Undefined index path

diff --git a/wp-content/plugins/custom-permalinks/custom-permalinks.php b/wp-content/plugins/custom-permalinks/custom-permalinks.php
index fa58f7b..afbada8 100644
--- a/wp-content/plugins/custom-permalinks/custom-permalinks.php
+++ b/wp-content/plugins/custom-permalinks/custom-permalinks.php
@@ -273,7 +273,7 @@ function custom_permalinks_trailingslash($string, $type) {

   if ( !trim($request) ) return $string;

-  if ( trim($_CPRegisteredURL,'/') == trim($request,'/') ) {
+  if ( isset( $url['path'] ) && trim($_CPRegisteredURL,'/') == trim($request,'/') ) {
     return ($string{0} == '/' ? '/' : '') . trailingslashit($url['path']) . $_CPRegisteredURL;
   }

https://ww.wp.xz.cn/plugins/custom-permalinks/