[PATCH 11/11] setup: allow "git init --ref-storage=" to specify a payload

@@ -58,7 +58,10 @@ values are `sha1` and (if enabled) `sha256`.  `sha1` is the default.
 include::object-format-disclaimer.adoc[]
 
 `--ref-storage=<format>`::
-Specify the given ref storage _<format>_ for the repository. The valid values are:
+Specify the given ref storage _<format>_ for the repository. Backends that
+require additional configuration accept a payload in the form
+`<format>://<payload>`, for example a connection string identifying the
+database that shall store the references. The valid values are:
 +
 include::ref-storage-format.adoc[]
 

@@ -1,8 +1,12 @@
-`files`;; for loose files with packed-refs.
+`files[://<path>]`;; for loose files with packed-refs. The optional payload can
+be specified to change the root directory where references are created. A
+relative path will be resolved relative to the repository's common directory.
 ifndef::with-breaking-changes[]
 	This is the default.
 endif::with-breaking-changes[]
-`reftable`;; for the reftable format.
+`reftable[://<path>]`;; for the reftable format. The optional payload can
+be specified to change the root directory where references are created. A
+relative path will be resolved relative to the repository's common directory.
 ifdef::with-breaking-changes[]
 	This is the default.
 endif::with-breaking-changes[]

@@ -1030,7 +1030,7 @@ int cmd_clone(int argc,
 		option_single_branch = deepen ? 1 : 0;
 
 	if (ref_storage) {
-		ref_storage_format = ref_storage_format_by_name(ref_storage);
+		ref_storage_format = ref_storage_format_by_uri(ref_storage, NULL);
 		if (ref_storage_format == REF_STORAGE_FORMAT_UNKNOWN)
 			die(_("unknown ref storage format '%s'"), ref_storage);
 	}

@@ -1188,7 +1188,7 @@ int cmd_clone(int argc,
 	 * their on-disk data structures.
 	 */
 	init_db(the_repository, git_dir, real_git_dir, work_tree, option_template,
-		GIT_HASH_UNKNOWN, ref_storage_format, NULL,
+		GIT_HASH_UNKNOWN, ref_storage, NULL,
 		do_not_override_repo_unix_permissions,
 		INIT_DB_QUIET | INIT_DB_SKIP_REFDB);
 

@@ -86,7 +86,6 @@ int cmd_init_db(int argc,
 	const char *ref_storage = NULL;
 	const char *initial_branch = NULL;
 	int hash_algo = GIT_HASH_UNKNOWN;
-	enum ref_storage_format ref_storage_format = REF_STORAGE_FORMAT_UNKNOWN;
 	int init_shared_repository = -1;
 	const struct option init_db_options[] = {
 		OPT_STRING(0, "template", &template_dir, N_("template-directory"),

@@ -175,12 +174,6 @@ int cmd_init_db(int argc,
 			die(_("unknown hash algorithm '%s'"), object_format);
 	}
 
-	if (ref_storage) {
-		ref_storage_format = ref_storage_format_by_name(ref_storage);
-		if (ref_storage_format == REF_STORAGE_FORMAT_UNKNOWN)
-			die(_("unknown ref storage format '%s'"), ref_storage);
-	}
-
 	if (init_shared_repository != -1)
 		repo_settings_set_shared_repository(the_repository, init_shared_repository);
 

@@ -251,7 +244,7 @@ int cmd_init_db(int argc,
 
 	flags |= INIT_DB_EXIST_OK;
 	ret = init_db(the_repository, git_dir, real_git_dir, work_tree,
-		      template_dir, hash_algo, ref_storage_format, initial_branch,
+		      template_dir, hash_algo, ref_storage, initial_branch,
 		      init_shared_repository, flags);
 
 	free(template_dir_to_free);

@@ -2727,7 +2727,7 @@ static int read_default_format_config(const char *key, const char *value,
 }
 
 static void repository_format_configure(struct repository_format *repo_fmt,
-					int hash, enum ref_storage_format ref_storage_format)
+					int hash, const char *ref_storage_uri)
 {
 	struct default_format_config cfg = {
 		.hash = GIT_HASH_UNKNOWN,

@@ -2738,6 +2738,7 @@ static void repository_format_configure(struct repository_format *repo_fmt,
 		.ignore_repo = 1,
 		.ignore_worktree = 1,
 	};
+	enum ref_storage_format ref_storage_format;
 	char *ref_storage_payload = NULL;
 	const char *env;
 

@@ -2788,8 +2789,11 @@ static void repository_format_configure(struct repository_format *repo_fmt,
 	 *   6. Otherwise, we fall back to the default ref storage format
 	 *      compiled into Git.
 	 */
-	if (ref_storage_format != REF_STORAGE_FORMAT_UNKNOWN) {
-		/* nothing to do */
+	if (ref_storage_uri) {
+		ref_storage_format = ref_storage_format_by_uri(ref_storage_uri, &ref_storage_payload);
+		if (ref_storage_format == REF_STORAGE_FORMAT_UNKNOWN)
+			die(_("unknown reference storage format specified via command line: '%s'"),
+			    ref_storage_uri);
 	} else if (((env = getenv(GIT_REF_STORAGE_ENVIRONMENT)) ||
 		    (env = getenv(GIT_REFERENCE_BACKEND_ENVIRONMENT)))) {
 		ref_storage_format = ref_storage_format_by_uri(env, &ref_storage_payload);

@@ -2834,7 +2838,7 @@ int init_db(struct repository *repo,
 	    const char *real_git_dir,
 	    const char *worktree,
 	    const char *template_dir, int hash,
-	    enum ref_storage_format ref_storage_format,
+	    const char *ref_storage_uri,
 	    const char *initial_branch,
 	    int init_shared_repository, unsigned int flags)
 {

@@ -2871,7 +2875,7 @@ int init_db(struct repository *repo,
 	 * is an attempt to reinitialize new repository with an old tool.
 	 */
 	read_and_verify_repository_format(&repo_fmt, repo_get_git_dir(repo), NULL);
-	repository_format_configure(&repo_fmt, hash, ref_storage_format);
+	repository_format_configure(&repo_fmt, hash, ref_storage_uri);
 	if (apply_repository_format(repo, &repo_fmt, APPLY_REPOSITORY_FORMAT_HONOR_ENV, &err) < 0)
 		die("%s", err.buf);
 

@@ -265,7 +265,7 @@ int init_db(struct repository *repo,
 	    const char *real_git_dir,
 	    const char *worktree,
 	    const char *template_dir, int hash_algo,
-	    enum ref_storage_format ref_storage_format,
+	    const char *ref_storage_uri,
 	    const char *initial_branch, int init_shared_repository,
 	    unsigned int flags);
 void initialize_repository_version(struct repository *repo,

@@ -833,7 +833,7 @@ done
 test_expect_success 'init with --ref-storage=garbage' '
 	test_when_finished "rm -rf refformat" &&
 	cat >expect <<-EOF &&
-	fatal: unknown ref storage format ${SQ}garbage${SQ}
+	fatal: unknown reference storage format specified via command line: ${SQ}garbage${SQ}
 	EOF
 	test_must_fail git init --ref-storage=garbage refformat 2>err &&
 	test_cmp expect err

@@ -254,6 +254,36 @@ test_expect_success 'initializing repository with alt ref directory' '
 	)
 '
 
+test_expect_success 'initializing repository with --ref-storage and payload' '
+	test_when_finished "rm -rf repo refdir" &&
+	mkdir refdir &&
+	BACKEND="$(test_detect_ref_format)://$(pwd)/refdir" &&
+	git init --ref-storage="$BACKEND" repo &&
+	verify_files_exist repo/.git refdir &&
+
+	git -C repo config get extensions.refstorage >actual &&
+	echo $BACKEND >expect &&
+	test_cmp expect actual &&
+
+	test_commit -C repo 1 &&
+	git -C repo refs list >out &&
+	test_grep "refs/tags/1" out &&
+
+	# Reinitializing the repository is fine when not specifying any format.
+	git -C repo init &&
+	# Reinitializing with the same backend is fine, too.
+	git -C repo init --ref-storage="$BACKEND" &&
+	# Reinitializing without a payload should fail.
+	test_must_fail git -C repo init --ref-storage="$(test_detect_ref_format)" 2>err &&
+	test_grep "attempt to reinitialize repository with different reference storage payload" err &&
+	# Reinitializing with a different payload should fail, too.
+	test_must_fail git -C repo init --ref-storage="$(test_detect_ref_format)://$(pwd)/other" 2>err &&
+	test_grep "attempt to reinitialize repository with different reference storage payload" err &&
+
+	git -C repo config get extensions.refstorage >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'cloning repository with alt ref directory' '
 	test_when_finished "rm -rf source repo refdir" &&
 	mkdir refdir &&