Cannot autowire service: Argument references class but no such service exists - php

Question

I'm upgrading a project from Symfony 3 to Symfony 4
(https://github.com/symfony/symfony/blob/master/UPGRADE-4.0.md) and I have many repository/services like this:
namespace App\Entity;
use App\Entity\Activation;
use Doctrine\ORM\EntityRepository;
use Predis\Client;
class ActivationRepository extends EntityRepository
{
// ...
}
And when I try to run the project in the browser like this:
http://localhost:8000/login
I get this error:
(1/1) RuntimeException
Cannot autowire service "App\Entity\ActivationRepository":
argument "$class" of method
"Doctrine\ORM\EntityRepository::__construct()"
references class "Doctrine\ORM\Mapping\ClassMetadata"
but no such service exists.
Does this mean you have to create a service for "Doctrine\ORM\Mapping\ClassMetadata" in your services.yaml file?
Thanks to autowiring my new services.yaml file is fairly small compared to the old one, which had 2000+ lines.
The new services.yaml just has several of these (so far):
App\:
resource: '../src/*'
# Controllers
App\Controller\:
resource: '../src/Controller'
autowire: true
public: true
tags: ['controller.service_arguments']
# Models
App\Model\:
resource: '../src/Model/'
autowire: true
public: true
// etc
Question:
Do you really need to add service definitions to services.yaml for third party vendor classes? And if so, can I get an example of how to do that please?
Any advice from anyone who has already upgraded from Symfony 3 to Symfony 4 would be great.
PHP 7.2.0-2+ubuntu16.04.1+deb.sury.org+2 (cli) (built: Dec 7 2017 20:14:31) ( NTS )
Linux Mint 18, Apache2 Ubuntu.
EDIT / FYI:
This is the "Doctrine\ORM\EntityRepository::__construct()" which the ActivationRepository extends:
/**
* Initializes a new <tt>EntityRepository</tt>.
*
* #param EntityManager $em The EntityManager to use.
* #param Mapping\ClassMetadata $class The class descriptor.
*/
public function __construct(EntityManagerInterface $em, Mapping\ClassMetadata $class)
{
$this->_entityName = $class->name;
$this->_em = $em;
$this->_class = $class;
}
which is located here:
/vendor/doctrine/orm/lib/Doctrine/ORM/EntityRepository.php

Answer 1

Starting from the 1.8 version of DoctrineBundle, you can extend your class using Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository instead of Doctrine\ORM\EntityRepository. The result will be the same, but this does support the autowire.
Example:
use App\Entity\Activation;
use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
use Doctrine\Common\Persistence\ManagerRegistry;
class ActivationRepository extends ServiceEntityRepository
{
public function __construct(ManagerRegistry $registry)
{
parent::__construct($registry, Activation::class);
}
// ...
}

Answer 2

Do you really need to add service definitions to services.yaml for third party vendor classes?
No, don't do that. My personal suggestion is: don't extend EntityRepository. Ever. You don't want your repository's interface to have method like createQuery or flush. At least, you don't want that if you consider a repository just like a collection of objects. If you extend EntityRepository you will have a leaky abstraction.
Instead you can inject the EntityManager inside your repository, and that's it:
use App\Entity\Activation;
use App\Repository\ActivationRepository;
use Doctrine\ORM\EntityManagerInterface;
final class DoctrineActivationRepository implements ActivationRepository
{
private $entityManager;
private $repository;
public function __construct(EntityManagerInterface $entityManager)
{
$this->entityManager = $entityManager;
$this->repository = $this->entityManager->getRepository(Activation::class);
}
public function store(Activation $activation): void
{
$this->entityManager->persist($activation);
$this->entityManager->flush();
}
public function get($id): ?Activation
{
return $this->repository->find($id);
}
// other methods, that you defined in your repository's interface.
}
No other steps are required.

Answer 3

My issue was a wrong namespace.
File real position was App\Infrastructure\MySQL\Rubric\Specification
But namespace was set to App\Infrastructure\Rubric\Specification
Result "[blah blah] but no such service exists".

Answer 4

I got this issue. My service had a private constructor. I had to change:
private function __construct(
to
public function __construct(