I have added like this (marked colour to make it visible:
public function actionLogin()
{
$data = $this->_input->filter(array(
'login' => XenForo_Input::STRING,
'password' => XenForo_Input::STRING,
'remember' => XenForo_Input::UINT,
'register' => XenForo_Input::UINT,
'cookie_check' => XenForo_Input::UINT,
'postData' => XenForo_Input::JSON_ARRAY
));
if ($data['register'] || $data['password'] === '')
{
return $this->responseReroute('XenForo_ControllerPublic_Register', 'index');
}
$redirect = $this->getDynamicRedirectIfNot(XenForo_Link::buildPublicLink('login'));
if (XenForo_Visitor::getUserId())
{
return $this->responseRedirect(
XenForo_ControllerResponse_Redirect::SUCCESS,
//$redirect
XenForo_Link::buildPublicLink('members', XenForo_Visitor::getInstance()->toArray())
);
}