clone: pass --single-branch during --recurse-submodules

Previously, performing "git clone --recurse-submodules --single-branch"
resulted in submodules cloning all branches even though the superproject
cloned only one branch. Pipe --single-branch through the submodule
helper framework to make it to 'clone' later on.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-submodule.txt

@@ -133,7 +133,7 @@ If you really want to remove a submodule from the repository and commit
 that use linkgit:git-rm[1] instead. See linkgit:gitsubmodules[7] for removal
 options.
 
-update [--init] [--remote] [-N|--no-fetch] [--[no-]recommend-shallow] [-f|--force] [--checkout|--rebase|--merge] [--reference <repository>] [--depth <depth>] [--recursive] [--jobs <n>] [--] [<path>...]::
+update [--init] [--remote] [-N|--no-fetch] [--[no-]recommend-shallow] [-f|--force] [--checkout|--rebase|--merge] [--reference <repository>] [--depth <depth>] [--recursive] [--jobs <n>] [--[no-]single-branch] [--] [<path>...]::
 +
 --
 Update the registered submodules to match what the superproject
@@ -430,6 +430,10 @@ options carefully.
 	Clone new submodules in parallel with as many jobs.
 	Defaults to the `submodule.fetchJobs` option.
 
+--[no-]single-branch::
+	This option is only valid for the update command.
+	Clone only one branch during update: HEAD or one specified by --branch.
+
 <path>...::
 	Paths to submodule(s). When specified this will restrict the command
 	to only operate on the submodules found at the specified paths.

builtin/clone.c

@@ -832,6 +832,11 @@ static int checkout(int submodule_progress)
 			argv_array_push(&args, "--no-fetch");
 		}
 
+		if (option_single_branch >= 0)
+			argv_array_push(&args, option_single_branch ?
+					       "--single-branch" :
+					       "--no-single-branch");
+
 		err = run_command_v_opt(args.argv, RUN_GIT_CMD);
 		argv_array_clear(&args);
 	}

builtin/submodule--helper.c

@@ -1225,7 +1225,7 @@ static int module_deinit(int argc, const char **argv, const char *prefix)
 
 static int clone_submodule(const char *path, const char *gitdir, const char *url,
 			   const char *depth, struct string_list *reference, int dissociate,
-			   int quiet, int progress)
+			   int quiet, int progress, int single_branch)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 
@@ -1247,6 +1247,10 @@ static int clone_submodule(const char *path, const char *gitdir, const char *url
 		argv_array_push(&cp.args, "--dissociate");
 	if (gitdir && *gitdir)
 		argv_array_pushl(&cp.args, "--separate-git-dir", gitdir, NULL);
+	if (single_branch >= 0)
+		argv_array_push(&cp.args, single_branch ?
+					  "--single-branch" :
+					  "--no-single-branch");
 
 	argv_array_push(&cp.args, "--");
 	argv_array_push(&cp.args, url);
@@ -1373,6 +1377,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	struct string_list reference = STRING_LIST_INIT_NODUP;
 	int dissociate = 0, require_init = 0;
 	char *sm_alternate = NULL, *error_strategy = NULL;
+	int single_branch = -1;
 
 	struct option module_clone_options[] = {
 		OPT_STRING(0, "prefix", &prefix,
@@ -1400,12 +1405,15 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 			   N_("force cloning progress")),
 		OPT_BOOL(0, "require-init", &require_init,
 			   N_("disallow cloning into non-empty directory")),
+		OPT_BOOL(0, "single-branch", &single_branch,
+			 N_("clone only one branch, HEAD or --branch")),
 		OPT_END()
 	};
 
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule--helper clone [--prefix=<path>] [--quiet] "
 		   "[--reference <repository>] [--name <name>] [--depth <depth>] "
+		   "[--single-branch] "
 		   "--url <url> --path <path>"),
 		NULL
 	};
@@ -1438,7 +1446,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 		prepare_possible_alternates(name, &reference);
 
 		if (clone_submodule(path, sm_gitdir, url, depth, &reference, dissociate,
-				    quiet, progress))
+				    quiet, progress, single_branch))
 			die(_("clone of '%s' into submodule path '%s' failed"),
 			    url, path);
 	} else {
@@ -1562,6 +1570,7 @@ struct submodule_update_clone {
 	const char *depth;
 	const char *recursive_prefix;
 	const char *prefix;
+	int single_branch;
 
 	/* to be consumed by git-submodule.sh */
 	struct update_clone_data *update_clone;
@@ -1581,6 +1590,7 @@ struct submodule_update_clone {
 	.update = SUBMODULE_UPDATE_STRATEGY_INIT, \
 	.recommend_shallow = -1, \
 	.references = STRING_LIST_INIT_DUP, \
+	.single_branch = -1, \
 	.max_jobs = 1, \
 }
 
@@ -1721,6 +1731,10 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		argv_array_push(&child->args, "--dissociate");
 	if (suc->depth)
 		argv_array_push(&child->args, suc->depth);
+	if (suc->single_branch >= 0)
+		argv_array_push(&child->args, suc->single_branch ?
+					      "--single-branch" :
+					      "--no-single-branch");
 
 cleanup:
 	strbuf_reset(&displaypath_sb);
@@ -1900,6 +1914,8 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 			    N_("force cloning progress")),
 		OPT_BOOL(0, "require-init", &suc.require_init,
 			   N_("disallow cloning into non-empty directory")),
+		OPT_BOOL(0, "single-branch", &suc.single_branch,
+			 N_("clone only one branch, HEAD or --branch")),
 		OPT_END()
 	};
 

git-submodule.sh

@@ -10,7 +10,7 @@ USAGE="[--quiet] [--cached]
    or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] init [--] [<path>...]
    or: $dashless [--quiet] deinit [-f|--force] (--all| [--] <path>...)
-   or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--] [<path>...]
+   or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--[no-]single-branch] [--] [<path>...]
    or: $dashless [--quiet] set-branch (--default|--branch <branch>) [--] <path>
    or: $dashless [--quiet] set-url [--] <path> <newurl>
    or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
@@ -47,6 +47,7 @@ custom_name=
 depth=
 progress=
 dissociate=
+single_branch=
 
 die_if_unmatched ()
 {
@@ -526,6 +527,12 @@ cmd_update()
 		--jobs=*)
 			jobs=$1
 			;;
+		--single-branch)
+			single_branch="--single-branch"
+			;;
+		--no-single-branch)
+			single_branch="--no-single-branch"
+			;;
 		--)
 			shift
 			break
@@ -555,6 +562,7 @@ cmd_update()
 		${dissociate:+"--dissociate"} \
 		${depth:+--depth "$depth"} \
 		${require_init:+--require-init} \
+		$single_branch \
 		$recommend_shallow \
 		$jobs \
 		-- \

t/t5617-clone-submodules-remote.sh

@@ -14,7 +14,8 @@ test_expect_success 'setup' '
 		cd sub &&
 		git init &&
 		test_commit subcommit1 &&
-		git tag sub_when_added_to_super
+		git tag sub_when_added_to_super &&
+		git branch other
 	) &&
 	git submodule add "file://$pwd/sub" sub &&
 	git commit -m "add submodule" &&
@@ -51,4 +52,14 @@ test_expect_success 'check the default is --no-remote-submodules' '
 	)
 '
 
+test_expect_success 'clone with --single-branch' '
+	test_when_finished "rm -rf super_clone" &&
+	git clone --recurse-submodules --single-branch "file://$pwd/." super_clone &&
+	(
+		cd super_clone/sub &&
+		git rev-parse --verify origin/master &&
+		test_must_fail git rev-parse --verify origin/other
+	)
+'
+
 test_done