Ticket #17170: 17170.diff

src/wp-includes/post.php

@@ -3831 +3831 @@
                 }
         } else {
                 // Post slugs must be unique across all posts.
-                $check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type = %s AND ID != %d LIMIT 1";
+                $check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND ( post_type = %s OR post_type = 'attachment' ) AND ID != %d LIMIT 1";
                 $post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_type, $post_ID ) );
 
                 // Prevent new post slugs that could result in URLs that conflict with date archives.