unlink(git_path_merge_mode());
unlink(git_path_squash_msg());
}
+
+static char *find_linked_symref(const char *symref, const char *branch,
+ const char *id)
+{
+ struct strbuf sb = STRBUF_INIT;
+ struct strbuf path = STRBUF_INIT;
+ struct strbuf gitdir = STRBUF_INIT;
+ char *existing = NULL;
+
+ /*
+ * $GIT_COMMON_DIR/$symref (e.g. HEAD) is practically outside
+ * $GIT_DIR so resolve_ref_unsafe() won't work (it uses
+ * git_path). Parse the ref ourselves.
+ */
+ if (id)
+ strbuf_addf(&path, "%s/worktrees/%s/%s", get_git_common_dir(), id, symref);
+ else
+ strbuf_addf(&path, "%s/%s", get_git_common_dir(), symref);
+
+ if (!strbuf_readlink(&sb, path.buf, 0)) {
+ if (!starts_with(sb.buf, "refs/") ||
+ check_refname_format(sb.buf, 0))
+ goto done;
+ } else if (strbuf_read_file(&sb, path.buf, 0) >= 0 &&
+ starts_with(sb.buf, "ref:")) {
+ strbuf_remove(&sb, 0, strlen("ref:"));
+ strbuf_trim(&sb);
+ } else
+ goto done;
+ if (strcmp(sb.buf, branch))
+ goto done;
+ if (id) {
+ strbuf_reset(&path);
+ strbuf_addf(&path, "%s/worktrees/%s/gitdir", get_git_common_dir(), id);
+ if (strbuf_read_file(&gitdir, path.buf, 0) <= 0)
+ goto done;
+ strbuf_rtrim(&gitdir);
+ } else
+ strbuf_addstr(&gitdir, get_git_common_dir());
+ strbuf_strip_suffix(&gitdir, ".git");
+
+ existing = strbuf_detach(&gitdir, NULL);
+done:
+ strbuf_release(&path);
+ strbuf_release(&sb);
+ strbuf_release(&gitdir);
+
+ return existing;
+}
+
+char *find_shared_symref(const char *symref, const char *target)
+{
+ struct strbuf path = STRBUF_INIT;
+ DIR *dir;
+ struct dirent *d;
+ char *existing;
+
+ if ((existing = find_linked_symref(symref, target, NULL)))
+ return existing;
+
+ strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
+ dir = opendir(path.buf);
+ strbuf_release(&path);
+ if (!dir)
+ return NULL;
+
+ while ((d = readdir(dir)) != NULL) {
+ if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+ continue;
+ existing = find_linked_symref(symref, target, d->d_name);
+ if (existing)
+ goto done;
+ }
+done:
+ closedir(dir);
+
+ return existing;
+}
+
+void die_if_checked_out(const char *branch)
+{
+ char *existing;
+
+ existing = find_shared_symref("HEAD", branch);
+ if (existing) {
+ skip_prefix(branch, "refs/heads/", &branch);
+ die(_("'%s' is already checked out at '%s'"), branch, existing);
+ }
+}