Merge branch 'vv/branch-recurse-no-start-ref' into jch

The --recurse-submodules option in 'git branch' has been fixed to
avoid a crash when the start point is not a reference (e.g., a raw
object ID).  The creation path now skips setting up tracking and
properly forwards the absent tracking name to the submodule helper.

* vv/branch-recurse-no-start-ref:
  branch: allow recursion with no tracking name
  branch: do not track a start point with no ref

branch.c

@@ -760,7 +760,15 @@ static int submodule_create_branch(struct repository *r,
 		break;
 	}
 
-	strvec_pushl(&child.args, name, start_oid, tracking_name, NULL);
+	/*
+	 * The tracking name is absent when the start point named no ref.
+	 * Push it separately: strvec_pushl() stops at the first NULL, so
+	 * passing it inline would drop the argument by accident rather
+	 * than by intent.
+	 */
+	strvec_pushl(&child.args, name, start_oid, NULL);
+	if (tracking_name)
+		strvec_push(&child.args, tracking_name);
 
 	if ((ret = start_command(&child)))
 		return ret;
@@ -840,7 +848,7 @@ void create_branches_recursively(struct repository *r, const char *name,
 	 * tedious to determine whether or not tracking was set up in the
 	 * superproject.
 	 */
-	if (track)
+	if (tracking_name && track)
 		setup_tracking(name, tracking_name, track, quiet);
 
 	for (i = 0; i < submodule_entry_list.entry_nr; i++) {

builtin/submodule--helper.c

@@ -3336,7 +3336,7 @@ static int module_create_branch(int argc, const char **argv, const char *prefix,
 		OPT_END()
 	};
 	const char *const usage[] = {
-		N_("git submodule--helper create-branch [-f|--force] [--create-reflog] [-q|--quiet] [-t|--track] [-n|--dry-run] <name> <start-oid> <start-name>"),
+		N_("git submodule--helper create-branch [-f|--force] [--create-reflog] [-q|--quiet] [-t|--track] [-n|--dry-run] <name> <start-oid> [<start-name>]"),
 		NULL
 	};
 	struct repo_config_values *cfg = repo_config_values(the_repository);
@@ -3345,13 +3345,14 @@ static int module_create_branch(int argc, const char **argv, const char *prefix,
 	track = cfg->branch_track;
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 
-	if (argc != 3)
+	if (argc < 2 || argc > 3)
 		usage_with_options(usage, options);
 
 	if (!quiet && !dry_run)
 		printf_ln(_("creating branch '%s'"), argv[0]);
 
-	create_branches_recursively(the_repository, argv[0], argv[1], argv[2],
+	create_branches_recursively(the_repository, argv[0], argv[1],
+				    argc > 2 ? argv[2] : NULL,
 				    force, reflog, quiet, track, dry_run);
 	return 0;
 }

t/t3207-branch-submodule.sh

@@ -98,6 +98,36 @@ test_expect_success 'should respect submodule.recurse when creating branches' '
 	)
 '
 
+test_expect_success 'should move a branch to a start point that names no ref' '
+	test_when_finished "rm -rf no-submodules" &&
+	git init no-submodules &&
+	(
+		cd no-submodules &&
+		test_commit one &&
+		test_commit two &&
+		git remote add origin . &&
+		git config submodule.propagateBranches true &&
+		git config submodule.recurse true &&
+		git branch branch-a HEAD~1 &&
+		oid=$(git rev-parse HEAD) &&
+		git branch -f branch-a "$oid" &&
+		test_cmp_rev HEAD branch-a
+	)
+'
+
+test_expect_success 'should recurse into submodules from a start point that names no ref' '
+	test_when_finished "reset_test" &&
+	(
+		cd super &&
+		oid=$(git rev-parse HEAD) &&
+		git branch --recurse-submodules branch-a "$oid" &&
+		git rev-parse branch-a &&
+		git -C sub rev-parse branch-a &&
+		git -C sub/sub-sub rev-parse branch-a &&
+		git -C second/sub rev-parse branch-a
+	)
+'
+
 test_expect_success 'should ignore submodule.recurse when not creating branches' '
 	test_when_finished "reset_test" &&
 	(