symfony - Custom ExceptionListener picks up 403 & 404, but not 500 errors -

exact same problem unanswered question symfony 2.4: why 500 errors not caught kernel.exception listener.

i have implemented custom exception "handler" works awesomely 403 , 404 issues, 500 errors (which want handle, want send email myself system when happens) not trigger custom "handler" , continues behave if custom "handler" not there. code relatively straight forward:

extract app/config/config.yml:

services:     core.exceptlistener:         class: pmb\licensingbundle\listener\exceptionlistener         arguments:  ["@service_container", "@router"]         tags:             - { name: kernel.event_listener, event: kernel.exception, method: onkernelexception, priority: 200 } 

entire \pmb\licensingbundle\listener\exceptionlistener.php:

<?php  namespace pmb\licensingbundle\listener;  use symfony\component\httpkernel\event\getresponseforexceptionevent; use symfony\component\httpfoundation\response; use symfony\component\httpfoundation\redirectresponse; use symfony\component\httpkernel\exception\httpexceptioninterface; use symfony\component\dependencyinjection\containerinterface; use symfony\bundle\twigbundle\twigengine; use sensio\bundle\frameworkextrabundle\configuration\template;  class exceptionlistener {     private $container;     private $router;      function __construct($container, $router)      {         $this->container = $container;         $this->router = $router;     }      public function onkernelexception(getresponseforexceptionevent $event)     {         $exception = $event->getexception();         die("test");         $request = $this->container->get('request');         $templating = $this->container->get('templating');              if ($exception instanceof \symfony\component\security\core\exception\accessdeniedexception)         {              # if ajax request, show not error page.             if ($request->isxmlhttprequest())              {                 $response = new response(json_encode(array('error' => 'access denied: not logged in administrator')));             }             else             {                 return new redirectresponse($this->router->generate('login'));             }              $event->setresponse($response);         }         elseif ($exception->getstatuscode() == 404)         {             # if ajax request, show not error page.             if ($request->isxmlhttprequest())              {                 $response = new response(json_encode(array('error' => 'requested route not found')));             }             else             {                 $response = new response($templating->render('pmblicensingbundle:exception:error404.html.twig', array(                     'exception' => $exception                 )));             }              $event->setresponse($response);         }                else         {              # todo: send email             # if ajax request, not show error page.             if ($request->isxmlhttprequest()) $response = new response(json_encode(array('error' => 'internal server error encountered. developer has been notified.')));             else             {                 $response = new response($templating->render('pmblicensingbundle:exception:error500.html.twig', array(                     'exception' => $exception                 )));             }          }     } } 

i put die("test") in there verify "handler" not being called @ , not problem if-else logic. stated before, works awesomely 404 or 403 errors, 500 errors ignores , behaves in default manner. pretty sure has registering of listener service, cannot find explains how make work properly.

edit: below screenshots of errors not being handled expected. notice on 1 (undefined variable) die("test"); displays @ bottom, on ohter (syntax error) not display, though both seems being caught symfony2. further testing showed die("test"); showed up, die(">> .$exception->getstatuscode()." <<"); did not. assuming causing second exception not seeing, accessdeniedexception did not have function call , had use instanceof, there many possible errors can come 500 error, how distinguish whether error 1 of these?

further edit: on error did print "test" @ bottom, noticed when $container->testerror();, not "test", @ bottom of error, when return $container;, do, though both errors contexterrorexception undefined variable.

the 500 errors got before symfony has chance start. since symfony doesn't start in case cannot handle errors. debug such cases, should @ web server (apache, ngnix, etc) logs.