[PATCH 3/5] submodule: teach and plumb append-superproject behavior

[William Hatfield <whatfield.git@gmail.com>]

Add --append-superproject flag to 'git submodule foreach' that runs the
command in the superproject after processing all submodules. This is
only executed at the top-level invocation, not during recursion.

The superproject execution sets the same environment variables as for
submodules (name, sm_path, displaypath, sha1, toplevel) so scripts
using these variables work uniformly. The '../<name>' displaypath
mirrors submodule output style and visually indicates ascent to the
parent repository.

When combined with --recursive and --reverse-traversal, this enables
full post-order traversal from deepest submodules up to the
superproject.

Implementation:
 - Add append_superproject field to struct foreach_cb
 - Parse --append-superproject in module_foreach() and git-submodule.sh
 - Add superproject execution block after submodule traversal
 - Only run at top-level (when super_prefix is not set)

Signed-off-by: William Hatfield <whatfield.git@gmail.com>
---
 builtin/submodule--helper.c    | 31 ++++++++++++++++++++++++++++++-
 git-submodule.sh               |  4 ++++
 t/t7425-submodule-reversion.sh | 29 +++++++----------------------
 3 files changed, 41 insertions(+), 23 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index b1e202399e..f6cba87a05 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -286,6 +286,7 @@ struct foreach_cb {
 	int quiet;
 	int recursive;
 	int reverse_traversal;
+	int append_superproject;
 };
 #define FOREACH_CB_INIT { 0 }
 
@@ -438,10 +439,12 @@ static int module_foreach(int argc, const char **argv, const char *prefix,
 			 N_("recurse into nested submodules")),
 		OPT_BOOL(0, "reverse-traversal", &info.reverse_traversal,
 			 N_("traverse submodules in reverse order (post-order)")),
+		OPT_BOOL(0, "append-superproject", &info.append_superproject,
+			 N_("also run command in superproject after submodules")),
 		OPT_END()
 	};
 	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule foreach [--quiet] [--recursive] [--reverse-traversal] [--] <command>"),
+		N_("git submodule foreach [--quiet] [--recursive] [--reverse-traversal] [--append-superproject] [--] <command>"),
 		NULL
 	};
 	int ret = 1;
@@ -459,6 +462,32 @@ static int module_foreach(int argc, const char **argv, const char *prefix,
 	for_each_listed_submodule(&list, runcommand_in_submodule_cb, &info,
 				  info.reverse_traversal);
 
+	/*
+	 * Run command in superproject after all submodules, but only at the
+	 * top-level invocation (not during recursion into nested submodules).
+	 */
+	if (info.append_superproject && !info.super_prefix) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		char *toplevel = xgetcwd();
+		const char *slash = find_last_dir_sep(toplevel);
+		const char *super_name = slash ? slash + 1 : toplevel;
+		char *displaypath = xstrfmt("../%s", super_name);
+
+		cp.use_shell = 1;
+		cp.dir = toplevel;
+		strvec_pushf(&cp.env, "displaypath=%s", displaypath);
+		strvec_pushv(&cp.args, info.argv);
+
+		if (!info.quiet)
+			printf(_("Entering '%s'\n"), displaypath);
+
+		if (run_command(&cp))
+			die(_("command failed in superproject\n"));
+
+		free(displaypath);
+		free(toplevel);
+	}
+
 	ret = 0;
 cleanup:
 	module_list_release(&list);
diff --git a/git-submodule.sh b/git-submodule.sh
index 49e9541a3d..58682a287d 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -176,6 +176,9 @@ cmd_foreach()
 		--reverse-traversal)
 			reverse_traversal=$1
 			;;
+		--append-superproject)
+			append_superproject=$1
+			;;
 		-*)
 			usage
 			;;
@@ -190,6 +193,7 @@ cmd_foreach()
 		$quiet \
 		$recursive \
 		$reverse_traversal \
+		$append_superproject \
 		-- \
 		"$@"
 }
diff --git a/t/t7425-submodule-reversion.sh b/t/t7425-submodule-reversion.sh
index c6733234aa..7a6a54de15 100755
--- a/t/t7425-submodule-reversion.sh
+++ b/t/t7425-submodule-reversion.sh
@@ -168,14 +168,14 @@ EOF
 	test_cmp expect actual
 '
 
-test_expect_failure '--recursive and --append-superproject parses' '
+test_expect_success '--recursive and --append-superproject parses' '
 	(
 		cd reversive/top &&
 		git submodule foreach --recursive --append-superproject "true"
 	)
 '
 
-test_expect_failure '--recursive and --append-superproject runs' '
+test_expect_success '--recursive and --append-superproject runs' '
 	(
 		cd reversive/top &&
 		git submodule --quiet foreach --recursive \
@@ -199,7 +199,7 @@ EOF
 	test_cmp expect actual
 '
 
-test_expect_failure '--reverse-traversal and --append-superproject parses' '
+test_expect_success '--reverse-traversal and --append-superproject parses' '
 	(
 		cd reversive/top &&
 		git submodule foreach \
@@ -207,7 +207,7 @@ test_expect_failure '--reverse-traversal and --append-superproject parses' '
 	)
 '
 
-test_expect_failure '--reverse-traversal and --append-superproject runs' '
+test_expect_success '--reverse-traversal and --append-superproject runs' '
 	(
 		cd reversive/top &&
 		git submodule --quiet foreach --recursive \
@@ -270,7 +270,7 @@ test_expect_failure '--reversive stops on command failure' '
 	)
 '
 
-test_expect_failure '--append-superproject with no submodules runs only superproject' '
+test_expect_success '--append-superproject with no submodules runs only superproject' '
 	test_create_repo empty_repo &&
 	(
 		cd empty_repo &&
@@ -285,22 +285,7 @@ EOF
 	test_cmp expect actual
 '
 
-test_expect_failure '--append-superproject sets all expected variables' '
-	(
-		cd reversive/top &&
-		git submodule --quiet foreach --append-superproject \
-			"echo name=\$name path=\$path displaypath=\$displaypath" |
-			tail -n 1
-	) >actual &&
-
-	cat >expect <<-\EOF &&
-name=top path=../top displaypath=../top
-EOF
-
-	test_cmp expect actual
-'
-
-test_expect_failure '--append-superproject from nested submodule appends correct superproject' '
+test_expect_success '--append-superproject from nested submodule appends correct superproject' '
 	(
 		cd reversive/top/sub6 &&
 		git submodule --quiet foreach --recursive --append-superproject \
@@ -317,7 +302,7 @@ EOF
 	test_cmp expect actual
 '
 
-test_expect_failure '--quiet suppresses Entering message for superproject' '
+test_expect_success '--quiet suppresses Entering message for superproject' '
 	(
 		cd reversive/top &&
 		git submodule foreach --quiet --append-superproject "true"
-- 
2.53.0-rc0