PhpBB 3.2.2 Twig Loader Error When Using PhpBB For Website Login

I am trying it use the authentication of PhpBB 3.2.2 to authenticate the websites users. I have added the code below to the top of a test page

define('IN_PHPBB', true);

$phpbb_root_path = '/forum/';
$phpEx = substr(strrchr(__FILE__, '.'), 1);
include($phpbb_root_path . 'common.' . $phpEx);

// Start session management
$user->session_begin();
$auth->acl($user->data);
$user->setup();

The problem that I am coming across is I get a PhpBB Warning:

[phpBB Debug] PHP Warning: in file [ROOT]/phpbb/template/twig/loader.php on line 176: Declaration of phpbb/template/twig/loader::findTemplate($name) should be compatible with Twig_Loader_Filesystem::findTemplate($name, $throw = true)

I am not trying to load a twig template I just want to access the PhpBB session data to check if a user is logged in or not.

When i navigate to the actual forum itself that works fine without any errors or warnings.

Does anyone have a suggestion as to what the issue might be?

Solution

I have had a further look into this and the problem appears to be something to do with my own bootloader which sets up the twig loader for the main part of the website, this is having an issue with the twig loader for PhpBB. As this is a different issue from the one i orginally posted i will close this question.