Relationships in Doctrine through an interface - how?

Question

symfony

Hello!
I have three models: User, Car and Driver. A user can add cars and drivers to their personal favorites, so the structure is (simplified):
A user who has a favorite:

namespace Acme\AppBundle\Entities;

use Acme\AppBundle\Interfaces\HasFavorites;

/** @ORM\Entity */
class User implements HasFavorites
{
    /** @ORM\ManyToMany(targetEntity="Acme\AppBundle\Entities\Favorite") */
    protected $favorites;

    public function getFavorites() : ArrayCollection
    {
        return $this->favorites;
    }

    public function addFavorite(Favorite $favorite)
    {
        $this->favorites->add($favorite);
    }
}

Favorite Item Model:

namespace Acme\AppBundle\Entities;

use Acme\AppBundle\Interfaces\Favoritable;

/** @ORM\Entity */
class Favorite
{
    /** @ORM\ManyToOne(targetEntity="Acme\AppBundle\Entities\User") */
    private $owner;

    /** @ORM\ManyToOne(targetEntity="Acme\AppBundle\Interfaces\Favoritable") */
    private $target;

    public function __construct(User $owner, Favoritable $target)
    {
        $this->owner  = $owner;
        $this->target = $target;
    }

    public function getOwner() : User
    {
        return $this->owner;
    }

    public function getTarget() : Favoritable
    {
        return $this->target;
    }
}

Car and driver are examples of models that can be added to favorites:

namespace Acme\AppBundle\Entities;

use Acme\AppBundle\Interfaces\Favoritable;

/** @ORM\Entity */
class Car implements Favoritable { /* ... */ }

/** @ORM\Entity */
class Driver implements Favoritable { /* ... */ }

However, when I run schema update `./bin/console doctrine:schema:update --force` I see an error

[Doctrine\Common\Persistence\Mapping\MappingException]
Class 'Acme\AppBundle\Interfaces\Favoritable' does not exist

This code from the tests is not particularly beautiful, but it works until it accesses the database (and, of course, it is waiting for refactoring when I learn how to prepare a doctrine so that it somehow works):

$user = $this->getMockUser();
$car  = $this->getMockCar();
$fav  = new Favorite($user, $car);
$user->addFavorite($fav);
static::assertCount(1, $user->getFavorites());
static::assertEquals($user, $fav->getUser());

As a result, I want to see in the database approximately a similar scheme:

+ ––––––––––––– +   + ––––––––––––– +   + –––––––––––––––––––––––––––––––––– +
|     users     |   |      cars     |   |            favorites               |
+ –– + –––––––– +   + –– + –––––––– +   + –––––––– + ––––––––– + ––––––––––– +
| id |   name   |   | id |   name   |   | owner_id | target_id | target_type |
+ –– + –––––––– +   + –– + –––––––– +   + –––––––– + ––––––––– + ––––––––––– +
| 42 | John Doe |   | 17 | BMW      |   |       42 |        17 | car         |
+ –– + –––––––– +   + –– + –––––––– +   + –––––––– + ––––––––– + ––––––––––– +

Answer 1

symfony.com/doc/current/doctrine/resolve_target_en...
The resolve_target_entities section in config.yml is responsible for interface mapping.