Delete an item from oneToMany relationship - symfony

Question

I have the following Gallery entity
class Gallery
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var ArrayCollection
* #ORM\OneToMany(targetEntity="Tessa\GalleryBundle\Entity\Photo", mappedBy="gallery", cascade={"persist", "remove"})
*/
private $photos;
/* ... */
}
This gallery is linked with a manyToOne relationship to a PointOfInterest entity. Here is the declaration
class PointOfInterest
{
/* ... */
/**
* #ORM\ManyToOne(targetEntity="Tessa\GalleryBundle\Entity\Gallery", cascade={"persist", "remove"})
* #ORM\JoinColumn(nullable=false)
*/
private $gallery;
/* ... */
I also use a Form to update the PointOfInterest entity. Here is the form declaration
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('name', 'text')
->add('gallery', new GalleryType())
;
}
and the GalleryType declaration.
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('photos', 'collection', array('type' => new PhotoType(),
'required' => false,
'allow_add' => true,
'allow_delete' => true,
'by_reference' => false
))
;
}
When I edit the PoI I can add photos to the gallery without problem, but I can't delete anything.
I tried to hook on gallery PreUpdate, but it is never called. I printed output in removePhotos method of Gallery entity, and the photos are removed from the gallery. I then suspect the Gallery to never be persisted.
Here is the code when I persist the PoI after editing.
private function handleForm($elem, $is_new)
{
$form = $this->createForm(new CircuitType, $elem);
$request = $this->get('request');
if ($request->getMethod() == 'POST') {
$form->bind($request);
if ($form->isValid()) {
$em = $this->getDoctrine()->getManager();
$em->persist($elem);
$em->flush();
return $this->redirect($this->generateUrl('tessa_circuit_index'));
}
}
return $this->render('TessaUserBundle:Circuits:add.'.'html'.'.twig',
array(
'form' => $form->createView(),
'is_new' => $is_new,
));
}

Answer 1

There is article in Symfony2 cookbook about handling this type of situation. As you have OneToMany relationship, you have to remove related objects manually in controller.
Edit:
Or you can make use of Doctrine's orphan removal feature.
class Gallery
{
//...
/**
* #ORM\OneToMany(targetEntity="Photo", mappedBy="gallery", cascade={"persist", "remove"}, orphanRemoval=true)
*/
private $photos;
//...
public function removePhotos($photo)
{
$this->photos->remove($photo);
$photo->setGallery(null);
}
}