struct ref_lock *lock;
        unsigned char old_sha1[20];
 
+       if (is_null_sha1(b->sha1))
+               return 0;
        if (read_ref(b->name, old_sha1))
                hashclr(old_sha1);
        lock = lock_any_ref_for_update(b->name, old_sha1, 0);
        else
                b = new_branch(sp);
        read_next_command();
-       if (!cmd_from(b) && command_buf.len > 0)
+       cmd_from(b);
+       if (command_buf.len > 0)
                unread_command_buf = 1;
 }