[PATCH v4 7/7] submodule: move core cmd_update() logic to C

From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>,
	"Atharva Raykar" <raykar.ath@gmail.com>,
	"Christian Couder" <christian.couder@gmail.com>,
	"Emily Shaffer" <emilyshaffer@google.com>,
	"Jonathan Nieder" <jrn@google.com>,
	"Kaartic Sivaraam" <kaartic.sivaraam@gmail.com>,
	pc44800@gmail.com, "Shourya Shukla" <periperidip@gmail.com>,
	"Glen Choo" <chooglen@google.com>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: [PATCH v4 7/7] submodule: move core cmd_update() logic to C
Date: Thu, 27 Jan 2022 17:22:56 +0100	[thread overview]
Message-ID: <patch-v4-7.7-02954603763-20220127T143552Z-avarab@gmail.com> (raw)
In-Reply-To: <cover-v4-0.7-00000000000-20220127T143552Z-avarab@gmail.com>

From: Atharva Raykar <raykar.ath@gmail.com>

This patch completes the conversion past the flag parsing of
`submodule update` by introducing a helper subcommand called
`submodule--helper update`. The behaviour of `submodule update` should
remain the same after this patch.

We add more fields to the `struct update_data` that are required by
`struct submodule_update_clone` to be able to perform a clone, when that
is needed to be done.

Recursing on a submodule is done by calling a subprocess that launches
`submodule--helper update`, with a modified `--recursive-prefix` and
`--prefix` parameter.

We also introduce `update_submodules2()` and `update_submodule2()`
which will supersede `update_submodules()` and `update_submodule()`.

When the `--init` flag is passed to the subcommand, we do not spawn a
new subprocess and call `submodule--helper init` on the submodule paths,
because the Git machinery is not able to pick up the configuration
changes introduced by that init call[1]. So we instead run the
`init_submodule_cb()` callback over each submodule in the same process.

While we are at it, we also remove the fetch_in_submodule() shell
function since it is no longer used anywhere.

[1] https://lore.kernel.org/git/CAP8UFD0NCQ5w_3GtT_xHr35i7h8BuLX4UcHNY6VHPGREmDVObA@mail.gmail.com/

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Shourya Shukla <periperidip@gmail.com>
Signed-off-by: Atharva Raykar <raykar.ath@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/submodule--helper.c | 662 ++++++++++++++++++++----------------
 git-submodule.sh            | 145 +-------
 2 files changed, 389 insertions(+), 418 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index a96976b1772..916df6d9947 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -73,21 +73,6 @@ static char *get_default_remote(void)
 	return repo_get_default_remote(the_repository, refname);
 }
 
-static int print_default_remote(int argc, const char **argv, const char *prefix)
-{
-	char *remote;
-
-	if (argc != 1)
-		die(_("submodule--helper print-default-remote takes no arguments"));
-
-	remote = get_default_remote();
-	if (remote)
-		printf("%s\n", remote);
-
-	free(remote);
-	return 0;
-}
-
 static int starts_with_dot_slash(const char *str)
 {
 	return str[0] == '.' && is_dir_sep(str[1]);
@@ -1967,29 +1952,6 @@ static void determine_submodule_update_strategy(struct repository *r,
 	free(key);
 }
 
-static int module_update_module_mode(int argc, const char **argv, const char *prefix)
-{
-	const char *path, *update = NULL;
-	int just_cloned;
-	struct submodule_update_strategy update_strategy = { .type = SM_UPDATE_CHECKOUT };
-
-	if (argc < 3 || argc > 4)
-		die("submodule--helper update-module-clone expects <just-cloned> <path> [<update>]");
-
-	just_cloned = git_config_int("just_cloned", argv[1]);
-	path = argv[2];
-
-	if (argc == 4)
-		update = argv[3];
-
-	determine_submodule_update_strategy(the_repository,
-					    just_cloned, path, update,
-					    &update_strategy);
-	fputs(submodule_strategy_to_string(&update_strategy), stdout);
-
-	return 0;
-}
-
 struct update_clone_data {
 	const struct submodule *sub;
 	struct object_id oid;
@@ -2017,7 +1979,6 @@ struct submodule_update_clone {
 	const char *prefix;
 	int single_branch;
 
-	/* to be consumed by git-submodule.sh */
 	struct update_clone_data *update_clone;
 	int update_clone_nr; int update_clone_alloc;
 
@@ -2040,20 +2001,62 @@ struct submodule_update_clone {
 }
 
 struct update_data {
+	const char *prefix;
 	const char *recursive_prefix;
 	const char *sm_path;
 	const char *displaypath;
 	struct object_id oid;
 	struct object_id suboid;
 	struct submodule_update_strategy update_strategy;
+	int max_jobs;
 	int depth;
-	unsigned int force: 1;
-	unsigned int quiet: 1;
-	unsigned int nofetch: 1;
-	unsigned int just_cloned: 1;
+	int recommend_shallow;
+	int single_branch;
+	unsigned int init;
+	unsigned int force;
+	unsigned int quiet;
+	unsigned int nofetch;
+	unsigned int remote;
+	unsigned int recursive;
+	unsigned int progress;
+	unsigned int dissociate;
+	unsigned int require_init;
+	unsigned warn_if_uninitialized ;
+	unsigned int just_cloned ;
+	struct string_list references;
+	struct module_list list;
 };
 #define UPDATE_DATA_INIT { \
+	.list = MODULE_LIST_INIT, \
 	.update_strategy = SUBMODULE_UPDATE_STRATEGY_INIT, \
+	.recommend_shallow = -1, \
+	.references = STRING_LIST_INIT_DUP, \
+	.single_branch = -1, \
+	.max_jobs = 1, \
+}
+
+static void update_clone_from_update_data(struct submodule_update_clone *suc,
+					  struct update_data *update_data)
+{
+	suc->prefix = update_data->prefix;
+	suc->recursive_prefix = update_data->recursive_prefix;
+	suc->max_jobs = update_data->max_jobs;
+	suc->progress = update_data->progress;
+	suc->quiet = update_data->quiet;
+	suc->dissociate = update_data->dissociate;
+	suc->require_init = update_data->require_init;
+	suc->single_branch = update_data->single_branch;
+	suc->warn_if_uninitialized = update_data->warn_if_uninitialized;
+	suc->list = update_data->list;
+	suc->update = update_data->update_strategy;
+	suc->recommend_shallow = update_data->recommend_shallow;
+	if (update_data->depth)
+		suc->depth = xstrfmt("--depth=%d", update_data->depth);
+	if (update_data->references.nr) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, &update_data->references)
+			string_list_append(&suc->references, item->string);
+	}
 }
 
 static void next_submodule_warn_missing(struct submodule_update_clone *suc,
@@ -2349,13 +2352,21 @@ static int fetch_in_submodule(const char *module_path, int depth, int quiet, str
 	return run_command(&cp);
 }
 
-static int run_update_command(struct update_data *ud, int subforce)
+static int run_update_command(struct update_data *ud, int subforce, struct string_list *err)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	char *oid = oid_to_hex(&ud->oid);
+	struct strbuf out = STRBUF_INIT;
 	int must_die_on_failure = 0;
+	struct submodule_update_strategy strategy = SUBMODULE_UPDATE_STRATEGY_INIT;
 
-	switch (ud->update_strategy.type) {
+	if (ud->update_strategy.type == SM_UPDATE_UNSPECIFIED || ud->just_cloned)
+		determine_submodule_update_strategy(the_repository, ud->just_cloned,
+						    ud->sm_path, NULL, &strategy);
+	else
+		strategy = ud->update_strategy;
+
+	switch (strategy.type) {
 	case SM_UPDATE_CHECKOUT:
 		cp.git_cmd = 1;
 		strvec_pushl(&cp.args, "checkout", "-q", NULL);
@@ -2378,80 +2389,76 @@ static int run_update_command(struct update_data *ud, int subforce)
 		break;
 	case SM_UPDATE_COMMAND:
 		cp.use_shell = 1;
-		strvec_push(&cp.args, ud->update_strategy.command);
+		strvec_push(&cp.args, strategy.command);
 		must_die_on_failure = 1;
 		break;
 	default:
 		BUG("unexpected update strategy type: %s",
-		    submodule_strategy_to_string(&ud->update_strategy));
+		    submodule_strategy_to_string(&strategy));
 	}
 	strvec_push(&cp.args, oid);
 
 	cp.dir = xstrdup(ud->sm_path);
 	prepare_submodule_repo_env(&cp.env_array);
-	if (run_command(&cp)) {
-		switch (ud->update_strategy.type) {
+	if (capture_command(&cp, &out, 0)) {
+		if (must_die_on_failure) {
+			switch (strategy.type) {
+			case SM_UPDATE_CHECKOUT:
+				die(_("Unable to checkout '%s' in submodule path '%s'"),
+				    oid, ud->displaypath);
+				break;
+			case SM_UPDATE_REBASE:
+				die(_("Unable to rebase '%s' in submodule path '%s'"),
+				    oid, ud->displaypath);
+				break;
+			case SM_UPDATE_MERGE:
+				die(_("Unable to merge '%s' in submodule path '%s'"),
+				    oid, ud->displaypath);
+				break;
+			case SM_UPDATE_COMMAND:
+				die(_("Execution of '%s %s' failed in submodule path '%s'"),
+				    strategy.command, oid, ud->displaypath);
+				break;
+			default:
+				BUG("unexpected update strategy type: %s",
+				    submodule_strategy_to_string(&strategy));
+			}
+		}
+
+		/* the command failed, but update must continue */
+		string_list_append_nodup(err, strbuf_detach(&out, NULL));
+		return 1;
+	}
+
+	if (!ud->quiet) {
+		switch (strategy.type) {
 		case SM_UPDATE_CHECKOUT:
-			printf(_("Unable to checkout '%s' in submodule path '%s'"),
-			       oid, ud->displaypath);
+			printf(_("Submodule path '%s': checked out '%s'\n"),
+			       ud->displaypath, oid);
 			break;
 		case SM_UPDATE_REBASE:
-			printf(_("Unable to rebase '%s' in submodule path '%s'"),
-			       oid, ud->displaypath);
+			printf(_("Submodule path '%s': rebased into '%s'\n"),
+			       ud->displaypath, oid);
 			break;
 		case SM_UPDATE_MERGE:
-			printf(_("Unable to merge '%s' in submodule path '%s'"),
-			       oid, ud->displaypath);
+			printf(_("Submodule path '%s': merged in '%s'\n"),
+			       ud->displaypath, oid);
 			break;
 		case SM_UPDATE_COMMAND:
-			printf(_("Execution of '%s %s' failed in submodule path '%s'"),
-			       ud->update_strategy.command, oid, ud->displaypath);
+			printf(_("Submodule path '%s': '%s %s'\n"),
+			       ud->displaypath, strategy.command, oid);
 			break;
 		default:
 			BUG("unexpected update strategy type: %s",
-			    submodule_strategy_to_string(&ud->update_strategy));
+			    submodule_strategy_to_string(&strategy));
 		}
-		/*
-		 * NEEDSWORK: We are currently printing to stdout with error
-		 * return so that the shell caller handles the error output
-		 * properly. Once we start handling the error messages within
-		 * C, we should use die() instead.
-		 */
-		if (must_die_on_failure)
-			return 2;
-		/*
-		 * This signifies to the caller in shell that the command
-		 * failed without dying
-		 */
-		return 1;
-	}
-
-	switch (ud->update_strategy.type) {
-	case SM_UPDATE_CHECKOUT:
-		printf(_("Submodule path '%s': checked out '%s'\n"),
-		       ud->displaypath, oid);
-		break;
-	case SM_UPDATE_REBASE:
-		printf(_("Submodule path '%s': rebased into '%s'\n"),
-		       ud->displaypath, oid);
-		break;
-	case SM_UPDATE_MERGE:
-		printf(_("Submodule path '%s': merged in '%s'\n"),
-		       ud->displaypath, oid);
-		break;
-	case SM_UPDATE_COMMAND:
-		printf(_("Submodule path '%s': '%s %s'\n"),
-		       ud->displaypath, ud->update_strategy.command, oid);
-		break;
-	default:
-		BUG("unexpected update strategy type: %s",
-		    submodule_strategy_to_string(&ud->update_strategy));
 	}
 
+	strbuf_release(&out);
 	return 0;
 }
 
-static int do_run_update_procedure(struct update_data *ud)
+static int run_update_procedure(struct update_data *ud, struct string_list *err)
 {
 	int subforce = is_null_oid(&ud->suboid) || ud->force;
 
@@ -2478,182 +2485,7 @@ static int do_run_update_procedure(struct update_data *ud)
 			    ud->displaypath, oid_to_hex(&ud->oid));
 	}
 
-	return run_update_command(ud, subforce);
-}
-
-static void update_submodule(struct update_clone_data *ucd)
-{
-	fprintf(stdout, "dummy %s %d\t%s\n",
-		oid_to_hex(&ucd->oid),
-		ucd->just_cloned,
-		ucd->sub->path);
-}
-
-static int update_submodules(struct submodule_update_clone *suc)
-{
-	int i;
-
-	run_processes_parallel_tr2(suc->max_jobs, update_clone_get_next_task,
-				   update_clone_start_failure,
-				   update_clone_task_finished, suc, "submodule",
-				   "parallel/update");
-
-	/*
-	 * We saved the output and put it out all at once now.
-	 * That means:
-	 * - the listener does not have to interleave their (checkout)
-	 *   work with our fetching.  The writes involved in a
-	 *   checkout involve more straightforward sequential I/O.
-	 * - the listener can avoid doing any work if fetching failed.
-	 */
-	if (suc->quickstop)
-		return 1;
-
-	for (i = 0; i < suc->update_clone_nr; i++)
-		update_submodule(&suc->update_clone[i]);
-
-	return 0;
-}
-
-static int update_clone(int argc, const char **argv, const char *prefix)
-{
-	const char *update = NULL;
-	struct pathspec pathspec;
-	struct submodule_update_clone opt = SUBMODULE_UPDATE_CLONE_INIT;
-
-	struct option module_update_clone_options[] = {
-		OPT_STRING(0, "prefix", &prefix,
-			   N_("path"),
-			   N_("path into the working tree")),
-		OPT_STRING(0, "recursive-prefix", &opt.recursive_prefix,
-			   N_("path"),
-			   N_("path into the working tree, across nested "
-			      "submodule boundaries")),
-		OPT_STRING(0, "update", &update,
-			   N_("string"),
-			   N_("rebase, merge, checkout or none")),
-		OPT_STRING_LIST(0, "reference", &opt.references, N_("repo"),
-			   N_("reference repository")),
-		OPT_BOOL(0, "dissociate", &opt.dissociate,
-			   N_("use --reference only while cloning")),
-		OPT_STRING(0, "depth", &opt.depth, "<depth>",
-			   N_("create a shallow clone truncated to the "
-			      "specified number of revisions")),
-		OPT_INTEGER('j', "jobs", &opt.max_jobs,
-			    N_("parallel jobs")),
-		OPT_BOOL(0, "recommend-shallow", &opt.recommend_shallow,
-			    N_("whether the initial clone should follow the shallow recommendation")),
-		OPT__QUIET(&opt.quiet, N_("don't print cloning progress")),
-		OPT_BOOL(0, "progress", &opt.progress,
-			    N_("force cloning progress")),
-		OPT_BOOL(0, "require-init", &opt.require_init,
-			   N_("disallow cloning into non-empty directory")),
-		OPT_BOOL(0, "single-branch", &opt.single_branch,
-			 N_("clone only one branch, HEAD or --branch")),
-		OPT_END()
-	};
-
-	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule--helper update-clone [--prefix=<path>] [<path>...]"),
-		NULL
-	};
-	opt.prefix = prefix;
-
-	update_clone_config_from_gitmodules(&opt.max_jobs);
-	git_config(git_update_clone_config, &opt.max_jobs);
-
-	argc = parse_options(argc, argv, prefix, module_update_clone_options,
-			     git_submodule_helper_usage, 0);
-
-	if (update)
-		if (parse_submodule_update_strategy(update, &opt.update) < 0)
-			die(_("bad value for update parameter"));
-
-	if (module_list_compute(argc, argv, prefix, &pathspec, &opt.list) < 0)
-		return 1;
-
-	if (pathspec.nr)
-		opt.warn_if_uninitialized = 1;
-
-	return update_submodules(&opt);
-}
-
-static int run_update_procedure(int argc, const char **argv, const char *prefix)
-{
-	int force = 0, quiet = 0, nofetch = 0, just_cloned = 0;
-	char *prefixed_path, *update = NULL;
-	struct update_data update_data = UPDATE_DATA_INIT;
-
-	struct option options[] = {
-		OPT__QUIET(&quiet, N_("suppress output for update by rebase or merge")),
-		OPT__FORCE(&force, N_("force checkout updates"), 0),
-		OPT_BOOL('N', "no-fetch", &nofetch,
-			 N_("don't fetch new objects from the remote site")),
-		OPT_BOOL(0, "just-cloned", &just_cloned,
-			 N_("overrides update mode in case the repository is a fresh clone")),
-		OPT_INTEGER(0, "depth", &update_data.depth, N_("depth for shallow fetch")),
-		OPT_STRING(0, "prefix", &prefix,
-			   N_("path"),
-			   N_("path into the working tree")),
-		OPT_STRING(0, "update", &update,
-			   N_("string"),
-			   N_("rebase, merge, checkout or none")),
-		OPT_STRING(0, "recursive-prefix", &update_data.recursive_prefix, N_("path"),
-			   N_("path into the working tree, across nested "
-			      "submodule boundaries")),
-		OPT_CALLBACK_F(0, "oid", &update_data.oid, N_("sha1"),
-			       N_("SHA1 expected by superproject"), PARSE_OPT_NONEG,
-			       parse_opt_object_id),
-		OPT_CALLBACK_F(0, "suboid", &update_data.suboid, N_("subsha1"),
-			       N_("SHA1 of submodule's HEAD"), PARSE_OPT_NONEG,
-			       parse_opt_object_id),
-		OPT_END()
-	};
-
-	const char *const usage[] = {
-		N_("git submodule--helper run-update-procedure [<options>] <path>"),
-		NULL
-	};
-
-	argc = parse_options(argc, argv, prefix, options, usage, 0);
-
-	if (argc != 1)
-		usage_with_options(usage, options);
-
-	update_data.force = !!force;
-	update_data.quiet = !!quiet;
-	update_data.nofetch = !!nofetch;
-	update_data.just_cloned = !!just_cloned;
-	update_data.sm_path = argv[0];
-
-	if (update_data.recursive_prefix)
-		prefixed_path = xstrfmt("%s%s", update_data.recursive_prefix, update_data.sm_path);
-	else
-		prefixed_path = xstrdup(update_data.sm_path);
-
-	update_data.displaypath = get_submodule_displaypath(prefixed_path, prefix);
-
-	determine_submodule_update_strategy(the_repository, update_data.just_cloned,
-					    update_data.sm_path, update,
-					    &update_data.update_strategy);
-
-	free(prefixed_path);
-
-	if (!oideq(&update_data.oid, &update_data.suboid) || update_data.force)
-		return do_run_update_procedure(&update_data);
-
-	return 3;
-}
-
-static int resolve_relative_path(int argc, const char **argv, const char *prefix)
-{
-	struct strbuf sb = STRBUF_INIT;
-	if (argc != 3)
-		die("submodule--helper relative-path takes exactly 2 arguments, got %d", argc);
-
-	printf("%s", relative_path(argv[1], argv[2], &sb));
-	strbuf_release(&sb);
-	return 0;
+	return run_update_command(ud, subforce, err);
 }
 
 static const char *remote_submodule_branch(const char *path)
@@ -2788,17 +2620,11 @@ static int push_check(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static int ensure_core_worktree(int argc, const char **argv, const char *prefix)
+static void ensure_core_worktree(const char *path)
 {
-	const char *path;
 	const char *cw;
 	struct repository subrepo;
 
-	if (argc != 2)
-		BUG("submodule--helper ensure-core-worktree <path>");
-
-	path = argv[1];
-
 	if (repo_submodule_init(&subrepo, the_repository, path, null_oid()))
 		die(_("could not get a repository handle for submodule '%s'"), path);
 
@@ -2818,8 +2644,6 @@ static int ensure_core_worktree(int argc, const char **argv, const char *prefix)
 		free(abs_path);
 		strbuf_release(&sb);
 	}
-
-	return 0;
 }
 
 static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
@@ -3006,6 +2830,279 @@ static int module_set_branch(int argc, const char **argv, const char *prefix)
 	return !!ret;
 }
 
+static void update_data_to_args(struct update_data *update_data, struct strvec *args)
+{
+	const char *update = submodule_strategy_to_string(&update_data->update_strategy);
+
+	strvec_pushl(args, "submodule--helper", "update", "--recursive", NULL);
+	strvec_pushf(args, "--jobs=%d", update_data->max_jobs);
+	if (update_data->prefix)
+		strvec_pushl(args, "--prefix", update_data->prefix, NULL);
+	if (update_data->recursive_prefix)
+		strvec_pushl(args, "--recursive-prefix",
+			     update_data->recursive_prefix, NULL);
+	if (update_data->quiet)
+		strvec_push(args, "--quiet");
+	if (update_data->force)
+		strvec_push(args, "--force");
+	if (update_data->init)
+		strvec_push(args, "--init");
+	if (update_data->remote)
+		strvec_push(args, "--remote");
+	if (update_data->nofetch)
+		strvec_push(args, "--no-fetch");
+	if (update_data->dissociate)
+		strvec_push(args, "--dissociate");
+	if (update_data->progress)
+		strvec_push(args, "--progress");
+	if (update_data->require_init)
+		strvec_push(args, "--require-init");
+	if (update_data->depth)
+		strvec_pushf(args, "--depth=%d", update_data->depth);
+	if (update)
+		strvec_pushl(args, "--update", update, NULL);
+	if (update_data->references.nr) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, &update_data->references)
+			strvec_pushl(args, "--reference", item->string, NULL);
+	}
+	if (update_data->recommend_shallow == 0)
+		strvec_push(args, "--no-recommend-shallow");
+	else if (update_data->recommend_shallow == 1)
+		strvec_push(args, "--recommend-shallow");
+	if (update_data->single_branch >= 0)
+		strvec_push(args, "--single-branch");
+}
+
+static int update_submodule(struct update_data *update_data)
+{
+	char *prefixed_path;
+	struct string_list err = STRING_LIST_INIT_DUP;
+
+	ensure_core_worktree(update_data->sm_path);
+
+	if (update_data->recursive_prefix)
+		prefixed_path = xstrfmt("%s%s", update_data->recursive_prefix,
+					update_data->sm_path);
+	else
+		prefixed_path = xstrdup(update_data->sm_path);
+
+	update_data->displaypath = get_submodule_displaypath(prefixed_path,
+							     update_data->prefix);
+	free(prefixed_path);
+
+	if (update_data->just_cloned) {
+		oidcpy(&update_data->suboid, null_oid());
+	} else {
+		if (resolve_gitlink_ref(update_data->sm_path, "HEAD", &update_data->suboid))
+			die(_("Unable to find current revision in submodule path '%s'"),
+			    update_data->displaypath);
+	}
+
+	if (update_data->remote) {
+		char *remote_name = get_default_remote_submodule(update_data->sm_path);
+		const char *branch = remote_submodule_branch(update_data->sm_path);
+		char *remote_ref = xstrfmt("refs/remotes/%s/%s", remote_name, branch);
+
+		if (!update_data->nofetch) {
+			if (fetch_in_submodule(update_data->sm_path, update_data->depth,
+					      0, NULL))
+				die(_("Unable to fetch in submodule path '%s'"),
+				    update_data->sm_path);
+		}
+
+		if (resolve_gitlink_ref(update_data->sm_path, remote_ref, &update_data->oid))
+			die(_("Unable to find %s revision in submodule path '%s'"),
+			    remote_ref, update_data->sm_path);
+
+		free(remote_ref);
+	}
+
+	if (!oideq(&update_data->oid, &update_data->suboid) || update_data->force)
+		if (run_update_procedure(update_data, &err))
+			return 1;
+
+	if (update_data->recursive) {
+		int res;
+		struct child_process cp = CHILD_PROCESS_INIT;
+		struct update_data next = *update_data;
+		char *die_msg = xstrfmt(_("Failed to recurse into submodule path '%s'"),
+					update_data->displaypath);
+
+		if (update_data->recursive_prefix)
+			prefixed_path = xstrfmt("%s%s/", update_data->recursive_prefix,
+						update_data->sm_path);
+		else
+			prefixed_path = xstrfmt("%s/", update_data->sm_path);
+
+		next.recursive_prefix = get_submodule_displaypath(prefixed_path,
+								  update_data->prefix);
+		next.prefix = NULL;
+		oidcpy(&next.oid, null_oid());
+		oidcpy(&next.suboid, null_oid());
+
+		cp.dir = update_data->sm_path;
+		cp.git_cmd = 1;
+		prepare_submodule_repo_env(&cp.env_array);
+		update_data_to_args(&next, &cp.args);
+
+		/* die() if child process die()'d */
+		if ((res = run_command(&cp)) == 128)
+			die("%s", die_msg);
+		if (res)
+			string_list_append(&err, die_msg);
+
+		free(die_msg);
+	}
+
+	if (err.nr) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, &err)
+			fputs(item->string, stderr);
+		string_list_clear(&err, 0);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int update_submodules(struct update_data *update_data)
+{
+	int i, res = 0;
+	struct submodule_update_clone suc = SUBMODULE_UPDATE_CLONE_INIT;
+
+	update_clone_from_update_data(&suc, update_data);
+	run_processes_parallel_tr2(suc.max_jobs, update_clone_get_next_task,
+				   update_clone_start_failure,
+				   update_clone_task_finished, &suc, "submodule",
+				   "parallel/update");
+
+	/*
+	 * We saved the output and put it out all at once now.
+	 * That means:
+	 * - the listener does not have to interleave their (checkout)
+	 *   work with our fetching.  The writes involved in a
+	 *   checkout involve more straightforward sequential I/O.
+	 * - the listener can avoid doing any work if fetching failed.
+	 */
+	if (suc.quickstop) {
+		res = 1;
+		goto cleanup;
+	}
+
+	for (i = 0; i < suc.update_clone_nr; i++) {
+		struct update_clone_data ucd = suc.update_clone[i];
+
+		oidcpy(&update_data->oid, &ucd.oid);
+		update_data->just_cloned = ucd.just_cloned;
+		update_data->sm_path = ucd.sub->path;
+
+		if (update_submodule(update_data))
+			res = 1;
+	}
+
+cleanup:
+	string_list_clear(&update_data->references, 0);
+	return res;
+}
+
+static int module_update(int argc, const char **argv, const char *prefix)
+{
+	const char *update = NULL;
+	struct pathspec pathspec;
+	struct update_data opt = UPDATE_DATA_INIT;
+
+	struct option module_update_clone_options[] = {
+		OPT__FORCE(&opt.force, N_("force checkout updates"), 0),
+		OPT_BOOL(0, "init", &opt.init,
+			 N_("initialize uninitialized submodules before update")),
+		OPT_BOOL(0, "remote", &opt.remote,
+			 N_("use SHA-1 of submodule's remote tracking branch")),
+		OPT_BOOL(0, "recursive", &opt.recursive,
+			 N_("traverse submodules recursively")),
+		OPT_BOOL('N', "no-fetch", &opt.nofetch,
+			 N_("don't fetch new objects from the remote site")),
+		OPT_STRING(0, "prefix", &opt.prefix,
+			   N_("path"),
+			   N_("path into the working tree")),
+		OPT_STRING(0, "recursive-prefix", &opt.recursive_prefix,
+			   N_("path"),
+			   N_("path into the working tree, across nested "
+			      "submodule boundaries")),
+		OPT_STRING(0, "update", &update,
+			   N_("string"),
+			   N_("rebase, merge, checkout or none")),
+		OPT_STRING_LIST(0, "reference", &opt.references, N_("repo"),
+				N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &opt.dissociate,
+			 N_("use --reference only while cloning")),
+		OPT_INTEGER(0, "depth", &opt.depth,
+			    N_("create a shallow clone truncated to the "
+			       "specified number of revisions")),
+		OPT_INTEGER('j', "jobs", &opt.max_jobs,
+			    N_("parallel jobs")),
+		OPT_BOOL(0, "recommend-shallow", &opt.recommend_shallow,
+			 N_("whether the initial clone should follow the shallow recommendation")),
+		OPT__QUIET(&opt.quiet, N_("don't print cloning progress")),
+		OPT_BOOL(0, "progress", &opt.progress,
+			 N_("force cloning progress")),
+		OPT_BOOL(0, "require-init", &opt.require_init,
+			 N_("disallow cloning into non-empty directory")),
+		OPT_BOOL(0, "single-branch", &opt.single_branch,
+			 N_("clone only one branch, HEAD or --branch")),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper update-clone [--prefix=<path>] [<path>...]"),
+		NULL
+	};
+
+	update_clone_config_from_gitmodules(&opt.max_jobs);
+	git_config(git_update_clone_config, &opt.max_jobs);
+
+	argc = parse_options(argc, argv, prefix, module_update_clone_options,
+			     git_submodule_helper_usage, 0);
+	oidcpy(&opt.oid, null_oid());
+	oidcpy(&opt.suboid, null_oid());
+
+	if (update)
+		if (parse_submodule_update_strategy(update,
+						    &opt.update_strategy) < 0)
+			die(_("bad value for update parameter"));
+
+	if (module_list_compute(argc, argv, prefix, &pathspec, &opt.list) < 0)
+		return 1;
+
+	if (pathspec.nr)
+		opt.warn_if_uninitialized = 1;
+
+	if (opt.init) {
+		struct module_list list = MODULE_LIST_INIT;
+		struct init_cb info = INIT_CB_INIT;
+
+		if (module_list_compute(argc, argv, opt.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);
+
+		info.prefix = opt.prefix;
+		info.superprefix = opt.recursive_prefix;
+		if (opt.quiet)
+			info.flags |= OPT_QUIET;
+
+		for_each_listed_submodule(&list, init_submodule_cb, &info);
+	}
+
+	return update_submodules(&opt);
+}
+
 struct add_data {
 	const char *prefix;
 	const char *branch;
@@ -3393,16 +3490,11 @@ static struct cmd_struct commands[] = {
 	{"name", module_name, 0},
 	{"clone", module_clone, 0},
 	{"add", module_add, SUPPORT_SUPER_PREFIX},
-	{"update-module-mode", module_update_module_mode, 0},
-	{"update-clone", update_clone, 0},
-	{"run-update-procedure", run_update_procedure, 0},
-	{"ensure-core-worktree", ensure_core_worktree, 0},
-	{"relative-path", resolve_relative_path, 0},
+	{"update", module_update, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"foreach", module_foreach, SUPPORT_SUPER_PREFIX},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"status", module_status, SUPPORT_SUPER_PREFIX},
-	{"print-default-remote", print_default_remote, 0},
 	{"sync", module_sync, SUPPORT_SUPER_PREFIX},
 	{"deinit", module_deinit, 0},
 	{"summary", module_summary, SUPPORT_SUPER_PREFIX},
diff --git a/git-submodule.sh b/git-submodule.sh
index 652861aa66a..bcd8b92aabd 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -246,20 +246,6 @@ cmd_deinit()
 	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper deinit ${GIT_QUIET:+--quiet} ${force:+--force} ${deinit_all:+--all} -- "$@"
 }
 
-# usage: fetch_in_submodule <module_path> [<depth>] [<sha1>]
-# Because arguments are positional, use an empty string to omit <depth>
-# but include <sha1>.
-fetch_in_submodule () (
-	sanitize_submodule_env &&
-	cd "$1" &&
-	if test $# -eq 3
-	then
-		echo "$3" | git fetch ${GIT_QUIET:+--quiet} --stdin ${2:+"$2"}
-	else
-		git fetch ${GIT_QUIET:+--quiet} ${2:+"$2"}
-	fi
-)
-
 #
 # Update each submodule path to correct revision, using clone and checkout as needed
 #
@@ -361,133 +347,26 @@ cmd_update()
 		shift
 	done
 
-	if test -n "$init"
-	then
-		cmd_init "--" "$@" || return
-	fi
-
-	{
-	git submodule--helper update-clone ${GIT_QUIET:+--quiet} \
-		${progress:+"--progress"} \
+	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper update \
+		${GIT_QUIET:+--quiet} \
+		${force:+--force} \
+		${progress:+--progress} \
+		${dissociate:+--dissociate} \
+		${remote:+--remote} \
+		${recursive:+--recursive} \
+		${init:+--init} \
+		${require_init:+--require-init} \
+		${nofetch:+--no-fetch} \
 		${wt_prefix:+--prefix "$wt_prefix"} \
 		${prefix:+--recursive-prefix "$prefix"} \
 		${update:+--update "$update"} \
 		${reference:+"$reference"} \
-		${dissociate:+"--dissociate"} \
-		${depth:+--depth "$depth"} \
-		${require_init:+--require-init} \
+		${depth:+"$depth"} \
 		$single_branch \
 		$recommend_shallow \
 		$jobs \
 		-- \
-		"$@" || echo "#unmatched" $?
-	} | {
-	err=
-	while read -r quickabort sha1 just_cloned sm_path
-	do
-		die_if_unmatched "$quickabort" "$sha1"
-
-		git submodule--helper ensure-core-worktree "$sm_path" || exit 1
-
-		displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
-
-		if test $just_cloned -eq 1
-		then
-			subsha1=
-		else
-			just_cloned=
-			subsha1=$(sanitize_submodule_env; cd "$sm_path" &&
-				git rev-parse --verify HEAD) ||
-			die "fatal: $(eval_gettext "Unable to find current revision in submodule path '\$displaypath'")"
-		fi
-
-		if test -n "$remote"
-		then
-			branch=$(git submodule--helper remote-branch "$sm_path")
-			if test -z "$nofetch"
-			then
-				# Fetch remote before determining tracking $sha1
-				fetch_in_submodule "$sm_path" $depth ||
-				die "fatal: $(eval_gettext "Unable to fetch in submodule path '\$sm_path'")"
-			fi
-			remote_name=$(sanitize_submodule_env; cd "$sm_path" && git submodule--helper print-default-remote)
-			sha1=$(sanitize_submodule_env; cd "$sm_path" &&
-				git rev-parse --verify "${remote_name}/${branch}") ||
-			die "fatal: $(eval_gettext "Unable to find current \${remote_name}/\${branch} revision in submodule path '\$sm_path'")"
-		fi
-
-		out=$(git submodule--helper run-update-procedure \
-			  ${wt_prefix:+--prefix "$wt_prefix"} \
-			  ${GIT_QUIET:+--quiet} \
-			  ${force:+--force} \
-			  ${just_cloned:+--just-cloned} \
-			  ${nofetch:+--no-fetch} \
-			  ${depth:+"$depth"} \
-			  ${update:+--update "$update"} \
-			  ${prefix:+--recursive-prefix "$prefix"} \
-			  ${sha1:+--oid "$sha1"} \
-			  ${subsha1:+--suboid "$subsha1"} \
-			  "--" \
-			  "$sm_path")
-
-		# exit codes for run-update-procedure:
-		# 0: update was successful, say command output
-		# 1: update procedure failed, but should not die
-		# 2 or 128: subcommand died during execution
-		# 3: no update procedure was run
-		res="$?"
-		case $res in
-		0)
-			say "$out"
-			;;
-		1)
-			err="${err};fatal: $out"
-			continue
-			;;
-		2|128)
-			die_with_status $res "fatal: $out"
-			;;
-		esac
-
-		if test -n "$recursive"
-		then
-			(
-				prefix=$(git submodule--helper relative-path "$prefix$sm_path/" "$wt_prefix")
-				wt_prefix=
-				sanitize_submodule_env
-				cd "$sm_path" &&
-				eval cmd_update
-			)
-			res=$?
-			if test $res -gt 0
-			then
-				die_msg="fatal: $(eval_gettext "Failed to recurse into submodule path '\$displaypath'")"
-				if test $res -ne 2
-				then
-					err="${err};$die_msg"
-					continue
-				else
-					die_with_status $res "$die_msg"
-				fi
-			fi
-		fi
-	done
-
-	if test -n "$err"
-	then
-		OIFS=$IFS
-		IFS=';'
-		for e in $err
-		do
-			if test -n "$e"
-			then
-				echo >&2 "$e"
-			fi
-		done
-		IFS=$OIFS
-		exit 1
-	fi
-	}
+		"$@"
 }
 
 #
-- 
2.35.0.894.g563b84683b9

