Symfony2.1 - The option "em" does not exist when using DataTransformer

Question

I am using this cookbook recipe to add a data transformer in Symfon 2.1, but I am getting the following error, The option "em" does not exist. Known options are: "attr", "block_name",....

Is this still a valid way to send the entity manager over to the form type?

$taskForm = $this->createForm(new TaskType(), $task, array(
    'em' => $this->getDoctrine()->getEntityManager(),
));

Answer 1

While I can't comment if that's the best way or not, I've always passed them to my task constructor as a hard dependency...

Services

services:
    my_bundle.form.type.task:
        class: Company\MyBundle\Form\Type\TaskType
        arguments:
            - @doctrine.orm.entity_manager

Controller

$form = $this->createForm($this->get('my_bundle.form.type.task'), $task);
// or
$form = $this->createForm(new TaskType($this->getDoctrine()->getEntityManager()));

Form Type

namespace Company\MyBundle\Form\Type;

use Doctrine\ORM\EntityManager;
use Symfony\Component\Form\AbstractType;
// ...

class TaskType extends AbstractType
{
    protected $em;

    public function __construct(EntityManager $em)
    {
        $this->em = $em;
    }

    // ...
}

As soon as my form types have any dependencies, I use the container to manage them. I personally find this method much more clear of what's going on, and what my custom classes require than relying on Symfony's complex form configuration to do it for me.