Symfony4 -如何使用Voter过滤EntityType字段

// src/Security/Authorization/Voter/ArticleVoter.php
namespace App\Security\Authorization\Voter;

use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
use Symfony\Component\Security\Core\Authorization\Voter\Voter;
use App\Entity\Article;

class ArticleVoter extends Voter
{
    const ARTICLE_EDIT = 'ARTICLE_EDIT';

    protected function supports($attribute, $subject)
    {
        return in_array($attribute, [self::ARTICLE_EDIT]) && $subject instanceof Article;
    }

    protected function voteOnAttribute($attribute, $subject, TokenInterface $token)
    {
        $user = $token->getUser();

        if (!$user instanceof User) {
            return false;
        }

        switch ($attribute) {
            case self::ARTICLE_EDIT:
                return $this->canEdit($subject, $user);
        }

        throw new \LogicException('This voter does not support the attribute "' . $attribute . '".');
    }

    private function canEdit(Article $article, User $user)
    {
        return $article->getAuthor() === $user || $user->hasRole('ROLE_ADMIN');
    }
}

# config/packages/security.yaml
security:
    # ...
    access_decision_manager:
        strategy: unanimous
    voters:
        App\Security\Authorization\Voter\ArticleVoter:
            id: 'app.article_voter'

// src/Form/Type/ArticleType.php
namespace App\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\EntityType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;
use App\Entity\Article;
use App\Entity\User;
use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;

class ArticleType extends AbstractType
{
    private $authorizationChecker;

    public function __construct(AuthorizationCheckerInterface $authorizationChecker)
    {
        $this->authorizationChecker = $authorizationChecker;
    }

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('author', EntityType::class, [
                'class' => User::class,
                'query_builder' => function (UserRepository $er) {
                    return $er->createQueryBuilder('u')
                        ->where('u.id = :userId')
                        ->setParameter('userId', $this->authorizationChecker->isGranted('ARTICLE_EDIT', $article) ? $article->getAuthor()->getId() : null);
                },
                'choice_label' => 'username',
            ])
            // ...
        ;
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'data_class' => Article::class,
        ]);
    }
}