Add git_repository_reset_filesystem and fix tests

When a repository is transferred from one file system to another,
many of the config settings that represent the properties of the
file system may be wrong.  This adds a new public API that will
refresh the config settings of the repository to account for the
change of file system.  This doesn't do a full "reinitialize" and
operates on a existing git_repository object refreshing the config
when done.

This commit then makes use of the new API in clar as each test
repository is set up.

This commit also has a number of other clar test fixes where we
were making assumptions about the type of filesystem, either based
on outdated config data or based on the OS instead of the FS.

9 files changed, 167 insertions, 53 deletions

diff --git a/include/git2/repository.h b/include/git2/repository.h
index b4d561992..74ab65bf7 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -288,6 +288,23 @@ GIT_EXTERN(int) git_repository_init_ext(
 	git_repository_init_options *opts);
 
 /**
+ * Update the filesystem config settings for an open repository
+ *
+ * When a repository is initialized, config values are set based on the
+ * properties of the filesystem that the repository is on, such as
+ * "core.ignorecase", "core.filemode", "core.symlinks", etc.  If the
+ * repository is moved to a new filesystem, these properties may no
+ * longer be correct and API calls may not behave as expected.  This
+ * call reruns the phase of repository initialization that sets those
+ * properties to compensate for the current filesystem of the repo.
+ *
+ * @param repo A repository object
+ * @returrn 0 on success, < 0 on error
+ */
+GIT_EXTERN(int) git_repository_reset_filesystem(
+	git_repository *repo);
+
+/**
  * Retrieve and resolve the reference pointed at by HEAD.
  *
  * The returned `git_reference` will be owned by caller and
diff --git a/src/config.h b/src/config.h
index 85db5e3e1..01e8465cc 100644
--- a/src/config.h
+++ b/src/config.h
@@ -47,7 +47,7 @@ extern int git_config_rename_section(
  * @param out the new backend
  * @param path where the config file is located
  */
-extern int git_config_file__ondisk(struct git_config_backend **out, const char *path);
+extern int git_config_file__ondisk(git_config_backend **out, const char *path);
 
 extern int git_config__normalize_name(const char *in, char **out);
 
diff --git a/src/repository.c b/src/repository.c
index f609e5779..52509ffc1 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -962,34 +962,46 @@ static int create_empty_file(const char *path, mode_t mode)
 }
 
 static int repo_init_config(
+	git_config *parent,
 	const char *repo_dir,
 	const char *work_dir,
-	git_repository_init_options *opts)
+	uint32_t flags,
+	uint32_t mode)
 {
 	int error = 0;
-	git_buf cfg_path = GIT_BUF_INIT;
+	git_buf buf = GIT_BUF_INIT;
+	const char *cfg_path = NULL;
 	git_config *config = NULL;
-	bool is_bare = ((opts->flags & GIT_REPOSITORY_INIT_BARE) != 0);
+	bool is_bare = ((flags & GIT_REPOSITORY_INIT_BARE) != 0);
 
 #define SET_REPO_CONFIG(TYPE, NAME, VAL) do {\
 	if ((error = git_config_set_##TYPE(config, NAME, VAL)) < 0) \
 		goto cleanup; } while (0)
 
-	if (git_buf_joinpath(&cfg_path, repo_dir, GIT_CONFIG_FILENAME_INREPO) < 0)
+	if (git_buf_joinpath(&buf, repo_dir, GIT_CONFIG_FILENAME_INREPO) < 0)
 		return -1;
+	cfg_path = git_buf_cstr(&buf);
 
-	if (!git_path_isfile(git_buf_cstr(&cfg_path)) &&
-		create_empty_file(git_buf_cstr(&cfg_path), GIT_CONFIG_FILE_MODE) < 0) {
-			git_buf_free(&cfg_path);
-			return -1;
-	}
+	if (!git_path_isfile(cfg_path) &&
+		(error = create_empty_file(cfg_path, GIT_CONFIG_FILE_MODE)) < 0)
+		goto cleanup;
 
-	if (git_config_open_ondisk(&config, git_buf_cstr(&cfg_path)) < 0) {
-		git_buf_free(&cfg_path);
-		return -1;
+	if (!parent)
+		error = git_config_open_ondisk(&config, cfg_path);
+	else if ((error = git_config_open_level(
+		&config, parent, GIT_CONFIG_LEVEL_LOCAL)) < 0)
+	{
+		giterr_clear();
+
+		if (!(error = git_config_add_file_ondisk(
+				parent, cfg_path, GIT_CONFIG_LEVEL_LOCAL, false)))
+			error = git_config_open_level(
+				&config, parent, GIT_CONFIG_LEVEL_LOCAL);
 	}
+	if (error < 0)
+		goto cleanup;
 
-	if ((opts->flags & GIT_REPOSITORY_INIT__IS_REINIT) != 0 &&
+	if ((flags & GIT_REPOSITORY_INIT__IS_REINIT) != 0 &&
 		(error = check_repositoryformatversion(config)) < 0)
 		goto cleanup;
 
@@ -998,7 +1010,7 @@ static int repo_init_config(
 	SET_REPO_CONFIG(
 		int32, "core.repositoryformatversion", GIT_REPO_VERSION);
 	SET_REPO_CONFIG(
-		bool, "core.filemode", is_chmod_supported(git_buf_cstr(&cfg_path)));
+		bool, "core.filemode", is_chmod_supported(cfg_path));
 
 #ifdef GIT_USE_ICONV
 	SET_REPO_CONFIG(
@@ -1009,38 +1021,70 @@ static int repo_init_config(
 	if (!are_symlinks_supported(is_bare ? repo_dir : work_dir))
 		SET_REPO_CONFIG(bool, "core.symlinks", false);
 
+	/* core git does not do this on a reinit, but it is a property of
+	 * the filesystem, so I think we should...
+	 */
+	if (!(flags & GIT_REPOSITORY_INIT__IS_REINIT) &&
+		is_filesystem_case_insensitive(repo_dir))
+		SET_REPO_CONFIG(bool, "core.ignorecase", true);
+
 	if (!is_bare) {
 		SET_REPO_CONFIG(bool, "core.logallrefupdates", true);
 
-		if (!(opts->flags & GIT_REPOSITORY_INIT__NATURAL_WD)) {
+		if (!(flags & GIT_REPOSITORY_INIT__NATURAL_WD)) {
 			SET_REPO_CONFIG(string, "core.worktree", work_dir);
 		}
-		else if ((opts->flags & GIT_REPOSITORY_INIT__IS_REINIT) != 0) {
+		else if ((flags & GIT_REPOSITORY_INIT__IS_REINIT) != 0) {
 			if (git_config_delete_entry(config, "core.worktree") < 0)
 				giterr_clear();
 		}
 	}
 
-	if (!(opts->flags & GIT_REPOSITORY_INIT__IS_REINIT) &&
-		is_filesystem_case_insensitive(repo_dir))
-		SET_REPO_CONFIG(bool, "core.ignorecase", true);
-
-	if (opts->mode == GIT_REPOSITORY_INIT_SHARED_GROUP) {
+	if (mode == GIT_REPOSITORY_INIT_SHARED_GROUP) {
 		SET_REPO_CONFIG(int32, "core.sharedrepository", 1);
 		SET_REPO_CONFIG(bool, "receive.denyNonFastforwards", true);
 	}
-	else if (opts->mode == GIT_REPOSITORY_INIT_SHARED_ALL) {
+	else if (mode == GIT_REPOSITORY_INIT_SHARED_ALL) {
 		SET_REPO_CONFIG(int32, "core.sharedrepository", 2);
 		SET_REPO_CONFIG(bool, "receive.denyNonFastforwards", true);
 	}
 
 cleanup:
-	git_buf_free(&cfg_path);
+	git_buf_free(&buf);
 	git_config_free(config);
 
 	return error;
 }
 
+int git_repository_reset_filesystem(git_repository *repo)
+{
+	int error = 0;
+	uint32_t flags = 0;
+	const char *repo_dir, *work_dir;
+	git_config *cfg;
+
+	assert(repo);
+
+	repo_dir = git_repository_path(repo);
+	work_dir = git_repository_workdir(repo);
+
+	if (git_repository_is_bare(repo))
+		flags |= GIT_REPOSITORY_INIT_BARE;
+	else if (!git__prefixcmp(repo_dir, work_dir) &&
+		!strcmp(repo_dir + strlen(work_dir), DOT_GIT "/"))
+		flags |= GIT_REPOSITORY_INIT__NATURAL_WD;
+
+	if ((error = git_repository_config(&cfg, repo)) < 0)
+		return error;
+
+	error = repo_init_config(cfg, repo_dir, work_dir, flags, 0);
+
+	git_config_free(cfg);
+	git_repository__cvar_cache_clear(repo);
+
+	return error;
+}
+
 static int repo_write_template(
 	const char *git_dir,
 	bool allow_overwrite,
@@ -1429,22 +1473,22 @@ int git_repository_init_ext(
 		opts->flags |= GIT_REPOSITORY_INIT__IS_REINIT;
 
 		error = repo_init_config(
-			git_buf_cstr(&repo_path), git_buf_cstr(&wd_path), opts);
+			NULL, repo_path.ptr, wd_path.ptr, opts->flags, opts->mode);
 
 		/* TODO: reinitialize the templates */
 	}
 	else {
 		if (!(error = repo_init_structure(
-				git_buf_cstr(&repo_path), git_buf_cstr(&wd_path), opts)) &&
+				repo_path.ptr, wd_path.ptr, opts)) &&
 			!(error = repo_init_config(
-				git_buf_cstr(&repo_path), git_buf_cstr(&wd_path), opts)))
+				NULL, repo_path.ptr, wd_path.ptr, opts->flags, opts->mode)))
 			error = repo_init_create_head(
-				git_buf_cstr(&repo_path), opts->initial_head);
+				repo_path.ptr, opts->initial_head);
 	}
 	if (error < 0)
 		goto cleanup;
 
-	error = git_repository_open(out, git_buf_cstr(&repo_path));
+	error = git_repository_open(out, repo_path.ptr);
 
 	if (!error && opts->origin_url)
 		error = repo_init_create_origin(*out, opts->origin_url);
diff --git a/tests-clar/clar_libgit2.c b/tests-clar/clar_libgit2.c
index 0f8f26efb..c3abc1f95 100644
--- a/tests-clar/clar_libgit2.c
+++ b/tests-clar/clar_libgit2.c
@@ -190,6 +190,9 @@ git_repository *cl_git_sandbox_init(const char *sandbox)
 	/* Now open the sandbox repository and make it available for tests */
 	cl_git_pass(git_repository_open(&_cl_repo, sandbox));
 
+	/* Adjust configs after copying to new filesystem */
+	cl_git_pass(git_repository_reset_filesystem(_cl_repo));
+
 	return _cl_repo;
 }
 
diff --git a/tests-clar/diff/diff_helpers.c b/tests-clar/diff/diff_helpers.c
index a5c322b4d..3452f231d 100644
--- a/tests-clar/diff/diff_helpers.c
+++ b/tests-clar/diff/diff_helpers.c
@@ -21,6 +21,35 @@ git_tree *resolve_commit_oid_to_tree(
 	return tree;
 }
 
+static char diff_pick_suffix(int mode)
+{
+	if (S_ISDIR(mode))
+		return '/';
+	else if (GIT_PERMS_IS_EXEC(mode))
+		return '*';
+	else
+		return ' ';
+}
+
+static void fprintf_delta(FILE *fp, const git_diff_delta *delta, float progress)
+{
+	char code = git_diff_status_char(delta->status);
+	char old_suffix = diff_pick_suffix(delta->old_file.mode);
+	char new_suffix = diff_pick_suffix(delta->new_file.mode);
+
+	fprintf(fp, "%c\t%s", code, delta->old_file.path);
+
+	if ((delta->old_file.path != delta->new_file.path &&
+		 strcmp(delta->old_file.path, delta->new_file.path) != 0) ||
+		(delta->old_file.mode != delta->new_file.mode &&
+		 delta->old_file.mode != 0 && delta->new_file.mode != 0))
+		fprintf(fp, "%c %s%c", old_suffix, delta->new_file.path, new_suffix);
+	else if (old_suffix != ' ')
+		fprintf(fp, "%c", old_suffix);
+
+	fprintf(fp, "\t[%.2f]\n", progress);
+}
+
 int diff_file_cb(
 	const git_diff_delta *delta,
 	float progress,
@@ -29,9 +58,7 @@ int diff_file_cb(
 	diff_expects *e = payload;
 
 	if (e->debug)
-		fprintf(stderr, "%c %s (%.3f)\n",
-			git_diff_status_char(delta->status),
-			delta->old_file.path, progress);
+		fprintf_delta(stderr, delta, progress);
 
 	if (e->names)
 		cl_assert_equal_s(e->names[e->files], delta->old_file.path);
@@ -55,8 +82,14 @@ int diff_print_file_cb(
 	float progress,
 	void *payload)
 {
-	fprintf(stderr, "%c %s\n",
-		git_diff_status_char(delta->status), delta->old_file.path);
+	if (!payload) {
+		fprintf_delta(stderr, delta, progress);
+		return 0;
+	}
+
+	if (!((diff_expects *)payload)->debug)
+		fprintf_delta(stderr, delta, progress);
+
 	return diff_file_cb(delta, progress, payload);
 }
 
diff --git a/tests-clar/diff/diffiter.c b/tests-clar/diff/diffiter.c
index 932d720f2..ea5908475 100644
--- a/tests-clar/diff/diffiter.c
+++ b/tests-clar/diff/diffiter.c
@@ -27,25 +27,25 @@ void test_diff_diffiter__create(void)
 	git_diff_list_free(diff);
 }
 
-void test_diff_diffiter__iterate_files(void)
+void test_diff_diffiter__iterate_files_1(void)
 {
 	git_repository *repo = cl_git_sandbox_init("attr");
 	git_diff_list *diff;
 	size_t d, num_d;
-	int count = 0;
+	diff_expects exp = { 0 };
 
 	cl_git_pass(git_diff_index_to_workdir(&diff, repo, NULL, NULL));
 
 	num_d = git_diff_num_deltas(diff);
-	cl_assert_equal_i(6, (int)num_d);
 
 	for (d = 0; d < num_d; ++d) {
 		const git_diff_delta *delta;
 		cl_git_pass(git_diff_get_patch(NULL, &delta, diff, d));
 		cl_assert(delta != NULL);
-		count++;
+
+		diff_file_cb(delta, (float)d / (float)num_d, &exp);
 	}
-	cl_assert_equal_i(6, count);
+	cl_assert_equal_sz(6, exp.files);
 
 	git_diff_list_free(diff);
 }
diff --git a/tests-clar/diff/drivers.c b/tests-clar/diff/drivers.c
index e02dd5c68..719d229fc 100644
--- a/tests-clar/diff/drivers.c
+++ b/tests-clar/diff/drivers.c
@@ -147,6 +147,13 @@ void test_diff_drivers__long_lines(void)
 	cl_git_pass(git_diff_get_patch(&patch, NULL, diff, 0));
 	cl_git_pass(git_diff_patch_to_str(&actual, patch));
 
+	/* if chmod not supported, overwrite mode bits since anything is possible */
+	if (!cl_is_chmod_supported()) {
+		size_t actual_len = strlen(actual);
+		if (actual_len > 72 && memcmp(&actual[66], "100644", 6) != 0)
+			memcpy(&actual[66], "100644", 6);
+	}
+
 	cl_assert_equal_s(expected, actual);
 
 	free(actual);
diff --git a/tests-clar/diff/patch.c b/tests-clar/diff/patch.c
index 6a33fa990..7aab8f409 100644
--- a/tests-clar/diff/patch.c
+++ b/tests-clar/diff/patch.c
@@ -238,6 +238,9 @@ void test_diff_patch__hunks_have_correct_line_numbers(void)
 
 	cl_git_pass(git_config_new(&cfg));
 	git_repository_set_config(g_repo, cfg);
+	git_config_free(cfg);
+
+	git_repository_reset_filesystem(g_repo);
 
 	cl_git_pass(
 		git_futils_readbuffer(&old_content, "renames/songof7cities.txt"));
@@ -408,7 +411,6 @@ void test_diff_patch__hunks_have_correct_line_numbers(void)
 	git_buf_free(&actual);
 	git_buf_free(&old_content);
 	git_tree_free(head);
-	git_config_free(cfg);
 }
 
 static void check_single_patch_stats(
@@ -520,6 +522,9 @@ void test_diff_patch__line_counts_with_eofnl(void)
 
 	cl_git_pass(git_config_new(&cfg));
 	git_repository_set_config(g_repo, cfg);
+	git_config_free(cfg);
+
+	git_repository_reset_filesystem(g_repo);
 
 	cl_git_pass(git_futils_readbuffer(&content, "renames/songof7cities.txt"));
 
@@ -574,5 +579,4 @@ void test_diff_patch__line_counts_with_eofnl(void)
 		g_repo, 1, 1, 1, 6, expected_sizes, expected);
 
 	git_buf_free(&content);
-	git_config_free(cfg);
 }
diff --git a/tests-clar/index/filemodes.c b/tests-clar/index/filemodes.c
index 02f83efba..8cbd6ff3a 100644
--- a/tests-clar/index/filemodes.c
+++ b/tests-clar/index/filemodes.c
@@ -51,18 +51,24 @@ static void replace_file_with_mode(
 	git_buf_free(&content);
 }
 
-static void add_and_check_mode(
-	git_index *index, const char *filename, unsigned int expect_mode)
+#define add_and_check_mode(I,F,X) add_and_check_mode_(I,F,X,__FILE__,__LINE__)
+
+static void add_and_check_mode_(
+	git_index *index, const char *filename, unsigned int expect_mode,
+	const char *file, int line)
 {
 	size_t pos;
 	const git_index_entry *entry;
 
 	cl_git_pass(git_index_add_bypath(index, filename));
 
-	cl_assert(!git_index_find(&pos, index, filename));
+	clar__assert(!git_index_find(&pos, index, filename),
+		file, line, "Cannot find index entry", NULL, 1);
 
 	entry = git_index_get_byindex(index, pos);
-	cl_assert(entry->mode == expect_mode);
+
+	clar__assert_equal(file, line, "Expected mode does not match index",
+		1, "%07o", (unsigned int)entry->mode, (unsigned int)expect_mode);
 }
 
 void test_index_filemodes__untrusted(void)
@@ -91,16 +97,16 @@ void test_index_filemodes__untrusted(void)
 	replace_file_with_mode("exec_on", "filemodes/exec_on.1", 0755);
 	add_and_check_mode(index, "exec_on", GIT_FILEMODE_BLOB_EXECUTABLE);
 
-	/*  5 - add new 0644 -> expect 0644 */
-	cl_git_write2file("filemodes/new_off", "blah", 0,
-		O_WRONLY | O_CREAT | O_TRUNC, 0644);
-	add_and_check_mode(index, "new_off", GIT_FILEMODE_BLOB);
-
-	/* this test won't give predictable results on a platform
-	 * that doesn't support filemodes correctly, so skip it.
+	/* these tests of newly added files won't give predictable results on
+	 * filesystems without actual filemode support, so skip them.
 	 */
 	if (can_filemode) {
-		/* 6 - add 0755 -> expect 0755 */
+		/*  5 - add new 0644 -> expect 0644 */
+		cl_git_write2file("filemodes/new_off", "blah", 0,
+			O_WRONLY | O_CREAT | O_TRUNC, 0644);
+		add_and_check_mode(index, "new_off", GIT_FILEMODE_BLOB);
+
+		/* 6 - add new 0755 -> expect 0755 */
 		cl_git_write2file("filemodes/new_on", "blah", 0,
 			O_WRONLY | O_CREAT | O_TRUNC, 0755);
 		add_and_check_mode(index, "new_on", GIT_FILEMODE_BLOB_EXECUTABLE);