/**
  * Generic callback, to catch uncaught exceptions when they bubble up to the top of the call chain.
  *
  * @ignore
  * @param Exception $exception
  */
 public static function exception_handler($exception)
 {
     StaticPagesQueue::has_error(self::$current_url);
     $errno = E_USER_ERROR;
     $type = get_class($exception);
     $message = "Uncaught " . $type . ": " . $exception->getMessage();
     $file = $exception->getFile();
     $line = $exception->getLine();
     $context = $exception->getTrace();
     Debug::fatalHandler($errno, $message, $file, $line, $context);
 }