submodule-config: pass repo upon blob config read

When reading the config of a submodule, if reading from a blob, read
using an explicitly specified repository instead of by adding the
submodule's ODB as an alternate and then reading an object from
the_repository.

This makes the "grep --recurse-submodules with submodules without
.gitmodules in the working tree" test in t7814 work when
GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB is true.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Reviewed-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 19 insertions, 9 deletions

diff --git a/config.c b/config.c
index f33abea..f401c1d 100644
--- a/config.c
+++ b/config.c
@@ -1796,6 +1796,7 @@ int git_config_from_mem(config_fn_t fn,
 
 int git_config_from_blob_oid(config_fn_t fn,
 			      const char *name,
+			      struct repository *repo,
 			      const struct object_id *oid,
 			      void *data)
 {
@@ -1804,7 +1805,7 @@ int git_config_from_blob_oid(config_fn_t fn,
 	unsigned long size;
 	int ret;
 
-	buf = read_object_file(oid, &type, &size);
+	buf = repo_read_object_file(repo, oid, &type, &size);
 	if (!buf)
 		return error(_("unable to load config blob object '%s'"), name);
 	if (type != OBJ_BLOB) {
@@ -1820,14 +1821,15 @@ int git_config_from_blob_oid(config_fn_t fn,
 }
 
 static int git_config_from_blob_ref(config_fn_t fn,
+				    struct repository *repo,
 				    const char *name,
 				    void *data)
 {
 	struct object_id oid;
 
-	if (get_oid(name, &oid) < 0)
+	if (repo_get_oid(repo, name, &oid) < 0)
 		return error(_("unable to resolve config blob '%s'"), name);
-	return git_config_from_blob_oid(fn, name, &oid, data);
+	return git_config_from_blob_oid(fn, name, repo, &oid, data);
 }
 
 char *git_system_config(void)
@@ -1958,12 +1960,16 @@ int config_with_options(config_fn_t fn, void *data,
 	 * If we have a specific filename, use it. Otherwise, follow the
 	 * regular lookup sequence.
 	 */
-	if (config_source && config_source->use_stdin)
+	if (config_source && config_source->use_stdin) {
 		return git_config_from_stdin(fn, data);
-	else if (config_source && config_source->file)
+	} else if (config_source && config_source->file) {
 		return git_config_from_file(fn, config_source->file, data);
-	else if (config_source && config_source->blob)
-		return git_config_from_blob_ref(fn, config_source->blob, data);
+	} else if (config_source && config_source->blob) {
+		struct repository *repo = config_source->repo ?
+			config_source->repo : the_repository;
+		return git_config_from_blob_ref(fn, repo, config_source->blob,
+						data);
+	}
 
 	return do_git_config_sequence(opts, fn, data);
 }
diff --git a/config.h b/config.h
index a2200f3..147f5e0 100644
--- a/config.h
+++ b/config.h
@@ -49,6 +49,8 @@ const char *config_scope_name(enum config_scope scope);
 struct git_config_source {
 	unsigned int use_stdin:1;
 	const char *file;
+	/* The repository if blob is not NULL; leave blank for the_repository */
+	struct repository *repo;
 	const char *blob;
 	enum config_scope scope;
 };
@@ -136,6 +138,7 @@ int git_config_from_mem(config_fn_t fn,
 			const char *buf, size_t len,
 			void *data, const struct config_options *opts);
 int git_config_from_blob_oid(config_fn_t fn, const char *name,
+			     struct repository *repo,
 			     const struct object_id *oid, void *data);
 void git_config_push_parameter(const char *text);
 void git_config_push_env(const char *spec);
diff --git a/submodule-config.c b/submodule-config.c
index 2026120..f953440 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -649,9 +649,10 @@ static void config_from_gitmodules(config_fn_t fn, struct repository *repo, void
 			config_source.file = file;
 		} else if (repo_get_oid(repo, GITMODULES_INDEX, &oid) >= 0 ||
 			   repo_get_oid(repo, GITMODULES_HEAD, &oid) >= 0) {
+			config_source.repo = repo;
 			config_source.blob = oidstr = xstrdup(oid_to_hex(&oid));
 			if (repo != the_repository)
-				add_to_alternates_memory(repo->objects->odb->path);
+				add_submodule_odb_by_path(repo->objects->odb->path);
 		} else {
 			goto out;
 		}
@@ -702,7 +703,7 @@ void gitmodules_config_oid(const struct object_id *commit_oid)
 
 	if (gitmodule_oid_from_commit(commit_oid, &oid, &rev)) {
 		git_config_from_blob_oid(gitmodules_cb, rev.buf,
-					 &oid, the_repository);
+					 the_repository, &oid, the_repository);
 	}
 	strbuf_release(&rev);