public function __construct(Request $request){
        $this->startGameSession($request);
}

Catchable Fatal Error: Argument 1 passed to MyController::__construct() must be an instance of SymfonyComponentHttpFoundationRequest, none given...

namespace AppBundleController;

use SymfonyBundleFrameworkBundleControllerController;
use SymfonyComponentHttpFoundationRequestStack;

class ServiceController extends Controller
{
    public function __construct(RequestStack $requestStack)
    {
        //do something with $requestStack->getCurrentRequest();
    }
}

# app/config/services.yml
services:
    service_controller:
        class: AppBundleControllerServiceController
        arguments: ['@request_stack']

# app/config/routing.yml
index:
    path: /index
    defaults: { _controller: service_controller:indexAction }

use SymfonyComponentHttpFoundationRequest;

namespace SymfonyComponentHttpKernelControllerControllerResolver;

...

public function getController(Request $request)
{
    if (!$controller = $request->attributes->get('_controller')) {
        if (null !== $this->logger) {
            $this->logger->warning('Unable to look for the controller as the "_controller" parameter is missing.');
        }

        return false;
    }

    if (is_array($controller)) {
        return $controller;
    }

    if (is_object($controller)) {
        if (method_exists($controller, '__invoke')) {
            return $controller;
        }

        throw new InvalidArgumentException(sprintf('Controller "%s" for URI "%s" is not callable.', get_class($controller), $request->getPathInfo()));
    }

    if (false === strpos($controller, ':')) {
        if (method_exists($controller, '__invoke')) {
            return $this->instantiateController($controller);
        } elseif (function_exists($controller)) {
            return $controller;
        }
    }

    $callable = $this->createController($controller);

    if (!is_callable($callable)) {
        throw new InvalidArgumentException(sprintf('The controller for URI "%s" is not callable. %s', $request->getPathInfo(), $this->getControllerError($callable)));
    }

    return $callable;
}

namespace AppBundleController;

use SymfonyBundleFrameworkBundleControllerController;
use SymfonyComponentHttpFoundationRequestStack;

class MyController extends Controller
{
    public function __construct(RequestStack $requestStack)
    {
        $request = $requestStack->getCurrentRequest();
        //do something with the $request

    }
}