branch: support more tracking modes when recursing

"git branch --recurse-submodules" does not propagate "--track=inherit"
or "--no-track" to submodules, which causes submodule branches to use
the wrong tracking mode [1]. To fix this, pass the correct options to
the "submodule--helper create-branch" child process and test for it.

While we are refactoring the same code, replace "--track" with the
synonymous, but more consistent-looking "--track=direct" option
(introduced at the same time as "--track=inherit", d3115660b4 (branch:
add flags and config to inherit tracking, 2021-12-20)).

[1] This bug is partially a timing issue: "branch --recurse-submodules"
 was introduced around the same time as "--track=inherit", and even
 though I rebased "branch --recurse-submodules" on top of that, I had
 neglected to support the new tracking mode. Omitting "--no-track"
 was just a plain old mistake, though.

Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

branch.c

@@ -233,6 +233,9 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
 	struct string_list tracking_srcs = STRING_LIST_INIT_DUP;
 	int config_flags = quiet ? 0 : BRANCH_CONFIG_VERBOSE;
 
+	if (!track)
+		BUG("asked to set up tracking, but tracking is disallowed");
+
 	memset(&tracking, 0, sizeof(tracking));
 	tracking.spec.dst = (char *)orig_ref;
 	tracking.srcs = &tracking_srcs;
@@ -529,8 +532,27 @@ static int submodule_create_branch(struct repository *r,
 		strvec_push(&child.args, "--quiet");
 	if (reflog)
 		strvec_push(&child.args, "--create-reflog");
-	if (track == BRANCH_TRACK_ALWAYS || track == BRANCH_TRACK_EXPLICIT)
-		strvec_push(&child.args, "--track");
+
+	switch (track) {
+	case BRANCH_TRACK_NEVER:
+		strvec_push(&child.args, "--no-track");
+		break;
+	case BRANCH_TRACK_ALWAYS:
+	case BRANCH_TRACK_EXPLICIT:
+		strvec_push(&child.args, "--track=direct");
+		break;
+	case BRANCH_TRACK_OVERRIDE:
+		BUG("BRANCH_TRACK_OVERRIDE cannot be used when creating a branch.");
+		break;
+	case BRANCH_TRACK_INHERIT:
+		strvec_push(&child.args, "--track=inherit");
+		break;
+	case BRANCH_TRACK_UNSPECIFIED:
+		/* Default for "git checkout". No need to pass --track. */
+	case BRANCH_TRACK_REMOTE:
+		/* Default for "git branch". No need to pass --track. */
+		break;
+	}
 
 	strvec_pushl(&child.args, name, start_oid, tracking_name, NULL);
 
@@ -609,6 +631,7 @@ 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)
 		setup_tracking(name, tracking_name, track, quiet);
 
 	for (i = 0; i < submodule_entry_list.entry_nr; i++) {

builtin/submodule--helper.c

@@ -2994,9 +2994,10 @@ static int module_create_branch(int argc, const char **argv, const char *prefix)
 		OPT__FORCE(&force, N_("force creation"), 0),
 		OPT_BOOL(0, "create-reflog", &reflog,
 			 N_("create the branch's reflog")),
-		OPT_SET_INT('t', "track", &track,
-			    N_("set up tracking mode (see git-pull(1))"),
-			    BRANCH_TRACK_EXPLICIT),
+		OPT_CALLBACK_F('t', "track",  &track, "(direct|inherit)",
+			N_("set branch tracking configuration"),
+			PARSE_OPT_OPTARG,
+			parse_opt_tracking_mode),
 		OPT__DRY_RUN(&dry_run,
 			     N_("show whether the branch would be created")),
 		OPT_END()

t/t3207-branch-submodule.sh

@@ -260,7 +260,7 @@ test_expect_success 'should get fatal error upon branch creation when submodule
 	)
 '
 
-test_expect_success 'should set up tracking of remote-tracking branches' '
+test_expect_success 'should set up tracking of remote-tracking branches by default' '
 	test_when_finished "reset_remote_test" &&
 	(
 		cd super-clone &&
@@ -289,4 +289,40 @@ test_expect_success 'should not fail when unable to set up tracking in submodule
 	)
 '
 
+test_expect_success '--track=inherit should set up tracking correctly' '
+	test_when_finished "reset_remote_test" &&
+	(
+		cd super-clone &&
+		git branch --recurse-submodules branch-a origin/branch-a &&
+		# Set this manually instead of using branch --set-upstream-to
+		# to circumvent the "nonexistent upstream" check.
+		git -C sub config branch.branch-a.remote origin &&
+		git -C sub config branch.branch-a.merge refs/heads/sub-branch-a &&
+		git -C sub/sub-sub config branch.branch-a.remote other &&
+		git -C sub/sub-sub config branch.branch-a.merge refs/heads/sub-sub-branch-a &&
+
+		git branch --recurse-submodules --track=inherit branch-b branch-a &&
+		test_cmp_config origin branch.branch-b.remote &&
+		test_cmp_config refs/heads/branch-a branch.branch-b.merge &&
+		test_cmp_config -C sub origin branch.branch-b.remote &&
+		test_cmp_config -C sub refs/heads/sub-branch-a branch.branch-b.merge &&
+		test_cmp_config -C sub/sub-sub other branch.branch-b.remote &&
+		test_cmp_config -C sub/sub-sub refs/heads/sub-sub-branch-a branch.branch-b.merge
+	)
+'
+
+test_expect_success '--no-track should not set up tracking' '
+	test_when_finished "reset_remote_test" &&
+	(
+		cd super-clone &&
+		git branch --recurse-submodules --no-track branch-a origin/branch-a &&
+		test_cmp_config "" --default "" branch.branch-a.remote &&
+		test_cmp_config "" --default "" branch.branch-a.merge &&
+		test_cmp_config -C sub "" --default "" branch.branch-a.remote &&
+		test_cmp_config -C sub "" --default "" branch.branch-a.merge &&
+		test_cmp_config -C sub/sub-sub "" --default "" branch.branch-a.remote &&
+		test_cmp_config -C sub/sub-sub "" --default "" branch.branch-a.merge
+	)
+'
+
 test_done