Fix submodule accounting for name and path changes

Wrote tests that try adding, removing, and updating the name of
submodules which showed a number of problems with how we account
for changes when incrementally updating the submodule info.  Most
of these issues didn't exist before because reloading would always
blow away the old submodule data.

2 files changed, 107 insertions, 10 deletions

diff --git a/src/submodule.c b/src/submodule.c
index 5061cadc6..913c97a87 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -1345,8 +1345,9 @@ static int submodule_load_from_config(
 	const git_config_entry *entry, void *payload)
 {
 	git_submodule_cache *cache = payload;
-	const char *namestart, *property, *alternate = NULL;
+	const char *namestart, *property;
 	const char *key = entry->name, *value = entry->value, *path;
+	char *alternate = NULL, *replaced = NULL;
 	git_buf name = GIT_BUF_INIT;
 	git_submodule *sm = NULL;
 	int error = 0;
@@ -1377,17 +1378,39 @@ static int submodule_load_from_config(
 	 * should be strcasecmp
 	 */
 
-	if (strcmp(sm->name, name.ptr) != 0) {
-		alternate = sm->name = git_buf_detach(&name);
-	} else if (path && strcmp(path, sm->path) != 0) {
-		alternate = sm->path = git__strdup(value);
-		if (!sm->path) {
-			error = -1;
-			goto done;
+	if (strcmp(sm->name, name.ptr) != 0) { /* name changed */
+		if (!strcmp(sm->path, name.ptr)) { /* already set as path */
+			replaced = sm->name;
+			sm->name = sm->path;
+		} else {
+			if (sm->name != sm->path)
+				replaced = sm->name;
+			alternate = sm->name = git_buf_detach(&name);
+		}
+	}
+	else if (path && strcmp(path, sm->path) != 0) { /* path changed */
+		if (!strcmp(sm->name, value)) { /* already set as name */
+			replaced = sm->path;
+			sm->path = sm->name;
+		} else {
+			if (sm->path != sm->name)
+				replaced = sm->path;
+			if ((alternate = git__strdup(value)) == NULL) {
+				error = -1;
+				goto done;
+			}
+			sm->path = alternate;
 		}
 	}
 
-	/* Found a alternate key for the submodule */
+	/* Deregister under name being replaced */
+	if (replaced) {
+		git_strmap_delete(cache->submodules, replaced);
+		git_submodule_free(sm);
+		git__free(replaced);
+	}
+
+	/* Insert under alternate key */
 	if (alternate) {
 		void *old_sm = NULL;
 		git_strmap_insert2(cache->submodules, alternate, sm, old_sm, error);
@@ -1684,6 +1707,8 @@ static int submodule_cache_refresh(git_submodule_cache *cache, int refresh)
 			GIT_SUBMODULE_STATUS__WD_SCANNED |
 			GIT_SUBMODULE_STATUS__WD_FLAGS |
 			GIT_SUBMODULE_STATUS__WD_OID_VALID;
+	else
+		goto cleanup; /* nothing to do */
 
 	submodule_cache_clear_flags(cache, mask);
 
@@ -1726,7 +1751,12 @@ static int submodule_cache_refresh(git_submodule_cache *cache, int refresh)
 	/* remove submodules that no longer exist */
 
 	git_strmap_foreach_value(cache->submodules, sm, {
-		if (sm && (sm->flags & GIT_SUBMODULE_STATUS__IN_FLAGS) == 0)
+		/* purge unless in HEAD, index, or .gitmodules; no sm for wd only */
+		if (sm != NULL &&
+			!(sm->flags &
+			 (GIT_SUBMODULE_STATUS_IN_HEAD |
+			  GIT_SUBMODULE_STATUS_IN_INDEX |
+			  GIT_SUBMODULE_STATUS_IN_CONFIG)))
 			submodule_cache_remove_item(cache, sm, true);
 	});
 
diff --git a/tests/submodule/nosubs.c b/tests/submodule/nosubs.c
index 5ef4f42ab..cabb53ead 100644
--- a/tests/submodule/nosubs.c
+++ b/tests/submodule/nosubs.c
@@ -2,6 +2,7 @@
 
 #include "clar_libgit2.h"
 #include "posix.h"
+#include "fileops.h"
 
 void test_submodule_nosubs__cleanup(void)
 {
@@ -93,3 +94,69 @@ void test_submodule_nosubs__bad_gitmodules(void)
 	cl_git_pass(git_submodule_lookup(NULL, repo, "foobar"));
 	cl_assert_equal_i(GIT_ENOTFOUND, git_submodule_lookup(NULL, repo, "subdir"));
 }
+
+void test_submodule_nosubs__add_and_delete(void)
+{
+	git_repository *repo = cl_git_sandbox_init("status");
+	git_submodule *sm;
+	git_buf buf = GIT_BUF_INIT;
+
+	/* note the lack of calls to git_submodule_reload - this *should* work */
+
+	cl_git_fail(git_submodule_lookup(NULL, repo, "libgit2"));
+	cl_git_fail(git_submodule_lookup(NULL, repo, "submodules/libgit2"));
+
+	/* create */
+
+	cl_git_pass(git_submodule_add_setup(
+		&sm, repo, "https://github.com/libgit2/libgit2.git", "submodules/libgit2", 1));
+	cl_assert_equal_s("submodules/libgit2", git_submodule_name(sm));
+	cl_assert_equal_s("submodules/libgit2", git_submodule_path(sm));
+	git_submodule_free(sm);
+
+	cl_git_pass(git_futils_readbuffer(&buf, "status/.gitmodules"));
+	cl_assert(strstr(buf.ptr, "[submodule \"submodules/libgit2\"]") != NULL);
+	cl_assert(strstr(buf.ptr, "path = submodules/libgit2") != NULL);
+	git_buf_free(&buf);
+
+	/* lookup */
+
+	cl_git_fail(git_submodule_lookup(&sm, repo, "libgit2"));
+	cl_git_pass(git_submodule_lookup(&sm, repo, "submodules/libgit2"));
+	cl_assert_equal_s("submodules/libgit2", git_submodule_name(sm));
+	cl_assert_equal_s("submodules/libgit2", git_submodule_path(sm));
+	git_submodule_free(sm);
+
+	/* update name */
+
+	cl_git_rewritefile(
+		"status/.gitmodules",
+		"[submodule \"libgit2\"]\n"
+		"  path = submodules/libgit2\n"
+		"  url = https://github.com/libgit2/libgit2.git\n");
+
+	cl_git_pass(git_submodule_lookup(&sm, repo, "libgit2"));
+	cl_assert_equal_s("libgit2", git_submodule_name(sm));
+	cl_assert_equal_s("submodules/libgit2", git_submodule_path(sm));
+	git_submodule_free(sm);
+	cl_git_pass(git_submodule_lookup(&sm, repo, "submodules/libgit2"));
+	git_submodule_free(sm);
+
+	/* revert name update */
+
+	cl_git_rewritefile(
+		"status/.gitmodules",
+		"[submodule \"submodules/libgit2\"]\n"
+		"  path = submodules/libgit2\n"
+		"  url = https://github.com/libgit2/libgit2.git\n");
+
+	cl_git_fail(git_submodule_lookup(&sm, repo, "libgit2"));
+	cl_git_pass(git_submodule_lookup(&sm, repo, "submodules/libgit2"));
+	git_submodule_free(sm);
+
+	/* remove completely */
+
+	cl_must_pass(p_unlink("status/.gitmodules"));
+	cl_git_fail(git_submodule_lookup(&sm, repo, "libgit2"));
+	cl_git_fail(git_submodule_lookup(&sm, repo, "submodules/libgit2"));
+}