Merge branch 'bw/submodule-config-cleanup'

Code clean-up to avoid mixing values read from the .gitmodules file
and values read from the .git/config file.

* bw/submodule-config-cleanup:
  submodule: remove gitmodules_config
  unpack-trees: improve loading of .gitmodules
  submodule-config: lazy-load a repository's .gitmodules file
  submodule-config: move submodule-config functions to submodule-config.c
  submodule-config: remove support for overlaying repository config
  diff: stop allowing diff to have submodules configured in .git/config
  submodule: remove submodule_config callback routine
  unpack-trees: don't respect submodule.update
  submodule: don't rely on overlayed config when setting diffopts
  fetch: don't overlay config with submodule-config
  submodule--helper: don't overlay config in update-clone
  submodule--helper: don't overlay config in remote_submodule_branch
  add, reset: ensure submodules can be added or reset
  submodule: don't use submodule_from_name
  t7411: check configuration parsing errors

submodule-config.c

@@ -18,6 +18,7 @@ struct submodule_cache {
 	struct hashmap for_path;
 	struct hashmap for_name;
 	unsigned initialized:1;
+	unsigned gitmodules_read:1;
 };
 
 /*
@@ -99,6 +100,7 @@ static void submodule_cache_clear(struct submodule_cache *cache)
 	hashmap_free(&cache->for_path, 1);
 	hashmap_free(&cache->for_name, 1);
 	cache->initialized = 0;
+	cache->gitmodules_read = 0;
 }
 
 void submodule_cache_free(struct submodule_cache *cache)
@@ -455,9 +457,9 @@ static int parse_config(const char *var, const char *value, void *data)
 	return ret;
 }
 
-int gitmodule_oid_from_commit(const struct object_id *treeish_name,
-				      struct object_id *gitmodules_oid,
-				      struct strbuf *rev)
+static int gitmodule_oid_from_commit(const struct object_id *treeish_name,
+				     struct object_id *gitmodules_oid,
+				     struct strbuf *rev)
 {
 	int ret = 0;
 
@@ -558,13 +560,11 @@ static void submodule_cache_check_init(struct repository *repo)
 	submodule_cache_init(repo->submodule_cache);
 }
 
-int submodule_config_option(struct repository *repo,
-			    const char *var, const char *value)
+static int gitmodules_cb(const char *var, const char *value, void *data)
 {
+	struct repository *repo = data;
 	struct parse_config_parameter parameter;
 
-	submodule_cache_check_init(repo);
-
 	parameter.cache = repo->submodule_cache;
 	parameter.treeish_name = NULL;
 	parameter.gitmodules_sha1 = null_sha1;
@@ -573,22 +573,63 @@ int submodule_config_option(struct repository *repo,
 	return parse_config(var, value, &parameter);
 }
 
-int parse_submodule_config_option(const char *var, const char *value)
+void repo_read_gitmodules(struct repository *repo)
 {
-	return submodule_config_option(the_repository, var, value);
+	submodule_cache_check_init(repo);
+
+	if (repo->worktree) {
+		char *gitmodules;
+
+		if (repo_read_index(repo) < 0)
+			return;
+
+		gitmodules = repo_worktree_path(repo, GITMODULES_FILE);
+
+		if (!is_gitmodules_unmerged(repo->index))
+			git_config_from_file(gitmodules_cb, gitmodules, repo);
+
+		free(gitmodules);
+	}
+
+	repo->submodule_cache->gitmodules_read = 1;
+}
+
+void gitmodules_config_oid(const struct object_id *commit_oid)
+{
+	struct strbuf rev = STRBUF_INIT;
+	struct object_id oid;
+
+	submodule_cache_check_init(the_repository);
+
+	if (gitmodule_oid_from_commit(commit_oid, &oid, &rev)) {
+		git_config_from_blob_oid(gitmodules_cb, rev.buf,
+					 &oid, the_repository);
+	}
+	strbuf_release(&rev);
+
+	the_repository->submodule_cache->gitmodules_read = 1;
+}
+
+static void gitmodules_read_check(struct repository *repo)
+{
+	submodule_cache_check_init(repo);
+
+	/* read the repo's .gitmodules file if it hasn't been already */
+	if (!repo->submodule_cache->gitmodules_read)
+		repo_read_gitmodules(repo);
 }
 
 const struct submodule *submodule_from_name(const struct object_id *treeish_name,
 		const char *name)
 {
-	submodule_cache_check_init(the_repository);
+	gitmodules_read_check(the_repository);
 	return config_from(the_repository->submodule_cache, treeish_name, name, lookup_name);
 }
 
 const struct submodule *submodule_from_path(const struct object_id *treeish_name,
 		const char *path)
 {
-	submodule_cache_check_init(the_repository);
+	gitmodules_read_check(the_repository);
 	return config_from(the_repository->submodule_cache, treeish_name, path, lookup_path);
 }
 
@@ -596,7 +637,7 @@ const struct submodule *submodule_from_cache(struct repository *repo,
 					     const struct object_id *treeish_name,
 					     const char *key)
 {
-	submodule_cache_check_init(repo);
+	gitmodules_read_check(repo);
 	return config_from(repo->submodule_cache, treeish_name,
 			   key, lookup_path);
 }