How to avoid "Entities passed to the choice field must be managed. Maybe persist them in the entity manager?"

Question

1. Generated Entities from existing database
2. Generated CRUD controller

But it does not work with exception message:

Entities passed to the choice field must be managed. Maybe persist them in the entity manager?

Entity

/**
 * Question
 *
 * @ORM\Table(name="question", indexes={@ORM\Index(name="question_category_id", columns={"question_category_id"})})
 * @ORM\Entity
 */
class Question
{
    //...

    /**
     * @var \AppBundle\Entity\QuestionCategory
     * @ORM\ManyToOne(targetEntity="AppBundle\Entity\QuestionCategory")
     * @ORM\JoinColumns({
     *   @ORM\JoinColumn(name="question_category_id", referencedColumnName="id")
     * })
     */
    private $questionCategory;

    public function __construct() 
    {
        $this->questionCategory = new QuestionCategory();
    }

    //...
}

Form

class QuestionType extends AbstractType
{
    /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('name')
            ->add('questionCategory');
    }

    /**
     * @param OptionsResolver $resolver
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Question'
        ));
    }
}

Controller

class QuestionController extends Controller
{
   //...

   /**
     * Creates a new Question entity.
     * @Route("/new", name="question_new")
     * @Method({"GET", "POST"})
     */
    public function newAction(Request $request)
    {
        $question = new Question();
        $form = $this->createForm('AppBundle\Form\QuestionType', $question);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $em->persist($question);
            $em->flush();

            return $this->redirectToRoute('question_show', array('id' => $question->getId()));
        }

        return $this->render('question/new.html.twig', array(
            'question' => $question,
            'form' => $form->createView(),
        ));
    }

//...
}

Deep debugging gives nothing to me. How to fix it?

Test repository to reproduce error: https://github.com/sectus/question.test.local

Answer 1

Beware, this error can also be raised when using 'by_reference' => false, in your form type with relations that are not ManyToMany.
An unfortunate copy/paste put me in this situation.

Answer 2

According to the code shown on your GitHub project, the Question entity has the following constructor:

public function __construct() 
{
    $this->questionCategory = new QuestionCategory();
}

When you create an entity form field, it can only contain values that are managed by doctrine, but your new questionCategory is not managed.

Usually, the best solution is just to not fill this entity field in the constructor, but only in those places you strictly need it. When building a form, Synfony will fill it for you after submitting and calling $form->handleRequest().

So, in your case, just remove the Question entity's constructor.

After that, you'll also need to implement the __toString() method in QuestionCategory entity:

 public function __toString(){
       return 'whatever you neet to see the type`;
 }

Answer 3

In my case I was having this issue because I was using EntityType instead of ChoiceType, to build the selectList.

EntityType display only data from database, instead ChoiceType can display "not managed" objects.

I hope this will help.