worktree.c - git - Git at Google

 #include "cache.h"
 #include "refs.h"
 #include "strbuf.h"
 #include "worktree.h"
 #include "dir.h"
 #include "wt-status.h"

 void free_worktrees(struct worktree **worktrees)
 {
 	int i = 0;

 	for (i = 0; worktrees[i]; i++) {
 		free(worktrees[i]->path);
 		free(worktrees[i]->id);
 		free(worktrees[i]->head_ref);
 		free(worktrees[i]->lock_reason);
 		free(worktrees[i]);
 	}
 	free (worktrees);
 }

 /*
  * read 'path_to_ref' into 'ref'.  Also if is_detached is not NULL,
  * set is_detached to 1 (0) if the ref is detached (is not detached).
  *
  * $GIT_COMMON_DIR/$symref (e.g. HEAD) is practically outside $GIT_DIR so
  * for linked worktrees, `resolve_ref_unsafe()` won't work (it uses
  * git_path). Parse the ref ourselves.
  *
  * return -1 if the ref is not a proper ref, 0 otherwise (success)
  */
 static int parse_ref(char *path_to_ref, struct strbuf *ref, int *is_detached)
 {
 	if (is_detached)
 		*is_detached = 0;
 	if (!strbuf_readlink(ref, path_to_ref, 0)) {
 		/* HEAD is symbolic link */
 		if (!starts_with(ref->buf, "refs/") ||
 				check_refname_format(ref->buf, 0))
 			return -1;
 	} else if (strbuf_read_file(ref, path_to_ref, 0) >= 0) {
 		/* textual symref or detached */
 		if (!starts_with(ref->buf, "ref:")) {
 			if (is_detached)
 				*is_detached = 1;
 		} else {
 			strbuf_remove(ref, 0, strlen("ref:"));
 			strbuf_trim(ref);
 			if (check_refname_format(ref->buf, 0))
 				return -1;
 		}
 	} else
 		return -1;
 	return 0;
 }

 /**
  * Add the head_sha1 and head_ref (if not detached) to the given worktree
  */
 static void add_head_info(struct strbuf *head_ref, struct worktree *worktree)
 {
 	if (head_ref->len) {
 		if (worktree->is_detached) {
 			get_sha1_hex(head_ref->buf, worktree->head_sha1);
 		} else {
 			resolve_ref_unsafe(head_ref->buf, 0, worktree->head_sha1, NULL);
 			worktree->head_ref = strbuf_detach(head_ref, NULL);
 		}
 	}
 }

 /**
  * get the main worktree
  */
 static struct worktree *get_main_worktree(void)
 {
 	struct worktree *worktree = NULL;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf worktree_path = STRBUF_INIT;
 	struct strbuf head_ref = STRBUF_INIT;
 	int is_bare = 0;
 	int is_detached = 0;

 	strbuf_add_absolute_path(&worktree_path, get_git_common_dir());
 	is_bare = !strbuf_strip_suffix(&worktree_path, "/.git");
 	if (is_bare)
 		strbuf_strip_suffix(&worktree_path, "/.");

 	strbuf_addf(&path, "%s/HEAD", get_git_common_dir());

 	worktree = xcalloc(1, sizeof(*worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
 	worktree->is_bare = is_bare;
 	worktree->is_detached = is_detached;
 	if (!parse_ref(path.buf, &head_ref, &is_detached))
 		add_head_info(&head_ref, worktree);

 	strbuf_release(&path);
 	strbuf_release(&worktree_path);
 	strbuf_release(&head_ref);
 	return worktree;
 }

 static struct worktree *get_linked_worktree(const char *id)
 {
 	struct worktree *worktree = NULL;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf worktree_path = STRBUF_INIT;
 	struct strbuf head_ref = STRBUF_INIT;
 	int is_detached = 0;

 	if (!id)
 		die("Missing linked worktree name");

 	strbuf_git_common_path(&path, "worktrees/%s/gitdir", id);
 	if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
 		/* invalid gitdir file */
 		goto done;

 	strbuf_rtrim(&worktree_path);
 	if (!strbuf_strip_suffix(&worktree_path, "/.git")) {
 		strbuf_reset(&worktree_path);
 		strbuf_add_absolute_path(&worktree_path, ".");
 		strbuf_strip_suffix(&worktree_path, "/.");
 	}

 	strbuf_reset(&path);
 	strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);

 	if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
 		goto done;

 	worktree = xcalloc(1, sizeof(*worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
 	worktree->id = xstrdup(id);
 	worktree->is_detached = is_detached;
 	add_head_info(&head_ref, worktree);

 done:
 	strbuf_release(&path);
 	strbuf_release(&worktree_path);
 	strbuf_release(&head_ref);
 	return worktree;
 }

 static void mark_current_worktree(struct worktree **worktrees)
 {
 	char *git_dir = absolute_pathdup(get_git_dir());
 	int i;

 	for (i = 0; worktrees[i]; i++) {
 		struct worktree *wt = worktrees[i];
 		const char *wt_git_dir = get_worktree_git_dir(wt);

 		if (!fspathcmp(git_dir, absolute_path(wt_git_dir))) {
 			wt->is_current = 1;
 			break;
 		}
 	}
 	free(git_dir);
 }

 static int compare_worktree(const void *a_, const void *b_)
 {
 	const struct worktree *const *a = a_;
 	const struct worktree *const *b = b_;
 	return fspathcmp((*a)->path, (*b)->path);
 }

 struct worktree **get_worktrees(unsigned flags)
 {
 	struct worktree **list = NULL;
 	struct strbuf path = STRBUF_INIT;
 	DIR *dir;
 	struct dirent *d;
 	int counter = 0, alloc = 2;

 	ALLOC_ARRAY(list, alloc);

 	list[counter++] = get_main_worktree();

 	strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
 	dir = opendir(path.buf);
 	strbuf_release(&path);
 	if (dir) {
 		while ((d = readdir(dir)) != NULL) {
 			struct worktree *linked = NULL;
 			if (is_dot_or_dotdot(d->d_name))
 				continue;

 			if ((linked = get_linked_worktree(d->d_name))) {
 				ALLOC_GROW(list, counter + 1, alloc);
 				list[counter++] = linked;
 			}
 		}
 		closedir(dir);
 	}
 	ALLOC_GROW(list, counter + 1, alloc);
 	list[counter] = NULL;

 	if (flags & GWT_SORT_LINKED)
 		/*
 		 * don't sort the first item (main worktree), which will
 		 * always be the first
 		 */
 		QSORT(list + 1, counter - 1, compare_worktree);

 	mark_current_worktree(list);
 	return list;
 }

 const char *get_worktree_git_dir(const struct worktree *wt)
 {
 	if (!wt)
 		return get_git_dir();
 	else if (!wt->id)
 		return get_git_common_dir();
 	else
 		return git_common_path("worktrees/%s", wt->id);
 }

 static struct worktree *find_worktree_by_suffix(struct worktree **list,
 						const char *suffix)
 {
 	struct worktree *found = NULL;
 	int nr_found = 0, suffixlen;

 	suffixlen = strlen(suffix);
 	if (!suffixlen)
 		return NULL;

 	for (; *list && nr_found < 2; list++) {
 		const char	*path	 = (*list)->path;
 		int		 pathlen = strlen(path);
 		int		 start	 = pathlen - suffixlen;

 		/* suffix must start at directory boundary */
 		if ((!start || (start > 0 && is_dir_sep(path[start - 1]))) &&
 		    !fspathcmp(suffix, path + start)) {
 			found = *list;
 			nr_found++;
 		}
 	}
 	return nr_found == 1 ? found : NULL;
 }

 struct worktree *find_worktree(struct worktree **list,
 			       const char *prefix,
 			       const char *arg)
 {
 	struct worktree *wt;
 	char *path;

 	if ((wt = find_worktree_by_suffix(list, arg)))
 		return wt;

 	arg = prefix_filename(prefix, strlen(prefix), arg);
 	path = real_pathdup(arg, 1);
 	for (; *list; list++)
 		if (!fspathcmp(path, real_path((*list)->path)))
 			break;
 	free(path);
 	return *list;
 }

 int is_main_worktree(const struct worktree *wt)
 {
 	return !wt->id;
 }

 const char *is_worktree_locked(struct worktree *wt)
 {
 	assert(!is_main_worktree(wt));

 	if (!wt->lock_reason_valid) {
 		struct strbuf path = STRBUF_INIT;

 		strbuf_addstr(&path, worktree_git_path(wt, "locked"));
 		if (file_exists(path.buf)) {
 			struct strbuf lock_reason = STRBUF_INIT;
 			if (strbuf_read_file(&lock_reason, path.buf, 0) < 0)
 				die_errno(_("failed to read '%s'"), path.buf);
 			strbuf_trim(&lock_reason);
 			wt->lock_reason = strbuf_detach(&lock_reason, NULL);
 		} else
 			wt->lock_reason = NULL;
 		wt->lock_reason_valid = 1;
 		strbuf_release(&path);
 	}

 	return wt->lock_reason;
 }

 int is_worktree_being_rebased(const struct worktree *wt,
 			      const char *target)
 {
 	struct wt_status_state state;
 	int found_rebase;

 	memset(&state, 0, sizeof(state));
 	found_rebase = wt_status_check_rebase(wt, &state) &&
 		((state.rebase_in_progress ||
 		  state.rebase_interactive_in_progress) &&
 		 state.branch &&
 		 starts_with(target, "refs/heads/") &&
 		 !strcmp(state.branch, target + strlen("refs/heads/")));
 	free(state.branch);
 	free(state.onto);
 	return found_rebase;
 }

 int is_worktree_being_bisected(const struct worktree *wt,
 			       const char *target)
 {
 	struct wt_status_state state;
 	int found_rebase;

 	memset(&state, 0, sizeof(state));
 	found_rebase = wt_status_check_bisect(wt, &state) &&
 		state.branch &&
 		starts_with(target, "refs/heads/") &&
 		!strcmp(state.branch, target + strlen("refs/heads/"));
 	free(state.branch);
 	return found_rebase;
 }

 /*
  * note: this function should be able to detect shared symref even if
  * HEAD is temporarily detached (e.g. in the middle of rebase or
  * bisect). New commands that do similar things should update this
  * function as well.
  */
 const struct worktree *find_shared_symref(const char *symref,
 					  const char *target)
 {
 	const struct worktree *existing = NULL;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	static struct worktree **worktrees;
 	int i = 0;

 	if (worktrees)
 		free_worktrees(worktrees);
 	worktrees = get_worktrees(0);

 	for (i = 0; worktrees[i]; i++) {
 		struct worktree *wt = worktrees[i];
 		if (wt->is_bare)
 			continue;

 		if (wt->is_detached && !strcmp(symref, "HEAD")) {
 			if (is_worktree_being_rebased(wt, target)) {
 				existing = wt;
 				break;
 			}
 			if (is_worktree_being_bisected(wt, target)) {
 				existing = wt;
 				break;
 			}
 		}

 		strbuf_reset(&path);
 		strbuf_reset(&sb);
 		strbuf_addf(&path, "%s/%s",
 			    get_worktree_git_dir(wt),
 			    symref);

 		if (parse_ref(path.buf, &sb, NULL)) {
 			continue;
 		}

 		if (!strcmp(sb.buf, target)) {
 			existing = wt;
 			break;
 		}
 	}

 	strbuf_release(&path);
 	strbuf_release(&sb);

 	return existing;
 }

 int submodule_uses_worktrees(const char *path)
 {
 	char *submodule_gitdir;
 	struct strbuf sb = STRBUF_INIT;
 	DIR *dir;
 	struct dirent *d;
 	int ret = 0;
 	struct repository_format format;

 	submodule_gitdir = git_pathdup_submodule(path, "%s", "");
 	if (!submodule_gitdir)
 		return 0;

 	/* The env would be set for the superproject. */
 	get_common_dir_noenv(&sb, submodule_gitdir);

 	/*
 	 * The check below is only known to be good for repository format
 	 * version 0 at the time of writing this code.
 	 */
 	strbuf_addstr(&sb, "/config");
 	read_repository_format(&format, sb.buf);
 	if (format.version != 0) {
 		strbuf_release(&sb);
 		return 1;
 	}

 	/* Replace config by worktrees. */
 	strbuf_setlen(&sb, sb.len - strlen("config"));
 	strbuf_addstr(&sb, "worktrees");

 	/* See if there is any file inside the worktrees directory. */
 	dir = opendir(sb.buf);
 	strbuf_release(&sb);
 	free(submodule_gitdir);

 	if (!dir)
 		return 0;

 	while ((d = readdir(dir)) != NULL) {
 		if (is_dot_or_dotdot(d->d_name))
 			continue;

 		ret = 1;
 		break;
 	}
 	closedir(dir);
 	return ret;
 }
	#include "cache.h"
	#include "refs.h"
	#include "strbuf.h"
	#include "worktree.h"
	#include "dir.h"
	#include "wt-status.h"

	void free_worktrees(struct worktree **worktrees)
	{
	int i = 0;

	for (i = 0; worktrees[i]; i++) {
	free(worktrees[i]->path);
	free(worktrees[i]->id);
	free(worktrees[i]->head_ref);
	free(worktrees[i]->lock_reason);
	free(worktrees[i]);
	}
	free (worktrees);
	}

	/*
	* read 'path_to_ref' into 'ref'. Also if is_detached is not NULL,
	* set is_detached to 1 (0) if the ref is detached (is not detached).
	*
	* $GIT_COMMON_DIR/$symref (e.g. HEAD) is practically outside $GIT_DIR so
	* for linked worktrees, `resolve_ref_unsafe()` won't work (it uses
	* git_path). Parse the ref ourselves.
	*
	* return -1 if the ref is not a proper ref, 0 otherwise (success)
	*/
	static int parse_ref(char path_to_ref, struct strbuf ref, int *is_detached)
	{
	if (is_detached)
	*is_detached = 0;
	if (!strbuf_readlink(ref, path_to_ref, 0)) {
	/* HEAD is symbolic link */
	if (!starts_with(ref->buf, "refs/") \|\|
	check_refname_format(ref->buf, 0))
	return -1;
	} else if (strbuf_read_file(ref, path_to_ref, 0) >= 0) {
	/* textual symref or detached */
	if (!starts_with(ref->buf, "ref:")) {
	if (is_detached)
	*is_detached = 1;
	} else {
	strbuf_remove(ref, 0, strlen("ref:"));
	strbuf_trim(ref);
	if (check_refname_format(ref->buf, 0))
	return -1;
	}
	} else
	return -1;
	return 0;
	}

	/**
	* Add the head_sha1 and head_ref (if not detached) to the given worktree
	*/
	static void add_head_info(struct strbuf head_ref, struct worktree worktree)
	{
	if (head_ref->len) {
	if (worktree->is_detached) {
	get_sha1_hex(head_ref->buf, worktree->head_sha1);
	} else {
	resolve_ref_unsafe(head_ref->buf, 0, worktree->head_sha1, NULL);
	worktree->head_ref = strbuf_detach(head_ref, NULL);
	}
	}
	}

	/**
	* get the main worktree
	*/
	static struct worktree *get_main_worktree(void)
	{
	struct worktree *worktree = NULL;
	struct strbuf path = STRBUF_INIT;
	struct strbuf worktree_path = STRBUF_INIT;
	struct strbuf head_ref = STRBUF_INIT;
	int is_bare = 0;
	int is_detached = 0;

	strbuf_add_absolute_path(&worktree_path, get_git_common_dir());
	is_bare = !strbuf_strip_suffix(&worktree_path, "/.git");
	if (is_bare)
	strbuf_strip_suffix(&worktree_path, "/.");

	strbuf_addf(&path, "%s/HEAD", get_git_common_dir());

	worktree = xcalloc(1, sizeof(*worktree));
	worktree->path = strbuf_detach(&worktree_path, NULL);
	worktree->is_bare = is_bare;
	worktree->is_detached = is_detached;
	if (!parse_ref(path.buf, &head_ref, &is_detached))
	add_head_info(&head_ref, worktree);

	strbuf_release(&path);
	strbuf_release(&worktree_path);
	strbuf_release(&head_ref);
	return worktree;
	}

	static struct worktree get_linked_worktree(const char id)
	{
	struct worktree *worktree = NULL;
	struct strbuf path = STRBUF_INIT;
	struct strbuf worktree_path = STRBUF_INIT;
	struct strbuf head_ref = STRBUF_INIT;
	int is_detached = 0;

	if (!id)
	die("Missing linked worktree name");

	strbuf_git_common_path(&path, "worktrees/%s/gitdir", id);
	if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
	/* invalid gitdir file */
	goto done;

	strbuf_rtrim(&worktree_path);
	if (!strbuf_strip_suffix(&worktree_path, "/.git")) {
	strbuf_reset(&worktree_path);
	strbuf_add_absolute_path(&worktree_path, ".");
	strbuf_strip_suffix(&worktree_path, "/.");
	}

	strbuf_reset(&path);
	strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);

	if (parse_ref(path.buf, &head_ref, &is_detached) < 0)
	goto done;

	worktree = xcalloc(1, sizeof(*worktree));
	worktree->path = strbuf_detach(&worktree_path, NULL);
	worktree->id = xstrdup(id);
	worktree->is_detached = is_detached;
	add_head_info(&head_ref, worktree);

	done:
	strbuf_release(&path);
	strbuf_release(&worktree_path);
	strbuf_release(&head_ref);
	return worktree;
	}

	static void mark_current_worktree(struct worktree **worktrees)
	{
	char *git_dir = absolute_pathdup(get_git_dir());
	int i;

	for (i = 0; worktrees[i]; i++) {
	struct worktree *wt = worktrees[i];
	const char *wt_git_dir = get_worktree_git_dir(wt);

	if (!fspathcmp(git_dir, absolute_path(wt_git_dir))) {
	wt->is_current = 1;
	break;
	}
	}
	free(git_dir);
	}

	static int compare_worktree(const void a_, const void b_)
	{
	const struct worktree const a = a_;
	const struct worktree const b = b_;
	return fspathcmp((a)->path, (b)->path);
	}

	struct worktree **get_worktrees(unsigned flags)
	{
	struct worktree **list = NULL;
	struct strbuf path = STRBUF_INIT;
	DIR *dir;
	struct dirent *d;
	int counter = 0, alloc = 2;

	ALLOC_ARRAY(list, alloc);

	list[counter++] = get_main_worktree();

	strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
	dir = opendir(path.buf);
	strbuf_release(&path);
	if (dir) {
	while ((d = readdir(dir)) != NULL) {
	struct worktree *linked = NULL;
	if (is_dot_or_dotdot(d->d_name))
	continue;

	if ((linked = get_linked_worktree(d->d_name))) {
	ALLOC_GROW(list, counter + 1, alloc);
	list[counter++] = linked;
	}
	}
	closedir(dir);
	}
	ALLOC_GROW(list, counter + 1, alloc);
	list[counter] = NULL;

	if (flags & GWT_SORT_LINKED)
	/*
	* don't sort the first item (main worktree), which will
	* always be the first
	*/
	QSORT(list + 1, counter - 1, compare_worktree);

	mark_current_worktree(list);
	return list;
	}

	const char get_worktree_git_dir(const struct worktree wt)
	{
	if (!wt)
	return get_git_dir();
	else if (!wt->id)
	return get_git_common_dir();
	else
	return git_common_path("worktrees/%s", wt->id);
	}

	static struct worktree find_worktree_by_suffix(struct worktree *list,
	const char *suffix)
	{
	struct worktree *found = NULL;
	int nr_found = 0, suffixlen;

	suffixlen = strlen(suffix);
	if (!suffixlen)
	return NULL;

	for (; *list && nr_found < 2; list++) {
	const char path = (list)->path;
	int pathlen = strlen(path);
	int start = pathlen - suffixlen;

	/* suffix must start at directory boundary */
	if ((!start \|\| (start > 0 && is_dir_sep(path[start - 1]))) &&
	!fspathcmp(suffix, path + start)) {
	found = *list;
	nr_found++;
	}
	}
	return nr_found == 1 ? found : NULL;
	}

	struct worktree find_worktree(struct worktree *list,
	const char *prefix,
	const char *arg)
	{
	struct worktree *wt;
	char *path;

	if ((wt = find_worktree_by_suffix(list, arg)))
	return wt;

	arg = prefix_filename(prefix, strlen(prefix), arg);
	path = real_pathdup(arg, 1);
	for (; *list; list++)
	if (!fspathcmp(path, real_path((*list)->path)))
	break;
	free(path);
	return *list;
	}

	int is_main_worktree(const struct worktree *wt)
	{
	return !wt->id;
	}

	const char is_worktree_locked(struct worktree wt)
	{
	assert(!is_main_worktree(wt));

	if (!wt->lock_reason_valid) {
	struct strbuf path = STRBUF_INIT;

	strbuf_addstr(&path, worktree_git_path(wt, "locked"));
	if (file_exists(path.buf)) {
	struct strbuf lock_reason = STRBUF_INIT;
	if (strbuf_read_file(&lock_reason, path.buf, 0) < 0)
	die_errno(_("failed to read '%s'"), path.buf);
	strbuf_trim(&lock_reason);
	wt->lock_reason = strbuf_detach(&lock_reason, NULL);
	} else
	wt->lock_reason = NULL;
	wt->lock_reason_valid = 1;
	strbuf_release(&path);
	}

	return wt->lock_reason;
	}

	int is_worktree_being_rebased(const struct worktree *wt,
	const char *target)
	{
	struct wt_status_state state;
	int found_rebase;

	memset(&state, 0, sizeof(state));
	found_rebase = wt_status_check_rebase(wt, &state) &&
	((state.rebase_in_progress \|\|
	state.rebase_interactive_in_progress) &&
	state.branch &&
	starts_with(target, "refs/heads/") &&
	!strcmp(state.branch, target + strlen("refs/heads/")));
	free(state.branch);
	free(state.onto);
	return found_rebase;
	}

	int is_worktree_being_bisected(const struct worktree *wt,
	const char *target)
	{
	struct wt_status_state state;
	int found_rebase;

	memset(&state, 0, sizeof(state));
	found_rebase = wt_status_check_bisect(wt, &state) &&
	state.branch &&
	starts_with(target, "refs/heads/") &&
	!strcmp(state.branch, target + strlen("refs/heads/"));
	free(state.branch);
	return found_rebase;
	}

	/*
	* note: this function should be able to detect shared symref even if
	* HEAD is temporarily detached (e.g. in the middle of rebase or
	* bisect). New commands that do similar things should update this
	* function as well.
	*/
	const struct worktree find_shared_symref(const char symref,
	const char *target)
	{
	const struct worktree *existing = NULL;
	struct strbuf path = STRBUF_INIT;
	struct strbuf sb = STRBUF_INIT;
	static struct worktree **worktrees;
	int i = 0;

	if (worktrees)
	free_worktrees(worktrees);
	worktrees = get_worktrees(0);

	for (i = 0; worktrees[i]; i++) {
	struct worktree *wt = worktrees[i];
	if (wt->is_bare)
	continue;

	if (wt->is_detached && !strcmp(symref, "HEAD")) {
	if (is_worktree_being_rebased(wt, target)) {
	existing = wt;
	break;
	}
	if (is_worktree_being_bisected(wt, target)) {
	existing = wt;
	break;
	}
	}

	strbuf_reset(&path);
	strbuf_reset(&sb);
	strbuf_addf(&path, "%s/%s",
	get_worktree_git_dir(wt),
	symref);

	if (parse_ref(path.buf, &sb, NULL)) {
	continue;
	}

	if (!strcmp(sb.buf, target)) {
	existing = wt;
	break;
	}
	}

	strbuf_release(&path);
	strbuf_release(&sb);

	return existing;
	}

	int submodule_uses_worktrees(const char *path)
	{
	char *submodule_gitdir;
	struct strbuf sb = STRBUF_INIT;
	DIR *dir;
	struct dirent *d;
	int ret = 0;
	struct repository_format format;

	submodule_gitdir = git_pathdup_submodule(path, "%s", "");
	if (!submodule_gitdir)
	return 0;

	/* The env would be set for the superproject. */
	get_common_dir_noenv(&sb, submodule_gitdir);

	/*
	* The check below is only known to be good for repository format
	* version 0 at the time of writing this code.
	*/
	strbuf_addstr(&sb, "/config");
	read_repository_format(&format, sb.buf);
	if (format.version != 0) {
	strbuf_release(&sb);
	return 1;
	}

	/* Replace config by worktrees. */
	strbuf_setlen(&sb, sb.len - strlen("config"));
	strbuf_addstr(&sb, "worktrees");

	/* See if there is any file inside the worktrees directory. */
	dir = opendir(sb.buf);
	strbuf_release(&sb);
	free(submodule_gitdir);

	if (!dir)
	return 0;

	while ((d = readdir(dir)) != NULL) {
	if (is_dot_or_dotdot(d->d_name))
	continue;

	ret = 1;
	break;
	}
	closedir(dir);
	return ret;
	}