Symfony2 ManyToMany relation doesn't link 2 entities - Doctrine2 tries to persist inverse entity

Question

Good evening,

I designed my application so that a User can subscribe to multiple events and an Event can have multiple subscribers of type User.

I opted to create a ManyToMany relationship between an entity Event and an entity User to achieve this.

More precisely, the Event entity owns the relation.

class Event implements EventInterface
{
/**
 * @ORM\ManyToMany(targetEntity="FS\UserBundle\Entity\User", inversedBy="events")
 */
private $subscribers;
public function __construct()
{
    $this->subscribers = new \Doctrine\Common\Collections\ArrayCollection();
}

/*
** FYI my app logic is to persist the event so i addEvent($this) to $subscriber
*/

public function addSubscriber(\FS\UserBundle\Entity\User $subscriber)
{
    $this->subscribers[] = $subscriber;

    $subscriber->addEvent($this);

    return $this;
}

My User entity is the inverse side of the relation.

class User implements UserInterface
{
/**
 * @ORM\ManyToMany(targetEntity="FS\EventBundle\Entity\Event", mappedBy="subscribers")
 */
private $events;

public function __construct()
{
    $this->events = new \Doctrine\Common\Collections\ArrayCollection();
}

public function addEvent(\FS\EventBundle\Entity\Event $event)
{
    $this->events[] = $event;

    return $this;
}
...

I addSubscriber($user) to a new Event. Then i send the Event with my EventForm's data to this controller :

private function processForm(EventInterface $event, array $parameters, $method = "PUT")
{
    $form = $this->formFactory->create(new EventType(), $event, array('method' => $method));
    $form->submit($parameters, 'PATCH' !== $method);

    $event = $form->getData();

    $validator = $this->container->get('validator');
    $listErrors = $validator->validate($event);

    if ($form->isValid() && count($listErrors) === 0) {
        $event->setAge();

        $this->om->persist($event);
        $this->om->flush($event);
    }

When i persist the Event, the User doesn't reflect any changes and i get the following exception : A new entity was found through the relationship 'FS\UserBundle\Entity\User#events' that was not configured to cascade persist operations for entity [user].

Why would Doctrine2 try to re-persist the User in this case ?

smarber smarber · Accepted Answer · 2015-11-05T18:32:11

Try with this:

class Event implements EventInterface
{
    /**
     * @ORM\ManyToMany(targetEntity="FS\UserBundle\Entity\User", inversedBy="events", cascade={"persist"})
     */
    private $subscribers;

Symfony2 ManyToMany relation doesn't link 2 entities - Doctrine2 tries to persist inverse entity

1 Answers