submodule: add --dissociate option to add/update commands

Add --dissociate option to add and update commands, both clone helper commands
that already have the --reference option --dissociate pairs with.

Signed-off-by: Casey Fitzpatrick <kcghost@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-submodule.txt

@@ -369,7 +369,15 @@ the submodule itself.
 	this option will be passed to the linkgit:git-clone[1] command.
 +
 *NOTE*: Do *not* use this option unless you have read the note
-for linkgit:git-clone[1]'s `--reference` and `--shared` options carefully.
+for linkgit:git-clone[1]'s `--reference`, `--shared`, and `--dissociate`
+options carefully.
+
+--dissociate::
+	This option is only valid for add and update commands.  These
+	commands sometimes need to clone a remote repository. In this case,
+	this option will be passed to the linkgit:git-clone[1] command.
++
+*NOTE*: see the NOTE for the `--reference` option.
 
 --recursive::
 	This option is only valid for foreach, update, status and sync commands.

builtin/submodule--helper.c

@@ -1056,7 +1056,7 @@ static int module_deinit(int argc, const char **argv, const char *prefix)
 }
 
 static int clone_submodule(const char *path, const char *gitdir, const char *url,
-			   const char *depth, struct string_list *reference,
+			   const char *depth, struct string_list *reference, int dissociate,
 			   int quiet, int progress)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
@@ -1075,6 +1075,8 @@ static int clone_submodule(const char *path, const char *gitdir, const char *url
 			argv_array_pushl(&cp.args, "--reference",
 					 item->string, NULL);
 	}
+	if (dissociate)
+		argv_array_push(&cp.args, "--dissociate");
 	if (gitdir && *gitdir)
 		argv_array_pushl(&cp.args, "--separate-git-dir", gitdir, NULL);
 
@@ -1190,6 +1192,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	char *p, *path = NULL, *sm_gitdir;
 	struct strbuf sb = STRBUF_INIT;
 	struct string_list reference = STRING_LIST_INIT_NODUP;
+	int dissociate = 0;
 	char *sm_alternate = NULL, *error_strategy = NULL;
 
 	struct option module_clone_options[] = {
@@ -1208,6 +1211,8 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 		OPT_STRING_LIST(0, "reference", &reference,
 			   N_("repo"),
 			   N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &dissociate,
+			   N_("use --reference only while cloning")),
 		OPT_STRING(0, "depth", &depth,
 			   N_("string"),
 			   N_("depth for shallow clones")),
@@ -1247,7 +1252,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 
 		prepare_possible_alternates(name, &reference);
 
-		if (clone_submodule(path, sm_gitdir, url, depth, &reference,
+		if (clone_submodule(path, sm_gitdir, url, depth, &reference, dissociate,
 				    quiet, progress))
 			die(_("clone of '%s' into submodule path '%s' failed"),
 			    url, path);
@@ -1300,6 +1305,7 @@ struct submodule_update_clone {
 	int quiet;
 	int recommend_shallow;
 	struct string_list references;
+	int dissociate;
 	const char *depth;
 	const char *recursive_prefix;
 	const char *prefix;
@@ -1315,7 +1321,7 @@ struct submodule_update_clone {
 	int failed_clones_nr, failed_clones_alloc;
 };
 #define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
-	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, \
+	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, \
 	NULL, NULL, NULL, \
 	STRING_LIST_INIT_DUP, 0, NULL, 0, 0}
 
@@ -1442,6 +1448,8 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		for_each_string_list_item(item, &suc->references)
 			argv_array_pushl(&child->args, "--reference", item->string, NULL);
 	}
+	if (suc->dissociate)
+		argv_array_push(&child->args, "--dissociate");
 	if (suc->depth)
 		argv_array_push(&child->args, suc->depth);
 
@@ -1575,6 +1583,8 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 			   N_("rebase, merge, checkout or none")),
 		OPT_STRING_LIST(0, "reference", &suc.references, N_("repo"),
 			   N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &suc.dissociate,
+			   N_("use --reference only while cloning")),
 		OPT_STRING(0, "depth", &suc.depth, "<depth>",
 			   N_("Create a shallow clone truncated to the "
 			      "specified number of revisions")),

git-submodule.sh

@@ -42,6 +42,7 @@ prefix=
 custom_name=
 depth=
 progress=
+dissociate=
 
 die_if_unmatched ()
 {
@@ -128,6 +129,9 @@ cmd_add()
 		--reference=*)
 			reference_path="${1#--reference=}"
 			;;
+		--dissociate)
+			dissociate=1
+			;;
 		--name)
 			case "$2" in '') usage ;; esac
 			custom_name=$2
@@ -258,7 +262,7 @@ or you are unsure what this means choose another name with the '--name' option."
 				eval_gettextln "Reactivating local git directory for submodule '\$sm_name'."
 			fi
 		fi
-		git submodule--helper clone ${GIT_QUIET:+--quiet} ${progress:+"--progress"} --prefix "$wt_prefix" --path "$sm_path" --name "$sm_name" --url "$realrepo" ${reference:+"$reference"} ${depth:+"$depth"} || exit
+		git submodule--helper clone ${GIT_QUIET:+--quiet} ${progress:+"--progress"} --prefix "$wt_prefix" --path "$sm_path" --name "$sm_name" --url "$realrepo" ${reference:+"$reference"} ${dissociate:+"--dissociate"} ${depth:+"$depth"} || exit
 		(
 			sanitize_submodule_env
 			cd "$sm_path" &&
@@ -493,6 +497,9 @@ cmd_update()
 		--reference=*)
 			reference="$1"
 			;;
+		--dissociate)
+			dissociate=1
+			;;
 		-m|--merge)
 			update="merge"
 			;;
@@ -550,6 +557,7 @@ cmd_update()
 		${prefix:+--recursive-prefix "$prefix"} \
 		${update:+--update "$update"} \
 		${reference:+"$reference"} \
+		${dissociate:+"--dissociate"} \
 		${depth:+--depth "$depth"} \
 		$recommend_shallow \
 		$jobs \

t/t7408-submodule-reference.sh

@@ -59,6 +59,16 @@ test_expect_success 'submodule add --reference uses alternates' '
 	test_alternate_is_used super/.git/modules/sub/objects/info/alternates super/sub
 '
 
+test_expect_success 'submodule add --reference with --dissociate does not use alternates' '
+	(
+		cd super &&
+		git submodule add --reference ../B --dissociate "file://$base_dir/A" sub-dissociate &&
+		git commit -m B-super-added &&
+		git repack -ad
+	) &&
+	test_path_is_missing super/.git/modules/sub-dissociate/objects/info/alternates
+'
+
 test_expect_success 'that reference gets used with add' '
 	(
 		cd super/sub &&
@@ -82,6 +92,13 @@ test_expect_success 'updating superproject keeps alternates' '
 	test_alternate_is_used super-clone/.git/modules/sub/objects/info/alternates super-clone/sub
 '
 
+test_expect_success 'updating superproject with --dissociate does not keep alternates' '
+	test_when_finished "rm -rf super-clone" &&
+	git clone super super-clone &&
+	git -C super-clone submodule update --init --reference ../B --dissociate &&
+	test_path_is_missing super-clone/.git/modules/sub/objects/info/alternates
+'
+
 test_expect_success 'submodules use alternates when cloning a superproject' '
 	test_when_finished "rm -rf super-clone" &&
 	git clone --reference super --recursive super super-clone &&