diff --git a/potx.inc b/potx.inc
index d5ed0ab..79d32f8 100644
--- a/potx.inc
+++ b/potx.inc
@@ -1953,7 +1953,7 @@ function _potx_parse_yaml_file($code, $file_name, $save_callback) {
 
   // Permission files cannot be described by our mapping system
   // so we parse them with custom PHP code.
-  if (substr($file, -16) === '.permissions.yml') {
+  if (substr($file_name, -16) === '.permissions.yml') {
     _potx_find_permissions_file_strings($code, $file_name, $save_callback);
     return;
   }