[PATCH] submodule update --init: displays correct path from submodule

In the submodule helper we did not correctly handled the display path
for initializing submodules when both the submodule is inside a
subdirectory as well as the command being invoked from a subdirectory
(as viewed from the superproject).

This was broken in 3604242f080, which was written at a time where
there was no super-prefix available, so we abused the --prefix option
for the same purpose and could get only one case right (the call from
within a subdirectory, not the submodule being in a subdirectory).

Test-provided-by: David Turner [off-list ref]
Signed-off-by: Stefan Beller <redacted>
---

  applies on sb/submodule-embed-gitdir as that contains 89c862655
  (submodule helper: support super prefix)

 builtin/submodule--helper.c | 13 +++++++------
 git-submodule.sh            |  2 +-
 t/t7406-submodule-update.sh | 17 +++++++++++++++++
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 242d9911a6..7b3f9fc293 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c

@@ -305,32 +305,36 @@ static int module_list(int argc, const char **argv, const char *prefix)
 
 		utf8_fprintf(stdout, "%s\n", ce->name);
 	}
 	return 0;
 }
 
 static void init_submodule(const char *path, const char *prefix, int quiet)
 {
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
 	/* Only loads from .gitmodules, no overlay with .git/config */
 	gitmodules_config();
 
-	if (prefix) {
-		strbuf_addf(&sb, "%s%s", prefix, path);
+	if (prefix && get_super_prefix())
+		die("BUG: cannot have prefix and superprefix");
+	else if (prefix)
+		displaypath = xstrdup(relative_path(path, prefix, &sb));
+	else if (get_super_prefix()) {
+		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
 		displaypath = strbuf_detach(&sb, NULL);
 	} else
 		displaypath = xstrdup(path);
 
 	sub = submodule_from_path(null_sha1, path);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
 			displaypath);
 
 	/*
 	 * Copy url setting when it is not set yet.
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */

@@ -391,33 +395,30 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	}
 	strbuf_release(&sb);
 	free(displaypath);
 	free(url);
 	free(upd);
 }
 
 static int module_init(int argc, const char **argv, const char *prefix)
 {
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
 	int i;
 
 	struct option module_init_options[] = {
-		OPT_STRING(0, "prefix", &prefix,
-			   N_("path"),
-			   N_("alternative anchor for relative paths")),
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
 		OPT_END()
 	};
 
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule--helper init [<path>]"),
 		NULL
 	};
 
 	argc = parse_options(argc, argv, prefix, module_init_options,
 			     git_submodule_helper_usage, 0);
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
 		return 1;
 

@@ -1117,31 +1118,31 @@ static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 
 struct cmd_struct {
 	const char *cmd;
 	int (*fn)(int, const char **, const char *);
 	unsigned option;
 };
 
 static struct cmd_struct commands[] = {
 	{"list", module_list, 0},
 	{"name", module_name, 0},
 	{"clone", module_clone, 0},
 	{"update-clone", update_clone, 0},
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
-	{"init", module_init, 0},
+	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
 	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
 {
 	int i;
 	if (argc < 2)
 		die(_("submodule--helper subcommand must be "
 		      "called with a subcommand"));
 
 	for (i = 0; i < ARRAY_SIZE(commands); i++) {
 		if (!strcmp(argv[1], commands[i].cmd)) {
 			if (get_super_prefix() &&
 			    !(commands[i].option & SUPPORT_SUPER_PREFIX))

diff --git a/git-submodule.sh b/git-submodule.sh
index 9285b5c43d..4e47ff8ad8 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh

@@ -362,31 +362,31 @@ cmd_init()
 			;;
 		--)
 			shift
 			break
 			;;
 		-*)
 			usage
 			;;
 		*)
 			break
 			;;
 		esac
 		shift
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper init ${GIT_QUIET:+--quiet} ${prefix:+--prefix "$prefix"} "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper init ${GIT_QUIET:+--quiet}  "$@"
 }
 
 #
 # Unregister submodules from .git/config and remove their work tree
 #
 cmd_deinit()
 {
 	# parse $args after "submodule ... deinit".
 	deinit_all=
 	while test $# -ne 0
 	do
 		case "$1" in
 		-f|--force)
 			force=$1
 			;;

diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index 64f322c4cc..725bbed1f8 100755
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh

@@ -128,30 +128,47 @@ done.
 Cloning into '$pwd/recursivesuper/super/submodule'...
 done.
 EOF
 
 test_expect_success 'submodule update --init --recursive from subdirectory' '
 	git -C recursivesuper/super reset --hard HEAD^ &&
 	(cd recursivesuper &&
 	 mkdir tmp &&
 	 cd tmp &&
 	 git submodule update --init --recursive ../super >../../actual 2>../../actual2
 	) &&
 	test_i18ncmp expect actual &&
 	test_i18ncmp expect2 actual2
 '
 
+cat <<EOF >expect2
+Submodule 'foo/sub' ($pwd/withsubs/../rebasing) registered for path 'sub'
+EOF
+
+test_expect_success 'submodule update --init from and of subdirectory' '
+	git init withsubs &&
+	(cd withsubs &&
+	 mkdir foo &&
+	 git submodule add "$(pwd)/../rebasing" foo/sub &&
+	 (cd foo &&
+	  git submodule deinit -f sub &&
+	  git submodule update --init sub 2>../../actual2
+	 )
+	) &&
+	test_i18ncmp expect2 actual2
+'
+
 apos="'";
 test_expect_success 'submodule update does not fetch already present commits' '
 	(cd submodule &&
 	  echo line3 >> file &&
 	  git add file &&
 	  test_tick &&
 	  git commit -m "upstream line3"
 	) &&
 	(cd super/submodule &&
 	  head=$(git rev-parse --verify HEAD) &&
 	  echo "Submodule path ${apos}submodule$apos: checked out $apos$head$apos" > ../../expected &&
 	  git reset --hard HEAD~1
 	) &&
 	(cd super &&
 	  git submodule update > ../actual 2> ../actual.err