Symfony2 ModelTransformer reverseTransform is never called - php

Question

In Symfony 2.8 I've got Movie entity with actors field, which is ArrayCollection of entity Actor (ManyToMany) and I wanted the field to be ajax-loaded Select2.
When I don't use Ajax, the form is:
->add('actors', EntityType::class, array(
'class' => Actor::class,
'label' => "Actors of the work",
'multiple' => true,
'attr' => array(
'class' => "select2-select",
),
))
It works, and this is what profiler displays after form submit: http://i.imgur.com/54iXbZy.png
Actors' amount grown up and I wanted to load them with Ajax autocompleter on Select2. I changed form to ChoiceType:
->add('actors', ChoiceType::class, array(
'multiple' => true,
'attr' => array(
'class' => "select2-ajax",
'data-entity' => "actor",
),
))
//...
$builder->get('actors')
->addModelTransformer(new ActorToNumberModelTransformer($this->manager));
I made DataTransformer:
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Persistence\ObjectManager;
use CompanyName\Common\CommonBundle\Entity\Actor;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;
class ActorToNumberModelTransformer implements DataTransformerInterface
{
private $manager;
public function __construct(ObjectManager $objectManager)
{
$this->manager = $objectManager;
}
public function transform($actors)
{
if(null === $actors)
return array();
$actorIds = array();
$actorsArray = $actors->toArray();
foreach($actorsArray as $actor)
$actorIds[] = $actor->getId();
return $actorIds;
}
public function reverseTransform($actorIds)
{
if($actorIds === null)
return new ArrayCollection();
$actors = new ArrayCollection();
$actorIdArray = $actorIds->toArray();
foreach($actorIdArray as $actorId)
{
$actor = $this->manager->getRepository('CommonBundle:Actor')->find($actorId);
if(null === $actor)
throw new TransformationFailedException(sprintf('An actor with id "%s" does not exist!', $actorId));
$actors->add($actor);
}
return $actors;
}
}
And registered form:
common.form.type.movie:
class: CompanyName\Common\CommonBundle\Form\Type\MovieType
arguments: ["#doctrine.orm.entity_manager"]
tags:
- { name: form.type }
But seems like the reverseTransform() is never called. I even put die() at the beginning of it - nothing happened. This is, what profiler displays after form submit: http://i.imgur.com/qkjLLot.png
I tried to add also ViewTransformer (code here: pastebin -> 52LizvhF - I don't want to paste more and I can't post more than 2 links), with the same result, except that reverseTransform() is being called and returns what it should return.

Answer 1

I know that this is an old question, but I was having a very similar problem. It turned out that I had to explicitly set the compound option to false.
That is to say, for the third parameter to the add() method, you need to add 'compound => false'.