Doctrine - how to check if a collection contains an entity - doctrine-orm

Question

I have two entities User and Article with many-to-many relation as Article can have many authors.
class User
{
/** #var string */
public $name;
/** #var Collection<Article> */
public $articles;
}
class Article
{
/** #var string */
public $title;
/** #var Collection<User> */
public $authors;
}
How I can find all Articles with specified (co)author using DQL?

Answer 1

Use MEMBER OF expression.
Your DQL query could like like
SELECT art FROM Article art WHERE :user MEMBER OF art.authors
or using query builder
$queryBuilder = $repository->createQueryBuilder("art");
$queryBuilder->where(":user MEMBER OF art.authors");
Alternatively you can join and filter collection
SELECT art FROM Article art JOIN art.authors aut WHERE aut = :user
or
$queryBuilder = $repository->createQueryBuilder("art");
$queryBuilder->join("art.authors", "aut");
$queryBuilder->where("aut = :user");

Answer 2

Use Query Builder
Summary
$qb->expr()->isMemberOf(':user', 'a.authors')
Solution
src/Repository/ArticleRepository.php
/**
* #param User $author
* #return Article[] List of articles filtered by $author
*/
public function findByAuthor(User $author): array
{
$qb = $this->createQueryBuilder('a');
$qb->setParameter('user', $author);
$qb->where($qb->expr()->isMemberOf(':user', 'a.authors'));
return $qb->getQuery()->getResult();
}
Example use
src/Controller/ArticleController.php
/**
* #Route("/article/{id<\d+>}", name="show-articles-by-author")
* #param ArticleRepository $articleRepository
* #param User $author
*/
public function showArticlesFromAuthor(ArticleRepository $articleRepository, User $author)
{
$articles = $articleRepository->findByAuthor($author);
return $this->render('articles.html.twig', [
'articles' => $articles,
'author' => $author->getName()
]);
}
templates/articles.html.twig
<h1>Articles from {{ author }}</h1>
<li>
{% for article in articles %}
<ul>
{{ article.title }}
</ul>
{% endfor %}
</li>