Index: modules/comment.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/comment.module,v
retrieving revision 1.446
diff -u -p -r1.446 comment.module
--- modules/comment.module	30 Mar 2006 17:23:29 -0000	1.446
+++ modules/comment.module	1 Apr 2006 10:39:53 -0000
@@ -493,6 +493,11 @@ function comment_reply($nid, $pid = NULL
       // else, we'll just show the user the node they're commenting on.
       if ($pid) {
         if ($comment = db_fetch_object(db_query('SELECT c.*, u.uid, u.name AS registered_name, u.picture, u.data FROM {comments} c INNER JOIN {users} u ON c.uid = u.uid WHERE c.cid = %d AND c.status = %d', $pid, COMMENT_PUBLISHED))) {
+          if ($comment->nid != $nid) {
+            // Attempting to reply to a comment not belonging to the current nid.
+            drupal_set_message(t('The comment you are replying to does not exist.'), 'error');
+            drupal_goto("node/$nid");
+          }
           $comment = drupal_unpack($comment);
           $comment->name = $comment->uid ? $comment->registered_name : $comment->name;
           $output .= theme('comment_view', $comment);