I think validateMaxPostSize method is actually never called in case POST data exceeds $_SERVER['CONTENT_LENGTH'].
It is meant to be called from validate() which is called from fireEvents but it can never be called due this condition as it calls https://github.com/nette/application/blob/master/src/Application/UI/Form.php#L108 which returns always FALSE in that case
I think validateMaxPostSize method is actually never called in case POST data exceeds
$_SERVER['CONTENT_LENGTH'].It is meant to be called from validate() which is called from fireEvents but it can never be called due this condition as it calls https://github.com/nette/application/blob/master/src/Application/UI/Form.php#L108 which returns always FALSE in that case