Symfony 2.1 collections with by_reference = false

Customer.php

<?php

namespace Ibms\CustomerBundle\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;

/**
 * @ORM\MappedSuperclass
 */
abstract class Customer
{
    /**
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     * @var integer
     */
    protected $id;

    /**
     * @ORM\OneToMany(targetEntity="Ibms\CustomerBundle\Entity\CustomerContact", mappedBy="customer", orphanRemoval=true, cascade={"persist"})
     * @var \Doctrine\Common\Collections\Collection
     */
    protected $contacts;

    public function __construct()
    {
        $this->contacts   = new ArrayCollection;
    }

    public function getContacts()
    {
        return $this->contacts;
    }

    public function addContact(CustomerContact $contact)
    {
        $this->contacts->add($contact);
        $contact->setCustomer($this);
    }

    public function removeContact(CustomerContact $contact)
    {
        $this->contacts->removeElement($contact);
        $contact->setCustomer(null);
    }

// ...
}

gistfile1.txt

<?php

namespace Ibms\CustomerBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;

class CustomerType extends AbstractType
{
    private $dataClass = 'Ibms\\CustomerBundle\\Entity\\Customer';

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

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('contacts', 'collection', array(
                'type' => new CustomerContactType(),
                'allow_add' => true,
                'allow_delete' => true,
                'prototype' => true,
                'by_reference' => false,
        ));
    }

    public function getDefaultOptions()
    {
         return array('data_class' => $this->dataClass);
    }

    public function getName()
    {
        return 'ibms_customer';
    }
}