I want to remove the need for a username in the FOSUserBundle. My users will login using an email address only and I've added real name fields as part of the user entity. I realised that I needed to redo the entire mapping as described here. I think I've done it correctly but when I try to submit the registration form I get the error:

"Only field names mapped by Doctrine can be validated for uniqueness."

The strange thing is that I haven't tried to assert a unique constraint to anything in the user entity.

Here is my full user entity file:

<?php
// src/MyApp/UserBundle/Entity/User.php

namespace MyApp\UserBundle\Entity;

use FOS\UserBundle\Model\User as BaseUser;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;

/**
 * @ORM\Entity
 * @ORM\Table(name="depbook_user")
 */
class User extends BaseUser
{
    /**
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    protected $id;

    /**
     * @ORM\Column(type="string", length=255)
     *
     * @Assert\NotBlank(message="Please enter your first name.", groups={"Registration", "Profile"})
     * @Assert\MaxLength(limit="255", message="The name is too long.", groups={"Registration", "Profile"})
     */
    protected $firstName;

    /**
     * @ORM\Column(type="string", length=255)
     *
     * @Assert\NotBlank(message="Please enter your last name.", groups={"Registration", "Profile"})
     * @Assert\MaxLength(limit="255", message="The name is too long.", groups={"Registration", "Profile"})
     */
    protected $lastName;

    /**
     * @ORM\Column(type="string", length=255)
     *
     * @Assert\NotBlank(message="Please enter your email address.", groups={"Registration", "Profile"})
     * @Assert\MaxLength(limit="255", message="The name is too long.", groups={"Registration", "Profile"})
     * @Assert\Email(groups={"Registration"})
     */
    protected $email;

    /**
     * @ORM\Column(type="string", length=255, name="email_canonical", unique=true)
     */
     protected $emailCanonical;

    /**
     * @ORM\Column(type="boolean")
     */
     protected $enabled;

    /**
     * @ORM\Column(type="string")
     */
     protected $salt;

    /**
     * @ORM\Column(type="string")
     */
     protected $password;

    /**
     * @ORM\Column(type="datetime", nullable=true, name="last_login")
     */
     protected $lastLogin;

    /**
     * @ORM\Column(type="boolean")
     */
     protected $locked;

    /**
     * @ORM\Column(type="boolean")
     */
     protected $expired;

    /**
     * @ORM\Column(type="datetime", nullable=true, name="expires_at")
     */
     protected $expiresAt;

    /**
     * @ORM\Column(type="string", nullable=true, name="confirmation_token")
     */
     protected $confirmationToken;

    /**
     * @ORM\Column(type="datetime", nullable=true, name="password_requested_at")
     */
     protected $passwordRequestedAt;

    /**
     * @ORM\Column(type="array")
     */
     protected $roles;

    /**
     * @ORM\Column(type="boolean", name="credentials_expired")
     */
     protected $credentialsExpired;

    /**
     * @ORM\Column(type="datetime", nullable=true, name="credentials_expired_at")
     */
     protected $credentialsExpiredAt;

    public function __construct()
    {
        parent::__construct();
        // your own logic
    }

    /**
     * @return string
     */
    public function getFirstName()
    {
        return $this->firstName;
    }

    /**
     * @return string
     */
    public function getLastName()
    {
        return $this->lastName;
    }

     /**
     * Sets the first name.
     *
     * @param string $firstname
     *
     * @return User
     */
    public function setFirstName($firstname)
    {
        $this->firstName = $firstname;

        return $this;
    }

         /**
     * Sets the last name.
     *
     * @param string $lastname
     *
     * @return User
     */
    public function setLastName($lastname)
    {
        $this->lastName = $lastname;

        return $this;

} }

I've seen various suggestions about this but none of the suggestions seem to work for me. The FOSUserBundle docs are very sparse about what must be a very common request.