Even though $this->filterProvider->getPageFilter()->filter(); should always return a string, it returns null when given null and is causing internal server errors for Kathmandu.
In addition I'm removing a class variable type restriction because this module is meant to support PHP 7.2.
Even though
$this->filterProvider->getPageFilter()->filter();
should always return a string, it returns null when given null and is causing internal server errors for Kathmandu.In addition I'm removing a class variable type restriction because this module is meant to support PHP 7.2.