1 files changed, 446 insertions, 93 deletions

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 899dc334e3..2086f0eb08 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -1,10 +1,11 @@
 #include "builtin.h"
+#include "repository.h"
 #include "cache.h"
+#include "config.h"
 #include "parse-options.h"
 #include "quote.h"
 #include "pathspec.h"
 #include "dir.h"
-#include "utf8.h"
 #include "submodule.h"
 #include "submodule-config.h"
 #include "string-list.h"
@@ -12,13 +13,22 @@
 #include "remote.h"
 #include "refs.h"
 #include "connect.h"
+#include "revision.h"
+#include "diffcore.h"
+#include "diff.h"
+
+#define OPT_QUIET (1 << 0)
+#define OPT_CACHED (1 << 1)
+#define OPT_RECURSIVE (1 << 2)
+
+typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
+				  void *cb_data);
 
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
-	unsigned char sha1[20];
 	struct strbuf sb = STRBUF_INIT;
-	const char *refname = resolve_ref_unsafe("HEAD", 0, sha1, NULL);
+	const char *refname = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
 
 	if (!refname)
 		die(_("No such ref: %s"), "HEAD");
@@ -219,6 +229,64 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+/* the result should be freed by the caller. */
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		return xstrfmt("%s%s", super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
+static char *compute_rev_name(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = { NULL };
+
+	static const char *describe_tags[] = { "--tags", NULL };
+
+	static const char *describe_contains[] = { "--contains", NULL };
+
+	static const char *describe_all_always[] = { "--all", "--always", NULL };
+
+	static const char **describe_argv[] = { describe_bare, describe_tags,
+						describe_contains,
+						describe_all_always, NULL };
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0)) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -233,8 +301,7 @@ static int module_list_compute(int argc, const char **argv,
 	int i, result = 0;
 	char *ps_matched = NULL;
 	parse_pathspec(pathspec, 0,
-		       PATHSPEC_PREFER_FULL |
-		       PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP,
+		       PATHSPEC_PREFER_FULL,
 		       prefix, argv);
 
 	if (pathspec->nr)
@@ -270,6 +337,27 @@ 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;
+
+	for (i = 0; i < list->nr; i++) {
+		const struct cache_entry *ce = list->entries[i];
+
+		if (!is_submodule_active(the_repository, 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;
@@ -303,50 +391,66 @@ static int module_list(int argc, const char **argv, const char *prefix)
 			printf("%06o %s %d\t", ce->ce_mode,
 			       oid_to_hex(&ce->oid), ce_stage(ce));
 
-		utf8_fprintf(stdout, "%s\n", ce->name);
+		fprintf(stdout, "%s\n", ce->name);
 	}
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_listed_submodule(const struct module_list *list,
+				      each_submodule_fn fn, void *cb_data)
+{
+	int i;
+	for (i = 0; i < list->nr; i++)
+		fn(list->entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int flags;
+};
+
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const char *path, const char *prefix,
+			   unsigned int flags)
 {
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	/* Only loads from .gitmodules, no overlay with .git/config */
-	gitmodules_config();
-
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
-	sub = submodule_from_path(null_sha1, path);
+	sub = submodule_from_path(&null_oid, path);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
 			displaypath);
 
 	/*
+	 * NEEDSWORK: In a multi-working-tree world, this needs to be
+	 * set in the per-worktree config.
+	 *
+	 * Set active flag for the submodule being initialized
+	 */
+	if (!is_submodule_active(the_repository, path)) {
+		strbuf_addf(&sb, "submodule.%s.active", sub->name);
+		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
+	}
+
+	/*
 	 * Copy url setting when it is not set yet.
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
-		url = xstrdup(sub->url);
-
-		if (!url)
+		if (!sub->url)
 			die(_("No url found for submodule path '%s' in .gitmodules"),
 				displaypath);
 
+		url = xstrdup(sub->url);
+
 		/* Possibly a url relative to parent */
 		if (starts_with_dot_dot_slash(url) ||
 		    starts_with_dot_slash(url)) {
@@ -356,12 +460,10 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 			strbuf_addf(&remotesb, "remote.%s.url", remote);
 			free(remote);
 
-			if (git_config_get_string(remotesb.buf, &remoteurl))
-				/*
-				 * The repository is its own
-				 * authoritative upstream
-				 */
+			if (git_config_get_string(remotesb.buf, &remoteurl)) {
+				warning(_("could not lookup configuration '%s'. Assuming this repository is its own authoritative upstream."), remotesb.buf);
 				remoteurl = xgetcwd();
+			}
 			relurl = relative_url(remoteurl, url, NULL);
 			strbuf_release(&remotesb);
 			free(remoteurl);
@@ -372,14 +474,14 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!(flags & OPT_QUIET))
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
@@ -399,12 +501,18 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	free(upd);
 }
 
+static void init_submodule_cb(const struct cache_entry *list_item, void *cb_data)
+{
+	struct init_cb *info = cb_data;
+	init_submodule(list_item->name, info->prefix, info->flags);
+}
+
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -422,8 +530,172 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
 		return 1;
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	/*
+	 * 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);
+
+	info.prefix = prefix;
+	if (quiet)
+		info.flags |= OPT_QUIET;
+
+	for_each_listed_submodule(&list, init_submodule_cb, &info);
+
+	return 0;
+}
+
+struct status_cb {
+	const char *prefix;
+	unsigned int flags;
+};
+
+#define STATUS_CB_INIT { NULL, 0 }
+
+static void print_status(unsigned int flags, char state, const char *path,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (flags & OPT_QUIET)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+')
+		printf(" (%s)", compute_rev_name(path, oid_to_hex(oid)));
+
+	printf("\n");
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const char *path, const struct object_id *ce_oid,
+			     unsigned int ce_flags, const char *prefix,
+			     unsigned int flags)
+{
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+	struct rev_info rev;
+	int diff_files_result;
+
+	if (!submodule_from_path(&null_oid, path))
+		die(_("no submodule mapping found in .gitmodules for path '%s'"),
+		      path);
+
+	displaypath = get_submodule_displaypath(path, prefix);
+
+	if ((CE_STAGEMASK & ce_flags) >> CE_STAGESHIFT) {
+		print_status(flags, 'U', path, &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, path)) {
+		print_status(flags, '-', path, ce_oid, displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 path, NULL);
+
+	git_config(git_diff_basic_config, NULL);
+	init_revisions(&rev, prefix);
+	rev.abbrev = 0;
+	diff_files_args.argc = setup_revisions(diff_files_args.argc,
+					       diff_files_args.argv,
+					       &rev, NULL);
+	diff_files_result = run_diff_files(&rev, 0);
+
+	if (!diff_result_code(&rev.diffopt, diff_files_result)) {
+		print_status(flags, ' ', path, ce_oid,
+			     displaypath);
+	} else if (!(flags & OPT_CACHED)) {
+		struct object_id oid;
+
+		if (refs_head_ref(get_submodule_ref_store(path),
+				  handle_submodule_head_ref, &oid))
+			die(_("could not resolve HEAD ref inside the"
+			      "submodule '%s'"), path);
+
+		print_status(flags, '+', path, &oid, displaypath);
+	} else {
+		print_status(flags, '+', path, ce_oid, displaypath);
+	}
+
+	if (flags & OPT_RECURSIVE) {
+		struct child_process cpr = CHILD_PROCESS_INIT;
+
+		cpr.git_cmd = 1;
+		cpr.dir = path;
+		prepare_submodule_repo_env(&cpr.env_array);
+
+		argv_array_push(&cpr.args, "--super-prefix");
+		argv_array_pushf(&cpr.args, "%s/", displaypath);
+		argv_array_pushl(&cpr.args, "submodule--helper", "status",
+				 "--recursive", NULL);
+
+		if (flags & OPT_CACHED)
+			argv_array_push(&cpr.args, "--cached");
+
+		if (flags & OPT_QUIET)
+			argv_array_push(&cpr.args, "--quiet");
+
+		if (run_command(&cpr))
+			die(_("failed to recurse into submodule '%s'"), path);
+	}
+
+cleanup:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+static void status_submodule_cb(const struct cache_entry *list_item,
+				void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	status_submodule(list_item->name, &list_item->oid, list_item->ce_flags,
+			 info->prefix, info->flags);
+}
+
+static int module_status(int argc, const char **argv, const char *prefix)
+{
+	struct status_cb info = STATUS_CB_INIT;
+	struct pathspec pathspec;
+	struct module_list list = MODULE_LIST_INIT;
+	int quiet = 0;
+
+	struct option module_status_options[] = {
+		OPT__QUIET(&quiet, N_("Suppress submodule status output")),
+		OPT_BIT(0, "cached", &info.flags, N_("Use commit stored in the index instead of the one stored in the submodule HEAD"), OPT_CACHED),
+		OPT_BIT(0, "recursive", &info.flags, N_("recurse into nested submodules"), OPT_RECURSIVE),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule status [--quiet] [--cached] [--recursive] [<path>...]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_status_options,
+			     git_submodule_helper_usage, 0);
+
+	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
+		return 1;
+
+	info.prefix = prefix;
+	if (quiet)
+		info.flags |= OPT_QUIET;
+
+	for_each_listed_submodule(&list, status_submodule_cb, &info);
 
 	return 0;
 }
@@ -435,8 +707,7 @@ static int module_name(int argc, const char **argv, const char *prefix)
 	if (argc != 2)
 		usage(_("git submodule--helper name <path>"));
 
-	gitmodules_config();
-	sub = submodule_from_path(null_sha1, argv[1]);
+	sub = submodule_from_path(&null_oid, argv[1]);
 
 	if (!sub)
 		die(_("no submodule mapping found in .gitmodules for path '%s'"),
@@ -579,9 +850,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	const char *name = NULL, *url = NULL, *depth = NULL;
 	int quiet = 0;
 	int progress = 0;
-	FILE *submodule_dot_git;
 	char *p, *path = NULL, *sm_gitdir;
-	struct strbuf rel_path = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	struct string_list reference = STRING_LIST_INIT_NODUP;
 	char *sm_alternate = NULL, *error_strategy = NULL;
@@ -653,27 +922,12 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 		strbuf_reset(&sb);
 	}
 
-	/* Write a .git file in the submodule to redirect to the superproject. */
-	strbuf_addf(&sb, "%s/.git", path);
-	if (safe_create_leading_directories_const(sb.buf) < 0)
-		die(_("could not create leading directories of '%s'"), sb.buf);
-	submodule_dot_git = fopen(sb.buf, "w");
-	if (!submodule_dot_git)
-		die_errno(_("cannot open file '%s'"), sb.buf);
-
-	fprintf_or_die(submodule_dot_git, "gitdir: %s\n",
-		       relative_path(sm_gitdir, path, &rel_path));
-	if (fclose(submodule_dot_git))
-		die(_("could not close file %s"), sb.buf);
-	strbuf_reset(&sb);
-	strbuf_reset(&rel_path);
+	/* Connect module worktree and git dir */
+	connect_work_tree_and_git_dir(path, sm_gitdir);
 
-	/* Redirect the worktree of the submodule in the superproject's config */
 	p = git_pathdup_submodule(path, "config");
 	if (!p)
 		die(_("could not get submodule directory for '%s'"), path);
-	git_config_set_in_file(p, "core.worktree",
-			       relative_path(path, sm_gitdir, &rel_path));
 
 	/* setup alternateLocation and alternateErrorStrategy in the cloned submodule if needed */
 	git_config_get_string("submodule.alternateLocation", &sm_alternate);
@@ -689,7 +943,6 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	free(error_strategy);
 
 	strbuf_release(&sb);
-	strbuf_release(&rel_path);
 	free(sm_gitdir);
 	free(path);
 	free(p);
@@ -758,10 +1011,13 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 					   struct strbuf *out)
 {
 	const struct submodule *sub = NULL;
+	const char *url = NULL;
+	const char *update_string;
+	enum submodule_update_type update_type;
+	char *key;
 	struct strbuf displaypath_sb = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	const char *displaypath = NULL;
-	char *url = NULL;
 	int needs_cloning = 0;
 
 	if (ce_stage(ce)) {
@@ -774,7 +1030,7 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		goto cleanup;
 	}
 
-	sub = submodule_from_path(null_sha1, ce->name);
+	sub = submodule_from_path(&null_oid, ce->name);
 
 	if (suc->recursive_prefix)
 		displaypath = relative_path(suc->recursive_prefix,
@@ -787,28 +1043,34 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		goto cleanup;
 	}
 
+	key = xstrfmt("submodule.%s.update", sub->name);
+	if (!repo_config_get_string_const(the_repository, key, &update_string)) {
+		update_type = parse_submodule_update_type(update_string);
+	} else {
+		update_type = sub->update_strategy.type;
+	}
+	free(key);
+
 	if (suc->update.type == SM_UPDATE_NONE
 	    || (suc->update.type == SM_UPDATE_UNSPECIFIED
-		&& sub->update_strategy.type == SM_UPDATE_NONE)) {
+		&& update_type == SM_UPDATE_NONE)) {
 		strbuf_addf(out, _("Skipping submodule '%s'"), displaypath);
 		strbuf_addch(out, '\n');
 		goto cleanup;
 	}
 
-	/*
-	 * Looking up the url in .git/config.
-	 * We must not fall back to .gitmodules as we only want
-	 * to process configured submodules.
-	 */
-	strbuf_reset(&sb);
-	strbuf_addf(&sb, "submodule.%s.url", sub->name);
-	git_config_get_string(sb.buf, &url);
-	if (!url) {
+	/* Check if the submodule has been initialized. */
+	if (!is_submodule_active(the_repository, ce->name)) {
 		next_submodule_warn_missing(suc, out, displaypath);
 		goto cleanup;
 	}
 
 	strbuf_reset(&sb);
+	strbuf_addf(&sb, "submodule.%s.url", sub->name);
+	if (repo_config_get_string_const(the_repository, sb.buf, &url))
+		url = sub->url;
+
+	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/.git", ce->name);
 	needs_cloning = !file_exists(sb.buf);
 
@@ -847,7 +1109,6 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		argv_array_push(&child->args, suc->depth);
 
 cleanup:
-	free(url);
 	strbuf_reset(&displaypath_sb);
 	strbuf_reset(&sb);
 
@@ -917,7 +1178,7 @@ static int update_clone_task_finished(int result,
 	const struct cache_entry *ce;
 	struct submodule_update_clone *suc = suc_cb;
 
-	int *idxP = *(int**)idx_task_cb;
+	int *idxP = idx_task_cb;
 	int idx = *idxP;
 	free(idxP);
 
@@ -947,10 +1208,19 @@ static int update_clone_task_finished(int result,
 	return 0;
 }
 
+static int gitmodules_update_clone_config(const char *var, const char *value,
+					  void *cb)
+{
+	int *max_jobs = cb;
+	if (!strcmp(var, "submodule.fetchjobs"))
+		*max_jobs = parse_submodule_fetchjobs(var, value);
+	return 0;
+}
+
 static int update_clone(int argc, const char **argv, const char *prefix)
 {
 	const char *update = NULL;
-	int max_jobs = -1;
+	int max_jobs = 1;
 	struct string_list_item *item;
 	struct pathspec pathspec;
 	struct submodule_update_clone suc = SUBMODULE_UPDATE_CLONE_INIT;
@@ -987,6 +1257,9 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 	};
 	suc.prefix = prefix;
 
+	config_from_gitmodules(gitmodules_update_clone_config, &max_jobs);
+	git_config(gitmodules_update_clone_config, &max_jobs);
+
 	argc = parse_options(argc, argv, prefix, module_update_clone_options,
 			     git_submodule_helper_usage, 0);
 
@@ -1000,13 +1273,6 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 	if (pathspec.nr)
 		suc.warn_if_uninitialized = 1;
 
-	/* Overlay the parsed .gitmodules file with .git/config */
-	gitmodules_config();
-	git_config(submodule_config, NULL);
-
-	if (max_jobs < 0)
-		max_jobs = parallel_submodules();
-
 	run_processes_parallel(max_jobs,
 			       update_clone_get_next_task,
 			       update_clone_start_failure,
@@ -1025,7 +1291,7 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 		return 1;
 
 	for_each_string_list_item(item, &suc.projectlines)
-		utf8_fprintf(stdout, "%s", item->string);
+		fprintf(stdout, "%s", item->string);
 
 	return 0;
 }
@@ -1044,19 +1310,23 @@ static int resolve_relative_path(int argc, const char **argv, const char *prefix
 static const char *remote_submodule_branch(const char *path)
 {
 	const struct submodule *sub;
-	gitmodules_config();
-	git_config(submodule_config, NULL);
+	const char *branch = NULL;
+	char *key;
 
-	sub = submodule_from_path(null_sha1, path);
+	sub = submodule_from_path(&null_oid, path);
 	if (!sub)
 		return NULL;
 
-	if (!sub->branch)
+	key = xstrfmt("submodule.%s.branch", sub->name);
+	if (repo_config_get_string_const(the_repository, key, &branch))
+		branch = sub->branch;
+	free(key);
+
+	if (!branch)
 		return "master";
 
-	if (!strcmp(sub->branch, ".")) {
-		unsigned char sha1[20];
-		const char *refname = resolve_ref_unsafe("HEAD", 0, sha1, NULL);
+	if (!strcmp(branch, ".")) {
+		const char *refname = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
 
 		if (!refname)
 			die(_("No such ref: %s"), "HEAD");
@@ -1072,7 +1342,7 @@ static const char *remote_submodule_branch(const char *path)
 		return refname;
 	}
 
-	return sub->branch;
+	return branch;
 }
 
 static int resolve_remote_submodule_branch(int argc, const char **argv,
@@ -1092,6 +1362,82 @@ static int resolve_remote_submodule_branch(int argc, const char **argv,
 	return 0;
 }
 
+static int push_check(int argc, const char **argv, const char *prefix)
+{
+	struct remote *remote;
+	const char *superproject_head;
+	char *head;
+	int detached_head = 0;
+	struct object_id head_oid;
+
+	if (argc < 3)
+		die("submodule--helper push-check requires at least 2 arguments");
+
+	/*
+	 * superproject's resolved head ref.
+	 * if HEAD then the superproject is in a detached head state, otherwise
+	 * it will be the resolved head ref.
+	 */
+	superproject_head = argv[1];
+	argv++;
+	argc--;
+	/* Get the submodule's head ref and determine if it is detached */
+	head = resolve_refdup("HEAD", 0, &head_oid, NULL);
+	if (!head)
+		die(_("Failed to resolve HEAD as a valid ref."));
+	if (!strcmp(head, "HEAD"))
+		detached_head = 1;
+
+	/*
+	 * The remote must be configured.
+	 * This is to avoid pushing to the exact same URL as the parent.
+	 */
+	remote = pushremote_get(argv[1]);
+	if (!remote || remote->origin == REMOTE_UNCONFIGURED)
+		die("remote '%s' not configured", argv[1]);
+
+	/* Check the refspec */
+	if (argc > 2) {
+		int i, refspec_nr = argc - 2;
+		struct ref *local_refs = get_local_heads();
+		struct refspec *refspec = parse_push_refspec(refspec_nr,
+							     argv + 2);
+
+		for (i = 0; i < refspec_nr; i++) {
+			struct refspec *rs = refspec + i;
+
+			if (rs->pattern || rs->matching)
+				continue;
+
+			/* LHS must match a single ref */
+			switch (count_refspec_match(rs->src, local_refs, NULL)) {
+			case 1:
+				break;
+			case 0:
+				/*
+				 * If LHS matches 'HEAD' then we need to ensure
+				 * that it matches the same named branch
+				 * checked out in the superproject.
+				 */
+				if (!strcmp(rs->src, "HEAD")) {
+					if (!detached_head &&
+					    !strcmp(head, superproject_head))
+						break;
+					die("HEAD does not match the named branch in the superproject");
+				}
+				/* fallthrough */
+			default:
+				die("src refspec '%s' must name a ref",
+				    rs->src);
+			}
+		}
+		free_refspec(refspec_nr, refspec);
+	}
+	free(head);
+
+	return 0;
+}
+
 static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 {
 	int i;
@@ -1116,9 +1462,6 @@ static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, embed_gitdir_options,
 			     git_submodule_helper_usage, 0);
 
-	gitmodules_config();
-	git_config(submodule_config, NULL);
-
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
 		return 1;
 
@@ -1129,6 +1472,14 @@ static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+static int is_active(int argc, const char **argv, const char *prefix)
+{
+	if (argc != 2)
+		die("submodule--helper is-active takes exactly 1 argument");
+
+	return !is_submodule_active(the_repository, argv[1]);
+}
+
 #define SUPPORT_SUPER_PREFIX (1<<0)
 
 struct cmd_struct {
@@ -1146,16 +1497,18 @@ static struct cmd_struct commands[] = {
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
+	{"status", module_status, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
+	{"push-check", push_check, 0},
 	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
+	{"is-active", is_active, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
 {
 	int i;
-	if (argc < 2)
-		die(_("submodule--helper subcommand must be "
-		      "called with a subcommand"));
+	if (argc < 2 || !strcmp(argv[1], "-h"))
+		usage("git submodule--helper <command>");
 
 	for (i = 0; i < ARRAY_SIZE(commands); i++) {
 		if (!strcmp(argv[1], commands[i].cmd)) {