Question

I have an User entity. And those users can be friends together. So I defined a self referencing manyToMany unidirectional association (because there is always reciprocity is friendship, right ?).

a piece of my user entity in YML

manyToMany:
    friendList:
    targetEntity: User
    joinTable:
      name: user_friend
      joinColumns:
        user_id:
          referencedColumnName: id
      inverseJoinColumns:
        friend_id:
          referencedColumnName: id
    cascade: [persist]

When I call $user->addFriendList($friend), and after a persist and a flush, I have PDOException:

SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry ‘1-2’ for fey ‘PRIMARY’

When I check in the logs, I can see that doctrine is trying to exectue the same insert query twice.

For your information, my addFriendList function

public function addFriendList(User $friend)
{
    if (!$this->friendList->contains($friend)) {
        $this->friendList[] = $friend;
        $friend->addFriendList($this);
    }
}

Where am I wrong here ?

Answer 1

I finally found a solution to my issue. However I still don’t know if it’s a Doctrine2 defect or if it works as designed.

I need to persist my user and flush before adding friends.

So my working code is:

$em->persist($user);
$em-flush();

$user->addFriendList($friend);
$em->persist($user);
$em->flush();