[PATCH 0/4] Submodule Groups

@@ -60,6 +60,8 @@ static void free_one_config(struct submodule_entry *entry)
 {
 	free((void *) entry->config->path);
 	free((void *) entry->config->name);
+	if (entry->config->groups)
+		string_list_clear(entry->config->groups, 0);
 	free(entry->config);
 }
 

@@ -184,6 +186,7 @@ static struct submodule *lookup_or_create_by_name(struct submodule_cache *cache,
 	submodule->update = NULL;
 	submodule->fetch_recurse = RECURSE_SUBMODULES_NONE;
 	submodule->ignore = NULL;
+	submodule->groups = NULL;
 
 	hashcpy(submodule->gitmodules_sha1, gitmodules_sha1);
 

@@ -324,6 +327,16 @@ static int parse_specific_submodule_config(const char *subsection, int subsectio
 			free((void *) submodule->update);
 			submodule->update = xstrdup(value);
 		}
+	} else if (!strcmp(key, "group")) {
+		if (!value)
+			ret = config_error_nonbool(var);
+		else {
+			if (!submodule->groups) {
+				submodule->groups = xmalloc(sizeof(*submodule->groups));
+				string_list_init(submodule->groups, 1);
+			}
+			string_list_insert(submodule->groups, value);
+		}
 	}
 
 	return ret;

@@ -17,6 +17,7 @@ struct submodule {
 	const char *update;
 	/* the sha1 blob id of the responsible .gitmodules file */
 	unsigned char gitmodules_sha1[20];
+	struct string_list *groups;
 };
 
 int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg);

@@ -9,7 +9,7 @@ git-submodule - Initialize, update or inspect submodules
 SYNOPSIS
 --------
 [verse]
-'git submodule' [--quiet] add [-b <branch>] [-f|--force] [--name <name>]
+'git submodule' [--quiet] add [-b <branch>] [-f|--force] [-g <group>][--name <name>]
 	      [--reference <repository>] [--depth <depth>] [--] <repository> [<path>]
 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]

@@ -59,6 +59,9 @@ instead of treating the other project as a submodule. Directories
 that come from both projects can be cloned and checked out as a whole
 if you choose to go that route.
 
+If you manage a large set of submodules, but do not require all of them
+to be checked out, you should look into the submodule groups feature.
+
 COMMANDS
 --------
 add::

@@ -101,6 +104,9 @@ is the superproject and submodule repositories will be kept
 together in the same relative location, and only the
 superproject's URL needs to be provided: git-submodule will correctly
 locate the submodule using the relative URL in .gitmodules.
++
+If at least one group argument was given, all groups are recorded in the
+.gitmodules file in the groups field.
 
 status::
 	Show the status of the submodules. This will print the SHA-1 of the

@@ -130,6 +130,7 @@ cmd_add()
 {
 	# parse $args after "submodule ... add".
 	reference_path=
+	submodule_groups=
 	while test $# -ne 0
 	do
 		case "$1" in

@@ -165,6 +166,10 @@ cmd_add()
 		--depth=*)
 			depth=$1
 			;;
+		-g|--group)
+			submodule_groups=${submodule_groups:+${submodule_groups};}"$2"
+			shift
+			;;
 		--)
 			shift
 			break

@@ -292,6 +297,16 @@ Use -f if you really want to add it." >&2
 
 	git config -f .gitmodules submodule."$sm_name".path "$sm_path" &&
 	git config -f .gitmodules submodule."$sm_name".url "$repo" &&
+	if test -n "$submodule_groups"
+	then
+		OIFS=$IFS
+		IFS=';'
+		for group in $submodule_groups
+		do
+			git config --add -f .gitmodules submodule."$sm_name".group "${group}"
+		done
+		IFS=$OIFS
+	fi &&
 	if test -n "$branch"
 	then
 		git config -f .gitmodules submodule."$sm_name".branch "$branch"

@@ -986,6 +986,7 @@ test_expect_success 'submodule with UTF-8 name' '
 '
 
 test_expect_success 'submodule add clone shallow submodule' '
+	test_when_finished "rm -rf super" &&
 	mkdir super &&
 	pwd=$(pwd) &&
 	(

@@ -999,5 +1000,36 @@ test_expect_success 'submodule add clone shallow submodule' '
 	)
 '
 
+test_expect_success 'submodule add records a group' '
+	test_when_finished "rm -rf super" &&
+	mkdir super &&
+	pwd=$(pwd) &&
+	(
+		cd super &&
+		git init &&
+		git submodule add --group groupA file://"$pwd"/example2 submodule &&
+		git config -f .gitmodules submodule."submodule".group >actual &&
+		echo groupA >expected &&
+		test_cmp expected actual
+	)
+'
+
+cat >expected <<-EOF
+groupA
+groupB
+EOF
+
+test_expect_success 'submodule add records groups' '
+	test_when_finished "rm -rf super" &&
+	mkdir super &&
+	pwd=$(pwd) &&
+	(
+		cd super &&
+		git init &&
+		git submodule add --group groupA -g groupB file://"$pwd"/example2 submodule &&
+		git config --get-all -f .gitmodules submodule."submodule".group >../actual
+	) &&
+	test_cmp expected actual
+'
 
 test_done

@@ -577,6 +577,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 
 struct submodule_update_clone {
 	/* states */
+	struct string_list *submodule_groups;
 	int count;
 	int print_unmatched;
 	/* configuration */

@@ -590,7 +591,7 @@ struct submodule_update_clone {
 	struct string_list projectlines;
 	struct pathspec pathspec;
 };
-#define SUBMODULE_UPDATE_CLONE_INIT {0, 0, 0, NULL, NULL, NULL, NULL, NULL, MODULE_LIST_INIT, STRING_LIST_INIT_DUP}
+#define SUBMODULE_UPDATE_CLONE_INIT {NULL, 0, 0, 0, NULL, NULL, NULL, NULL, NULL, MODULE_LIST_INIT, STRING_LIST_INIT_DUP}
 
 static void fill_clone_command(struct child_process *cp, int quiet,
 			       const char *prefix, const char *path,

@@ -633,6 +634,7 @@ static int update_clone_get_next_task(struct child_process *cp,
 		const char *update_module = NULL;
 		char *url = NULL;
 		int needs_cloning = 0;
+		int in_submodule_groups = 0;
 
 		if (ce_stage(ce)) {
 			if (pp->recursive_prefix)

@@ -676,6 +678,22 @@ static int update_clone_get_next_task(struct child_process *cp,
 		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.url", sub->name);
 		git_config_get_string(sb.buf, &url);
+		if (pp->submodule_groups && sub->groups){
+			struct string_list_item *item;
+			for_each_string_list_item(item, sub->groups) {
+				if (string_list_has_string(
+				    pp->submodule_groups, item->string)) {
+					in_submodule_groups = 1;
+					break;
+				}
+			}
+			if (in_submodule_groups) {
+				if (!url) {
+					init_submodule(sub->name, pp->prefix, pp->quiet);
+					url = xstrdup(sub->url);
+				}
+			}
+		}
 		if (!url) {
 			/*
 			 * Only mention uninitialized submodules when its

@@ -687,6 +705,7 @@ static int update_clone_get_next_task(struct child_process *cp,
 			continue;
 		}
 
+
 		strbuf_reset(&sb);
 		strbuf_addf(&sb, "%s/.git", ce->name);
 		needs_cloning = !file_exists(sb.buf);

@@ -742,6 +761,7 @@ static int update_clone_task_finished(int result,
 static int update_clone(int argc, const char **argv, const char *prefix)
 {
 	int max_jobs = -1;
+	const struct string_list *list;
 	struct string_list_item *item;
 	struct submodule_update_clone pp = SUBMODULE_UPDATE_CLONE_INIT;
 

@@ -786,6 +806,14 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 	/* Overlay the parsed .gitmodules file with .git/config */
 	git_config(git_submodule_config, NULL);
 
+	list = git_config_get_value_multi("submodule.groups");
+	if (list) {
+		pp.submodule_groups = xmalloc(sizeof(*pp.submodule_groups));
+		string_list_init(pp.submodule_groups, 1);
+		for_each_string_list_item(item, list)
+			string_list_insert(pp.submodule_groups, item->string);
+	}
+
 	if (max_jobs < 0)
 		max_jobs = config_parallel_submodules();
 	if (max_jobs < 0)

@@ -1032,4 +1032,30 @@ test_expect_success 'submodule add records groups' '
 	test_cmp expected actual
 '
 
+cat <<EOF > expected
+submodule
+-submodule1
+EOF
+
+test_expect_success 'submodule update works with groups implied' '
+	test_when_finished "rm -rf super super_clone" &&
+	mkdir super &&
+	pwd=$(pwd) &&
+	(
+		cd super &&
+		git init &&
+		git submodule add --group groupA file://"$pwd"/example2 submodule &&
+		git submodule add file://"$pwd"/example2 submodule1 &&
+		git commit -a -m "create repository with 2 submodules, one is in a group"
+	) &&
+	git clone super super_clone &&
+	(
+		cd super_clone &&
+		git config submodule.groups groupA &&
+		git submodule update &&
+		git submodule status |cut -c1,42-52 | tr -d " " >../actual
+	) &&
+	test_cmp actual expected
+'
+
 test_done

@@ -214,6 +214,19 @@ objects from the source repository into a pack in the cloned repository.
 	repository does not have a worktree/checkout (i.e. if any of
 	`--no-checkout`/`-n`, `--bare`, or `--mirror` is given)
 
+--group::
+	After the clone is created, all submodules which are part of the
+	given groups are cloned. To specify multiple groups, you can either
+	give the group argument multiple times or comma separate the groups.
+	This option will be recorded in the `submodule.groups` config,
+	which will affect the behavior of other submodule related commands,
+	such as `git submodule update`.
+	This option implies recursive submodule checkout. If you don't
+	want to recurse into nested submodules, you need to specify
+	`--no-recursive`. The group selection will be passed on recursively,
+	i.e. if a submodule is cloned because of group membership, its
+	submodules will be cloned according to group membership, too.
+
 --separate-git-dir=<git dir>::
 	Instead of placing the cloned repository where it is supposed
 	to be, place the cloned repository at the specified directory,

@@ -51,6 +51,22 @@ static struct string_list option_config;
 static struct string_list option_reference;
 static int option_dissociate;
 static int max_jobs = -1;
+static struct string_list submodule_groups;
+
+static int groups_cb(const struct option *opt, const char *arg, int unset)
+{
+	struct string_list_item *item;
+	struct string_list sl = STRING_LIST_INIT_DUP;
+
+	if (unset)
+		return -1;
+
+	string_list_split(&sl, arg, ',', -1);
+	for_each_string_list_item(item, &sl)
+		string_list_append((struct string_list *)opt->value, item->string);
+
+	return 0;
+}
 
 static struct option builtin_clone_options[] = {
 	OPT__VERBOSITY(&option_verbosity),

@@ -95,6 +111,8 @@ static struct option builtin_clone_options[] = {
 		   N_("separate git dir from working tree")),
 	OPT_STRING_LIST('c', "config", &option_config, N_("key=value"),
 			N_("set config inside the new repository")),
+	OPT_CALLBACK('g', "group", &submodule_groups, N_("string"),
+			N_("clone specific submodule groups"), groups_cb),
 	OPT_END()
 };
 

@@ -723,9 +741,17 @@ static int checkout(void)
 	err |= run_hook_le(NULL, "post-checkout", sha1_to_hex(null_sha1),
 			   sha1_to_hex(sha1), "1", NULL);
 
-	if (!err && option_recursive) {
+	if (err)
+		goto out;
+
+	if (option_recursive || submodule_groups.nr > 0) {
 		struct argv_array args = ARGV_ARRAY_INIT;
-		argv_array_pushl(&args, "submodule", "update", "--init", "--recursive", NULL);
+		argv_array_pushl(&args, "submodule", "update", NULL);
+
+		if (option_recursive) {
+			argv_array_pushf(&args, "--init");
+			argv_array_pushf(&args, "--recursive");
+		}
 
 		if (max_jobs != -1)
 			argv_array_pushf(&args, "--jobs=%d", max_jobs);

@@ -733,7 +759,7 @@ static int checkout(void)
 		err = run_command_v_opt(args.argv, RUN_GIT_CMD);
 		argv_array_clear(&args);
 	}
-
+out:
 	return err;
 }
 

@@ -867,6 +893,20 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 			die(_("--bare and --separate-git-dir are incompatible."));
 		option_no_checkout = 1;
 	}
+	if (option_recursive == -1) {
+		if (submodule_groups.nr > 0)
+			option_recursive = 1; /* submodule groups implies recursive */
+		else
+			option_recursive = 0; /* preserve historical default */
+	}
+	if (submodule_groups.nr > 0) {
+		struct string_list_item *item;
+		struct strbuf sb = STRBUF_INIT;
+		for_each_string_list_item(item, &submodule_groups) {
+			strbuf_addf(&sb, "submodule.groups=%s", item->string);
+			string_list_append(&option_config, strbuf_detach(&sb, 0));
+		}
+	}
 
 	if (!option_origin)
 		option_origin = "origin";

@@ -1058,4 +1058,58 @@ test_expect_success 'submodule update works with groups implied' '
 	test_cmp actual expected
 '
 
+cat <<EOF > expected
+submodule
+-submodule1
+EOF
+
+test_expect_success 'clone --group works' '
+	test_when_finished "rm -rf super super_clone" &&
+	mkdir super &&
+	pwd=$(pwd) &&
+	(
+		cd super &&
+		git init &&
+		git submodule add --group groupA file://"$pwd"/example2 submodule &&
+		git submodule add file://"$pwd"/example2 submodule1 &&
+		git commit -a -m "create repository with 2 submodules, one is in a group"
+	) &&
+	git clone --group groupA super super_clone &&
+	(
+		cd super_clone &&
+		git submodule status |cut -c1,42-52 | tr -d " " >../actual
+	) &&
+	test_cmp actual expected
+'
+
+cat <<EOF > expected
+-submodule1
+submoduleA
+submoduleB
+submoduleC
+-submoduleD
+EOF
+
+test_expect_success 'clone with multiple groups works' '
+	test_when_finished "rm -rf super super_clone" &&
+	mkdir super &&
+	pwd=$(pwd) &&
+	(
+		cd super &&
+		git init &&
+		git submodule add --group groupA file://"$pwd"/example2 submoduleA &&
+		git submodule add --group groupB file://"$pwd"/example2 submoduleB &&
+		git submodule add --group groupC file://"$pwd"/example2 submoduleC &&
+		git submodule add --group groupD file://"$pwd"/example2 submoduleD &&
+		git submodule add file://"$pwd"/example2 submodule1 &&
+		git commit -a -m "create repository with submodules groups"
+	) &&
+	git clone --group groupA,groupB --group groupC super super_clone &&
+	(
+		cd super_clone &&
+		git submodule status |cut -c1,42-52 | tr -d " " >../actual
+	) &&
+	test_cmp actual expected
+'
+
 test_done