submodule--helper: eliminate internal "--update" option

Follow-up on the preceding commit which taught "git submodule--helper
update" to understand "--merge", "--checkout" and "--rebase" and use
those options instead of "--update=(rebase|merge|checkout|none)" when
the command invokes itself.

Unlike the preceding change this isn't strictly necessary to
eventually change "git-submodule.sh" so that it invokes "git
submodule--helper update" directly, but let's remove this
inconsistency in the command-line interface. We shouldn't need to
carry special synonyms for existing options in "git submodule--helper"
when that command can use the primary documented names instead.

But, as seen in the post-image this makes the control flow within
"builtin/submodule--helper.c" simpler, we can now write directly to
the "update_default" member of "struct update_data" when parsing the
options in "module_update()".

Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/submodule--helper.c

@@ -1818,7 +1818,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 static void determine_submodule_update_strategy(struct repository *r,
 						int just_cloned,
 						const char *path,
-						const char *update,
+						enum submodule_update_type update,
 						struct submodule_update_strategy *out)
 {
 	const struct submodule *sub = submodule_from_path(r, null_oid(), path);
@@ -1828,9 +1828,7 @@ static void determine_submodule_update_strategy(struct repository *r,
 	key = xstrfmt("submodule.%s.update", sub->name);
 
 	if (update) {
-		if (parse_submodule_update_strategy(update, out) < 0)
-			die(_("Invalid update mode '%s' for submodule path '%s'"),
-				update, path);
+		out->type = update;
 	} else if (!repo_config_get_string_tmp(r, key, &val)) {
 		if (parse_submodule_update_strategy(val, out) < 0)
 			die(_("Invalid update mode '%s' configured for submodule path '%s'"),
@@ -1882,7 +1880,7 @@ struct update_data {
 	const char *prefix;
 	const char *recursive_prefix;
 	const char *displaypath;
-	const char *update_default;
+	enum submodule_update_type update_default;
 	struct object_id suboid;
 	struct string_list references;
 	struct submodule_update_strategy update_strategy;
@@ -2423,6 +2421,8 @@ static const char *submodule_update_type_to_label(enum submodule_update_type typ
 
 static void update_data_to_args(struct update_data *update_data, struct strvec *args)
 {
+	enum submodule_update_type update_type = update_data->update_default;
+
 	strvec_pushl(args, "submodule--helper", "update", "--recursive", NULL);
 	strvec_pushf(args, "--jobs=%d", update_data->max_jobs);
 	if (update_data->recursive_prefix)
@@ -2446,8 +2446,10 @@ static void update_data_to_args(struct update_data *update_data, struct strvec *
 		strvec_push(args, "--require-init");
 	if (update_data->depth)
 		strvec_pushf(args, "--depth=%d", update_data->depth);
-	if (update_data->update_default)
-		strvec_pushl(args, "--update", update_data->update_default, NULL);
+	if (update_type != SM_UPDATE_UNSPECIFIED)
+		strvec_pushf(args, "--%s",
+			     submodule_update_type_to_label(update_type));
+
 	if (update_data->references.nr) {
 		struct string_list_item *item;
 		for_each_string_list_item(item, &update_data->references)
@@ -2599,7 +2601,6 @@ static int module_update(int argc, const char **argv, const char *prefix)
 	struct update_data opt = UPDATE_DATA_INIT;
 	struct list_objects_filter_options filter_options;
 	int ret;
-	enum submodule_update_type update_type = SM_UPDATE_UNSPECIFIED;
 
 	struct option module_update_options[] = {
 		OPT__FORCE(&opt.force, N_("force checkout updates"), 0),
@@ -2618,16 +2619,13 @@ static int module_update(int argc, const char **argv, const char *prefix)
 			   N_("path"),
 			   N_("path into the working tree, across nested "
 			      "submodule boundaries")),
-		OPT_STRING(0, "update", &opt.update_default,
-			   N_("string"),
-			   N_("rebase, merge, checkout or none")),
-		OPT_SET_INT(0, "checkout", &update_type,
+		OPT_SET_INT(0, "checkout", &opt.update_default,
 			N_("use the 'checkout' update strategy (default)"),
 			SM_UPDATE_CHECKOUT),
-		OPT_SET_INT('m', "merge", &update_type,
+		OPT_SET_INT('m', "merge", &opt.update_default,
 			N_("use the 'merge' update strategy"),
 			SM_UPDATE_MERGE),
-		OPT_SET_INT('r', "rebase", &update_type,
+		OPT_SET_INT('r', "rebase", &opt.update_default,
 			N_("use the 'rebase' update strategy"),
 			SM_UPDATE_REBASE),
 		OPT_STRING_LIST(0, "reference", &opt.references, N_("repo"),
@@ -2679,13 +2677,8 @@ static int module_update(int argc, const char **argv, const char *prefix)
 
 	opt.filter_options = &filter_options;
 
-	if (update_type != SM_UPDATE_UNSPECIFIED)
-		opt.update_default = submodule_update_type_to_label(update_type);
-
 	if (opt.update_default)
-		if (parse_submodule_update_strategy(opt.update_default,
-						    &opt.update_strategy) < 0)
-			die(_("bad value for update parameter"));
+		opt.update_strategy.type = opt.update_default;
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &opt.list) < 0) {
 		list_objects_filter_release(&filter_options);