len = cp + tmp_len - name;
cp = xstrndup(name, cp - name);
upstream = branch_get(*cp ? cp : NULL);
- if (!upstream
- || !upstream->merge
- || !upstream->merge[0]->dst)
- return error("No upstream branch found for '%s'", cp);
+ /*
+ * Upstream can be NULL only if cp refers to HEAD and HEAD
+ * points to something different than a branch.
+ */
+ if (!upstream)
+ return error(_("HEAD does not point to a branch"));
+ if (!upstream->merge || !upstream->merge[0]->dst) {
+ if (!ref_exists(upstream->refname))
+ return error(_("No such branch: '%s'"), cp);
+ if (!upstream->merge)
+ return error(_("No upstream configured for branch '%s'"),
+ upstream->name);
+ return error(
+ _("Upstream branch '%s' not stored as a remote-tracking branch"),
+ upstream->merge[0]->src);
+ }
free(cp);
cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
strbuf_reset(buf);