Doctrine 2.1 - Relation Lost After ManyToMany Cascade Merge - Symfony2

Question

After merging an entity that has related entities with relations set to cascade both persist and merge operations the relations are lost!

Here are the entities:

class Event implements NormalizableInterface
{
    /**
     * @ORM\ManyToMany(targetEntity="Participant", inversedBy="events", cascade={"persist", "merge"})
     * @ORM\JoinTable(name="event_participant",
     *      joinColumns={@ORM\JoinColumn(name="event_id", referencedColumnName="id", onDelete="CASCADE")},
     *      inverseJoinColumns={@ORM\JoinColumn(name="participant_id", referencedColumnName="id", onDelete="CASCADE")}
     *      )
     */
    private $participants;
}


class Participant implements NormalizableInterface
{
    /**
     * @ORM\ManyToMany(targetEntity="Event", mappedBy="participants", cascade={"persist", "merge"})
     */
    protected $events;
}

Here are my joins:

foreach ($events as $event)
{
    if (!$event->hasParticipant($participant)) {

        $event->addParticipant($participant);
    }
    if (!$participant->hasEvent($event)) {

        $participant->addEvent($event);
    }
}

Here is my merge code:

echo "Before merge participant count: ".count($event->getParticipants()).PHP_EOL;

$event = $em->merge($event);

echo "After merge participant count: ".count($event->getParticipants()).PHP_EOL;

...and here is the output:

Before merge participant count: 2
After merge participant count: 0

..and the database looks like this:

table               | rows
-------------------------------
event               | 1
-------------------------------
participant         | 2
-------------------------------
event_participant   | 0
-------------------------------

Can anyone see where I'm being dumb?

BTW there are more relationships than this. I've simplified things here to make the explanation clearer. My other relations aren't affected negatively by the merge. Also I'm doing the merge in a console Command not a in a controller. I can post more code if it'll help :)

Also I'm using Doctrine 2.1.7 and Symfony 2.0.15

Many thanks, Matthew

Answer 1

I've faced the same issue, and fixed it by refreshing the entity after merge:

$mergedEntity = $entityManager->merge($serializedEntity);
$entityManager->refresh($mergedEntity);