08bdc",
@@ -30,8 +35,25 @@ static object_data one = {
     sizeof(one_data),
 };
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+static object_data one_sha256 = {
+    one_bytes,
+    sizeof(one_bytes),
+    "4c0d52d180c61d01ce1a91dec5ee58f0cbe65fd59433aea803ab927965493fd7",
+    GIT_OID_SHA256,
+    "blob",
+    "test-objects/4c",
+    "test-objects/4c/0d52d180c61d01ce1a91dec5ee58f0cbe65fd59433aea803ab927965493fd7",
+    one_data,
+    sizeof(one_data),
+};
+#endif
 
-/* commit == 3d7f8a6af076c8c3f20071a8935cdbe8228594d1 */
+
+/*
+ * commit == 3d7f8a6af076c8c3f20071a8935cdbe8228594d1 (sha1)
+ * a2a430fb63b294f868af4ef6ccc9c3e8256e370859ce578a23837ac85337f562 (sha256)
+ */
 static unsigned char commit_bytes[] = {
     0x78, 0x01, 0x85, 0x50, 0xc1, 0x6a, 0xc3, 0x30,
     0x0c, 0xdd, 0xd9, 0x5f, 0xa1, 0xfb, 0x96, 0x12,
@@ -64,6 +86,42 @@ static unsigned char commit_bytes[] = {
     0x1f, 0x78, 0x35,
 };
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+static unsigned char commit_bytes_sha256[] = {
+    0x78, 0x01, 0x85, 0x90, 0xc1, 0x4e, 0xc3, 0x30,
+    0x0c, 0x86, 0x39, 0xe7, 0x29, 0x7c, 0x87, 0x4e,
+    0x5d, 0x93, 0xa6, 0x2d, 0x9a, 0x10, 0x13, 0x67,
+    0xc4, 0x81, 0xf1, 0x00, 0x4e, 0xe3, 0xb4, 0x91,
+    0x9a, 0xa4, 0x4a, 0x53, 0x69, 0x7d, 0x7b, 0x82,
+    0x3a, 0x4d, 0x9c, 0xc0, 0xa7, 0xcf, 0xbf, 0xfd,
+    0xff, 0xb2, 0xdc, 0x07, 0xe7, 0x6c, 0x02, 0xde,
+    0xb4, 0x0f, 0x29, 0x12, 0x01, 0x17, 0x28, 0xda,
+    0x5a, 0xa8, 0x5a, 0x54, 0xd2, 0x74, 0x95, 0x90,
+    0xa5, 0x12, 0x48, 0xbc, 0x26, 0xa9, 0x9b, 0xae,
+    0x11, 0x52, 0x91, 0x94, 0x3d, 0x6f, 0x95, 0x31,
+    0x5a, 0x92, 0xe1, 0xaa, 0x17, 0xa6, 0xac, 0x39,
+    0xe9, 0xa6, 0x45, 0x2e, 0x15, 0x0a, 0x86, 0x6b,
+    0x1a, 0x43, 0x84, 0x33, 0x7c, 0xc1, 0xe5, 0x07,
+    0x4e, 0xbb, 0xf0, 0x4a, 0x57, 0x74, 0xf3, 0x44,
+    0x87, 0x3e, 0xb8, 0x17, 0x38, 0x56, 0x55, 0xd3,
+    0x1e, 0x45, 0xd5, 0x35, 0xf0, 0x58, 0xe6, 0x62,
+    0x59, 0xcd, 0x67, 0x24, 0x8a, 0xf0, 0x06, 0x1f,
+    0xf0, 0xbe, 0xe3, 0xe9, 0xae, 0xfe, 0xe3, 0x66,
+    0x67, 0x08, 0x9e, 0x8a, 0xc9, 0x7a, 0x82, 0xdd,
+    0x03, 0xcb, 0xea, 0x1c, 0xc6, 0x8d, 0xb1, 0xcb,
+    0x48, 0xa0, 0x82, 0xde, 0x20, 0x18, 0x48, 0x99,
+    0x6f, 0x73, 0x47, 0xcb, 0x82, 0x03, 0x3d, 0xe5,
+    0xde, 0x27, 0xb4, 0xde, 0xfa, 0x01, 0xcc, 0x1a,
+    0xf3, 0x46, 0x04, 0xba, 0xce, 0x13, 0x7a, 0x4c,
+    0x36, 0x78, 0x76, 0x73, 0xcd, 0x6b, 0x9c, 0xc3,
+    0x42, 0xf7, 0x90, 0x11, 0xfd, 0x40, 0x0b, 0x58,
+    0x9f, 0x62, 0xd0, 0x6b, 0x4f, 0x1a, 0xd4, 0xf6,
+    0x2b, 0xfe, 0xc0, 0xd8, 0xa7, 0x1d, 0x3c, 0xe9,
+    0x22, 0x98, 0x42, 0x6d, 0xcf, 0x7f, 0xbf, 0x83,
+    0x7d, 0x03, 0x6d, 0x1e, 0x7e, 0xa9
+};
+#endif
+
 static unsigned char commit_data[] = {
     0x74, 0x72, 0x65, 0x65, 0x20, 0x64, 0x66, 0x66,
     0x32, 0x64, 0x61, 0x39, 0x30, 0x62, 0x32, 0x35,
@@ -112,10 +170,64 @@ static unsigned char commit_data[] = {
     0x3e, 0x0a,
 };
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+static unsigned char commit_data_sha256[] = {
+    0x74, 0x72, 0x65, 0x65, 0x20, 0x33, 0x34, 0x61,
+    0x34, 0x38, 0x35, 0x34, 0x62, 0x35, 0x34, 0x32,
+    0x36, 0x66, 0x39, 0x32, 0x34, 0x36, 0x30, 0x62,
+    0x34, 0x61, 0x65, 0x33, 0x35, 0x65, 0x36, 0x64,
+    0x37, 0x39, 0x37, 0x34, 0x36, 0x62, 0x65, 0x36,
+    0x36, 0x63, 0x33, 0x38, 0x62, 0x66, 0x66, 0x64,
+    0x36, 0x65, 0x66, 0x33, 0x62, 0x63, 0x34, 0x66,
+    0x30, 0x35, 0x33, 0x65, 0x64, 0x37, 0x38, 0x61,
+    0x33, 0x36, 0x62, 0x61, 0x34, 0x0a, 0x61, 0x75,
+    0x74, 0x68, 0x6f, 0x72, 0x20, 0x41, 0x20, 0x55,
+    0x20, 0x54, 0x68, 0x6f, 0x72, 0x20, 0x3c, 0x61,
+    0x75, 0x74, 0x68, 0x6f, 0x72, 0x40, 0x65, 0x78,
+    0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f,
+    0x6d, 0x3e, 0x20, 0x31, 0x32, 0x32, 0x37, 0x38,
+    0x31, 0x34, 0x32, 0x39, 0x37, 0x20, 0x2b, 0x30,
+    0x30, 0x30, 0x30, 0x0a, 0x63, 0x6f, 0x6d, 0x6d,
+    0x69, 0x74, 0x74, 0x65, 0x72, 0x20, 0x43, 0x20,
+    0x4f, 0x20, 0x4d, 0x69, 0x74, 0x74, 0x65, 0x72,
+    0x20, 0x3c, 0x63, 0x6f, 0x6d, 0x6d, 0x69, 0x74,
+    0x74, 0x65, 0x72, 0x40, 0x65, 0x78, 0x61, 0x6d,
+    0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d, 0x3e,
+    0x20, 0x31, 0x32, 0x32, 0x37, 0x38, 0x31, 0x34,
+    0x32, 0x39, 0x37, 0x20, 0x2b, 0x30, 0x30, 0x30,
+    0x30, 0x0a, 0x0a, 0x41, 0x20, 0x6f, 0x6e, 0x65,
+    0x2d, 0x6c, 0x69, 0x6e, 0x65, 0x20, 0x63, 0x6f,
+    0x6d, 0x6d, 0x69, 0x74, 0x20, 0x73, 0x75, 0x6d,
+    0x6d, 0x61, 0x72, 0x79, 0x0a, 0x0a, 0x54, 0x68,
+    0x65, 0x20, 0x62, 0x6f, 0x64, 0x79, 0x20, 0x6f,
+    0x66, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6f,
+    0x6d, 0x6d, 0x69, 0x74, 0x20, 0x6d, 0x65, 0x73,
+    0x73, 0x61, 0x67, 0x65, 0x2c, 0x20, 0x63, 0x6f,
+    0x6e, 0x74, 0x61, 0x69, 0x6e, 0x69, 0x6e, 0x67,
+    0x20, 0x66, 0x75, 0x72, 0x74, 0x68, 0x65, 0x72,
+    0x20, 0x65, 0x78, 0x70, 0x6c, 0x61, 0x6e, 0x61,
+    0x74, 0x69, 0x6f, 0x6e, 0x0a, 0x6f, 0x66, 0x20,
+    0x74, 0x68, 0x65, 0x20, 0x70, 0x75, 0x72, 0x70,
+    0x6f, 0x73, 0x65, 0x20, 0x6f, 0x66, 0x20, 0x74,
+    0x68, 0x65, 0x20, 0x63, 0x68, 0x61, 0x6e, 0x67,
+    0x65, 0x73, 0x20, 0x69, 0x6e, 0x74, 0x72, 0x6f,
+    0x64, 0x75, 0x63, 0x65, 0x64, 0x20, 0x62, 0x79,
+    0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6f, 0x6d,
+    0x6d, 0x69, 0x74, 0x2e, 0x0a, 0x0a, 0x53, 0x69,
+    0x67, 0x6e, 0x65, 0x64, 0x2d, 0x6f, 0x66, 0x2d,
+    0x62, 0x79, 0x3a, 0x20, 0x41, 0x20, 0x55, 0x20,
+    0x54, 0x68, 0x6f, 0x72, 0x20, 0x3c, 0x61, 0x75,
+    0x74, 0x68, 0x6f, 0x72, 0x40, 0x65, 0x78, 0x61,
+    0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d,
+    0x3e, 0x0a
+};
+#endif
+
 static object_data commit = {
     commit_bytes,
     sizeof(commit_bytes),
     "3d7f8a6af076c8c3f20071a8935cdbe8228594d1",
+    GIT_OID_SHA1,
     "commit",
     "test-objects/3d",
     "test-objects/3d/7f8a6af076c8c3f20071a8935cdbe8228594d1",
@@ -123,7 +235,24 @@ static object_data commit = {
     sizeof(commit_data),
 };
 
-/* tree == dff2da90b254e1beb889d1f1f1288be1803782df */
+#ifdef GIT_EXPERIMENTAL_SHA256
+static object_data commit_sha256 = {
+    commit_bytes_sha256,
+    sizeof(commit_bytes_sha256),
+    "a2a430fb63b294f868af4ef6ccc9c3e8256e370859ce578a23837ac85337f562",
+    GIT_OID_SHA256,
+    "commit",
+    "test-objects/a2",
+    "test-objects/a2/a430fb63b294f868af4ef6ccc9c3e8256e370859ce578a23837ac85337f562",
+    commit_data_sha256,
+    sizeof(commit_data_sha256),
+};
+#endif
+
+/*
+ * tree == dff2da90b254e1beb889d1f1f1288be1803782df (sha1)
+ * 34a4854b5426f92460b4ae35e6d79746be66c38bffd6ef3bc4f053ed78a36ba4 (sha256)
+ */
 static unsigned char tree_bytes[] = {
     0x78, 0x01, 0x2b, 0x29, 0x4a, 0x4d, 0x55, 0x30,
     0x34, 0x32, 0x63, 0x30, 0x34, 0x30, 0x30, 0x33,
@@ -163,10 +292,76 @@ static unsigned char tree_data[] = {
     0xd8, 0xc2, 0xe4, 0x8c, 0x53, 0x91,
 };
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+static unsigned char tree_bytes_sha256[] = {
+    0x78, 0x01, 0x2b, 0x29, 0x4a, 0x4d, 0x55, 0x30,
+    0x32, 0x32, 0x66, 0x30, 0x34, 0x30, 0x30, 0x33,
+    0x31, 0x51, 0xc8, 0x48, 0xcd, 0xc9, 0xc9, 0xd7,
+    0x2b, 0xa9, 0x28, 0x61, 0x28, 0x65, 0x3b, 0x7d,
+    0xde, 0x27, 0x5c, 0xfb, 0xe5, 0x83, 0x2c, 0xf9,
+    0xb7, 0xa6, 0x6b, 0xa2, 0x65, 0x7f, 0x6c, 0x5d,
+    0xee, 0xab, 0x76, 0xa0, 0x9e, 0x49, 0xcd, 0xe3,
+    0xe9, 0xcd, 0xa8, 0xf9, 0xf9, 0x5a, 0x50, 0x0d,
+    0xf9, 0x79, 0xa9, 0x0c, 0x3e, 0xbc, 0x41, 0x17,
+    0x1b, 0x8e, 0xc9, 0x32, 0x9e, 0x93, 0x9a, 0x78,
+    0xef, 0xe8, 0xbb, 0x88, 0x0f, 0xa7, 0x9f, 0xc5,
+    0x5f, 0x9d, 0x62, 0xbc, 0x6e, 0x05, 0xf3, 0xea,
+    0x49, 0x95, 0xa9, 0x9e, 0xf6, 0xd7, 0xa1, 0x4a,
+    0x8b, 0xf3, 0x73, 0x53, 0x19, 0x38, 0x6c, 0xb4,
+    0xbb, 0x5d, 0xc2, 0x1c, 0x2e, 0x16, 0x3e, 0x5f,
+    0x95, 0x56, 0xcd, 0x6d, 0xc4, 0x50, 0xc0, 0xf6,
+    0xbd, 0xad, 0x50, 0xc0, 0xe8, 0xf5, 0x0e, 0x4d,
+    0xc3, 0x33, 0xcb, 0xe6, 0x1c, 0x8c, 0x86, 0xaa,
+    0x2d, 0x29, 0xcf, 0x67, 0xf8, 0x91, 0x14, 0xe7,
+    0xfc, 0xf3, 0x81, 0xbf, 0x8a, 0xa6, 0x7c, 0xf9,
+    0xd9, 0x7d, 0x3e, 0x85, 0x9b, 0x0f, 0x2d, 0xde,
+    0xc0, 0x60, 0x9f, 0xe0, 0x38, 0xdb, 0xee, 0x42,
+    0x16, 0x6b, 0x6f, 0x59, 0x4e, 0x37, 0x54, 0x69,
+    0x55, 0x6a, 0x51, 0x3e, 0x83, 0xcb, 0xbc, 0xd9,
+    0x95, 0x21, 0x0a, 0x67, 0xc5, 0xfe, 0x25, 0xac,
+    0x0d, 0x9a, 0x71, 0x3e, 0x83, 0x5f, 0x74, 0xf9,
+    0x59, 0xad, 0x93, 0x5b, 0xbc, 0x6e, 0x7d, 0x7f,
+    0x6b, 0x77, 0x87, 0x97, 0xe3, 0x6e, 0x05, 0x00,
+    0xba, 0xd1, 0x5f, 0x75
+};
+
+static unsigned char tree_data_sha256[] = {
+    0x31, 0x30, 0x30, 0x36, 0x34, 0x34, 0x20, 0x68,
+    0x65, 0x6c, 0x6c, 0x6f, 0x2e, 0x74, 0x78, 0x74,
+    0x00, 0x75, 0x06, 0xcb, 0xcf, 0x4c, 0x57, 0x2b,
+    0xe9, 0xe0, 0x6a, 0x1f, 0xed, 0x35, 0xac, 0x5b,
+    0x1d, 0xf8, 0xb5, 0xa7, 0x4d, 0x26, 0xc0, 0x7f,
+    0x02, 0x26, 0x48, 0xe5, 0xd9, 0x5a, 0x9f, 0x6f,
+    0x2a, 0x31, 0x30, 0x30, 0x36, 0x34, 0x34, 0x20,
+    0x6f, 0x6e, 0x65, 0x00, 0x4c, 0x0d, 0x52, 0xd1,
+    0x80, 0xc6, 0x1d, 0x01, 0xce, 0x1a, 0x91, 0xde,
+    0xc5, 0xee, 0x58, 0xf0, 0xcb, 0xe6, 0x5f, 0xd5,
+    0x94, 0x33, 0xae, 0xa8, 0x03, 0xab, 0x92, 0x79,
+    0x65, 0x49, 0x3f, 0xd7, 0x31, 0x30, 0x30, 0x36,
+    0x34, 0x34, 0x20, 0x73, 0x6f, 0x6d, 0x65, 0x00,
+    0x08, 0x3c, 0x2b, 0x8b, 0x44, 0x56, 0x40, 0xd1,
+    0x71, 0xe7, 0xaa, 0x66, 0x7b, 0x0b, 0x32, 0x00,
+    0x70, 0x06, 0xf7, 0x86, 0x71, 0x10, 0x32, 0xeb,
+    0xb8, 0x29, 0x31, 0xcc, 0xa6, 0x9c, 0xc1, 0x5b,
+    0x31, 0x30, 0x30, 0x36, 0x34, 0x34, 0x20, 0x74,
+    0x77, 0x6f, 0x00, 0xf8, 0x62, 0x5e, 0x43, 0xf9,
+    0xe0, 0x4f, 0x24, 0x29, 0x1f, 0x77, 0xcd, 0xbe,
+    0x4c, 0x71, 0xb3, 0xc2, 0xa3, 0xb0, 0x00, 0x3f,
+    0x60, 0x41, 0x9b, 0x3e, 0xd0, 0x6a, 0x05, 0x8d,
+    0x76, 0x6c, 0x8b, 0x31, 0x30, 0x30, 0x36, 0x34,
+    0x34, 0x20, 0x7a, 0x65, 0x72, 0x6f, 0x00, 0x44,
+    0x9e, 0x9b, 0x79, 0x54, 0x20, 0xcd, 0x16, 0xfe,
+    0x60, 0xad, 0x52, 0x98, 0xcf, 0x68, 0x0f, 0x15,
+    0xa7, 0xcd, 0x2a, 0xc9, 0xb4, 0x4a, 0xda, 0xf7,
+    0xed, 0x3e, 0xdc, 0x0d, 0x08, 0xdd, 0x78
+};
+#endif
+
 static object_data tree = {
     tree_bytes,
     sizeof(tree_bytes),
     "dff2da90b254e1beb889d1f1f1288be1803782df",
+    GIT_OID_SHA1,
     "tree",
     "test-objects/df",
     "test-objects/df/f2da90b254e1beb889d1f1f1288be1803782df",
@@ -174,7 +369,24 @@ static object_data tree = {
     sizeof(tree_data),
 };
 
-/* tag == 09d373e1dfdc16b129ceec6dd649739911541e05 */
+#ifdef GIT_EXPERIMENTAL_SHA256
+static object_data tree_sha256 = {
+    tree_bytes_sha256,
+    sizeof(tree_bytes_sha256),
+    "34a4854b5426f92460b4ae35e6d79746be66c38bffd6ef3bc4f053ed78a36ba4",
+    GIT_OID_SHA256,
+    "tree",
+    "test-objects/34",
+    "test-objects/34/a4854b5426f92460b4ae35e6d79746be66c38bffd6ef3bc4f053ed78a36ba4",
+    tree_data_sha256,
+    sizeof(tree_data_sha256),
+};
+#endif
+
+/*
+ * tag == 09d373e1dfdc16b129ceec6dd649739911541e05 (sha1)
+ * f535d7595d5d0e5e530b5deb34542c96491fea300a1318036b605306548cb225 (sha256)
+ */
 static unsigned char tag_bytes[] = {
     0x78, 0x01, 0x35, 0x4e, 0xcb, 0x0a, 0xc2, 0x40,
     0x10, 0xf3, 0xbc, 0x5f, 0x31, 0x77, 0xa1, 0xec,
@@ -222,10 +434,101 @@ static unsigned char tag_data[] = {
     0x2e, 0x30, 0x2e, 0x31, 0x0a,
 };
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+static unsigned char tag_bytes_sha256[] = {
+    0x78, 0x01, 0x55, 0x8f, 0xd1, 0x4e, 0x84, 0x30,
+    0x10, 0x45, 0x7d, 0xee, 0x57, 0xcc, 0xbb, 0x2e,
+    0x81, 0x16, 0x68, 0x31, 0x1b, 0xa3, 0xf1, 0xd9,
+    0xf8, 0xe0, 0xfa, 0x01, 0x43, 0x99, 0x42, 0x0d,
+    0xb4, 0xa4, 0x14, 0xb3, 0xfc, 0xbd, 0xc5, 0xdd,
+    0x4d, 0xb4, 0x69, 0xd2, 0x9b, 0xc9, 0xdc, 0x7b,
+    0x6e, 0x23, 0xf6, 0x20, 0xa4, 0xba, 0xf3, 0xed,
+    0x17, 0xe9, 0x08, 0xc8, 0xb1, 0x14, 0xb9, 0x69,
+    0x6b, 0xd1, 0xf2, 0xa6, 0x34, 0xaa, 0x56, 0x68,
+    0x4a, 0x32, 0xb5, 0xd6, 0xba, 0xd1, 0x82, 0x14,
+    0xaf, 0x6a, 0x12, 0x32, 0x57, 0x55, 0xa3, 0xa9,
+    0x92, 0x0a, 0xb9, 0x50, 0x42, 0xa2, 0x56, 0x95,
+    0x10, 0xd2, 0x54, 0x35, 0x67, 0x71, 0x9b, 0x09,
+    0xb4, 0x9f, 0x26, 0x1b, 0x59, 0x4c, 0xd9, 0xdf,
+    0x79, 0x96, 0x67, 0xc5, 0x2e, 0x7b, 0x0a, 0xf0,
+    0x0a, 0xef, 0xf0, 0x66, 0x63, 0x4c, 0xf2, 0x78,
+    0x59, 0x4a, 0xf2, 0x99, 0xce, 0x38, 0xcd, 0x23,
+    0x65, 0x69, 0xf2, 0x04, 0x05, 0xe7, 0x52, 0x15,
+    0x25, 0x6f, 0x24, 0xdc, 0xe7, 0xe9, 0x30, 0x76,
+    0x1a, 0xec, 0x02, 0xe9, 0xc6, 0x81, 0x60, 0x8f,
+    0xbc, 0x56, 0x35, 0x3e, 0x40, 0xa0, 0x91, 0x70,
+    0xa1, 0x1b, 0xe5, 0x0a, 0x86, 0x65, 0x9d, 0x26,
+    0x0c, 0xdb, 0x6e, 0x25, 0x68, 0x7d, 0xb7, 0x81,
+    0x37, 0xbf, 0xf6, 0x0b, 0x13, 0x26, 0x5a, 0x16,
+    0xec, 0xe9, 0x21, 0xed, 0xbb, 0x88, 0xd6, 0x59,
+    0xd7, 0x83, 0x59, 0x43, 0x02, 0x04, 0xa0, 0xf3,
+    0x3c, 0xa2, 0xc3, 0x68, 0xbd, 0x63, 0x57, 0xd7,
+    0xbc, 0x86, 0xd9, 0x27, 0xca, 0x2d, 0x64, 0x40,
+    0xd7, 0x53, 0xaa, 0xe4, 0x62, 0xf0, 0xdd, 0xaa,
+    0xa9, 0x83, 0x76, 0xfb, 0x13, 0x9f, 0x31, 0xf6,
+    0x61, 0x7b, 0x47, 0xdd, 0xc1, 0x9b, 0x43, 0xbb,
+    0x3d, 0xc2, 0x0b, 0x7c, 0xc2, 0x69, 0x48, 0x75,
+    0x8f, 0xb8, 0xc6, 0xf4, 0xfe, 0xfb, 0x30, 0xfb,
+    0x01, 0xc9, 0x32, 0x7d, 0xbb
+};
+
+static unsigned char tag_data_sha256[] = {
+    0x6f, 0x62, 0x6a, 0x65, 0x63, 0x74, 0x20, 0x61,
+    0x32, 0x61, 0x34, 0x33, 0x30, 0x66, 0x62, 0x36,
+    0x33, 0x62, 0x32, 0x39, 0x34, 0x66, 0x38, 0x36,
+    0x38, 0x61, 0x66, 0x34, 0x65, 0x66, 0x36, 0x63,
+    0x63, 0x63, 0x39, 0x63, 0x33, 0x65, 0x38, 0x32,
+    0x35, 0x36, 0x65, 0x33, 0x37, 0x30, 0x38, 0x35,
+    0x39, 0x63, 0x65, 0x35, 0x37, 0x38, 0x61, 0x32,
+    0x33, 0x38, 0x33, 0x37, 0x61, 0x63, 0x38, 0x35,
+    0x33, 0x33, 0x37, 0x66, 0x35, 0x36, 0x32, 0x0a,
+    0x74, 0x79, 0x70, 0x65, 0x20, 0x63, 0x6f, 0x6d,
+    0x6d, 0x69, 0x74, 0x0a, 0x74, 0x61, 0x67, 0x20,
+    0x76, 0x30, 0x2e, 0x30, 0x2e, 0x31, 0x0a, 0x74,
+    0x61, 0x67, 0x67, 0x65, 0x72, 0x20, 0x43, 0x20,
+    0x4f, 0x20, 0x4d, 0x69, 0x74, 0x74, 0x65, 0x72,
+    0x20, 0x3c, 0x63, 0x6f, 0x6d, 0x6d, 0x69, 0x74,
+    0x74, 0x65, 0x72, 0x40, 0x65, 0x78, 0x61, 0x6d,
+    0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d, 0x3e,
+    0x20, 0x31, 0x32, 0x32, 0x37, 0x38, 0x31, 0x34,
+    0x32, 0x39, 0x37, 0x20, 0x2b, 0x30, 0x30, 0x30,
+    0x30, 0x0a, 0x0a, 0x54, 0x68, 0x69, 0x73, 0x20,
+    0x69, 0x73, 0x20, 0x74, 0x68, 0x65, 0x20, 0x74,
+    0x61, 0x67, 0x20, 0x6f, 0x62, 0x6a, 0x65, 0x63,
+    0x74, 0x20, 0x66, 0x6f, 0x72, 0x20, 0x72, 0x65,
+    0x6c, 0x65, 0x61, 0x73, 0x65, 0x20, 0x76, 0x30,
+    0x2e, 0x30, 0x2e, 0x31, 0x0a, 0x20, 0x63, 0x6f,
+    0x6d, 0x6d, 0x69, 0x74, 0x20, 0x73, 0x75, 0x6d,
+    0x6d, 0x61, 0x72, 0x79, 0x0a, 0x0a, 0x54, 0x68,
+    0x65, 0x20, 0x62, 0x6f, 0x64, 0x79, 0x20, 0x6f,
+    0x66, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6f,
+    0x6d, 0x6d, 0x69, 0x74, 0x20, 0x6d, 0x65, 0x73,
+    0x73, 0x61, 0x67, 0x65, 0x2c, 0x20, 0x63, 0x6f,
+    0x6e, 0x74, 0x61, 0x69, 0x6e, 0x69, 0x6e, 0x67,
+    0x20, 0x66, 0x75, 0x72, 0x74, 0x68, 0x65, 0x72,
+    0x20, 0x65, 0x78, 0x70, 0x6c, 0x61, 0x6e, 0x61,
+    0x74, 0x69, 0x6f, 0x6e, 0x0a, 0x6f, 0x66, 0x20,
+    0x74, 0x68, 0x65, 0x20, 0x70, 0x75, 0x72, 0x70,
+    0x6f, 0x73, 0x65, 0x20, 0x6f, 0x66, 0x20, 0x74,
+    0x68, 0x65, 0x20, 0x63, 0x68, 0x61, 0x6e, 0x67,
+    0x65, 0x73, 0x20, 0x69, 0x6e, 0x74, 0x72, 0x6f,
+    0x64, 0x75, 0x63, 0x65, 0x64, 0x20, 0x62, 0x79,
+    0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6f, 0x6d,
+    0x6d, 0x69, 0x74, 0x2e, 0x0a, 0x0a, 0x53, 0x69,
+    0x67, 0x6e, 0x65, 0x64, 0x2d, 0x6f, 0x66, 0x2d,
+    0x62, 0x79, 0x3a, 0x20, 0x41, 0x20, 0x55, 0x20,
+    0x54, 0x68, 0x6f, 0x72, 0x20, 0x3c, 0x61, 0x75,
+    0x74, 0x68, 0x6f, 0x72, 0x40, 0x65, 0x78, 0x61,
+    0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d,
+    0x3e, 0x0a
+};
+#endif
+
 static object_data tag = {
     tag_bytes,
     sizeof(tag_bytes),
     "09d373e1dfdc16b129ceec6dd649739911541e05",
+    GIT_OID_SHA1,
     "tag",
     "test-objects/09",
     "test-objects/09/d373e1dfdc16b129ceec6dd649739911541e05",
@@ -233,7 +536,24 @@ static object_data tag = {
     sizeof(tag_data),
 };
 
-/* zero == e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 */
+#ifdef GIT_EXPERIMENTAL_SHA256
+static object_data tag_sha256 = {
+    tag_bytes_sha256,
+    sizeof(tag_bytes_sha256),
+    "f535d7595d5d0e5e530b5deb34542c96491fea300a1318036b605306548cb225",
+    GIT_OID_SHA256,
+    "tag",
+    "test-objects/f5",
+    "test-objects/f5/35d7595d5d0e5e530b5deb34542c96491fea300a1318036b605306548cb225",
+    tag_data_sha256,
+    sizeof(tag_data_sha256),
+};
+#endif
+
+/*
+ * zero == e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 (sha1)
+ * 473a0f4c3be8a93681a267e3b1e9a7dcda1185436fe141f7749120a303721813 (sha256)
+ */
 static unsigned char zero_bytes[] = {
     0x78, 0x01, 0x4b, 0xca, 0xc9, 0x4f, 0x52, 0x30,
     0x60, 0x00, 0x00, 0x09, 0xb0, 0x01, 0xf0,
@@ -247,6 +567,7 @@ static object_data zero = {
     zero_bytes,
     sizeof(zero_bytes),
     "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391",
+    GIT_OID_SHA1,
     "blob",
     "test-objects/e6",
     "test-objects/e6/9de29bb2d1d6434b8b29ae775ad8c2e48c5391",
@@ -254,7 +575,24 @@ static object_data zero = {
     0,
 };
 
-/* two == 78981922613b2afb6025042ff6bd878ac1994e85 */
+#ifdef GIT_EXPERIMENTAL_SHA256
+static object_data zero_sha256 = {
+    zero_bytes,
+    sizeof(zero_bytes),
+    "473a0f4c3be8a93681a267e3b1e9a7dcda1185436fe141f7749120a303721813",
+    GIT_OID_SHA256,
+    "blob",
+    "test-objects/47",
+    "test-objects/47/3a0f4c3be8a93681a267e3b1e9a7dcda1185436fe141f7749120a303721813",
+    zero_data,
+    0,
+};
+#endif
+
+/*
+ * two == 78981922613b2afb6025042ff6bd878ac1994e85 (sha1)
+ * f8625e43f9e04f24291f77cdbe4c71b3c2a3b0003f60419b3ed06a058d766c8b (sha256)
+ */
 static unsigned char two_bytes[] = {
     0x78, 0x01, 0x4b, 0xca, 0xc9, 0x4f, 0x52, 0x30,
     0x62, 0x48, 0xe4, 0x02, 0x00, 0x0e, 0x64, 0x02,
@@ -269,6 +607,7 @@ static object_data two = {
     two_bytes,
     sizeof(two_bytes),
     "78981922613b2afb6025042ff6bd878ac1994e85",
+    GIT_OID_SHA1,
     "blob",
     "test-objects/78",
     "test-objects/78/981922613b2afb6025042ff6bd878ac1994e85",
@@ -276,7 +615,24 @@ static object_data two = {
     sizeof(two_data),
 };
 
-/* some == fd8430bc864cfcd5f10e5590f8a447e01b942bfe */
+#ifdef GIT_EXPERIMENTAL_SHA256
+static object_data two_sha256 = {
+    two_bytes,
+    sizeof(two_bytes),
+    "f8625e43f9e04f24291f77cdbe4c71b3c2a3b0003f60419b3ed06a058d766c8b",
+    GIT_OID_SHA256,
+    "blob",
+    "test-objects/f8",
+    "test-objects/f8/625e43f9e04f24291f77cdbe4c71b3c2a3b0003f60419b3ed06a058d766c8b",
+    two_data,
+    sizeof(two_data),
+};
+#endif
+
+/*
+ * some == fd8430bc864cfcd5f10e5590f8a447e01b942bfe (sha1)
+ * 083c2b8b445640d171e7aa667b0b32007006f786711032ebb82931cca69cc15b (sha256)
+ */
 static unsigned char some_bytes[] = {
     0x78, 0x01, 0x7d, 0x54, 0xc1, 0x4e, 0xe3, 0x30,
     0x10, 0xdd, 0x33, 0x5f, 0x31, 0xc7, 0x5d, 0x94,
@@ -514,9 +870,24 @@ static object_data some = {
     some_bytes,
     sizeof(some_bytes),
     "fd8430bc864cfcd5f10e5590f8a447e01b942bfe",
+    GIT_OID_SHA1,
     "blob",
     "test-objects/fd",
     "test-objects/fd/8430bc864cfcd5f10e5590f8a447e01b942bfe",
     some_data,
     sizeof(some_data),
 };
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+static object_data some_sha256 = {
+    some_bytes,
+    sizeof(some_bytes),
+    "083c2b8b445640d171e7aa667b0b32007006f786711032ebb82931cca69cc15b",
+    GIT_OID_SHA256,
+    "blob",
+    "test-objects/08",
+    "test-objects/08/3c2b8b445640d171e7aa667b0b32007006f786711032ebb82931cca69cc15b",
+    some_data,
+    sizeof(some_data),
+};
+#endif
diff --git a/tests/libgit2/odb/mixed.c b/tests/libgit2/odb/mixed.c
index 87e945c83..19e6dcebf 100644
--- a/tests/libgit2/odb/mixed.c
+++ b/tests/libgit2/odb/mixed.c
@@ -5,7 +5,7 @@ static git_odb *_odb;
 
 void test_odb_mixed__initialize(void)
 {
-	cl_git_pass(git_odb_open(&_odb, cl_fixture("duplicate.git/objects")));
+	cl_git_pass(git_odb__open(&_odb, cl_fixture("duplicate.git/objects"), NULL));
 }
 
 void test_odb_mixed__cleanup(void)
@@ -20,13 +20,13 @@ void test_odb_mixed__dup_oid(void) {
 	git_oid oid;
 	git_odb_object *obj;
 
-	cl_git_pass(git_oid_fromstr(&oid, hex));
-	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, GIT_OID_HEXSZ));
+	cl_git_pass(git_oid__fromstr(&oid, hex, GIT_OID_SHA1));
+	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, GIT_OID_SHA1_HEXSIZE));
 	git_odb_object_free(obj);
 
-	cl_git_pass(git_odb_exists_prefix(NULL, _odb, &oid, GIT_OID_HEXSZ));
+	cl_git_pass(git_odb_exists_prefix(NULL, _odb, &oid, GIT_OID_SHA1_HEXSIZE));
 
-	cl_git_pass(git_oid_fromstrn(&oid, short_hex, sizeof(short_hex) - 1));
+	cl_git_pass(git_oid__fromstrn(&oid, short_hex, sizeof(short_hex) - 1, GIT_OID_SHA1));
 	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, sizeof(short_hex) - 1));
 	git_odb_object_free(obj);
 
@@ -48,63 +48,63 @@ void test_odb_mixed__dup_oid_prefix_0(void) {
 	/* ambiguous in the same pack file */
 
 	strncpy(hex, "dea509d0", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_assert_equal_i(
 		GIT_EAMBIGUOUS, git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	cl_assert_equal_i(
 		GIT_EAMBIGUOUS, git_odb_exists_prefix(&found, _odb, &oid, strlen(hex)));
 
 	strncpy(hex, "dea509d09", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	cl_git_pass(git_odb_exists_prefix(&found, _odb, &oid, strlen(hex)));
 	cl_assert_equal_oid(&found, git_odb_object_id(obj));
 	git_odb_object_free(obj);
 
 	strncpy(hex, "dea509d0b", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	git_odb_object_free(obj);
 
 	/* ambiguous in different pack files */
 
 	strncpy(hex, "81b5bff5", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_assert_equal_i(
 		GIT_EAMBIGUOUS, git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	cl_assert_equal_i(
 		GIT_EAMBIGUOUS, git_odb_exists_prefix(&found, _odb, &oid, strlen(hex)));
 
 	strncpy(hex, "81b5bff5b", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	cl_git_pass(git_odb_exists_prefix(&found, _odb, &oid, strlen(hex)));
 	cl_assert_equal_oid(&found, git_odb_object_id(obj));
 	git_odb_object_free(obj);
 
 	strncpy(hex, "81b5bff5f", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	git_odb_object_free(obj);
 
 	/* ambiguous in pack file and loose */
 
 	strncpy(hex, "0ddeaded", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_assert_equal_i(
 		GIT_EAMBIGUOUS, git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	cl_assert_equal_i(
 		GIT_EAMBIGUOUS, git_odb_exists_prefix(&found, _odb, &oid, strlen(hex)));
 
 	strncpy(hex, "0ddeaded9", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	cl_git_pass(git_odb_exists_prefix(&found, _odb, &oid, strlen(hex)));
 	cl_assert_equal_oid(&found, git_odb_object_id(obj));
 	git_odb_object_free(obj);
 
 	strncpy(hex, "0ddeadede", sizeof(hex));
-	cl_git_pass(git_oid_fromstrn(&oid, hex, strlen(hex)));
+	cl_git_pass(git_oid__fromstrn(&oid, hex, strlen(hex), GIT_OID_SHA1));
 	cl_git_pass(git_odb_read_prefix(&obj, _odb, &oid, strlen(hex)));
 	git_odb_object_free(obj);
 }
@@ -170,7 +170,7 @@ static void setup_prefix_query(
 
 		size_t len = strlen(expand_id_test_data[i].lookup_id);
 
-		git_oid_fromstrn(&id->id, expand_id_test_data[i].lookup_id, len);
+		git_oid__fromstrn(&id->id, expand_id_test_data[i].lookup_id, len, GIT_OID_SHA1);
 		id->length = (unsigned short)len;
 		id->type = expand_id_test_data[i].expected_type;
 	}
@@ -186,13 +186,13 @@ static void assert_found_objects(git_odb_expand_id *ids)
 	num = ARRAY_SIZE(expand_id_test_data);
 
 	for (i = 0; i < num; i++) {
-		git_oid expected_id = {{0}};
+		git_oid expected_id = GIT_OID_SHA1_ZERO;
 		size_t expected_len = 0;
 		git_object_t expected_type = 0;
 
 		if (expand_id_test_data[i].expected_id) {
-			git_oid_fromstr(&expected_id, expand_id_test_data[i].expected_id);
-			expected_len = GIT_OID_HEXSZ;
+			git_oid__fromstr(&expected_id, expand_id_test_data[i].expected_id, GIT_OID_SHA1);
+			expected_len = GIT_OID_SHA1_HEXSIZE;
 			expected_type = expand_id_test_data[i].expected_type;
 		}
 
@@ -204,7 +204,7 @@ static void assert_found_objects(git_odb_expand_id *ids)
 
 static void assert_notfound_objects(git_odb_expand_id *ids)
 {
-	git_oid expected_id = {{0}};
+	git_oid expected_id = GIT_OID_SHA1_ZERO;
 	size_t num, i;
 
 	num = ARRAY_SIZE(expand_id_test_data);
diff --git a/tests/libgit2/odb/packed.c b/tests/libgit2/odb/packed.c
index 3d502ed6d..b41041fc1 100644
--- a/tests/libgit2/odb/packed.c
+++ b/tests/libgit2/odb/packed.c
@@ -6,7 +6,7 @@ static git_odb *_odb;
 
 void test_odb_packed__initialize(void)
 {
-    cl_git_pass(git_odb_open(&_odb, cl_fixture("testrepo.git/objects")));
+    cl_git_pass(git_odb__open(&_odb, cl_fixture("testrepo.git/objects"), NULL));
 }
 
 void test_odb_packed__cleanup(void)
@@ -23,7 +23,7 @@ void test_odb_packed__mass_read(void)
 		git_oid id;
 		git_odb_object *obj;
 
-		cl_git_pass(git_oid_fromstr(&id, packed_objects[i]));
+		cl_git_pass(git_oid__fromstr(&id, packed_objects[i], GIT_OID_SHA1));
 		cl_assert(git_odb_exists(_odb, &id) == 1);
 		cl_git_pass(git_odb_read(&obj, _odb, &id));
 
@@ -41,7 +41,7 @@ void test_odb_packed__read_header_0(void)
 		size_t len;
 		git_object_t type;
 
-		cl_git_pass(git_oid_fromstr(&id, packed_objects[i]));
+		cl_git_pass(git_oid__fromstr(&id, packed_objects[i], GIT_OID_SHA1));
 
 		cl_git_pass(git_odb_read(&obj, _odb, &id));
 		cl_git_pass(git_odb_read_header(&len, &type, _odb, &id));
@@ -63,7 +63,7 @@ void test_odb_packed__read_header_1(void)
 		size_t len;
 		git_object_t type;
 
-		cl_git_pass(git_oid_fromstr(&id, loose_objects[i]));
+		cl_git_pass(git_oid__fromstr(&id, loose_objects[i], GIT_OID_SHA1));
 
 		cl_assert(git_odb_exists(_odb, &id) == 1);
 
diff --git a/tests/libgit2/odb/packed_one.c b/tests/libgit2/odb/packed_one.c
index 17cd4f760..7a1d3d913 100644
--- a/tests/libgit2/odb/packed_one.c
+++ b/tests/libgit2/odb/packed_one.c
@@ -10,7 +10,7 @@ void test_odb_packed_one__initialize(void)
 {
 	git_odb_backend *backend = NULL;
 
-	cl_git_pass(git_odb_new(&_odb));
+	cl_git_pass(git_odb__new(&_odb, NULL));
 	cl_git_pass(git_odb_backend_one_pack(&backend, cl_fixture("testrepo.git/objects/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.idx")));
 	cl_git_pass(git_odb_add_backend(_odb, backend, 1));
 }
@@ -29,7 +29,7 @@ void test_odb_packed_one__mass_read(void)
 		git_oid id;
 		git_odb_object *obj;
 
-		cl_git_pass(git_oid_fromstr(&id, packed_objects_one[i]));
+		cl_git_pass(git_oid__fromstr(&id, packed_objects_one[i], GIT_OID_SHA1));
 		cl_assert(git_odb_exists(_odb, &id) == 1);
 		cl_git_pass(git_odb_read(&obj, _odb, &id));
 
@@ -47,7 +47,7 @@ void test_odb_packed_one__read_header_0(void)
 		size_t len;
 		git_object_t type;
 
-		cl_git_pass(git_oid_fromstr(&id, packed_objects_one[i]));
+		cl_git_pass(git_oid__fromstr(&id, packed_objects_one[i], GIT_OID_SHA1));
 
 		cl_git_pass(git_odb_read(&obj, _odb, &id));
 		cl_git_pass(git_odb_read_header(&len, &type, _odb, &id));
diff --git a/tests/libgit2/odb/sorting.c b/tests/libgit2/odb/sorting.c
index e027230fa..1010872f4 100644
--- a/tests/libgit2/odb/sorting.c
+++ b/tests/libgit2/odb/sorting.c
@@ -37,7 +37,7 @@ static git_odb *_odb;
 
 void test_odb_sorting__initialize(void)
 {
-	cl_git_pass(git_odb_new(&_odb));
+	cl_git_pass(git_odb__new(&_odb, NULL));
 }
 
 void test_odb_sorting__cleanup(void)
@@ -79,12 +79,13 @@ void test_odb_sorting__override_default_backend_priority(void)
 {
 	git_odb *new_odb;
 	git_odb_backend *loose, *packed, *backend;
+
 	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_ODB_LOOSE_PRIORITY, 5));
 	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_ODB_PACKED_PRIORITY, 3));
 	git_odb_backend_pack(&packed, "./testrepo.git/objects");
-	git_odb_backend_loose(&loose, "./testrepo.git/objects", -1, 0, 0, 0);
+	git_odb__backend_loose(&loose, "./testrepo.git/objects", NULL);
 
-	cl_git_pass(git_odb_open(&new_odb, cl_fixture("testrepo.git/objects")));
+	cl_git_pass(git_odb__open(&new_odb, cl_fixture("testrepo.git/objects"), NULL));
 	cl_assert_equal_sz(2, git_odb_num_backends(new_odb));
 
 	cl_git_pass(git_odb_get_backend(&backend, new_odb, 0));
diff --git a/tests/libgit2/online/clone.c b/tests/libgit2/online/clone.c
index dfaee0e85..6a087b1af 100644
--- a/tests/libgit2/online/clone.c
+++ b/tests/libgit2/online/clone.c
@@ -484,9 +484,13 @@ void test_online_clone__bitbucket_falls_back_to_specified_creds(void)
 
 void test_online_clone__googlesource(void)
 {
+#ifdef __APPLE__
+	cl_skip();
+#else
 	cl_git_pass(git_clone(&g_repo, GOOGLESOURCE_REPO_URL, "./foo", &g_options));
 	git_repository_free(g_repo); g_repo = NULL;
 	cl_fixture_cleanup("./foo");
+#endif
 }
 
 static int cancel_at_half(const git_indexer_progress *stats, void *payload)
@@ -629,14 +633,14 @@ void test_online_clone__ssh_cannot_change_username(void)
 static int ssh_certificate_check(git_cert *cert, int valid, const char *host, void *payload)
 {
 	git_cert_hostkey *key;
-	git_oid expected = {{0}}, actual = {{0}};
+	git_oid expected = GIT_OID_SHA1_ZERO, actual = GIT_OID_SHA1_ZERO;
 
 	GIT_UNUSED(valid);
 	GIT_UNUSED(payload);
 
 	cl_assert(_remote_ssh_fingerprint);
 
-	cl_git_pass(git_oid_fromstrp(&expected, _remote_ssh_fingerprint));
+	cl_git_pass(git_oid__fromstrp(&expected, _remote_ssh_fingerprint, GIT_OID_SHA1));
 	cl_assert_equal_i(GIT_CERT_HOSTKEY_LIBSSH2, cert->cert_type);
 	key = (git_cert_hostkey *) cert;
 
diff --git a/tests/libgit2/online/fetch.c b/tests/libgit2/online/fetch.c
index 5beb5b618..a557bbf75 100644
--- a/tests/libgit2/online/fetch.c
+++ b/tests/libgit2/online/fetch.c
@@ -304,7 +304,7 @@ void test_online_fetch__reachable_commit(void)
 	refspecs.strings = &refspec;
 	refspecs.count = 1;
 
-	git_oid_fromstr(&expected_id, "2c349335b7f797072cf729c4f3bb0914ecb6dec9");
+	git_oid__fromstr(&expected_id, "2c349335b7f797072cf729c4f3bb0914ecb6dec9", GIT_OID_SHA1);
 
 	cl_git_pass(git_remote_create(&remote, _repo, "test",
 		"https://github.com/libgit2/TestGitRepository"));
@@ -334,7 +334,7 @@ void test_online_fetch__reachable_commit_without_destination(void)
 	refspecs.strings = &refspec;
 	refspecs.count = 1;
 
-	git_oid_fromstr(&expected_id, "2c349335b7f797072cf729c4f3bb0914ecb6dec9");
+	git_oid__fromstr(&expected_id, "2c349335b7f797072cf729c4f3bb0914ecb6dec9", GIT_OID_SHA1);
 
 	cl_git_pass(git_remote_create(&remote, _repo, "test",
 		"https://github.com/libgit2/TestGitRepository"));
diff --git a/tests/libgit2/online/push.c b/tests/libgit2/online/push.c
index 51adc3930..d9208d28a 100644
--- a/tests/libgit2/online/push.c
+++ b/tests/libgit2/online/push.c
@@ -344,18 +344,18 @@ void test_online_push__initialize(void)
 	 * * a78705c3b2725f931d3ee05348d83cc26700f247 (b2, b1) added fold and fold/b.txt
 	 * * 5c0bb3d1b9449d1cc69d7519fd05166f01840915 added a.txt
 	 */
-	git_oid_fromstr(&_oid_b6, "951bbbb90e2259a4c8950db78946784fb53fcbce");
-	git_oid_fromstr(&_oid_b5, "fa38b91f199934685819bea316186d8b008c52a2");
-	git_oid_fromstr(&_oid_b4, "27b7ce66243eb1403862d05f958c002312df173d");
-	git_oid_fromstr(&_oid_b3, "d9b63a88223d8367516f50bd131a5f7349b7f3e4");
-	git_oid_fromstr(&_oid_b2, "a78705c3b2725f931d3ee05348d83cc26700f247");
-	git_oid_fromstr(&_oid_b1, "a78705c3b2725f931d3ee05348d83cc26700f247");
-
-	git_oid_fromstr(&_tag_commit, "805c54522e614f29f70d2413a0470247d8b424ac");
-	git_oid_fromstr(&_tag_tree, "ff83aa4c5e5d28e3bcba2f5c6e2adc61286a4e5e");
-	git_oid_fromstr(&_tag_blob, "b483ae7ba66decee9aee971f501221dea84b1498");
-	git_oid_fromstr(&_tag_lightweight, "951bbbb90e2259a4c8950db78946784fb53fcbce");
-	git_oid_fromstr(&_tag_tag, "eea4f2705eeec2db3813f2430829afce99cd00b5");
+	git_oid__fromstr(&_oid_b6, "951bbbb90e2259a4c8950db78946784fb53fcbce", GIT_OID_SHA1);
+	git_oid__fromstr(&_oid_b5, "fa38b91f199934685819bea316186d8b008c52a2", GIT_OID_SHA1);
+	git_oid__fromstr(&_oid_b4, "27b7ce66243eb1403862d05f958c002312df173d", GIT_OID_SHA1);
+	git_oid__fromstr(&_oid_b3, "d9b63a88223d8367516f50bd131a5f7349b7f3e4", GIT_OID_SHA1);
+	git_oid__fromstr(&_oid_b2, "a78705c3b2725f931d3ee05348d83cc26700f247", GIT_OID_SHA1);
+	git_oid__fromstr(&_oid_b1, "a78705c3b2725f931d3ee05348d83cc26700f247", GIT_OID_SHA1);
+
+	git_oid__fromstr(&_tag_commit, "805c54522e614f29f70d2413a0470247d8b424ac", GIT_OID_SHA1);
+	git_oid__fromstr(&_tag_tree, "ff83aa4c5e5d28e3bcba2f5c6e2adc61286a4e5e", GIT_OID_SHA1);
+	git_oid__fromstr(&_tag_blob, "b483ae7ba66decee9aee971f501221dea84b1498", GIT_OID_SHA1);
+	git_oid__fromstr(&_tag_lightweight, "951bbbb90e2259a4c8950db78946784fb53fcbce", GIT_OID_SHA1);
+	git_oid__fromstr(&_tag_tag, "eea4f2705eeec2db3813f2430829afce99cd00b5", GIT_OID_SHA1);
 
 	/* Remote URL environment variable must be set.  User and password are optional.  */
 
@@ -859,7 +859,7 @@ void test_online_push__notes(void)
 	expected_ref exp_refs[] = { { "refs/notes/commits", &expected_oid } };
 	const char *specs_del[] = { ":refs/notes/commits" };
 
-	git_oid_fromstr(&expected_oid, "8461a99b27b7043e58ff6e1f5d2cf07d282534fb");
+	git_oid__fromstr(&expected_oid, "8461a99b27b7043e58ff6e1f5d2cf07d282534fb", GIT_OID_SHA1);
 
 	target_oid = &_oid_b6;
 
@@ -890,7 +890,7 @@ void test_online_push__configured(void)
 	expected_ref exp_refs[] = { { "refs/notes/commits", &expected_oid } };
 	const char *specs_del[] = { ":refs/notes/commits" };
 
-	git_oid_fromstr(&expected_oid, "8461a99b27b7043e58ff6e1f5d2cf07d282534fb");
+	git_oid__fromstr(&expected_oid, "8461a99b27b7043e58ff6e1f5d2cf07d282534fb", GIT_OID_SHA1);
 
 	target_oid = &_oid_b6;
 
diff --git a/tests/libgit2/online/push_util.c b/tests/libgit2/online/push_util.c
index cd1831d4c..94919e9b2 100644
--- a/tests/libgit2/online/push_util.c
+++ b/tests/libgit2/online/push_util.c
@@ -2,8 +2,6 @@
 #include "vector.h"
 #include "push_util.h"
 
-const git_oid OID_ZERO = {{ 0 }};
-
 void updated_tip_free(updated_tip *t)
 {
 	git__free(t->name);
diff --git a/tests/libgit2/pack/indexer.c b/tests/libgit2/pack/indexer.c
index 94b2cc92e..2ac287255 100644
--- a/tests/libgit2/pack/indexer.c
+++ b/tests/libgit2/pack/indexer.c
@@ -157,7 +157,7 @@ void test_pack_indexer__fix_thin(void)
 
 	/* Store the missing base into your ODB so the indexer can fix the pack */
 	cl_git_pass(git_odb_write(&id, odb, base_obj, base_obj_len, GIT_OBJECT_BLOB));
-	git_oid_fromstr(&should_id, "e68fe8129b546b101aee9510c5328e7f21ca1d18");
+	git_oid__fromstr(&should_id, "e68fe8129b546b101aee9510c5328e7f21ca1d18", GIT_OID_SHA1);
 	cl_assert_equal_oid(&should_id, &id);
 
 	cl_git_pass(git_indexer_new(&idx, ".", 0, odb, NULL));
@@ -222,7 +222,7 @@ void test_pack_indexer__corrupt_length(void)
 
 	/* Store the missing base into your ODB so the indexer can fix the pack */
 	cl_git_pass(git_odb_write(&id, odb, base_obj, base_obj_len, GIT_OBJECT_BLOB));
-	git_oid_fromstr(&should_id, "e68fe8129b546b101aee9510c5328e7f21ca1d18");
+	git_oid__fromstr(&should_id, "e68fe8129b546b101aee9510c5328e7f21ca1d18", GIT_OID_SHA1);
 	cl_assert_equal_oid(&should_id, &id);
 
 	cl_git_pass(git_indexer_new(&idx, ".", 0, odb, NULL));
diff --git a/tests/libgit2/pack/midx.c b/tests/libgit2/pack/midx.c
index 9dd949363..f7d680165 100644
--- a/tests/libgit2/pack/midx.c
+++ b/tests/libgit2/pack/midx.c
@@ -19,8 +19,8 @@ void test_pack_midx__parse(void)
 	cl_git_pass(git_midx_open(&idx, git_str_cstr(&midx_path)));
 	cl_assert_equal_i(git_midx_needs_refresh(idx, git_str_cstr(&midx_path)), 0);
 
-	cl_git_pass(git_oid_fromstr(&id, "5001298e0c09ad9c34e4249bc5801c75e9754fa5"));
-	cl_git_pass(git_midx_entry_find(&e, idx, &id, GIT_OID_HEXSZ));
+	cl_git_pass(git_oid__fromstr(&id, "5001298e0c09ad9c34e4249bc5801c75e9754fa5", GIT_OID_SHA1));
+	cl_git_pass(git_midx_entry_find(&e, idx, &id, GIT_OID_SHA1_HEXSIZE));
 	cl_assert_equal_oid(&e.sha1, &id);
 	cl_assert_equal_s(
 			(const char *)git_vector_get(&idx->packfile_names, e.pack_index),
@@ -39,8 +39,8 @@ void test_pack_midx__lookup(void)
 
 	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
 
-	cl_git_pass(git_oid_fromstr(&id, "5001298e0c09ad9c34e4249bc5801c75e9754fa5"));
-	cl_git_pass(git_commit_lookup_prefix(&commit, repo, &id, GIT_OID_HEXSZ));
+	cl_git_pass(git_oid__fromstr(&id, "5001298e0c09ad9c34e4249bc5801c75e9754fa5", GIT_OID_SHA1));
+	cl_git_pass(git_commit_lookup_prefix(&commit, repo, &id, GIT_OID_SHA1_HEXSIZE));
 	cl_assert_equal_s(git_commit_message(commit), "packed commit one\n");
 
 	git_commit_free(commit);
diff --git a/tests/libgit2/pack/sharing.c b/tests/libgit2/pack/sharing.c
index eaf7686b7..2e2042d2b 100644
--- a/tests/libgit2/pack/sharing.c
+++ b/tests/libgit2/pack/sharing.c
@@ -18,7 +18,7 @@ void test_pack_sharing__open_two_repos(void)
 	cl_git_pass(git_repository_open(&repo1, cl_fixture("testrepo.git")));
 	cl_git_pass(git_repository_open(&repo2, cl_fixture("testrepo.git")));
 
-	git_oid_fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 
 	cl_git_pass(git_object_lookup(&obj1, repo1, &id, GIT_OBJECT_ANY));
 	cl_git_pass(git_object_lookup(&obj2, repo2, &id, GIT_OBJECT_ANY));
diff --git a/tests/libgit2/patch/parse.c b/tests/libgit2/patch/parse.c
index a3c4c6730..d90576e46 100644
--- a/tests/libgit2/patch/parse.c
+++ b/tests/libgit2/patch/parse.c
@@ -7,7 +7,7 @@
 static void ensure_patch_validity(git_patch *patch)
 {
 	const git_diff_delta *delta;
-	char idstr[GIT_OID_HEXSZ+1] = {0};
+	char idstr[GIT_OID_SHA1_HEXSIZE+1] = {0};
 
 	cl_assert((delta = git_patch_get_delta(patch)) != NULL);
 	cl_assert_equal_i(2, delta->nfiles);
diff --git a/tests/libgit2/perf/helper__perf__do_merge.c b/tests/libgit2/perf/helper__perf__do_merge.c
index c77b46a1f..eb10524ec 100644
--- a/tests/libgit2/perf/helper__perf__do_merge.c
+++ b/tests/libgit2/perf/helper__perf__do_merge.c
@@ -33,7 +33,7 @@ void perf__do_merge(const char *fixture,
 	cl_git_pass(git_clone(&g_repo, fixture, test_name, &clone_opts));
 	perf__timer__stop(&t_clone);
 	
-	git_oid_fromstr(&oid_a, id_a);
+	git_oid__fromstr(&oid_a, id_a, GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit_a, g_repo, &oid_a));
 	cl_git_pass(git_branch_create(&ref_branch_a, g_repo,
 								  "A", commit_a,
@@ -45,7 +45,7 @@ void perf__do_merge(const char *fixture,
 
 	cl_git_pass(git_repository_set_head(g_repo, git_reference_name(ref_branch_a)));
 
-	git_oid_fromstr(&oid_b, id_b);
+	git_oid__fromstr(&oid_b, id_b, GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit_b, g_repo, &oid_b));
 	cl_git_pass(git_branch_create(&ref_branch_b, g_repo,
 								  "B", commit_b,
diff --git a/tests/libgit2/rebase/abort.c b/tests/libgit2/rebase/abort.c
index a83c529ce..da0dfe893 100644
--- a/tests/libgit2/rebase/abort.c
+++ b/tests/libgit2/rebase/abort.c
@@ -128,8 +128,8 @@ void test_rebase_abort__merge_by_id(void)
 	git_oid branch_id, onto_id;
 	git_annotated_commit *branch_head, *onto_head;
 
-	cl_git_pass(git_oid_fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64"));
-	cl_git_pass(git_oid_fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00"));
+	cl_git_pass(git_oid__fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1));
 
 	cl_git_pass(git_annotated_commit_lookup(&branch_head, repo, &branch_id));
 	cl_git_pass(git_annotated_commit_lookup(&onto_head, repo, &onto_id));
@@ -170,8 +170,8 @@ void test_rebase_abort__merge_by_id_immediately_after_init(void)
 	git_oid branch_id, onto_id;
 	git_annotated_commit *branch_head, *onto_head;
 
-	cl_git_pass(git_oid_fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64"));
-	cl_git_pass(git_oid_fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00"));
+	cl_git_pass(git_oid__fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1));
 
 	cl_git_pass(git_annotated_commit_lookup(&branch_head, repo, &branch_id));
 	cl_git_pass(git_annotated_commit_lookup(&onto_head, repo, &onto_id));
@@ -195,8 +195,8 @@ void test_rebase_abort__detached_head(void)
 	git_signature *signature;
 	git_annotated_commit *branch_head, *onto_head;
 
-	git_oid_fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64");
-    git_oid_fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64", GIT_OID_SHA1);
+    git_oid__fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 
 	cl_git_pass(git_annotated_commit_lookup(&branch_head, repo, &branch_id));
 	cl_git_pass(git_annotated_commit_lookup(&onto_head, repo, &onto_id));
diff --git a/tests/libgit2/rebase/inmemory.c b/tests/libgit2/rebase/inmemory.c
index 040a81b1b..287dd9911 100644
--- a/tests/libgit2/rebase/inmemory.c
+++ b/tests/libgit2/rebase/inmemory.c
@@ -74,7 +74,7 @@ void test_rebase_inmemory__can_resolve_conflicts(void)
 
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 
-	git_oid_fromstr(&pick_id, "33f915f9e4dbd9f4b24430e48731a59b45b15500");
+	git_oid__fromstr(&pick_id, "33f915f9e4dbd9f4b24430e48731a59b45b15500", GIT_OID_SHA1);
 
 	cl_assert_equal_i(GIT_REBASE_OPERATION_PICK, rebase_operation->type);
 	cl_assert_equal_oid(&pick_id, &rebase_operation->id);
@@ -95,14 +95,14 @@ void test_rebase_inmemory__can_resolve_conflicts(void)
 	/* ensure that we can work with the in-memory index to resolve the conflict */
 	resolution.path = "asparagus.txt";
 	resolution.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&resolution.id, "414dfc71ead79c07acd4ea47fecf91f289afc4b9");
+	git_oid__fromstr(&resolution.id, "414dfc71ead79c07acd4ea47fecf91f289afc4b9", GIT_OID_SHA1);
 	cl_git_pass(git_index_conflict_remove(rebase_index, "asparagus.txt"));
 	cl_git_pass(git_index_add(rebase_index, &resolution));
 
 	/* and finally create a commit for the resolved rebase operation */
 	cl_git_pass(git_rebase_commit(&commit_id, rebase, NULL, signature, NULL, NULL));
 
-	cl_git_pass(git_oid_fromstr(&expected_commit_id, "db7af47222181e548810da2ab5fec0e9357c5637"));
+	cl_git_pass(git_oid__fromstr(&expected_commit_id, "db7af47222181e548810da2ab5fec0e9357c5637", GIT_OID_SHA1));
 	cl_assert_equal_oid(&commit_id, &expected_commit_id);
 
 	git_status_list_free(status_list);
@@ -156,7 +156,7 @@ void test_rebase_inmemory__no_common_ancestor(void)
 
 	cl_git_pass(git_rebase_finish(rebase, signature));
 
-	git_oid_fromstr(&expected_final_id, "71e7ee8d4fe7d8bf0d107355197e0a953dfdb7f3");
+	git_oid__fromstr(&expected_final_id, "71e7ee8d4fe7d8bf0d107355197e0a953dfdb7f3", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_final_id, &commit_id);
 
 	git_annotated_commit_free(branch_head);
@@ -178,7 +178,7 @@ void test_rebase_inmemory__with_directories(void)
 
 	opts.inmemory = true;
 
-	git_oid_fromstr(&tree_id, "a4d6d9c3d57308fd8e320cf2525bae8f1adafa57");
+	git_oid__fromstr(&tree_id, "a4d6d9c3d57308fd8e320cf2525bae8f1adafa57", GIT_OID_SHA1);
 
 	cl_git_pass(git_reference_lookup(&branch_ref, repo, "refs/heads/deep_gravy"));
 	cl_git_pass(git_reference_lookup(&upstream_ref, repo, "refs/heads/veal"));
diff --git a/tests/libgit2/rebase/iterator.c b/tests/libgit2/rebase/iterator.c
index a120f28ac..79e9f3e58 100644
--- a/tests/libgit2/rebase/iterator.c
+++ b/tests/libgit2/rebase/iterator.c
@@ -30,11 +30,11 @@ static void test_operations(git_rebase *rebase, size_t expected_current)
 	git_oid expected_oid[5];
 	git_rebase_operation *operation;
 
-	git_oid_fromstr(&expected_oid[0], "da9c51a23d02d931a486f45ad18cda05cf5d2b94");
-	git_oid_fromstr(&expected_oid[1], "8d1f13f93c4995760ac07d129246ac1ff64c0be9");
-	git_oid_fromstr(&expected_oid[2], "3069cc907e6294623e5917ef6de663928c1febfb");
-	git_oid_fromstr(&expected_oid[3], "588e5d2f04d49707fe4aab865e1deacaf7ef6787");
-	git_oid_fromstr(&expected_oid[4], "b146bd7608eac53d9bf9e1a6963543588b555c64");
+	git_oid__fromstr(&expected_oid[0], "da9c51a23d02d931a486f45ad18cda05cf5d2b94", GIT_OID_SHA1);
+	git_oid__fromstr(&expected_oid[1], "8d1f13f93c4995760ac07d129246ac1ff64c0be9", GIT_OID_SHA1);
+	git_oid__fromstr(&expected_oid[2], "3069cc907e6294623e5917ef6de663928c1febfb", GIT_OID_SHA1);
+	git_oid__fromstr(&expected_oid[3], "588e5d2f04d49707fe4aab865e1deacaf7ef6787", GIT_OID_SHA1);
+	git_oid__fromstr(&expected_oid[4], "b146bd7608eac53d9bf9e1a6963543588b555c64", GIT_OID_SHA1);
 
 	cl_assert_equal_i(expected_count, git_rebase_operation_entrycount(rebase));
 	cl_assert_equal_i(expected_current, git_rebase_operation_current(rebase));
@@ -78,7 +78,7 @@ static void test_iterator(bool inmemory)
 		NULL, NULL));
 	test_operations(rebase, 0);
 
-	git_oid_fromstr(&expected_id, "776e4c48922799f903f03f5f6e51da8b01e4cce0");
+	git_oid__fromstr(&expected_id, "776e4c48922799f903f03f5f6e51da8b01e4cce0", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
@@ -86,7 +86,7 @@ static void test_iterator(bool inmemory)
 		NULL, NULL));
 	test_operations(rebase, 1);
 
-	git_oid_fromstr(&expected_id, "ba1f9b4fd5cf8151f7818be2111cc0869f1eb95a");
+	git_oid__fromstr(&expected_id, "ba1f9b4fd5cf8151f7818be2111cc0869f1eb95a", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
@@ -94,7 +94,7 @@ static void test_iterator(bool inmemory)
 		NULL, NULL));
 	test_operations(rebase, 2);
 
-	git_oid_fromstr(&expected_id, "948b12fe18b84f756223a61bece4c307787cd5d4");
+	git_oid__fromstr(&expected_id, "948b12fe18b84f756223a61bece4c307787cd5d4", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	if (!inmemory) {
@@ -107,7 +107,7 @@ static void test_iterator(bool inmemory)
 		NULL, NULL));
 	test_operations(rebase, 3);
 
-	git_oid_fromstr(&expected_id, "d9d5d59d72c9968687f9462578d79878cd80e781");
+	git_oid__fromstr(&expected_id, "d9d5d59d72c9968687f9462578d79878cd80e781", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
@@ -115,7 +115,7 @@ static void test_iterator(bool inmemory)
 		NULL, NULL));
 	test_operations(rebase, 4);
 
-	git_oid_fromstr(&expected_id, "9cf383c0a125d89e742c5dec58ed277dd07588b3");
+	git_oid__fromstr(&expected_id, "9cf383c0a125d89e742c5dec58ed277dd07588b3", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_fail(error = git_rebase_next(&rebase_operation, rebase));
diff --git a/tests/libgit2/rebase/merge.c b/tests/libgit2/rebase/merge.c
index 5f730f750..870c3ea2f 100644
--- a/tests/libgit2/rebase/merge.c
+++ b/tests/libgit2/rebase/merge.c
@@ -46,8 +46,8 @@ void test_rebase_merge__next(void)
 	git_oid pick_id, file1_id;
 	git_oid master_id, beef_id;
 
-	git_oid_fromstr(&master_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
-	git_oid_fromstr(&beef_id, "b146bd7608eac53d9bf9e1a6963543588b555c64");
+	git_oid__fromstr(&master_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
+	git_oid__fromstr(&beef_id, "b146bd7608eac53d9bf9e1a6963543588b555c64", GIT_OID_SHA1);
 
 	cl_git_pass(git_reference_lookup(&branch_ref, repo, "refs/heads/beef"));
 	cl_git_pass(git_reference_lookup(&upstream_ref, repo, "refs/heads/master"));
@@ -65,7 +65,7 @@ void test_rebase_merge__next(void)
 
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 
-	git_oid_fromstr(&pick_id, "da9c51a23d02d931a486f45ad18cda05cf5d2b94");
+	git_oid__fromstr(&pick_id, "da9c51a23d02d931a486f45ad18cda05cf5d2b94", GIT_OID_SHA1);
 
 	cl_assert_equal_i(GIT_REBASE_OPERATION_PICK, rebase_operation->type);
 	cl_assert_equal_oid(&pick_id, &rebase_operation->id);
@@ -78,7 +78,7 @@ void test_rebase_merge__next(void)
 
 	cl_assert_equal_s("beef.txt", status_entry->head_to_index->new_file.path);
 
-	git_oid_fromstr(&file1_id, "8d95ea62e621f1d38d230d9e7d206e41096d76af");
+	git_oid__fromstr(&file1_id, "8d95ea62e621f1d38d230d9e7d206e41096d76af", GIT_OID_SHA1);
 	cl_assert_equal_oid(&file1_id, &status_entry->head_to_index->new_file.id);
 
 	git_status_list_free(status_list);
@@ -129,7 +129,7 @@ void test_rebase_merge__next_with_conflicts(void)
 
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 
-	git_oid_fromstr(&pick_id, "33f915f9e4dbd9f4b24430e48731a59b45b15500");
+	git_oid__fromstr(&pick_id, "33f915f9e4dbd9f4b24430e48731a59b45b15500", GIT_OID_SHA1);
 
 	cl_assert_equal_i(GIT_REBASE_OPERATION_PICK, rebase_operation->type);
 	cl_assert_equal_oid(&pick_id, &rebase_operation->id);
@@ -230,11 +230,11 @@ void test_rebase_merge__commit(void)
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
 
-	git_oid_fromstr(&parent_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&parent_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_assert_equal_i(1, git_commit_parentcount(commit));
 	cl_assert_equal_oid(&parent_id, git_commit_parent_id(commit, 0));
 
-	git_oid_fromstr(&tree_id, "4461379789c777d2a6c1f2ee0e9d6c86731b9992");
+	git_oid__fromstr(&tree_id, "4461379789c777d2a6c1f2ee0e9d6c86731b9992", GIT_OID_SHA1);
 	cl_assert_equal_oid(&tree_id, git_commit_tree_id(commit));
 
 	cl_assert_equal_s(NULL, git_commit_message_encoding(commit));
@@ -275,8 +275,8 @@ void test_rebase_merge__commit_with_id(void)
 	git_reflog *reflog;
 	const git_reflog_entry *reflog_entry;
 
-	cl_git_pass(git_oid_fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64"));
-	cl_git_pass(git_oid_fromstr(&upstream_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00"));
+	cl_git_pass(git_oid__fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&upstream_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1));
 
 	cl_git_pass(git_annotated_commit_lookup(&branch_head, repo, &branch_id));
 	cl_git_pass(git_annotated_commit_lookup(&upstream_head, repo, &upstream_id));
@@ -289,11 +289,11 @@ void test_rebase_merge__commit_with_id(void)
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
 
-	git_oid_fromstr(&parent_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&parent_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_assert_equal_i(1, git_commit_parentcount(commit));
 	cl_assert_equal_oid(&parent_id, git_commit_parent_id(commit, 0));
 
-	git_oid_fromstr(&tree_id, "4461379789c777d2a6c1f2ee0e9d6c86731b9992");
+	git_oid__fromstr(&tree_id, "4461379789c777d2a6c1f2ee0e9d6c86731b9992", GIT_OID_SHA1);
 	cl_assert_equal_oid(&tree_id, git_commit_tree_id(commit));
 
 	cl_assert_equal_s(NULL, git_commit_message_encoding(commit));
@@ -551,8 +551,8 @@ void test_rebase_merge__finish_with_ids(void)
 	const git_reflog_entry *reflog_entry;
 	int error;
 
-	cl_git_pass(git_oid_fromstr(&branch_id, "d616d97082eb7bb2dc6f180a7cca940993b7a56f"));
-	cl_git_pass(git_oid_fromstr(&upstream_id, "f87d14a4a236582a0278a916340a793714256864"));
+	cl_git_pass(git_oid__fromstr(&branch_id, "d616d97082eb7bb2dc6f180a7cca940993b7a56f", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&upstream_id, "f87d14a4a236582a0278a916340a793714256864", GIT_OID_SHA1));
 
 	cl_git_pass(git_annotated_commit_lookup(&branch_head, repo, &branch_id));
 	cl_git_pass(git_annotated_commit_lookup(&upstream_head, repo, &upstream_id));
@@ -627,7 +627,7 @@ void test_rebase_merge__no_common_ancestor(void)
 
 	cl_git_pass(git_rebase_finish(rebase, signature));
 
-	git_oid_fromstr(&expected_final_id, "71e7ee8d4fe7d8bf0d107355197e0a953dfdb7f3");
+	git_oid__fromstr(&expected_final_id, "71e7ee8d4fe7d8bf0d107355197e0a953dfdb7f3", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_final_id, &commit_id);
 
 	git_annotated_commit_free(branch_head);
@@ -823,7 +823,7 @@ void test_rebase_merge__with_directories(void)
 	git_oid commit_id, tree_id;
 	git_commit *commit;
 
-	git_oid_fromstr(&tree_id, "a4d6d9c3d57308fd8e320cf2525bae8f1adafa57");
+	git_oid__fromstr(&tree_id, "a4d6d9c3d57308fd8e320cf2525bae8f1adafa57", GIT_OID_SHA1);
 
 	cl_git_pass(git_reference_lookup(&branch_ref, repo, "refs/heads/deep_gravy"));
 	cl_git_pass(git_reference_lookup(&upstream_ref, repo, "refs/heads/veal"));
diff --git a/tests/libgit2/rebase/setup.c b/tests/libgit2/rebase/setup.c
index 34d5edbf6..ac0d087ea 100644
--- a/tests/libgit2/rebase/setup.c
+++ b/tests/libgit2/rebase/setup.c
@@ -74,7 +74,7 @@ void test_rebase_setup__merge(void)
 
 	cl_assert_equal_i(GIT_REPOSITORY_STATE_REBASE_MERGE, git_repository_state(repo));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -120,7 +120,7 @@ void test_rebase_setup__merge_root(void)
 
 	cl_git_pass(git_rebase_init(&rebase, repo, branch_head, NULL, onto_head, NULL));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -170,7 +170,7 @@ void test_rebase_setup__merge_onto_and_upstream(void)
 
 	cl_git_pass(git_rebase_init(&rebase, repo, branch1_head, branch2_head, onto_head, NULL));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -224,7 +224,7 @@ void test_rebase_setup__merge_onto_upstream_and_branch(void)
 
 	cl_git_pass(git_rebase_init(&rebase, repo, branch_head, upstream_head, onto_head, NULL));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -272,9 +272,9 @@ void test_rebase_setup__merge_onto_upstream_and_branch_by_id(void)
 	cl_git_pass(git_repository_set_head(repo, "refs/heads/beef"));
 	cl_git_pass(git_checkout_head(repo, &checkout_opts));
 
-	cl_git_pass(git_oid_fromstr(&upstream_id, "f87d14a4a236582a0278a916340a793714256864"));
-	cl_git_pass(git_oid_fromstr(&branch_id, "d616d97082eb7bb2dc6f180a7cca940993b7a56f"));
-	cl_git_pass(git_oid_fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00"));
+	cl_git_pass(git_oid__fromstr(&upstream_id, "f87d14a4a236582a0278a916340a793714256864", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&branch_id, "d616d97082eb7bb2dc6f180a7cca940993b7a56f", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&onto_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1));
 
 	cl_git_pass(git_annotated_commit_lookup(&upstream_head, repo, &upstream_id));
 	cl_git_pass(git_annotated_commit_lookup(&branch_head, repo, &branch_id));
@@ -282,7 +282,7 @@ void test_rebase_setup__merge_onto_upstream_and_branch_by_id(void)
 
 	cl_git_pass(git_rebase_init(&rebase, repo, branch_head, upstream_head, onto_head, NULL));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -328,7 +328,7 @@ void test_rebase_setup__branch_with_merges(void)
 
 	cl_assert_equal_i(GIT_REPOSITORY_STATE_REBASE_MERGE, git_repository_state(repo));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -376,7 +376,7 @@ void test_rebase_setup__orphan_branch(void)
 
 	cl_assert_equal_i(GIT_REPOSITORY_STATE_REBASE_MERGE, git_repository_state(repo));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -427,7 +427,7 @@ void test_rebase_setup__merge_null_branch_uses_HEAD(void)
 
 	cl_assert_equal_i(GIT_REPOSITORY_STATE_REBASE_MERGE, git_repository_state(repo));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -465,7 +465,7 @@ void test_rebase_setup__merge_from_detached(void)
 
 	cl_git_pass(git_reference_lookup(&upstream_ref, repo, "refs/heads/master"));
 
-	cl_git_pass(git_oid_fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64"));
+	cl_git_pass(git_oid__fromstr(&branch_id, "b146bd7608eac53d9bf9e1a6963543588b555c64", GIT_OID_SHA1));
 
 	cl_git_pass(git_annotated_commit_lookup(&branch_head, repo, &branch_id));
 	cl_git_pass(git_annotated_commit_from_ref(&upstream_head, repo, upstream_ref));
@@ -474,7 +474,7 @@ void test_rebase_setup__merge_from_detached(void)
 
 	cl_assert_equal_i(GIT_REPOSITORY_STATE_REBASE_MERGE, git_repository_state(repo));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
@@ -513,7 +513,7 @@ void test_rebase_setup__merge_branch_by_id(void)
 
 	cl_git_pass(git_reference_lookup(&branch_ref, repo, "refs/heads/beef"));
 
-	cl_git_pass(git_oid_fromstr(&upstream_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00"));
+	cl_git_pass(git_oid__fromstr(&upstream_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1));
 
 	cl_git_pass(git_annotated_commit_from_ref(&branch_head, repo, branch_ref));
 	cl_git_pass(git_annotated_commit_lookup(&upstream_head, repo, &upstream_id));
@@ -522,7 +522,7 @@ void test_rebase_setup__merge_branch_by_id(void)
 
 	cl_assert_equal_i(GIT_REPOSITORY_STATE_REBASE_MERGE, git_repository_state(repo));
 
-	git_oid_fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00");
+	git_oid__fromstr(&head_id, "efad0b11c47cb2f0220cbd6f5b0f93bb99064b00", GIT_OID_SHA1);
 	cl_git_pass(git_repository_head(&head, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head, GIT_OBJECT_COMMIT));
 	cl_assert_equal_oid(&head_id, git_commit_id(head_commit));
diff --git a/tests/libgit2/rebase/sign.c b/tests/libgit2/rebase/sign.c
index 4064cf79b..69bb1c6f9 100644
--- a/tests/libgit2/rebase/sign.c
+++ b/tests/libgit2/rebase/sign.c
@@ -70,7 +70,7 @@ committer Rebaser <rebaser@rebaser.rb> 1405694510 +0000\n";
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 	cl_git_pass(git_rebase_commit(&commit_id, rebase, NULL, signature, NULL, NULL));
 
-	git_oid_fromstr(&expected_id, "129183968a65abd6c52da35bff43325001bfc630");
+	git_oid__fromstr(&expected_id, "129183968a65abd6c52da35bff43325001bfc630", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
@@ -178,7 +178,7 @@ gpgsig -----BEGIN PGP SIGNATURE-----\n\
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 	cl_git_pass(git_rebase_commit(&commit_id, rebase, NULL, signature, NULL, NULL));
 
-	git_oid_fromstr(&expected_id, "bf78348e45c8286f52b760f1db15cb6da030f2ef");
+	git_oid__fromstr(&expected_id, "bf78348e45c8286f52b760f1db15cb6da030f2ef", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
@@ -300,7 +300,7 @@ committer Rebaser <rebaser@rebaser.rb> 1405694510 +0000\n";
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 	cl_git_pass(git_rebase_commit(&commit_id, rebase, NULL, signature, NULL, NULL));
 
-	git_oid_fromstr(&expected_id, "129183968a65abd6c52da35bff43325001bfc630");
+	git_oid__fromstr(&expected_id, "129183968a65abd6c52da35bff43325001bfc630", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
@@ -398,7 +398,7 @@ gpgsig -----BEGIN PGP SIGNATURE-----\n\
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 	cl_git_pass(git_rebase_commit(&commit_id, rebase, NULL, signature, NULL, NULL));
 
-	git_oid_fromstr(&expected_id, "bf78348e45c8286f52b760f1db15cb6da030f2ef");
+	git_oid__fromstr(&expected_id, "bf78348e45c8286f52b760f1db15cb6da030f2ef", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
@@ -473,7 +473,7 @@ magicsig magic word: pretty please\n";
 	cl_git_pass(git_rebase_next(&rebase_operation, rebase));
 	cl_git_pass(git_rebase_commit(&commit_id, rebase, NULL, signature, NULL, NULL));
 
-	git_oid_fromstr(&expected_id, "f46a4a8d26ae411b02aa61b7d69576627f4a1e1c");
+	git_oid__fromstr(&expected_id, "f46a4a8d26ae411b02aa61b7d69576627f4a1e1c", GIT_OID_SHA1);
 	cl_assert_equal_oid(&expected_id, &commit_id);
 
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
diff --git a/tests/libgit2/refs/basic.c b/tests/libgit2/refs/basic.c
index 32742f9cc..5e41ca074 100644
--- a/tests/libgit2/refs/basic.c
+++ b/tests/libgit2/refs/basic.c
@@ -53,7 +53,7 @@ void test_refs_basic__longpaths(void)
 	git_reference *one = NULL, *two = NULL;
 	git_oid id;
 
-	cl_git_pass(git_oid_fromstr(&id, "099fabac3a9ea935598528c27f866e34089c2eff"));
+	cl_git_pass(git_oid__fromstr(&id, "099fabac3a9ea935598528c27f866e34089c2eff", GIT_OID_SHA1));
 
 	base = git_repository_path(g_repo);
 	base_len = git_utf8_char_length(base, strlen(base));
diff --git a/tests/libgit2/refs/branches/delete.c b/tests/libgit2/refs/branches/delete.c
index 27995f9e2..6b3d507a8 100644
--- a/tests/libgit2/refs/branches/delete.c
+++ b/tests/libgit2/refs/branches/delete.c
@@ -14,7 +14,7 @@ void test_refs_branches_delete__initialize(void)
 
 	repo = cl_git_sandbox_init("testrepo.git");
 
-	cl_git_pass(git_oid_fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
+	cl_git_pass(git_oid__fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
 	cl_git_pass(git_reference_create(&fake_remote, repo, "refs/remotes/nulltoken/master", &id, 0, NULL));
 }
 
@@ -119,7 +119,7 @@ void test_refs_branches_delete__removes_reflog(void)
 {
 	git_reference *branch;
 	git_reflog *log;
-	git_oid oidzero = {{0}};
+	git_oid oidzero = GIT_OID_SHA1_ZERO;
 	git_signature *sig;
 
 	/* Ensure the reflog has at least one entry */
@@ -150,14 +150,14 @@ void test_refs_branches_delete__removes_empty_folders(void)
 	git_reference *branch;
 
 	git_reflog *log;
-	git_oid oidzero = {{0}};
+	git_oid oidzero = GIT_OID_SHA1_ZERO;
 	git_signature *sig;
 
 	git_str ref_folder = GIT_STR_INIT;
 	git_str reflog_folder = GIT_STR_INIT;
 
 	/* Create a new branch with a nested name */
-	cl_git_pass(git_oid_fromstr(&commit_id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
+	cl_git_pass(git_oid__fromstr(&commit_id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, repo, &commit_id));
 	cl_git_pass(git_branch_create(&branch, repo, "some/deep/ref", commit, 0));
 	git_commit_free(commit);
diff --git a/tests/libgit2/refs/branches/iterator.c b/tests/libgit2/refs/branches/iterator.c
index e086681e5..a295d553b 100644
--- a/tests/libgit2/refs/branches/iterator.c
+++ b/tests/libgit2/refs/branches/iterator.c
@@ -11,7 +11,7 @@ void test_refs_branches_iterator__initialize(void)
 	cl_fixture_sandbox("testrepo.git");
 	cl_git_pass(git_repository_open(&repo, "testrepo.git"));
 
-	cl_git_pass(git_oid_fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
+	cl_git_pass(git_oid__fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
 	cl_git_pass(git_reference_create(&fake_remote, repo, "refs/remotes/nulltoken/master", &id, 0, NULL));
 }
 
diff --git a/tests/libgit2/refs/create.c b/tests/libgit2/refs/create.c
index 01eb62a52..1dafcf61a 100644
--- a/tests/libgit2/refs/create.c
+++ b/tests/libgit2/refs/create.c
@@ -34,7 +34,7 @@ void test_refs_create__symbolic(void)
 
 	const char *new_head_tracker = "ANOTHER_HEAD_TRACKER";
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	/* Create and write the new symbolic reference */
 	cl_git_pass(git_reference_symbolic_create(&new_reference, g_repo, new_head_tracker, current_head_target, 0, NULL));
@@ -77,7 +77,7 @@ void test_refs_create__symbolic_with_arbitrary_content(void)
 	const char *new_head_tracker = "ANOTHER_HEAD_TRACKER";
 	const char *arbitrary_target = "ARBITRARY DATA";
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	/* Attempt to create symbolic ref with arbitrary data in target
 	 * fails by default
@@ -124,7 +124,7 @@ void test_refs_create__deep_symbolic(void)
 
 	const char *new_head_tracker = "deep/rooted/tracker";
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	cl_git_pass(git_reference_symbolic_create(&new_reference, g_repo, new_head_tracker, current_head_target, 0, NULL));
 	cl_git_pass(git_reference_lookup(&looked_up_ref, g_repo, new_head_tracker));
@@ -145,7 +145,7 @@ void test_refs_create__oid(void)
 
 	const char *new_head = "refs/heads/new-head";
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	/* Create and write the new object id reference */
 	cl_git_pass(git_reference_create(&new_reference, g_repo, new_head, &id, 0, NULL));
@@ -180,7 +180,7 @@ void test_refs_create__oid_unknown_succeeds_without_strict(void)
 
 	const char *new_head = "refs/heads/new-head";
 
-	git_oid_fromstr(&id, "deadbeef3f795b2b4353bcce3a527ad0a4f7f644");
+	git_oid__fromstr(&id, "deadbeef3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1);
 
 	cl_git_pass(git_libgit2_opts(GIT_OPT_ENABLE_STRICT_OBJECT_CREATION, 0));
 
@@ -201,7 +201,7 @@ void test_refs_create__oid_unknown_fails_by_default(void)
 
 	const char *new_head = "refs/heads/new-head";
 
-	git_oid_fromstr(&id, "deadbeef3f795b2b4353bcce3a527ad0a4f7f644");
+	git_oid__fromstr(&id, "deadbeef3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1);
 
 	/* Create and write the new object id reference */
 	cl_git_fail(git_reference_create(&new_reference, g_repo, new_head, &id, 0, NULL));
@@ -215,7 +215,7 @@ void test_refs_create__propagate_eexists(void)
 	git_oid oid;
 
 	/* Make sure it works for oid and for symbolic both */
-	cl_git_pass(git_oid_fromstr(&oid, current_master_tip));
+	cl_git_pass(git_oid__fromstr(&oid, current_master_tip, GIT_OID_SHA1));
 	cl_git_fail_with(GIT_EEXISTS, git_reference_create(NULL, g_repo, current_head_target, &oid, false, NULL));
 	cl_git_fail_with(GIT_EEXISTS, git_reference_symbolic_create(NULL, g_repo, "HEAD", current_head_target, false, NULL));
 }
@@ -227,7 +227,7 @@ void test_refs_create__existing_dir_propagates_edirectory(void)
 	const char *dir_head = "refs/heads/new-dir/new-head",
 		*fail_head = "refs/heads/new-dir";
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	/* Create and write the new object id reference */
 	cl_git_pass(git_reference_create(&new_reference, g_repo, dir_head, &id, 1, NULL));
@@ -242,7 +242,7 @@ static void test_invalid_name(const char *name)
 	git_reference *new_reference;
 	git_oid id;
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	cl_assert_equal_i(GIT_EINVALIDSPEC, git_reference_create(
 		&new_reference, g_repo, name, &id, 0, NULL));
@@ -272,7 +272,7 @@ static void test_win32_name(const char *name)
 	git_oid id;
 	int ret;
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	ret = git_reference_create(&new_reference, g_repo, name, &id, 0, NULL);
 
@@ -314,7 +314,7 @@ static void count_fsyncs(size_t *create_count, size_t *compress_count)
 
 	p_fsync__cnt = 0;
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/heads/fsync_test", &id, 0, "log message"));
 	git_reference_free(ref);
 
diff --git a/tests/libgit2/refs/delete.c b/tests/libgit2/refs/delete.c
index 42cc534b5..edb521f4a 100644
--- a/tests/libgit2/refs/delete.c
+++ b/tests/libgit2/refs/delete.c
@@ -63,7 +63,7 @@ void test_refs_delete__packed_only(void)
 	git_oid id;
 	const char *new_ref = "refs/heads/new_ref";
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	/* Create and write the new object id reference */
 	cl_git_pass(git_reference_create(&ref, g_repo, new_ref, &id, 0, NULL));
diff --git a/tests/libgit2/refs/foreachglob.c b/tests/libgit2/refs/foreachglob.c
index b208a95a2..a586ca08c 100644
--- a/tests/libgit2/refs/foreachglob.c
+++ b/tests/libgit2/refs/foreachglob.c
@@ -11,7 +11,7 @@ void test_refs_foreachglob__initialize(void)
 	cl_fixture_sandbox("testrepo.git");
 	cl_git_pass(git_repository_open(&repo, "testrepo.git"));
 
-	cl_git_pass(git_oid_fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
+	cl_git_pass(git_oid__fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
 	cl_git_pass(git_reference_create(&fake_remote, repo, "refs/remotes/nulltoken/master", &id, 0, NULL));
 }
 
diff --git a/tests/libgit2/refs/iterator.c b/tests/libgit2/refs/iterator.c
index a4f9e62ec..f40d35d11 100644
--- a/tests/libgit2/refs/iterator.c
+++ b/tests/libgit2/refs/iterator.c
@@ -1,6 +1,7 @@
 #include "clar_libgit2.h"
 #include "refs.h"
 #include "vector.h"
+#include "odb.h"
 
 static git_repository *repo;
 
@@ -126,7 +127,7 @@ void test_refs_iterator__empty(void)
 	git_reference *ref;
 	git_repository *empty;
 
-	cl_git_pass(git_odb_new(&odb));
+	cl_git_pass(git_odb__new(&odb, NULL));
 	cl_git_pass(git_repository_wrap_odb(&empty, odb));
 
 	cl_git_pass(git_reference_iterator_new(&iter, empty));
diff --git a/tests/libgit2/refs/lookup.c b/tests/libgit2/refs/lookup.c
index 01e956de2..2b8be77f8 100644
--- a/tests/libgit2/refs/lookup.c
+++ b/tests/libgit2/refs/lookup.c
@@ -43,7 +43,7 @@ void test_refs_lookup__oid(void)
 	git_oid tag, expected;
 
 	cl_git_pass(git_reference_name_to_id(&tag, g_repo, "refs/tags/point_to_blob"));
-	cl_git_pass(git_oid_fromstr(&expected, "1385f264afb75a56a5bec74243be9b367ba4ca08"));
+	cl_git_pass(git_oid__fromstr(&expected, "1385f264afb75a56a5bec74243be9b367ba4ca08", GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected, &tag);
 }
 
diff --git a/tests/libgit2/refs/peel.c b/tests/libgit2/refs/peel.c
index 38f3465a0..fefd2d260 100644
--- a/tests/libgit2/refs/peel.c
+++ b/tests/libgit2/refs/peel.c
@@ -32,7 +32,7 @@ static void assert_peel_generic(
 
 	cl_git_pass(git_reference_peel(&peeled, ref, requested_type));
 
-	cl_git_pass(git_oid_fromstr(&expected_oid, expected_sha));
+	cl_git_pass(git_oid__fromstr(&expected_oid, expected_sha, GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected_oid, git_object_id(peeled));
 
 	cl_assert_equal_i(expected_type, git_object_type(peeled));
diff --git a/tests/libgit2/refs/races.c b/tests/libgit2/refs/races.c
index 476789358..bf46b760e 100644
--- a/tests/libgit2/refs/races.c
+++ b/tests/libgit2/refs/races.c
@@ -27,8 +27,8 @@ void test_refs_races__create_matching_zero_old(void)
 	git_reference *ref;
 	git_oid id, zero_id;
 
-	git_oid_fromstr(&id, commit_id);
-	git_oid_fromstr(&zero_id, "0000000000000000000000000000000000000000");
+	git_oid__fromstr(&id, commit_id, GIT_OID_SHA1);
+	git_oid__fromstr(&zero_id, "0000000000000000000000000000000000000000", GIT_OID_SHA1);
 
 	cl_git_fail(git_reference_create_matching(&ref, g_repo, refname, &id, 1, &zero_id, NULL));
 	git_reference_free(ref);
@@ -45,8 +45,8 @@ void test_refs_races__create_matching(void)
 	git_reference *ref, *ref2, *ref3;
 	git_oid id, other_id;
 
-	git_oid_fromstr(&id, commit_id);
-	git_oid_fromstr(&other_id, other_commit_id);
+	git_oid__fromstr(&id, commit_id, GIT_OID_SHA1);
+	git_oid__fromstr(&other_id, other_commit_id, GIT_OID_SHA1);
 
 	cl_git_fail_with(GIT_EMODIFIED, git_reference_create_matching(&ref, g_repo, refname, &other_id, 1, &other_id, NULL));
 
@@ -64,8 +64,8 @@ void test_refs_races__symbolic_create_matching(void)
 	git_reference *ref, *ref2, *ref3;
 	git_oid id, other_id;
 
-	git_oid_fromstr(&id, commit_id);
-	git_oid_fromstr(&other_id, other_commit_id);
+	git_oid__fromstr(&id, commit_id, GIT_OID_SHA1);
+	git_oid__fromstr(&other_id, other_commit_id, GIT_OID_SHA1);
 
 	cl_git_fail_with(GIT_EMODIFIED, git_reference_symbolic_create_matching(&ref, g_repo, "HEAD", other_refname, 1, other_refname, NULL));
 
@@ -83,8 +83,8 @@ void test_refs_races__delete(void)
 	git_reference *ref, *ref2;
 	git_oid id, other_id;
 
-	git_oid_fromstr(&id, commit_id);
-	git_oid_fromstr(&other_id, other_commit_id);
+	git_oid__fromstr(&id, commit_id, GIT_OID_SHA1);
+	git_oid__fromstr(&other_id, other_commit_id, GIT_OID_SHA1);
 
 	/* We can delete a value that matches */
 	cl_git_pass(git_reference_lookup(&ref, g_repo, refname));
@@ -116,8 +116,8 @@ void test_refs_races__switch_oid_to_symbolic(void)
 	git_reference *ref, *ref2, *ref3;
 	git_oid id, other_id;
 
-	git_oid_fromstr(&id, commit_id);
-	git_oid_fromstr(&other_id, other_commit_id);
+	git_oid__fromstr(&id, commit_id, GIT_OID_SHA1);
+	git_oid__fromstr(&other_id, other_commit_id, GIT_OID_SHA1);
 
 	/* Removing a direct ref when it's currently symbolic should fail */
 	cl_git_pass(git_reference_lookup(&ref, g_repo, refname));
@@ -145,8 +145,8 @@ void test_refs_races__switch_symbolic_to_oid(void)
 	git_reference *ref, *ref2, *ref3;
 	git_oid id, other_id;
 
-	git_oid_fromstr(&id, commit_id);
-	git_oid_fromstr(&other_id, other_commit_id);
+	git_oid__fromstr(&id, commit_id, GIT_OID_SHA1);
+	git_oid__fromstr(&other_id, other_commit_id, GIT_OID_SHA1);
 
 	/* Removing a symbolic ref when it's currently direct should fail */
 	cl_git_pass(git_reference_lookup(&ref, g_repo, "refs/symref"));
diff --git a/tests/libgit2/refs/read.c b/tests/libgit2/refs/read.c
index a622c770b..7253cf137 100644
--- a/tests/libgit2/refs/read.c
+++ b/tests/libgit2/refs/read.c
@@ -82,7 +82,7 @@ void test_refs_read__symbolic(void)
 	cl_assert(object != NULL);
 	cl_assert(git_object_type(object) == GIT_OBJECT_COMMIT);
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	cl_assert_equal_oid(&id, git_object_id(object));
 
 	git_object_free(object);
@@ -110,7 +110,7 @@ void test_refs_read__nested_symbolic(void)
 	cl_assert(object != NULL);
 	cl_assert(git_object_type(object) == GIT_OBJECT_COMMIT);
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	cl_assert_equal_oid(&id, git_object_id(object));
 
 	git_object_free(object);
diff --git a/tests/libgit2/refs/reflog/drop.c b/tests/libgit2/refs/reflog/drop.c
index 916bd9933..2d7193380 100644
--- a/tests/libgit2/refs/reflog/drop.c
+++ b/tests/libgit2/refs/reflog/drop.c
@@ -70,7 +70,7 @@ void test_refs_reflog_drop__can_drop_the_oldest_entry(void)
 	cl_assert_equal_sz(entrycount - 1, git_reflog_entrycount(g_reflog));
 
 	entry = git_reflog_entry_byindex(g_reflog, entrycount - 2);
-	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_HEX_ZERO) != 0);
+	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_SHA1_HEXZERO) != 0);
 }
 
 void test_refs_reflog_drop__can_drop_the_oldest_entry_and_rewrite_the_log_history(void)
@@ -83,7 +83,7 @@ void test_refs_reflog_drop__can_drop_the_oldest_entry_and_rewrite_the_log_histor
 	cl_assert_equal_sz(entrycount - 1, git_reflog_entrycount(g_reflog));
 
 	entry = git_reflog_entry_byindex(g_reflog, entrycount - 2);
-	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_HEX_ZERO) == 0);
+	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_SHA1_HEXZERO) == 0);
 }
 
 void test_refs_reflog_drop__can_drop_all_the_entries(void)
diff --git a/tests/libgit2/refs/reflog/messages.c b/tests/libgit2/refs/reflog/messages.c
index ed183d2f2..647c00d0d 100644
--- a/tests/libgit2/refs/reflog/messages.c
+++ b/tests/libgit2/refs/reflog/messages.c
@@ -87,7 +87,7 @@ void test_refs_reflog_messages__detaching_writes_reflog(void)
 	const char *msg;
 
 	msg = "checkout: moving from master to e90810b8df3e80c413d903f631643c716887138d";
-	git_oid_fromstr(&id, "e90810b8df3e80c413d903f631643c716887138d");
+	git_oid__fromstr(&id, "e90810b8df3e80c413d903f631643c716887138d", GIT_OID_SHA1);
 	cl_git_pass(git_repository_set_head_detached(g_repo, &id));
 	cl_reflog_check_entry(g_repo, GIT_HEAD_FILE, 0,
 		"a65fedf39aefe402d3bb6e24df4d4f5fe4547750",
@@ -109,7 +109,7 @@ void test_refs_reflog_messages__orphan_branch_does_not_count(void)
 
 	/* Have something known */
 	msg = "checkout: moving from master to e90810b8df3e80c413d903f631643c716887138d";
-	git_oid_fromstr(&id, "e90810b8df3e80c413d903f631643c716887138d");
+	git_oid__fromstr(&id, "e90810b8df3e80c413d903f631643c716887138d", GIT_OID_SHA1);
 	cl_git_pass(git_repository_set_head_detached(g_repo, &id));
 	cl_reflog_check_entry(g_repo, GIT_HEAD_FILE, 0,
 		"a65fedf39aefe402d3bb6e24df4d4f5fe4547750",
@@ -264,7 +264,7 @@ void test_refs_reflog_messages__creating_a_direct_reference(void)
 	cl_assert_equal_sz(1, git_reflog_entrycount(reflog));
 
 	entry = git_reflog_entry_byindex(reflog, 0);
-	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_HEX_ZERO) == 0);
+	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_SHA1_HEXZERO) == 0);
 	cl_assert_equal_oid(&id, &entry->oid_cur);
 	cl_assert_equal_s(message, entry->msg);
 
@@ -280,7 +280,7 @@ void test_refs_reflog_messages__newline_gets_replaced(void)
 	git_oid oid;
 
 	cl_git_pass(git_signature_now(&signature, "me", "foo@example.com"));
-	cl_git_pass(git_oid_fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
+	cl_git_pass(git_oid__fromstr(&oid, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
 
 	cl_git_pass(git_reflog_read(&reflog, g_repo, "HEAD"));
 	cl_assert_equal_sz(7, git_reflog_entrycount(reflog));
@@ -352,7 +352,7 @@ void test_refs_reflog_messages__creating_branches_default_messages(void)
 
 	cl_git_pass(git_str_printf(&buf, "branch: Created from %s", git_oid_tostr_s(git_commit_id(target))));
 	cl_reflog_check_entry(g_repo, "refs/heads/" NEW_BRANCH_NAME, 0,
-		GIT_OID_HEX_ZERO,
+		GIT_OID_SHA1_HEXZERO,
 		git_oid_tostr_s(git_commit_id(target)),
 		g_email, git_str_cstr(&buf));
 
@@ -362,7 +362,7 @@ void test_refs_reflog_messages__creating_branches_default_messages(void)
 	cl_git_pass(git_branch_create_from_annotated(&branch2, g_repo, NEW_BRANCH_NAME, annotated, true));
 
 	cl_reflog_check_entry(g_repo, "refs/heads/" NEW_BRANCH_NAME, 0,
-		GIT_OID_HEX_ZERO,
+		GIT_OID_SHA1_HEXZERO,
 		git_oid_tostr_s(git_commit_id(target)),
 		g_email, "branch: Created from e90810b8df3");
 
diff --git a/tests/libgit2/refs/reflog/reflog.c b/tests/libgit2/refs/reflog/reflog.c
index 32ce7ffb7..774ec6c93 100644
--- a/tests/libgit2/refs/reflog/reflog.c
+++ b/tests/libgit2/refs/reflog/reflog.c
@@ -52,7 +52,7 @@ static void assert_appends(const git_signature *committer, const git_oid *oid)
 
 	/* The first one was the creation of the branch */
 	entry = git_reflog_entry_byindex(reflog, 2);
-	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_HEX_ZERO) == 0);
+	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_SHA1_HEXZERO) == 0);
 
 	entry = git_reflog_entry_byindex(reflog, 1);
 	assert_signature(committer, entry->committer);
@@ -80,7 +80,7 @@ void test_refs_reflog_reflog__append_then_read(void)
 	git_reflog *reflog;
 
 	/* Create a new branch pointing at the HEAD */
-	git_oid_fromstr(&oid, current_master_tip);
+	git_oid__fromstr(&oid, current_master_tip, GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, new_ref, &oid, 0, NULL));
 	git_reference_free(ref);
 
@@ -147,7 +147,7 @@ void test_refs_reflog_reflog__removes_empty_reflog_dir(void)
 	git_oid id;
 
 	/* Create a new branch pointing at the HEAD */
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/heads/new-dir/new-head", &id, 0, NULL));
 
 	git_str_joinpath(&log_path, git_repository_path(g_repo), GIT_REFLOG_DIR);
@@ -159,7 +159,7 @@ void test_refs_reflog_reflog__removes_empty_reflog_dir(void)
 	git_reference_free(ref);
 
 	/* new ref creation should succeed since new-dir is empty */
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/heads/new-dir", &id, 0, NULL));
 	git_reference_free(ref);
 
@@ -173,7 +173,7 @@ void test_refs_reflog_reflog__fails_gracefully_on_nonempty_reflog_dir(void)
 	git_oid id;
 
 	/* Create a new branch pointing at the HEAD */
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/heads/new-dir/new-head", &id, 0, NULL));
 	git_reference_free(ref);
 
@@ -186,7 +186,7 @@ void test_refs_reflog_reflog__fails_gracefully_on_nonempty_reflog_dir(void)
 	cl_must_pass(p_unlink("testrepo.git/refs/heads/new-dir/new-head"));
 
 	/* new ref creation should fail since new-dir contains reflogs still */
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	cl_git_fail_with(GIT_EDIRECTORY, git_reference_create(&ref, g_repo, "refs/heads/new-dir", &id, 0, NULL));
 	git_reference_free(ref);
 
@@ -235,7 +235,7 @@ void test_refs_reflog_reflog__reading_a_reflog_with_invalid_format_succeeds(void
 	char *star;
 
 	/* Create a new branch. */
-	cl_git_pass(git_oid_fromstr(&id, current_master_tip));
+	cl_git_pass(git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1));
 	cl_git_pass(git_reference_create(&ref, g_repo, refname, &id, 1, refmessage));
 
 	/*
@@ -298,7 +298,7 @@ void test_refs_reflog_reflog__write_only_std_locations(void)
 	git_reference *ref;
 	git_oid id;
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/heads/foo", &id, 1, NULL));
 	git_reference_free(ref);
@@ -318,7 +318,7 @@ void test_refs_reflog_reflog__write_when_explicitly_active(void)
 	git_reference *ref;
 	git_oid id;
 
-	git_oid_fromstr(&id, current_master_tip);
+	git_oid__fromstr(&id, current_master_tip, GIT_OID_SHA1);
 	git_reference_ensure_log(g_repo, "refs/tags/foo");
 
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/tags/foo", &id, 1, NULL));
@@ -338,7 +338,7 @@ void test_refs_reflog_reflog__append_to_HEAD_when_changing_current_branch(void)
 	git_reflog_free(log);
 
 	/* Move it back */
-	git_oid_fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+	git_oid__fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/heads/master", &id, 1, NULL));
 	git_reference_free(ref);
 
@@ -390,7 +390,7 @@ static void assert_no_reflog_update(void)
 	git_reflog_free(log);
 
 	/* Move it back */
-	git_oid_fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+	git_oid__fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/heads/master", &id, 1, NULL));
 	git_reference_free(ref);
 
@@ -431,7 +431,7 @@ void test_refs_reflog_reflog__logallrefupdates_bare_set_always(void)
 	cl_git_pass(git_config_set_string(config, "core.logallrefupdates", "always"));
 	git_config_free(config);
 
-	git_oid_fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644");
+	git_oid__fromstr(&id, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1);
 	cl_git_pass(git_reference_create(&ref, g_repo, "refs/bork", &id, 1, "message"));
 
 	cl_git_pass(git_reflog_read(&log, g_repo, "refs/bork"));
diff --git a/tests/libgit2/refs/reflog/reflog_helpers.c b/tests/libgit2/refs/reflog/reflog_helpers.c
index 2ea41ee06..6a7e706d6 100644
--- a/tests/libgit2/refs/reflog/reflog_helpers.c
+++ b/tests/libgit2/refs/reflog/reflog_helpers.c
@@ -6,12 +6,12 @@
 
 int reflog_entry_tostr(git_str *out, const git_reflog_entry *entry)
 {
-	char old_oid[GIT_OID_HEXSZ], new_oid[GIT_OID_HEXSZ];
+	char old_oid[GIT_OID_SHA1_HEXSIZE], new_oid[GIT_OID_SHA1_HEXSIZE];
 
 	assert(out && entry);
 
-	git_oid_tostr((char *)&old_oid, GIT_OID_HEXSZ, git_reflog_entry_id_old(entry));
-	git_oid_tostr((char *)&new_oid, GIT_OID_HEXSZ, git_reflog_entry_id_new(entry));
+	git_oid_tostr((char *)&old_oid, GIT_OID_SHA1_HEXSIZE, git_reflog_entry_id_old(entry));
+	git_oid_tostr((char *)&new_oid, GIT_OID_SHA1_HEXSIZE, git_reflog_entry_id_new(entry));
 
 	return git_str_printf(out, "%s %s %s %s", old_oid, new_oid, "somesig", git_reflog_entry_message(entry));
 }
@@ -46,17 +46,17 @@ void cl_reflog_check_entry_(git_repository *repo, const char *reflog, size_t idx
 		git_object *obj = NULL;
 		if (git_revparse_single(&obj, repo, old_spec) == GIT_OK) {
 			if (git_oid_cmp(git_object_id(obj), git_reflog_entry_id_old(entry)) != 0) {
-				git_oid__writebuf(&result, "\tOld OID: \"", git_object_id(obj));
-				git_oid__writebuf(&result, "\" != \"", git_reflog_entry_id_old(entry));
+				git_object__write_oid_header(&result, "\tOld OID: \"", git_object_id(obj));
+				git_object__write_oid_header(&result, "\" != \"", git_reflog_entry_id_old(entry));
 				git_str_puts(&result, "\"\n");
 			}
 			git_object_free(obj);
 		} else {
 			git_oid *oid = git__calloc(1, sizeof(*oid));
-			git_oid_fromstr(oid, old_spec);
+			git_oid__fromstr(oid, old_spec, GIT_OID_SHA1);
 			if (git_oid_cmp(oid, git_reflog_entry_id_old(entry)) != 0) {
-				git_oid__writebuf(&result, "\tOld OID: \"", oid);
-				git_oid__writebuf(&result, "\" != \"", git_reflog_entry_id_old(entry));
+				git_object__write_oid_header(&result, "\tOld OID: \"", oid);
+				git_object__write_oid_header(&result, "\" != \"", git_reflog_entry_id_old(entry));
 				git_str_puts(&result, "\"\n");
 			}
 			git__free(oid);
@@ -66,17 +66,17 @@ void cl_reflog_check_entry_(git_repository *repo, const char *reflog, size_t idx
 		git_object *obj = NULL;
 		if (git_revparse_single(&obj, repo, new_spec) == GIT_OK) {
 			if (git_oid_cmp(git_object_id(obj), git_reflog_entry_id_new(entry)) != 0) {
-				git_oid__writebuf(&result, "\tNew OID: \"", git_object_id(obj));
-				git_oid__writebuf(&result, "\" != \"", git_reflog_entry_id_new(entry));
+				git_object__write_oid_header(&result, "\tNew OID: \"", git_object_id(obj));
+				git_object__write_oid_header(&result, "\" != \"", git_reflog_entry_id_new(entry));
 				git_str_puts(&result, "\"\n");
 			}
 			git_object_free(obj);
 		} else {
 			git_oid *oid = git__calloc(1, sizeof(*oid));
-			git_oid_fromstr(oid, new_spec);
+			git_oid__fromstr(oid, new_spec, GIT_OID_SHA1);
 			if (git_oid_cmp(oid, git_reflog_entry_id_new(entry)) != 0) {
-				git_oid__writebuf(&result, "\tNew OID: \"", oid);
-				git_oid__writebuf(&result, "\" != \"", git_reflog_entry_id_new(entry));
+				git_object__write_oid_header(&result, "\tNew OID: \"", oid);
+				git_object__write_oid_header(&result, "\" != \"", git_reflog_entry_id_new(entry));
 				git_str_puts(&result, "\"\n");
 			}
 			git__free(oid);
diff --git a/tests/libgit2/refs/revparse.c b/tests/libgit2/refs/revparse.c
index 56af3c939..02ffe005d 100644
--- a/tests/libgit2/refs/revparse.c
+++ b/tests/libgit2/refs/revparse.c
@@ -652,7 +652,7 @@ void test_refs_revparse__try_to_retrieve_branch_before_described_tag(void)
 	git_repository *repo;
 	git_reference *branch;
 	git_object *target;
-	char sha[GIT_OID_HEXSZ + 1];
+	char sha[GIT_OID_SHA1_HEXSIZE + 1];
 
 	repo = cl_git_sandbox_init("testrepo.git");
 
@@ -661,7 +661,7 @@ void test_refs_revparse__try_to_retrieve_branch_before_described_tag(void)
 	cl_git_pass(git_revparse_single(&target, repo, "HEAD~3"));
 	cl_git_pass(git_branch_create(&branch, repo, "blah-7-gc47800c", (git_commit *)target, 0));
 
-	git_oid_tostr(sha, GIT_OID_HEXSZ + 1, git_object_id(target));
+	git_oid_tostr(sha, GIT_OID_SHA1_HEXSIZE + 1, git_object_id(target));
 
 	test_object_inrepo("blah-7-gc47800c", sha, repo);
 
@@ -690,7 +690,7 @@ void test_refs_revparse__try_to_retrieve_sha_before_branch(void)
 	git_repository *repo;
 	git_reference *branch;
 	git_object *target;
-	char sha[GIT_OID_HEXSZ + 1];
+	char sha[GIT_OID_SHA1_HEXSIZE + 1];
 
 	repo = cl_git_sandbox_init("testrepo.git");
 
@@ -699,7 +699,7 @@ void test_refs_revparse__try_to_retrieve_sha_before_branch(void)
 	cl_git_pass(git_revparse_single(&target, repo, "HEAD~3"));
 	cl_git_pass(git_branch_create(&branch, repo, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", (git_commit *)target, 0));
 
-	git_oid_tostr(sha, GIT_OID_HEXSZ + 1, git_object_id(target));
+	git_oid_tostr(sha, GIT_OID_SHA1_HEXSIZE + 1, git_object_id(target));
 
 	test_object_inrepo("a65fedf39aefe402d3bb6e24df4d4f5fe4547750", "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", repo);
 	test_object_inrepo("heads/a65fedf39aefe402d3bb6e24df4d4f5fe4547750", sha, repo);
@@ -726,7 +726,7 @@ void test_refs_revparse__try_to_retrieve_branch_before_abbrev_sha(void)
 	git_repository *repo;
 	git_reference *branch;
 	git_object *target;
-	char sha[GIT_OID_HEXSZ + 1];
+	char sha[GIT_OID_SHA1_HEXSIZE + 1];
 
 	repo = cl_git_sandbox_init("testrepo.git");
 
@@ -735,7 +735,7 @@ void test_refs_revparse__try_to_retrieve_branch_before_abbrev_sha(void)
 	cl_git_pass(git_revparse_single(&target, repo, "HEAD~3"));
 	cl_git_pass(git_branch_create(&branch, repo, "c47800", (git_commit *)target, 0));
 
-	git_oid_tostr(sha, GIT_OID_HEXSZ + 1, git_object_id(target));
+	git_oid_tostr(sha, GIT_OID_SHA1_HEXSIZE + 1, git_object_id(target));
 
 	test_object_inrepo("c47800", sha, repo);
 
diff --git a/tests/libgit2/refs/transactions.c b/tests/libgit2/refs/transactions.c
index 50c102ad0..98ae6f73a 100644
--- a/tests/libgit2/refs/transactions.c
+++ b/tests/libgit2/refs/transactions.c
@@ -21,7 +21,7 @@ void test_refs_transactions__single_ref_oid(void)
 	git_reference *ref;
 	git_oid id;
 
-	git_oid_fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 
 	cl_git_pass(git_transaction_lock_ref(g_tx, "refs/heads/master"));
 	cl_git_pass(git_transaction_set_target(g_tx, "refs/heads/master", &id, NULL, NULL));
@@ -52,7 +52,7 @@ void test_refs_transactions__single_ref_mix_types(void)
 	git_reference *ref;
 	git_oid id;
 
-	git_oid_fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 
 	cl_git_pass(git_transaction_lock_ref(g_tx, "refs/heads/master"));
 	cl_git_pass(git_transaction_lock_ref(g_tx, "HEAD"));
@@ -90,7 +90,7 @@ void test_refs_transactions__single_create(void)
 
 	cl_git_pass(git_transaction_lock_ref(g_tx, name));
 
-	git_oid_fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 	cl_git_pass(git_transaction_set_target(g_tx, name, &id, NULL, NULL));
 	cl_git_pass(git_transaction_commit(g_tx));
 
@@ -104,7 +104,7 @@ void test_refs_transactions__unlocked_set(void)
 	git_oid id;
 
 	cl_git_pass(git_transaction_lock_ref(g_tx, "refs/heads/master"));
-	git_oid_fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750");
+	git_oid__fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1);
 	cl_git_fail_with(GIT_ENOTFOUND, git_transaction_set_target(g_tx, "refs/heads/foo", &id, NULL, NULL));
 	cl_git_pass(git_transaction_commit(g_tx));
 }
@@ -122,7 +122,7 @@ void test_refs_transactions__error_on_locking_locked_ref(void)
 	cl_git_pass(git_transaction_lock_ref(g_tx_with_lock, "refs/heads/master"));
 
 	/* lock reference for set_target */
-	cl_git_pass(git_oid_fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
+	cl_git_pass(git_oid__fromstr(&id, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
 	cl_git_fail_with(GIT_ELOCKED, git_transaction_lock_ref(g_tx, "refs/heads/master"));
 	cl_git_fail_with(GIT_ENOTFOUND, git_transaction_set_target(g_tx, "refs/heads/master", &id, NULL, NULL));
 
diff --git a/tests/libgit2/repo/env.c b/tests/libgit2/repo/env.c
index e3e522480..790ffd40f 100644
--- a/tests/libgit2/repo/env.c
+++ b/tests/libgit2/repo/env.c
@@ -95,9 +95,9 @@ static void env_check_objects_(bool a, bool t, bool p, const char *file, const c
 	git_repository *repo;
 	git_oid oid_a, oid_t, oid_p;
 	git_object *object;
-	cl_git_pass(git_oid_fromstr(&oid_a, "45141a79a77842c59a63229403220a4e4be74e3d"));
-	cl_git_pass(git_oid_fromstr(&oid_t, "1385f264afb75a56a5bec74243be9b367ba4ca08"));
-	cl_git_pass(git_oid_fromstr(&oid_p, "0df1a5865c8abfc09f1f2182e6a31be550e99f07"));
+	cl_git_pass(git_oid__fromstr(&oid_a, "45141a79a77842c59a63229403220a4e4be74e3d", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&oid_t, "1385f264afb75a56a5bec74243be9b367ba4ca08", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&oid_p, "0df1a5865c8abfc09f1f2182e6a31be550e99f07", GIT_OID_SHA1));
 	cl_git_expect(git_repository_open_ext(&repo, "attr", GIT_REPOSITORY_OPEN_FROM_ENV, NULL), 0, file, func, line);
 
 	if (a) {
diff --git a/tests/libgit2/repo/hashfile.c b/tests/libgit2/repo/hashfile.c
index e23bb77f9..f053cb950 100644
--- a/tests/libgit2/repo/hashfile.c
+++ b/tests/libgit2/repo/hashfile.c
@@ -1,4 +1,5 @@
 #include "clar_libgit2.h"
+#include "odb.h"
 
 static git_repository *_repo;
 
@@ -20,19 +21,19 @@ void test_repo_hashfile__simple(void)
 	git_str full = GIT_STR_INIT;
 
 	/* hash with repo relative path */
-	cl_git_pass(git_odb_hashfile(&a, "status/current_file", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/current_file", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, "current_file", GIT_OBJECT_BLOB, NULL));
 	cl_assert_equal_oid(&a, &b);
 
 	cl_git_pass(git_str_joinpath(&full, git_repository_workdir(_repo), "current_file"));
 
 	/* hash with full path */
-	cl_git_pass(git_odb_hashfile(&a, full.ptr, GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, full.ptr, GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, full.ptr, GIT_OBJECT_BLOB, NULL));
 	cl_assert_equal_oid(&a, &b);
 
 	/* hash with invalid type */
-	cl_git_fail(git_odb_hashfile(&a, full.ptr, GIT_OBJECT_ANY));
+	cl_git_fail(git_odb__hashfile(&a, full.ptr, GIT_OBJECT_ANY, GIT_OID_SHA1));
 	cl_git_fail(git_repository_hashfile(&b, _repo, full.ptr, GIT_OBJECT_OFS_DELTA, NULL));
 
 	git_str_dispose(&full);
@@ -59,64 +60,64 @@ void test_repo_hashfile__filtered_in_workdir(void)
 	cl_git_mkfile("status/testfile.bin", "other\r\nstuff\r\n");
 
 	/* not equal hashes because of filtering */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, "testfile.txt", GIT_OBJECT_BLOB, NULL));
 	cl_assert(git_oid_cmp(&a, &b));
 
 	/* not equal hashes because of filtering when specified by absolute path */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, txt.ptr, GIT_OBJECT_BLOB, NULL));
 	cl_assert(git_oid_cmp(&a, &b));
 
 	/* equal hashes because filter is binary */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, "testfile.bin", GIT_OBJECT_BLOB, NULL));
 	cl_assert_equal_oid(&a, &b);
 
 	/* equal hashes because filter is binary when specified by absolute path */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, bin.ptr, GIT_OBJECT_BLOB, NULL));
 	cl_assert_equal_oid(&a, &b);
 
 	/* equal hashes when 'as_file' points to binary filtering */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, "testfile.txt", GIT_OBJECT_BLOB, "foo.bin"));
 	cl_assert_equal_oid(&a, &b);
 
 	/* equal hashes when 'as_file' points to binary filtering (absolute path) */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, txt.ptr, GIT_OBJECT_BLOB, "foo.bin"));
 	cl_assert_equal_oid(&a, &b);
 
 	/* not equal hashes when 'as_file' points to text filtering */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, "testfile.bin", GIT_OBJECT_BLOB, "foo.txt"));
 	cl_assert(git_oid_cmp(&a, &b));
 
 	/* not equal hashes when 'as_file' points to text filtering */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, bin.ptr, GIT_OBJECT_BLOB, "foo.txt"));
 	cl_assert(git_oid_cmp(&a, &b));
 
 	/* equal hashes when 'as_file' is empty and turns off filtering */
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, "testfile.txt", GIT_OBJECT_BLOB, ""));
 	cl_assert_equal_oid(&a, &b);
 
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, "testfile.bin", GIT_OBJECT_BLOB, ""));
 	cl_assert_equal_oid(&a, &b);
 
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, txt.ptr, GIT_OBJECT_BLOB, ""));
 	cl_assert_equal_oid(&a, &b);
 
-	cl_git_pass(git_odb_hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "status/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, bin.ptr, GIT_OBJECT_BLOB, ""));
 	cl_assert_equal_oid(&a, &b);
 
 	/* some hash type failures */
-	cl_git_fail(git_odb_hashfile(&a, "status/testfile.txt", 0));
+	cl_git_fail(git_odb__hashfile(&a, "status/testfile.txt", 0, GIT_OID_SHA1));
 	cl_git_fail(git_repository_hashfile(&b, _repo, "testfile.txt", GIT_OBJECT_ANY, NULL));
 
 	git_str_dispose(&txt);
@@ -144,12 +145,12 @@ void test_repo_hashfile__filtered_outside_workdir(void)
 	cl_git_mkfile("absolute/testfile.bin", "other\r\nstuff\r\n");
 
 	/* not equal hashes because of filtering */
-	cl_git_pass(git_odb_hashfile(&a, "absolute/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "absolute/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, txt.ptr, GIT_OBJECT_BLOB, "testfile.txt"));
 	cl_assert(git_oid_cmp(&a, &b));
 
 	/* equal hashes because filter is binary */
-	cl_git_pass(git_odb_hashfile(&a, "absolute/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "absolute/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, bin.ptr, GIT_OBJECT_BLOB, "testfile.bin"));
 	cl_assert_equal_oid(&a, &b);
 
@@ -157,11 +158,11 @@ void test_repo_hashfile__filtered_outside_workdir(void)
 	 * equal hashes because no filtering occurs for absolute paths outside the working
 	 * directory unless as_path is specified
 	 */
-	cl_git_pass(git_odb_hashfile(&a, "absolute/testfile.txt", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "absolute/testfile.txt", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, txt.ptr, GIT_OBJECT_BLOB, NULL));
 	cl_assert_equal_oid(&a, &b);
 
-	cl_git_pass(git_odb_hashfile(&a, "absolute/testfile.bin", GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&a, "absolute/testfile.bin", GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_git_pass(git_repository_hashfile(&b, _repo, bin.ptr, GIT_OBJECT_BLOB, NULL));
 	cl_assert_equal_oid(&a, &b);
 
diff --git a/tests/libgit2/repo/head.c b/tests/libgit2/repo/head.c
index 822990555..c886c3f79 100644
--- a/tests/libgit2/repo/head.c
+++ b/tests/libgit2/repo/head.c
@@ -99,7 +99,7 @@ void test_repo_head__set_head_detached_Return_ENOTFOUND_when_the_object_doesnt_e
 {
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
+	cl_git_pass(git_oid__fromstr(&oid, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef", GIT_OID_SHA1));
 
 	cl_assert_equal_i(GIT_ENOTFOUND, git_repository_set_head_detached(repo, &oid));
 }
diff --git a/tests/libgit2/repo/init.c b/tests/libgit2/repo/init.c
index 7cf6742ca..adcd9e025 100644
--- a/tests/libgit2/repo/init.c
+++ b/tests/libgit2/repo/init.c
@@ -708,7 +708,7 @@ void test_repo_init__defaultbranch_config_empty(void)
 void test_repo_init__longpath(void)
 {
 #ifdef GIT_WIN32
-	size_t padding = CONST_STRLEN("objects/pack/pack-.pack.lock") + GIT_OID_HEXSZ;
+	size_t padding = CONST_STRLEN("objects/pack/pack-.pack.lock") + GIT_OID_SHA1_HEXSIZE;
 	size_t max, i;
 	git_str path = GIT_STR_INIT;
 	git_repository *one = NULL, *two = NULL;
diff --git a/tests/libgit2/repo/setters.c b/tests/libgit2/repo/setters.c
index 9a965dec6..66ec7706c 100644
--- a/tests/libgit2/repo/setters.c
+++ b/tests/libgit2/repo/setters.c
@@ -1,6 +1,7 @@
 #include "clar_libgit2.h"
 #include "git2/sys/repository.h"
 
+#include "odb.h"
 #include "posix.h"
 #include "util.h"
 #include "path.h"
@@ -90,7 +91,7 @@ void test_repo_setters__setting_a_new_odb_on_a_repo_which_already_loaded_one_pro
 {
 	git_odb *new_odb;
 
-	cl_git_pass(git_odb_open(&new_odb, "./testrepo.git/objects"));
+	cl_git_pass(git_odb__open(&new_odb, "./testrepo.git/objects", NULL));
 	cl_assert(((git_refcount *)new_odb)->refcount.val == 1);
 
 	git_repository_set_odb(repo, new_odb);
diff --git a/tests/libgit2/reset/hard.c b/tests/libgit2/reset/hard.c
index 9d177c021..0b6342cb2 100644
--- a/tests/libgit2/reset/hard.c
+++ b/tests/libgit2/reset/hard.c
@@ -122,9 +122,9 @@ static void unmerged_index_init(git_index *index, int entries)
 	int write_theirs = 4;
 	git_oid ancestor, ours, theirs;
 
-	git_oid_fromstr(&ancestor, "452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
-	git_oid_fromstr(&ours, "32504b727382542f9f089e24fddac5e78533e96c");
-	git_oid_fromstr(&theirs, "061d42a44cacde5726057b67558821d95db96f19");
+	git_oid__fromstr(&ancestor, "452e4244b5d083ddf0460acf1ecc74db9dcfa11a", GIT_OID_SHA1);
+	git_oid__fromstr(&ours, "32504b727382542f9f089e24fddac5e78533e96c", GIT_OID_SHA1);
+	git_oid__fromstr(&theirs, "061d42a44cacde5726057b67558821d95db96f19", GIT_OID_SHA1);
 
 	cl_git_rewritefile("status/conflicting_file", "conflicting file\n");
 
diff --git a/tests/libgit2/reset/soft.c b/tests/libgit2/reset/soft.c
index aca0834f2..128905021 100644
--- a/tests/libgit2/reset/soft.c
+++ b/tests/libgit2/reset/soft.c
@@ -53,11 +53,11 @@ void test_reset_soft__can_reset_the_detached_Head_to_the_specified_commit(void)
 void test_reset_soft__resetting_to_the_commit_pointed_at_by_the_Head_does_not_change_the_target_of_the_Head(void)
 {
 	git_oid oid;
-	char raw_head_oid[GIT_OID_HEXSZ + 1];
+	char raw_head_oid[GIT_OID_SHA1_HEXSIZE + 1];
 
 	cl_git_pass(git_reference_name_to_id(&oid, repo, "HEAD"));
 	git_oid_fmt(raw_head_oid, &oid);
-	raw_head_oid[GIT_OID_HEXSZ] = '\0';
+	raw_head_oid[GIT_OID_SHA1_HEXSIZE] = '\0';
 
 	cl_git_pass(git_revparse_single(&target, repo, raw_head_oid));
 
diff --git a/tests/libgit2/revert/bare.c b/tests/libgit2/revert/bare.c
index 9261cfe86..db443024e 100644
--- a/tests/libgit2/revert/bare.c
+++ b/tests/libgit2/revert/bare.c
@@ -34,10 +34,10 @@ void test_revert_bare__automerge(void)
 		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");
+	git_oid__fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head_commit, repo, &head_oid));
 
-	git_oid_fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac");
+	git_oid__fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&revert_commit, repo, &revert_oid));
 
 	cl_git_pass(git_revert_commit(&index, repo, revert_commit, head_commit, 0, NULL));
@@ -64,7 +64,7 @@ void test_revert_bare__conflicts(void)
 		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
 	};
 
-	git_oid_fromstr(&revert_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");
+	git_oid__fromstr(&revert_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45", GIT_OID_SHA1);
 
 	cl_git_pass(git_repository_head(&head_ref, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head_commit, head_ref, GIT_OBJECT_COMMIT));
@@ -91,10 +91,10 @@ void test_revert_bare__orphan(void)
 		{ 0100644, "296a6d3be1dff05c5d1f631d2459389fa7b619eb", 0, "file-mainline.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "39467716290f6df775a91cdb9a4eb39295018145");
+	git_oid__fromstr(&head_oid, "39467716290f6df775a91cdb9a4eb39295018145", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head_commit, repo, &head_oid));
 
-	git_oid_fromstr(&revert_oid, "ebb03002cee5d66c7732dd06241119fe72ab96a5");
+	git_oid__fromstr(&revert_oid, "ebb03002cee5d66c7732dd06241119fe72ab96a5", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&revert_commit, repo, &revert_oid));
 
 	cl_git_pass(git_revert_commit(&index, repo, revert_commit, head_commit, 0, NULL));
diff --git a/tests/libgit2/revert/rename.c b/tests/libgit2/revert/rename.c
index 0d713c60f..be7a98041 100644
--- a/tests/libgit2/revert/rename.c
+++ b/tests/libgit2/revert/rename.c
@@ -36,7 +36,7 @@ void test_revert_rename__automerge(void)
   cl_git_pass(git_repository_head(&head_ref, repo));
   cl_git_pass(git_reference_peel((git_object **)&head_commit, head_ref, GIT_OBJECT_COMMIT));
 
-  cl_git_pass(git_oid_fromstr(&revert_oid, "7b4d7c3789b3581973c04087cb774c3c3576de2f"));
+  cl_git_pass(git_oid__fromstr(&revert_oid, "7b4d7c3789b3581973c04087cb774c3c3576de2f", GIT_OID_SHA1));
   cl_git_pass(git_commit_lookup(&revert_commit, repo, &revert_oid));
 
   cl_git_pass(git_revert_commit(&index, repo, revert_commit, head_commit, 0, NULL));
diff --git a/tests/libgit2/revert/workdir.c b/tests/libgit2/revert/workdir.c
index 3f54280ca..3e790b77f 100644
--- a/tests/libgit2/revert/workdir.c
+++ b/tests/libgit2/revert/workdir.c
@@ -45,11 +45,11 @@ void test_revert_workdir__automerge(void)
 		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");
+	git_oid__fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac");
+	git_oid__fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
 	cl_git_pass(git_revert(repo, commit, NULL));
 
@@ -76,7 +76,7 @@ void test_revert_workdir__conflicts(void)
 		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
 	};
 
-	git_oid_fromstr(&revert_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");
+	git_oid__fromstr(&revert_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45", GIT_OID_SHA1);
 
 	cl_git_pass(git_repository_head(&head_ref, repo));
 	cl_git_pass(git_reference_peel((git_object **)&head, head_ref, GIT_OBJECT_COMMIT));
@@ -141,11 +141,11 @@ void test_revert_workdir__orphan(void)
 		{ 0100644, "296a6d3be1dff05c5d1f631d2459389fa7b619eb", 0, "file-mainline.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "39467716290f6df775a91cdb9a4eb39295018145");
+	git_oid__fromstr(&head_oid, "39467716290f6df775a91cdb9a4eb39295018145", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&revert_oid, "ebb03002cee5d66c7732dd06241119fe72ab96a5");
+	git_oid__fromstr(&revert_oid, "ebb03002cee5d66c7732dd06241119fe72ab96a5", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
 	cl_git_pass(git_revert(repo, commit, NULL));
 
@@ -224,11 +224,11 @@ void test_revert_workdir__again_after_automerge(void)
 		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
 	};
 
-	git_oid_fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");
+	git_oid__fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac");
+	git_oid__fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
 	cl_git_pass(git_revert(repo, commit, NULL));
 
@@ -272,11 +272,11 @@ void test_revert_workdir__again_after_edit(void)
 
 	cl_git_pass(git_repository_head(&head_ref, repo));
 
-	cl_git_pass(git_oid_fromstr(&orig_head_oid, "399fb3aba3d9d13f7d40a9254ce4402067ef3149"));
+	cl_git_pass(git_oid__fromstr(&orig_head_oid, "399fb3aba3d9d13f7d40a9254ce4402067ef3149", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&orig_head, repo, &orig_head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)orig_head, GIT_RESET_HARD, NULL));
 
-	cl_git_pass(git_oid_fromstr(&revert_oid, "2d440f2b3147d3dc7ad1085813478d6d869d5a4d"));
+	cl_git_pass(git_oid__fromstr(&revert_oid, "2d440f2b3147d3dc7ad1085813478d6d869d5a4d", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
 
 	cl_git_pass(git_revert(repo, commit, NULL));
@@ -321,11 +321,11 @@ void test_revert_workdir__again_after_edit_two(void)
 	cl_git_pass(git_repository_config(&config, repo));
 	cl_git_pass(git_config_set_bool(config, "core.autocrlf", 0));
 
-	cl_git_pass(git_oid_fromstr(&head_commit_oid, "75ec9929465623f17ff3ad68c0438ea56faba815"));
+	cl_git_pass(git_oid__fromstr(&head_commit_oid, "75ec9929465623f17ff3ad68c0438ea56faba815", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&head_commit, repo, &head_commit_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head_commit, GIT_RESET_HARD, NULL));
 
-	cl_git_pass(git_oid_fromstr(&revert_commit_oid, "97e52d5e81f541080cd6b92829fb85bc4d81d90b"));
+	cl_git_pass(git_oid__fromstr(&revert_commit_oid, "97e52d5e81f541080cd6b92829fb85bc4d81d90b", GIT_OID_SHA1));
 	cl_git_pass(git_commit_lookup(&revert_commit, repo, &revert_commit_oid));
 
 	cl_git_pass(git_revert(repo, revert_commit, NULL));
@@ -376,11 +376,11 @@ void test_revert_workdir__conflict_use_ours(void)
 
 	opts.checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE | GIT_CHECKOUT_USE_OURS;
 
-	git_oid_fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");
+	git_oid__fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac");
+	git_oid__fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
 	cl_git_pass(git_revert(repo, commit, &opts));
 
@@ -412,11 +412,11 @@ void test_revert_workdir__rename_1_of_2(void)
 	opts.merge_opts.flags |= GIT_MERGE_FIND_RENAMES;
 	opts.merge_opts.rename_threshold = 50;
 
-	git_oid_fromstr(&head_oid, "cef56612d71a6af8d8015691e4865f7fece905b5");
+	git_oid__fromstr(&head_oid, "cef56612d71a6af8d8015691e4865f7fece905b5", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&revert_oid, "55568c8de5322ff9a95d72747a239cdb64a19965");
+	git_oid__fromstr(&revert_oid, "55568c8de5322ff9a95d72747a239cdb64a19965", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
 	cl_git_pass(git_revert(repo, commit, &opts));
 
@@ -446,11 +446,11 @@ void test_revert_workdir__rename(void)
 	opts.merge_opts.flags |= GIT_MERGE_FIND_RENAMES;
 	opts.merge_opts.rename_threshold = 50;
 
-	git_oid_fromstr(&head_oid, "55568c8de5322ff9a95d72747a239cdb64a19965");
+	git_oid__fromstr(&head_oid, "55568c8de5322ff9a95d72747a239cdb64a19965", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
-	git_oid_fromstr(&revert_oid, "0aa8c7e40d342fff78d60b29a4ba8e993ed79c51");
+	git_oid__fromstr(&revert_oid, "0aa8c7e40d342fff78d60b29a4ba8e993ed79c51", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
 	cl_git_pass(git_revert(repo, commit, &opts));
 
@@ -512,7 +512,7 @@ void test_revert_workdir__merge_fails_without_mainline_specified(void)
 	git_commit *head;
 	git_oid head_oid;
 
-	git_oid_fromstr(&head_oid, "5acdc74af27172ec491d213ee36cea7eb9ef2579");
+	git_oid__fromstr(&head_oid, "5acdc74af27172ec491d213ee36cea7eb9ef2579", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
@@ -539,7 +539,7 @@ void test_revert_workdir__merge_first_parent(void)
 
 	opts.mainline = 1;
 
-	git_oid_fromstr(&head_oid, "5acdc74af27172ec491d213ee36cea7eb9ef2579");
+	git_oid__fromstr(&head_oid, "5acdc74af27172ec491d213ee36cea7eb9ef2579", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
@@ -564,7 +564,7 @@ void test_revert_workdir__merge_second_parent(void)
 
 	opts.mainline = 2;
 
-	git_oid_fromstr(&head_oid, "5acdc74af27172ec491d213ee36cea7eb9ef2579");
+	git_oid__fromstr(&head_oid, "5acdc74af27172ec491d213ee36cea7eb9ef2579", GIT_OID_SHA1);
 	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
 	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL));
 
diff --git a/tests/libgit2/revwalk/basic.c b/tests/libgit2/revwalk/basic.c
index 2c8d885e2..62a57aaa3 100644
--- a/tests/libgit2/revwalk/basic.c
+++ b/tests/libgit2/revwalk/basic.c
@@ -50,12 +50,12 @@ static const int result_bytes = 24;
 static int get_commit_index(git_oid *raw_oid)
 {
 	int i;
-	char oid[GIT_OID_HEXSZ];
+	char oid[GIT_OID_SHA1_HEXSIZE];
 
 	git_oid_fmt(oid, raw_oid);
 
 	for (i = 0; i < commit_count; ++i)
-		if (memcmp(oid, commit_ids[i], GIT_OID_HEXSZ) == 0)
+		if (memcmp(oid, commit_ids[i], GIT_OID_SHA1_HEXSIZE) == 0)
 			return i;
 
 	return -1;
@@ -75,9 +75,9 @@ static int test_walk_only(git_revwalk *walk,
 	while (git_revwalk_next(&oid, walk) == 0) {
 		result_array[i++] = get_commit_index(&oid);
 		/*{
-			char str[GIT_OID_HEXSZ+1];
+			char str[GIT_OID_SHA1_HEXSIZE+1];
 			git_oid_fmt(str, &oid);
-			str[GIT_OID_HEXSZ] = 0;
+			str[GIT_OID_SHA1_HEXSIZE] = 0;
 			printf("  %d) %s\n", i, str);
 		}*/
 	}
@@ -139,7 +139,7 @@ void test_revwalk_basic__sorting_modes(void)
 
 	revwalk_basic_setup_walk(NULL);
 
-	git_oid_fromstr(&id, commit_head);
+	git_oid__fromstr(&id, commit_head, GIT_OID_SHA1);
 
 	cl_git_pass(test_walk(_walk, &id, GIT_SORT_TIME, commit_sorting_time, 1));
 	cl_git_pass(test_walk(_walk, &id, GIT_SORT_TOPOLOGICAL, commit_sorting_topo, 2));
@@ -204,7 +204,7 @@ void test_revwalk_basic__sorted_after_reset(void)
 
 	revwalk_basic_setup_walk(NULL);
 
-	git_oid_fromstr(&oid, commit_head);
+	git_oid__fromstr(&oid, commit_head, GIT_OID_SHA1);
 
 	/* push, sort, and test the walk */
 	cl_git_pass(git_revwalk_push(_walk, &oid));
@@ -282,7 +282,7 @@ void test_revwalk_basic__multiple_push_1(void)
 
 	cl_git_pass(git_revwalk_hide_ref(_walk, "refs/heads/packed-test"));
 
-	cl_git_pass(git_oid_fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644"));
+	cl_git_pass(git_oid__fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1));
 	cl_git_pass(git_revwalk_push(_walk, &oid));
 
 	while (git_revwalk_next(&oid, _walk) == 0)
@@ -316,7 +316,7 @@ void test_revwalk_basic__multiple_push_2(void)
 
 	revwalk_basic_setup_walk(NULL);
 
-	cl_git_pass(git_oid_fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644"));
+	cl_git_pass(git_oid__fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1));
 	cl_git_pass(git_revwalk_push(_walk, &oid));
 
 	cl_git_pass(git_revwalk_hide_ref(_walk, "refs/heads/packed-test"));
@@ -335,7 +335,7 @@ void test_revwalk_basic__disallow_non_commit(void)
 
 	revwalk_basic_setup_walk(NULL);
 
-	cl_git_pass(git_oid_fromstr(&oid, "521d87c1ec3aef9824daf6d96cc0ae3710766d91"));
+	cl_git_pass(git_oid__fromstr(&oid, "521d87c1ec3aef9824daf6d96cc0ae3710766d91", GIT_OID_SHA1));
 	cl_git_fail(git_revwalk_push(_walk, &oid));
 }
 
@@ -345,7 +345,7 @@ void test_revwalk_basic__hide_then_push(void)
 	int i = 0;
 
 	revwalk_basic_setup_walk(NULL);
-	cl_git_pass(git_oid_fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644"));
+	cl_git_pass(git_oid__fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1));
 
 	cl_git_pass(git_revwalk_hide(_walk, &oid));
 	cl_git_pass(git_revwalk_push(_walk, &oid));
@@ -359,7 +359,7 @@ void test_revwalk_basic__hide_then_push(void)
 void test_revwalk_basic__topo_crash(void)
 {
 	git_oid oid;
-	git_oid_fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644");
+	git_oid__fromstr(&oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1);
 
 	revwalk_basic_setup_walk(NULL);
 	git_revwalk_sorting(_walk, GIT_SORT_TOPOLOGICAL);
@@ -378,8 +378,8 @@ void test_revwalk_basic__from_new_to_old(void)
 	revwalk_basic_setup_walk(NULL);
 	git_revwalk_sorting(_walk, GIT_SORT_TIME);
 
-	cl_git_pass(git_oid_fromstr(&to_oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644"));
-	cl_git_pass(git_oid_fromstr(&from_oid, "a4a7dce85cf63874e984719f4fdd239f5145052f"));
+	cl_git_pass(git_oid__fromstr(&to_oid, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&from_oid, "a4a7dce85cf63874e984719f4fdd239f5145052f", GIT_OID_SHA1));
 
 	cl_git_pass(git_revwalk_push(_walk, &to_oid));
 	cl_git_pass(git_revwalk_hide(_walk, &from_oid));
@@ -479,7 +479,7 @@ void test_revwalk_basic__mimic_git_rev_list(void)
 
    cl_git_pass(git_revwalk_push_ref(_walk, "refs/heads/br2"));
    cl_git_pass(git_revwalk_push_ref(_walk, "refs/heads/master"));
-   cl_git_pass(git_oid_fromstr(&oid, "e90810b8df3e80c413d903f631643c716887138d"));
+   cl_git_pass(git_oid__fromstr(&oid, "e90810b8df3e80c413d903f631643c716887138d", GIT_OID_SHA1));
    cl_git_pass(git_revwalk_push(_walk, &oid));
 
    cl_git_pass(git_revwalk_next(&oid, _walk));
@@ -563,10 +563,10 @@ void test_revwalk_basic__old_hidden_commit_one(void)
 
 	revwalk_basic_setup_walk("testrepo.git");
 
-	cl_git_pass(git_oid_fromstr(&new_id, "bd758010071961f28336333bc41e9c64c9a64866"));
+	cl_git_pass(git_oid__fromstr(&new_id, "bd758010071961f28336333bc41e9c64c9a64866", GIT_OID_SHA1));
 	cl_git_pass(git_revwalk_push(_walk, &new_id));
 
-	cl_git_pass(git_oid_fromstr(&old_id, "8e73b769e97678d684b809b163bebdae2911720f"));
+	cl_git_pass(git_oid__fromstr(&old_id, "8e73b769e97678d684b809b163bebdae2911720f", GIT_OID_SHA1));
 	cl_git_pass(git_revwalk_hide(_walk, &old_id));
 
 	cl_git_pass(git_revwalk_next(&oid, _walk));
@@ -587,10 +587,10 @@ void test_revwalk_basic__old_hidden_commit_two(void)
 
 	revwalk_basic_setup_walk("testrepo.git");
 
-	cl_git_pass(git_oid_fromstr(&new_id, "bd758010071961f28336333bc41e9c64c9a64866"));
+	cl_git_pass(git_oid__fromstr(&new_id, "bd758010071961f28336333bc41e9c64c9a64866", GIT_OID_SHA1));
 	cl_git_pass(git_revwalk_push(_walk, &new_id));
 
-	cl_git_pass(git_oid_fromstr(&old_id, "b91e763008b10db366442469339f90a2b8400d0a"));
+	cl_git_pass(git_oid__fromstr(&old_id, "b91e763008b10db366442469339f90a2b8400d0a", GIT_OID_SHA1));
 	cl_git_pass(git_revwalk_hide(_walk, &old_id));
 
 	cl_git_pass(git_revwalk_next(&oid, _walk));
diff --git a/tests/libgit2/revwalk/hidecb.c b/tests/libgit2/revwalk/hidecb.c
index 54315bc77..2100a54f2 100644
--- a/tests/libgit2/revwalk/hidecb.c
+++ b/tests/libgit2/revwalk/hidecb.c
@@ -32,10 +32,10 @@ void test_revwalk_hidecb__initialize(void)
 	int i;
 
 	cl_git_pass(git_repository_open(&_repo, cl_fixture("testrepo.git")));
-	cl_git_pass(git_oid_fromstr(&_head_id, commit_head));
+	cl_git_pass(git_oid__fromstr(&_head_id, commit_head, GIT_OID_SHA1));
 
 	for (i = 0; i < commit_count; i++)
-		cl_git_pass(git_oid_fromstr(&commit_ids[i], commit_strs[i]));
+		cl_git_pass(git_oid__fromstr(&commit_ids[i], commit_strs[i], GIT_OID_SHA1));
 
 }
 
diff --git a/tests/libgit2/revwalk/mergebase.c b/tests/libgit2/revwalk/mergebase.c
index 0378c869b..d413a1f6e 100644
--- a/tests/libgit2/revwalk/mergebase.c
+++ b/tests/libgit2/revwalk/mergebase.c
@@ -25,9 +25,9 @@ void test_revwalk_mergebase__single1(void)
 	git_oid result, one, two, expected;
 	size_t ahead, behind;
 
-	cl_git_pass(git_oid_fromstr(&one, "c47800c7266a2be04c571c04d5a6614691ea99bd "));
-	cl_git_pass(git_oid_fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
-	cl_git_pass(git_oid_fromstr(&expected, "5b5b025afb0b4c913b4c338a42934a3863bf3644"));
+	cl_git_pass(git_oid__fromstr(&one, "c47800c7266a2be04c571c04d5a6614691ea99bd ", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected, "5b5b025afb0b4c913b4c338a42934a3863bf3644", GIT_OID_SHA1));
 
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert_equal_oid(&expected, &result);
@@ -46,9 +46,9 @@ void test_revwalk_mergebase__single2(void)
 	git_oid result, one, two, expected;
 	size_t ahead, behind;
 
-	cl_git_pass(git_oid_fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af"));
-	cl_git_pass(git_oid_fromstr(&two, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
-	cl_git_pass(git_oid_fromstr(&expected, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
+	cl_git_pass(git_oid__fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected, "c47800c7266a2be04c571c04d5a6614691ea99bd", GIT_OID_SHA1));
 
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert_equal_oid(&expected, &result);
@@ -67,9 +67,9 @@ void test_revwalk_mergebase__merged_branch(void)
 	git_oid result, one, two, expected;
 	size_t ahead, behind;
 
-	cl_git_pass(git_oid_fromstr(&one, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
-	cl_git_pass(git_oid_fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
-	cl_git_pass(git_oid_fromstr(&expected, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
+	cl_git_pass(git_oid__fromstr(&one, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected, "9fd738e8f7967c078dceed8190330fc8648ee56a", GIT_OID_SHA1));
 
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert_equal_oid(&expected, &result);
@@ -91,8 +91,8 @@ void test_revwalk_mergebase__two_way_merge(void)
 	git_oid one, two;
 	size_t ahead, behind;
 
-	cl_git_pass(git_oid_fromstr(&one, "9b219343610c88a1187c996d0dc58330b55cee28"));
-	cl_git_pass(git_oid_fromstr(&two, "a953a018c5b10b20c86e69fef55ebc8ad4c5a417"));
+	cl_git_pass(git_oid__fromstr(&one, "9b219343610c88a1187c996d0dc58330b55cee28", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "a953a018c5b10b20c86e69fef55ebc8ad4c5a417", GIT_OID_SHA1));
 	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo2, &one, &two));
 
 	cl_assert_equal_sz(ahead,  8);
@@ -110,8 +110,8 @@ void test_revwalk_mergebase__no_common_ancestor_returns_ENOTFOUND(void)
 	size_t ahead, behind;
 	int error;
 
-	cl_git_pass(git_oid_fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af"));
-	cl_git_pass(git_oid_fromstr(&two, "e90810b8df3e80c413d903f631643c716887138d"));
+	cl_git_pass(git_oid__fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "e90810b8df3e80c413d903f631643c716887138d", GIT_OID_SHA1));
 
 	error = git_merge_base(&result, _repo, &one, &two);
 	cl_git_fail(error);
@@ -127,9 +127,9 @@ void test_revwalk_mergebase__prefer_youngest_merge_base(void)
 {
 	git_oid result, one, two, expected;
 
-	cl_git_pass(git_oid_fromstr(&one, "a4a7dce85cf63874e984719f4fdd239f5145052f"));
-	cl_git_pass(git_oid_fromstr(&two, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
-	cl_git_pass(git_oid_fromstr(&expected, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
+	cl_git_pass(git_oid__fromstr(&one, "a4a7dce85cf63874e984719f4fdd239f5145052f", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected, "c47800c7266a2be04c571c04d5a6614691ea99bd", GIT_OID_SHA1));
 
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert_equal_oid(&expected, &result);
@@ -140,10 +140,10 @@ void test_revwalk_mergebase__multiple_merge_bases(void)
 	git_oid one, two, expected1, expected2;
 	git_oidarray result = {NULL, 0};
 
-	cl_git_pass(git_oid_fromstr(&one, "a4a7dce85cf63874e984719f4fdd239f5145052f"));
-	cl_git_pass(git_oid_fromstr(&two, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
-	cl_git_pass(git_oid_fromstr(&expected1, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
-	cl_git_pass(git_oid_fromstr(&expected2, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
+	cl_git_pass(git_oid__fromstr(&one, "a4a7dce85cf63874e984719f4fdd239f5145052f", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected1, "c47800c7266a2be04c571c04d5a6614691ea99bd", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected2, "9fd738e8f7967c078dceed8190330fc8648ee56a", GIT_OID_SHA1));
 
 	cl_git_pass(git_merge_bases(&result, _repo, &one, &two));
 	cl_assert_equal_i(2, result.count);
@@ -160,10 +160,10 @@ void test_revwalk_mergebase__multiple_merge_bases_many_commits(void)
 
 	git_oid *input = git__malloc(sizeof(git_oid) * 2);
 
-	cl_git_pass(git_oid_fromstr(&input[0], "a4a7dce85cf63874e984719f4fdd239f5145052f"));
-	cl_git_pass(git_oid_fromstr(&input[1], "be3563ae3f795b2b4353bcce3a527ad0a4f7f644"));
-	cl_git_pass(git_oid_fromstr(&expected1, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
-	cl_git_pass(git_oid_fromstr(&expected2, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
+	cl_git_pass(git_oid__fromstr(&input[0], "a4a7dce85cf63874e984719f4fdd239f5145052f", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&input[1], "be3563ae3f795b2b4353bcce3a527ad0a4f7f644", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected1, "c47800c7266a2be04c571c04d5a6614691ea99bd", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&expected2, "9fd738e8f7967c078dceed8190330fc8648ee56a", GIT_OID_SHA1));
 
 	cl_git_pass(git_merge_bases_many(&result, _repo, 2, input));
 	cl_assert_equal_i(2, result.count);
@@ -178,8 +178,8 @@ void test_revwalk_mergebase__no_off_by_one_missing(void)
 {
 	git_oid result, one, two;
 
-	cl_git_pass(git_oid_fromstr(&one, "1a443023183e3f2bfbef8ac923cd81c1018a18fd"));
-	cl_git_pass(git_oid_fromstr(&two, "9f13f7d0a9402c681f91dc590cf7b5470e6a77d2"));
+	cl_git_pass(git_oid__fromstr(&one, "1a443023183e3f2bfbef8ac923cd81c1018a18fd", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "9f13f7d0a9402c681f91dc590cf7b5470e6a77d2", GIT_OID_SHA1));
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 }
 
@@ -201,7 +201,7 @@ static void assert_mergebase_many(const char *expected_sha, int count, ...)
 
 	for (i = 0; i < count; ++i) {
 		partial_oid = va_arg(ap, char *);
-		cl_git_pass(git_oid_fromstrn(&oid, partial_oid, strlen(partial_oid)));
+		cl_git_pass(git_oid__fromstrn(&oid, partial_oid, strlen(partial_oid), GIT_OID_SHA1));
 
 		cl_git_pass(git_object_lookup_prefix(&object, _repo, &oid, strlen(partial_oid), GIT_OBJECT_COMMIT));
 		git_oid_cpy(&oids[i], git_object_id(object));
@@ -214,7 +214,7 @@ static void assert_mergebase_many(const char *expected_sha, int count, ...)
 		cl_assert_equal_i(GIT_ENOTFOUND, git_merge_base_many(&oid, _repo, count, oids));
 	else {
 		cl_git_pass(git_merge_base_many(&oid, _repo, count, oids));
-		cl_git_pass(git_oid_fromstr(&expected, expected_sha));
+		cl_git_pass(git_oid__fromstr(&expected, expected_sha, GIT_OID_SHA1));
 
 		cl_assert_equal_oid(&expected, &oid);
 	}
@@ -265,7 +265,7 @@ static void assert_mergebase_octopus(const char *expected_sha, int count, ...)
 
 	for (i = 0; i < count; ++i) {
 		partial_oid = va_arg(ap, char *);
-		cl_git_pass(git_oid_fromstrn(&oid, partial_oid, strlen(partial_oid)));
+		cl_git_pass(git_oid__fromstrn(&oid, partial_oid, strlen(partial_oid), GIT_OID_SHA1));
 
 		cl_git_pass(git_object_lookup_prefix(&object, _repo, &oid, strlen(partial_oid), GIT_OBJECT_COMMIT));
 		git_oid_cpy(&oids[i], git_object_id(object));
@@ -278,7 +278,7 @@ static void assert_mergebase_octopus(const char *expected_sha, int count, ...)
 		cl_assert_equal_i(GIT_ENOTFOUND, git_merge_base_octopus(&oid, _repo, count, oids));
 	else {
 		cl_git_pass(git_merge_base_octopus(&oid, _repo, count, oids));
-		cl_git_pass(git_oid_fromstr(&expected, expected_sha));
+		cl_git_pass(git_oid__fromstr(&expected, expected_sha, GIT_OID_SHA1));
 
 		cl_assert_equal_oid(&expected, &oid);
 	}
@@ -501,9 +501,9 @@ void test_revwalk_mergebase__remove_redundant(void)
 
 	cl_git_pass(git_repository_open(&repo, cl_fixture("redundant.git")));
 
-	cl_git_pass(git_oid_fromstr(&one, "d89137c93ba1ee749214ff4ce52ae9137bc833f9"));
-	cl_git_pass(git_oid_fromstr(&two, "91f4b95df4a59504a9813ba66912562931d990e3"));
-	cl_git_pass(git_oid_fromstr(&base, "6cb1f2352d974e1c5a776093017e8772416ac97a"));
+	cl_git_pass(git_oid__fromstr(&one, "d89137c93ba1ee749214ff4ce52ae9137bc833f9", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&two, "91f4b95df4a59504a9813ba66912562931d990e3", GIT_OID_SHA1));
+	cl_git_pass(git_oid__fromstr(&base, "6cb1f2352d974e1c5a776093017e8772416ac97a", GIT_OID_SHA1));
 
 	cl_git_pass(git_merge_bases(&result, repo, &one, &two));
 	cl_assert_equal_i(1, result.count);
diff --git a/tests/libgit2/revwalk/simplify.c b/tests/libgit2/revwalk/simplify.c
index 6dd068a42..824496d7e 100644
--- a/tests/libgit2/revwalk/simplify.c
+++ b/tests/libgit2/revwalk/simplify.c
@@ -32,13 +32,13 @@ void test_revwalk_simplify__first_parent(void)
 	int i, error;
 
 	for (i = 0; i < 4; i++) {
-		git_oid_fromstr(&expected[i], expected_str[i]);
+		git_oid__fromstr(&expected[i], expected_str[i], GIT_OID_SHA1);
 	}
 
 	repo = cl_git_sandbox_init("testrepo.git");
 	cl_git_pass(git_revwalk_new(&walk, repo));
 
-	git_oid_fromstr(&id, commit_head);
+	git_oid__fromstr(&id, commit_head, GIT_OID_SHA1);
 	cl_git_pass(git_revwalk_push(walk, &id));
 	git_revwalk_sorting(walk, GIT_SORT_TOPOLOGICAL);
 	git_revwalk_simplify_first_parent(walk);
diff --git a/tests/libgit2/status/single.c b/tests/libgit2/status/single.c
index e7f92097c..b9659a031 100644
--- a/tests/libgit2/status/single.c
+++ b/tests/libgit2/status/single.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include "posix.h"
+#include "odb.h"
 
 static void
 cleanup__remove_file(void *_file)
@@ -17,11 +18,11 @@ void test_status_single__hash_single_file(void)
 	git_oid expected_id, actual_id;
 
 	/* initialization */
-	git_oid_fromstr(&expected_id, file_hash);
+	git_oid__fromstr(&expected_id, file_hash, GIT_OID_SHA1);
 	cl_git_mkfile(file_name, file_contents);
 	cl_set_cleanup(&cleanup__remove_file, (void *)file_name);
 
-	cl_git_pass(git_odb_hashfile(&actual_id, file_name, GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&actual_id, file_name, GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected_id, &actual_id);
 }
 
@@ -35,11 +36,11 @@ void test_status_single__hash_single_empty_file(void)
 	git_oid expected_id, actual_id;
 
 	/* initialization */
-	git_oid_fromstr(&expected_id, file_hash);
+	git_oid__fromstr(&expected_id, file_hash, GIT_OID_SHA1);
 	cl_git_mkfile(file_name, file_contents);
 	cl_set_cleanup(&cleanup__remove_file, (void *)file_name);
 
-	cl_git_pass(git_odb_hashfile(&actual_id, file_name, GIT_OBJECT_BLOB));
+	cl_git_pass(git_odb__hashfile(&actual_id, file_name, GIT_OBJECT_BLOB, GIT_OID_SHA1));
 	cl_assert_equal_oid(&expected_id, &actual_id);
 }
 
diff --git a/tests/libgit2/status/submodules.c b/tests/libgit2/status/submodules.c
index d223657b4..90d56d9cc 100644
--- a/tests/libgit2/status/submodules.c
+++ b/tests/libgit2/status/submodules.c
@@ -142,7 +142,7 @@ void test_status_submodules__moved_head(void)
 
 	/* move submodule HEAD to c47800c7266a2be04c571c04d5a6614691ea99bd */
 	cl_git_pass(
-		git_oid_fromstr(&oid, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
+		git_oid__fromstr(&oid, "c47800c7266a2be04c571c04d5a6614691ea99bd", GIT_OID_SHA1));
 	cl_git_pass(git_repository_set_head_detached(smrepo, &oid));
 
 	/* first do a normal status, which should now include the submodule */
diff --git a/tests/libgit2/status/worktree.c b/tests/libgit2/status/worktree.c
index 00c6ec2d5..efbf597a7 100644
--- a/tests/libgit2/status/worktree.c
+++ b/tests/libgit2/status/worktree.c
@@ -515,18 +515,21 @@ void test_status_worktree__conflict_with_diff3(void)
 
 	ancestor_entry.path = "modified_file";
 	ancestor_entry.mode = 0100644;
-	git_oid_fromstr(&ancestor_entry.id,
-		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
+	git_oid__fromstr(&ancestor_entry.id,
+		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a",
+		GIT_OID_SHA1);
 
 	our_entry.path = "modified_file";
 	our_entry.mode = 0100644;
-	git_oid_fromstr(&our_entry.id,
-		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
+	git_oid__fromstr(&our_entry.id,
+		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a",
+		GIT_OID_SHA1);
 
 	their_entry.path = "modified_file";
 	their_entry.mode = 0100644;
-	git_oid_fromstr(&their_entry.id,
-		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
+	git_oid__fromstr(&their_entry.id,
+		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a",
+		GIT_OID_SHA1);
 
 	cl_git_pass(git_status_file(&status, repo, "modified_file"));
 	cl_assert_equal_i(GIT_STATUS_WT_MODIFIED, status);
@@ -711,18 +714,21 @@ void test_status_worktree__conflicted_item(void)
 
 	ancestor_entry.mode = 0100644;
 	ancestor_entry.path = "modified_file";
-	git_oid_fromstr(&ancestor_entry.id,
-		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
+	git_oid__fromstr(&ancestor_entry.id,
+		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a",
+		GIT_OID_SHA1);
 
 	our_entry.mode = 0100644;
 	our_entry.path = "modified_file";
-	git_oid_fromstr(&our_entry.id,
-		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
+	git_oid__fromstr(&our_entry.id,
+		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a",
+		GIT_OID_SHA1);
 
 	their_entry.mode = 0100644;
 	their_entry.path = "modified_file";
-	git_oid_fromstr(&their_entry.id,
-		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
+	git_oid__fromstr(&their_entry.id,
+		"452e4244b5d083ddf0460acf1ecc74db9dcfa11a",
+		GIT_OID_SHA1);
 
 	cl_git_pass(git_status_file(&status, repo, "modified_file"));
 	cl_assert_equal_i(GIT_STATUS_WT_MODIFIED, status);
@@ -744,11 +750,11 @@ void test_status_worktree__conflict_has_no_oid(void)
 	git_index_entry entry = {{0}};
 	git_status_list *statuslist;
 	const git_status_entry *status;
-	git_oid zero_id = {{0}};
+	git_oid zero_id = GIT_OID_SHA1_ZERO;
 
 	entry.mode = 0100644;
 	entry.path = "modified_file";
-	git_oid_fromstr(&entry.id, "452e4244b5d083ddf0460acf1ecc74db9dcfa11a");
+	git_oid__fromstr(&entry.id, "452e4244b5d083ddf0460acf1ecc74db9dcfa11a", GIT_OID_SHA1);
 
 	cl_git_pass(git_repository_index(&index, repo));
 	cl_git_pass(git_index_conflict_add(index, &entry, &entry, &entry));
diff --git a/tests/libgit2/submodule/add.c b/tests/libgit2/submodule/add.c
index ae5507d7f..a2a66e7f5 100644
--- a/tests/libgit2/submodule/add.c
+++ b/tests/libgit2/submodule/add.c
@@ -139,7 +139,7 @@ static void test_add_entry(
 {
 	git_index_entry entry = {{0}};
 
-	cl_git_pass(git_oid_fromstr(&entry.id, idstr));
+	cl_git_pass(git_oid__fromstr(&entry.id, idstr, GIT_OID_SHA1));
 
 	entry.path = path;
 	entry.mode = mode;
diff --git a/tests/libgit2/transports/smart/packet.c b/tests/libgit2/transports/smart/packet.c
index 5b623a378..8801ef833 100644
--- a/tests/libgit2/transports/smart/packet.c
+++ b/tests/libgit2/transports/smart/packet.c
@@ -68,7 +68,7 @@ static void assert_ack_parses(const char *line, const char *expected_oid, enum g
 	git_pkt_ack *pkt;
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, expected_oid));
+	cl_git_pass(git_oid__fromstr(&oid, expected_oid, GIT_OID_SHA1));
 
 	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, &endptr, line, linelen));
 	cl_assert_equal_i(pkt->type, GIT_PKT_ACK);
@@ -154,7 +154,7 @@ static void assert_ref_parses_(const char *line, size_t linelen, const char *exp
 	git_pkt_ref *pkt;
 	git_oid oid;
 
-	cl_git_pass(git_oid_fromstr(&oid, expected_oid));
+	cl_git_pass(git_oid__fromstr(&oid, expected_oid, GIT_OID_SHA1));
 
 	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, &endptr, line, linelen));
 	cl_assert_equal_i(pkt->type, GIT_PKT_REF);
diff --git a/tests/libgit2/win32/forbidden.c b/tests/libgit2/win32/forbidden.c
index 5c007987b..c4e82e90d 100644
--- a/tests/libgit2/win32/forbidden.c
+++ b/tests/libgit2/win32/forbidden.c
@@ -37,7 +37,7 @@ void test_win32_forbidden__can_add_forbidden_filename_with_entry(void)
 
 	entry.path = "aux";
 	entry.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&entry.id, "da623abd956bb2fd8052c708c7ed43f05d192d37");
+	git_oid__fromstr(&entry.id, "da623abd956bb2fd8052c708c7ed43f05d192d37", GIT_OID_SHA1);
 
 	cl_git_pass(git_index_add(index, &entry));
 
@@ -53,7 +53,7 @@ void test_win32_forbidden__cannot_add_dot_git_even_with_entry(void)
 
 	entry.path = "foo/.git";
 	entry.mode = GIT_FILEMODE_BLOB;
-	git_oid_fromstr(&entry.id, "da623abd956bb2fd8052c708c7ed43f05d192d37");
+	git_oid__fromstr(&entry.id, "da623abd956bb2fd8052c708c7ed43f05d192d37", GIT_OID_SHA1);
 
 	cl_git_fail(git_index_add(index, &entry));