Symfony2 Outside class - php

Question

I use symfony2 (2.6) and I have class to global variable to twig. For Example, class menu:
namespace Cms\PageBundle\Twig;
use Doctrine\ORM\EntityManager;
class Menu {
protected $em;
public function __construct(EntityManager $em)
{
$this->em = $em;
}
public function show(){
/******/
}
}
and services.yml
services:
class_menu:
class: Cms\PageBundle\Twig\Menu
arguments: ['#doctrine.orm.entity_manager']
twig_menu:
class: Cms\PageBundle\Twig\Menu
See:
ContextErrorException in Menu.php line 9:
Catchable Fatal Error: Argument 1 passed to
Cms\PageBundle\Twig\Menu::__construct() must be an instance of
Doctrine\ORM\EntityManager, none given, called in
/home/cms/public_html/app/cache/dev/appDevDebugProjectContainer.php on
line 3834 and defined
General, any class (outside) have problem with the constructor and (argument) doctrine.
Why?
Symfony2 getdoctrine outside of Model/Controller

Answer 1

This error is totally expected. Symfony2 expects to create service instance by invoking the __construct constructor. If you want to keep the single class in play, you will need to remove that __construct and use setter dependency injection instead.
There is an official documentation on this: Optional Dependencies: Setter Injection
Basically, you do not pass the EntityManager instance during the creation of an service instance but rather "set it later".
Hope this helps.
Update:
If you fallback to your original solution, make sure you pass EntityManager in both instances:
services:
class_menu:
class: Cms\PageBundle\Twig\Menu
arguments: ['#doctrine.orm.entity_manager']
twig_menu:
class: Cms\PageBundle\Twig\Menu
arguments: ['#doctrine.orm.entity_manager']