Two multi-family self-reference collections

I am using FOSUserBundle, and in my User class I want two things:

• user can invite another user for friendship. A friend must confirm this friendship. Thus, the user has two attributes, $inviteeForFriendsand $invitedFriends, which is a large association of self-references for managing pending friendships

• if a friendship is confirmed, it is removed from the associated partner and added to the friendly partner: $myFriendsand $friendsWithMe, which is also a multi-mass assistant.

Now in the controller I do this:

public function addAction() {
    $email = trim($this->get('request')->request->get("email"));
    // ...

    // find requested friend
    $userManager = $this->get('fos_user.user_manager');
    $friend = $userManager->findUserByEmail($email);
    // ...
    $user = $this->container->get('security.context')->getToken()->getUser();

    // ...

    // friend has not already asked the user
    if ($user->getInviteeForFriends()->contains($friend)) {
            throw new Exception(self::FRIEND_HAS_ALREADY_ASKED_MSG, self::FRIEND_HAS_ALREADY_ASKED);
    }
}

This ultimately $user->getInviteeForFriends()->contains($friend)leads to this error:

Notice: Undefined index: $invitedFriends in /home/r/workspace/MyProject/vendor/doctrine/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php line 764

A echo get_class($user->getInviteeForFriends())echos a Doctrine\ORM\PersistentCollection. A echo $user->getInviteeForFriends()->count();results in the same Undefined index error.

These statements work:

$user->getMyFriends()->contains($friend)
$user->getInvitedFriends()->contains($friend)

$user->getInviteeForFriends()->contains($friend) . ? ?

User:

/**
 * @ORM\Entity
 * @ORM\Table(name="fos_user")
 */
class User extends BaseUser
{
/**
 * @ORM\ManyToMany(targetEntity="User", mappedBy="myFriends")
 */
protected $friendsWithMe;

/**
 * @ORM\ManyToMany(targetEntity="User", inversedBy="friendsWithMe")
 * @ORM\JoinTable(name="friends",
 *     joinColumns={@ORM\JoinColumn(name="user_id", referencedColumnName="id")},
 *     inverseJoinColumns={@ORM\JoinColumn(name="friend_user_id", referencedColumnName="id")}
 * )
 */
protected $myFriends;


/**
 * I am invited for a friendship from these friends.
 * 
 * @ORM\ManyToMany(targetEntity="User", mappedBy="$invitedFriends")
 */
protected $inviteeForFriends;

/**
 * I invited those friends for a friendship.
 * 
 * @ORM\ManyToMany(targetEntity="User", inversedBy="$inviteeForFriends")
 * @ORM\JoinTable(name="pending_friendships",
 *     joinColumns={@ORM\JoinColumn(name="inviter_user_id", referencedColumnName="id")},
 *     inverseJoinColumns={@ORM\JoinColumn(name="invitee_user_id", referencedColumnName="id")}
 * )
 */
protected $invitedFriends;

public function __construct()
{
    parent::__construct();
    $this->friendsWithMe = new \Doctrine\Common\Collections\ArrayCollection();
    $this->myFriends = new \Doctrine\Common\Collections\ArrayCollection();
    $this->inviteeForFriends = new \Doctrine\Common\Collections\ArrayCollection();
    $this->invitedFriends = new \Doctrine\Common\Collections\ArrayCollection();
}


/**
 * Add friendsWithMe
 *
 * @param MyProject\SiteBundle\Entity\User $friendsWithMe
 */
public function addFriendsWithMe(\MyProject\SiteBundle\Entity\User $friendsWithMe)
{
    $this->friendsWithMe[] = $friendsWithMe;
}

/**
 * Get friendsWithMe
 *
 * @return Doctrine\Common\Collections\Collection $friendsWithMe
 */
public function getFriendsWithMe()
{
    return $this->friendsWithMe;
}

/**
 * Add myFriends
 *
 * @param MyProject\SiteBundle\Entity\User $myFriends
 */
public function addMyFriends(\MyProject\SiteBundle\Entity\User $myFriends)
{
    $this->myFriends[] = $myFriends;
}

/**
 * Get myFriends
 *
 * @return Doctrine\Common\Collections\Collection $myFriends
 */
public function getMyFriends()
{
    return $this->myFriends;
}

/**
 * Add inviteeForFriend
 *
 * @param MyProject\SiteBundle\Entity\User $inviteeForFriend
 */
public function addInviteeForFriends(\MyProject\SiteBundle\Entity\User $inviteeForFriend)
{
    $this->inviteeForFriends[] = $inviteeForFriend;
}

/**
 * Get inviteeForFriends
 *
 * @return Doctrine\Common\Collections\Collection $inviteeForFriends
 */
public function getInviteeForFriends()
{
    return $this->inviteeForFriends;
}

/**
 * Add invitedFriend
 *
 * @param MyProject\SiteBundle\Entity\User $invitedFriend
 */
public function addInvitedFriends(\MyProject\SiteBundle\Entity\User $invitedFriend)
{
    $this->invitedFriends[] = $invitedFriend;
}

/**
 * Get invitedFriends
 *
 * @return Doctrine\Common\Collections\Collection $invitedFriends
 */
public function getInvitedFriends()
{
    return $this->invitedFriends;
}
}