Ticket #21609: 21609.patch

wp-includes/comment.php

@@ -636 +636 @@
 
         // Simple duplicate check
         // expected_slashed ($comment_post_ID, $comment_author, $comment_author_email, $comment_content)
-        $dupe = "SELECT comment_ID FROM $wpdb->comments WHERE comment_post_ID = '$comment_post_ID' AND comment_approved != 'trash' AND ( comment_author = '$comment_author' ";
+        $dupe = "SELECT comment_ID FROM $wpdb->comments WHERE comment_post_ID = '$comment_post_ID' AND comment_parent = '$comment_parent' AND comment_approved != 'trash' AND ( comment_author = '$comment_author' ";
         if ( $comment_author_email )
                 $dupe .= "OR comment_author_email = '$comment_author_email' ";
         $dupe .= ") AND comment_content = '$comment_content' LIMIT 1";