checkout: teach check_linked_checkout() about symbolic link HEAD

diff --git a/builtin/checkout.c b/builtin/checkout.c
index b1e68b3263a0c6b1bfcb3b7db65f20c59600085f..f04dcaaf1f714504a37181658d70351b1110c002 100644 (file)
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -873,27 +873,33 @@ static const char *unique_tracking_name(const char *name, unsigned char *sha1)
        return NULL;
 }
 
-static void check_linked_checkout(struct branch_info *new, const char *id)
+static void check_linked_checkout(const char *branch, const char *id)
 {
        struct strbuf sb = STRBUF_INIT;
        struct strbuf path = STRBUF_INIT;
        struct strbuf gitdir = STRBUF_INIT;
-       const char *start, *end;
 
+       /*
+        * $GIT_COMMON_DIR/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/HEAD", get_git_common_dir(), id);
        else
                strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
 
-       if (strbuf_read_file(&sb, path.buf, 0) < 0 ||
-           !skip_prefix(sb.buf, "ref:", &start))
+       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;
-       while (isspace(*start))
-               start++;
-       end = start;
-       while (*end && !isspace(*end))
-               end++;
-       if (strncmp(start, new->path, end - start) || new->path[end - start] != '\0')
+       if (strcmp(sb.buf, branch))
                goto done;
        if (id) {
                strbuf_reset(&path);
@@ -903,38 +909,34 @@ static void check_linked_checkout(struct branch_info *new, const char *id)
                strbuf_rtrim(&gitdir);
        } else
                strbuf_addstr(&gitdir, get_git_common_dir());
-       die(_("'%s' is already checked out at '%s'"), new->name, gitdir.buf);
+       skip_prefix(branch, "refs/heads/", &branch);
+       strbuf_strip_suffix(&gitdir, ".git");
+       die(_("'%s' is already checked out at '%s'"), branch, gitdir.buf);
 done:
        strbuf_release(&path);
        strbuf_release(&sb);
        strbuf_release(&gitdir);
 }
 
-static void check_linked_checkouts(struct branch_info *new)
+static void die_if_checked_out(const char *branch)
 {
        struct strbuf path = STRBUF_INIT;
        DIR *dir;
        struct dirent *d;
 
+       check_linked_checkout(branch, NULL);
+
        strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
-       if ((dir = opendir(path.buf)) == NULL) {
-               strbuf_release(&path);
+       dir = opendir(path.buf);
+       strbuf_release(&path);
+       if (!dir)
                return;
-       }
-
-       /*
-        * $GIT_COMMON_DIR/HEAD is practically outside
-        * $GIT_DIR so resolve_ref_unsafe() won't work (it
-        * uses git_path). Parse the ref ourselves.
-        */
-       check_linked_checkout(new, NULL);
 
        while ((d = readdir(dir)) != NULL) {
                if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
                        continue;
-               check_linked_checkout(new, d->d_name);
+               check_linked_checkout(branch, d->d_name);
        }
-       strbuf_release(&path);
        closedir(dir);
 }
 
@@ -1145,14 +1147,14 @@ static int checkout_branch(struct checkout_opts *opts,
                die(_("Cannot switch branch to a non-commit '%s'"),
                    new->name);
 
-       if (new->path && !opts->force_detach && !opts->new_branch) {
+       if (new->path && !opts->force_detach && !opts->new_branch &&
+           !opts->ignore_other_worktrees) {
                unsigned char sha1[20];
                int flag;
                char *head_ref = resolve_refdup("HEAD", 0, sha1, &flag);
                if (head_ref &&
-                   (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)) &&
-                   !opts->ignore_other_worktrees)
-                       check_linked_checkouts(new);
+                   (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
+                       die_if_checked_out(new->path);
                free(head_ref);
        }
 
@@ -1218,8 +1220,6 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 
        opts.new_worktree_mode = getenv("GIT_CHECKOUT_NEW_WORKTREE") != NULL;
 
-       setup_work_tree();
-
        if (conflict_style) {
                opts.merge = 1; /* implied */
                git_xmerge_config("merge.conflictstyle", conflict_style, NULL);