Check if cached file exists

lib/Twig/Cache/Filesystem.php

@@ -87,6 +87,10 @@ class Twig_Cache_Filesystem implements Twig_CacheInterface
      */
     public function getTimestamp($key)
     {
-        return (int) @filemtime($key);
+        if (\file_exists($key)) {
+            return (int) @filemtime($key);
+        }
+
+        return 0;
     }
 }