submodule init: initialize active submodules

Teach `submodule init` to initialize submodules which have been
configured to be active by setting 'submodule.active' with a pathspec.

Now if no path arguments are given and 'submodule.active' is configured,
`init` will initialize all submodules which have been configured to be
active.  If no path arguments are given and 'submodule.active' is not
configured, then `init` will retain the old behavior of initializing all
submodules.

This allows users to record more complex patterns as it saves retyping
them whenever you invoke update.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-submodule.txt

@@ -129,7 +129,9 @@ init [--] [<path>...]::
 	repository will be assumed to be upstream.
 +
 Optional <path> arguments limit which submodules will be initialized.
-If no path is specified, all submodules are initialized.
+If no path is specified and submodule.active has been configured, submodules
+configured to be active will be initialized, otherwise all submodules are
+initialized.
 +
 When present, it will also copy the value of `submodule.$name.update`.
 This command does not alter existing information in .git/config.

builtin/submodule--helper.c

@@ -270,6 +270,29 @@ static int module_list_compute(int argc, const char **argv,
 	return result;
 }
 
+static void module_list_active(struct module_list *list)
+{
+	int i;
+	struct module_list active_modules = MODULE_LIST_INIT;
+
+	gitmodules_config();
+
+	for (i = 0; i < list->nr; i++) {
+		const struct cache_entry *ce = list->entries[i];
+
+		if (!is_submodule_initialized(ce->name))
+			continue;
+
+		ALLOC_GROW(active_modules.entries,
+			   active_modules.nr + 1,
+			   active_modules.alloc);
+		active_modules.entries[active_modules.nr++] = ce;
+	}
+
+	free(list->entries);
+	*list = active_modules;
+}
+
 static int module_list(int argc, const char **argv, const char *prefix)
 {
 	int i;
@@ -420,6 +443,13 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
 		return 1;
 
+	/*
+	 * If there are no path args and submodule.active is set then,
+	 * by default, only initialize 'active' modules.
+	 */
+	if (!argc && git_config_get_value_multi("submodule.active"))
+		module_list_active(&list);
+
 	for (i = 0; i < list.nr; i++)
 		init_submodule(list.entries[i]->name, prefix, quiet);
 

t/t7400-submodule-basic.sh

@@ -1130,5 +1130,62 @@ test_expect_success 'submodule helper list is not confused by common prefixes' '
 	test_cmp expect actual
 '
 
+test_expect_success 'setup superproject with submodules' '
+	git init sub1 &&
+	test_commit -C sub1 test &&
+	test_commit -C sub1 test2 &&
+	git init multisuper &&
+	git -C multisuper submodule add ../sub1 sub0 &&
+	git -C multisuper submodule add ../sub1 sub1 &&
+	git -C multisuper submodule add ../sub1 sub2 &&
+	git -C multisuper submodule add ../sub1 sub3 &&
+	git -C multisuper commit -m "add some submodules"
+'
+
+cat >expect <<-EOF
+-sub0
+ sub1 (test2)
+ sub2 (test2)
+ sub3 (test2)
+EOF
+
+test_expect_success 'submodule update --init with a specification' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	git -C multisuper_clone submodule update --init . ":(exclude)sub0" &&
+	git -C multisuper_clone submodule status |cut -c 1,43- >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'submodule update --init with submodule.active set' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	git -C multisuper_clone config submodule.active "." &&
+	git -C multisuper_clone config --add submodule.active ":(exclude)sub0" &&
+	git -C multisuper_clone submodule update --init &&
+	git -C multisuper_clone submodule status |cut -c 1,43- >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'submodule update and setting submodule.<name>.active' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	git -C multisuper_clone config --bool submodule.sub0.active "true" &&
+	git -C multisuper_clone config --bool submodule.sub1.active "false" &&
+	git -C multisuper_clone config --bool submodule.sub2.active "true" &&
+
+	cat >expect <<-\EOF &&
+	 sub0 (test2)
+	-sub1
+	 sub2 (test2)
+	-sub3
+	EOF
+	git -C multisuper_clone submodule update &&
+	git -C multisuper_clone submodule status |cut -c 1,43- >actual &&
+	test_cmp expect actual
+'
 
 test_done