submodule--helper: replace connect-gitdir-workingtree by ensure-core-worktree

e98317508c (submodule: ensure core.worktree is set after update,
2018-06-18) was overly aggressive in calling connect_work_tree_and_git_dir
as that ensures both the 'core.worktree' configuration is set as well as
setting up correct gitlink file pointing at the git directory.

We do not need to check for the gitlink in this part of the cmd_update
in git-submodule.sh, as the initial call to update-clone will have ensured
that. So we can reduce the work to only (check and potentially) set the
'core.worktree' setting.

While at it move the check from shell to C as that proves to be useful in
a follow up patch, as we do not need the 'name' in shell now.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/submodule--helper.c

@@ -1964,6 +1964,45 @@ static int push_check(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+static int ensure_core_worktree(int argc, const char **argv, const char *prefix)
+{
+	const struct submodule *sub;
+	const char *path;
+	char *cw;
+	struct repository subrepo;
+
+	if (argc != 2)
+		BUG("submodule--helper connect-gitdir-workingtree <name> <path>");
+
+	path = argv[1];
+
+	sub = submodule_from_path(the_repository, &null_oid, path);
+	if (!sub)
+		BUG("We could get the submodule handle before?");
+
+	if (repo_submodule_init(&subrepo, the_repository, path))
+		die(_("could not get a repository handle for submodule '%s'"), path);
+
+	if (!repo_config_get_string(&subrepo, "core.worktree", &cw)) {
+		char *cfg_file, *abs_path;
+		const char *rel_path;
+		struct strbuf sb = STRBUF_INIT;
+
+		cfg_file = repo_git_path(&subrepo, "config");
+
+		abs_path = absolute_pathdup(path);
+		rel_path = relative_path(abs_path, subrepo.gitdir, &sb);
+
+		git_config_set_in_file(cfg_file, "core.worktree", rel_path);
+
+		free(cfg_file);
+		free(abs_path);
+		strbuf_release(&sb);
+	}
+
+	return 0;
+}
+
 static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 {
 	int i;
@@ -2029,29 +2068,6 @@ static int check_name(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static int connect_gitdir_workingtree(int argc, const char **argv, const char *prefix)
-{
-	struct strbuf sb = STRBUF_INIT;
-	const char *name, *path;
-	char *sm_gitdir;
-
-	if (argc != 3)
-		BUG("submodule--helper connect-gitdir-workingtree <name> <path>");
-
-	name = argv[1];
-	path = argv[2];
-
-	strbuf_addf(&sb, "%s/modules/%s", get_git_dir(), name);
-	sm_gitdir = absolute_pathdup(sb.buf);
-
-	connect_work_tree_and_git_dir(path, sm_gitdir, 0);
-
-	strbuf_release(&sb);
-	free(sm_gitdir);
-
-	return 0;
-}
-
 #define SUPPORT_SUPER_PREFIX (1<<0)
 
 struct cmd_struct {
@@ -2065,7 +2081,7 @@ static struct cmd_struct commands[] = {
 	{"name", module_name, 0},
 	{"clone", module_clone, 0},
 	{"update-clone", update_clone, 0},
-	{"connect-gitdir-workingtree", connect_gitdir_workingtree, 0},
+	{"ensure-core-worktree", ensure_core_worktree, 0},
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},

git-submodule.sh

@@ -535,6 +535,8 @@ cmd_update()
 	do
 		die_if_unmatched "$quickabort" "$sha1"
 
+		git submodule--helper ensure-core-worktree "$sm_path"
+
 		name=$(git submodule--helper name "$sm_path") || exit
 		if ! test -z "$update"
 		then
@@ -577,11 +579,6 @@ cmd_update()
 			die "$(eval_gettext "Unable to find current \${remote_name}/\${branch} revision in submodule path '\$sm_path'")"
 		fi
 
-		if ! $(git config -f "$(git rev-parse --git-common-dir)/modules/$name/config" core.worktree) 2>/dev/null
-		then
-			git submodule--helper connect-gitdir-workingtree "$name" "$sm_path"
-		fi
-
 		if test "$subsha1" != "$sha1" || test -n "$force"
 		then
 			subforce=$force