How to Instantly Decouple Symfony Doctrine Repository Inheritance to Clean Composition

The Single Class Fallacy of The Best Practise

It's always very simple to show an example of one polished class, with final, constructor injection, SOLID principles, design patterns and modern PHP 8.0 features. That's why it's easy to write such posts as the one above :)

But what about real-life projects that have 50+ repositories? Would you read a post about how someone refactored 50 repositories to services one by one? Probably not, because it would take dozens of hours just to write the post.

Turn Fallacy to Pattern Refactoring with Rector

What if you could change just 1 case and it would be promoted to the rest of your application? From many cases, to just one. That's exactly what Rector help you with.

Let's see how it works. We'll use the example from the original post, where the goal is to turn inheritance to composition - one of SOLID principles.

Instead of inheritance...

namespace App\Repository;

use App\Entity\Post;
use Doctrine\ORM\EntityRepository;

final class PostRepository extends EntityRepository
{
}

...we use composition:

namespace App\Repository;

use App\Entity\Post;
use Doctrine\ORM\EntityManager;
use Doctrine\ORM\EntityRepository;

final class PostRepository
{
    private EntityRepository $repository;

    public function __construct(EntityManager $entityManager)
    {
        $this->repository = $entityManager->getRepository(Post::class);
    }
}

4 Steps to Instant Refactoring of All Repositories

1. Install Rector

composer install rector/rector --dev

2. Setup rector.php

use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
use Rector\Doctrine\Rector\MethodCall\ReplaceParentRepositoryCallsByRepositoryPropertyRector;
use Rector\Doctrine\Rector\Class_\MoveRepositoryFromParentToConstructorRector;

return function (ContainerConfigurator $containerConfigurator): void {
    $services = $containerConfigurator->services();

    // order matters, this needs to be first to correctly detect parent repository

    // this will replace parent calls by "$this->repository" property
    $services->set(ReplaceParentRepositoryCallsByRepositoryPropertyRector::class);

    // this will move the repository from parent to constructor
    $services->set(MoveRepositoryFromParentToConstructorRector::class);
};

3. Run Rector on Your Code

Now the fun part:

vendor/bin/rector process /app

You will see diffs like:

 use App\Entity\Post;
 use Doctrine\ORM\EntityRepository;

-final class PostRepository extends EntityRepository
+final class PostRepository
 {
+    private \Doctrine\ORM\EntityRepository $repository;
+    public function __construct(\Doctrine\ORM\EntityManager $entityManager)
+    {
+        $this->repository = $entityManager->getRepository(\App\Entity\Post::class);
+    }
     /**
      * Our custom method
      *
      * @return Post[]
@@ -14,7 +22,7 @@
      */
     public function findPostsByAuthor(int $authorId): array
     {
-        return $this->findBy([
+        return $this->repository->findBy([
             'author' => $authorId
         ]);
     }

And your code is now both refactored to more the cleanest version possible. That's it!

Happy instant refactoring!