diff --git a/helpers.inc.php b/helpers.inc.php
index e6e1366..03568f6 100644
--- a/helpers.inc.php
+++ b/helpers.inc.php
@@ -180,7 +180,7 @@ function need_to_regen(string $file, array $deps, bool $debug = false) : bool
   $fmtime = filemtime($file); 
   foreach($deps as $dep)
   {
-    if(is_file($dep) && (filemtime($dep) > $fmtime))
+    if($dep && is_file($dep) && (filemtime($dep) > $fmtime))
     {
       if($debug)
         echo "$dep > $file\n";