Symfony 3.4 autowire service - symfony

Question

Am developing a mini app in Symfony 3.4. Am putting together an authentication process using Guard. I have created a class called LoginFormAuthenticator which extends AbstractFormLoginAuthenticator.
Receiving error:
Cannot autowire service "app.security.login_form_authenticator": argument "$em" of method
"AppBundle\Security\LoginFormAuthenticator::__construct()" references
class "Doctrine\ORM\EntityManager" but no such service exists. Try
changing the type-hint to one of its parents: interface
"Doctrine\ORM\EntityManagerInterface", or interface
"Doctrine\Common\Persistence\ObjectManager".
My code in my form authenticating class:
<?php
namespace AppBundle\Security;
use AppBundle\Form\LoginForm;
use Doctrine\ORM\EntityManager;
use Symfony\Component\Form\FormFactoryInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\RouterInterface;
use Symfony\Component\Security\Core\Exception\AuthenticationException;
use Symfony\Component\Security\Core\User\UserInterface;
use Symfony\Component\Security\Core\User\UserProviderInterface;
use Symfony\Component\Security\Guard\Authenticator\AbstractFormLoginAuthenticator;
use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
class LoginFormAuthenticator extends AbstractFormLoginAuthenticator
{
private $formFactory;
private $em;
private $router;
public function __construct(FormFactoryInterface $formFactory, EntityManager $em, RouterInterface $router)
{
$this->formFactory = $formFactory;
$this->em = $em;
$this->router = $router;
}
public function getCredentials(Request $request)
{
$isLoginSubmit = $request->getPathInfo() == '/login' && $request->isMethod('POST');
if(!$isLoginSubmit){
return false;
}
$form = $this->formFactory->create(LoginForm::class);
$form->handleRequest($request);
$data = $form->getData();
return $data;
}
public function getUser($credentials, UserProviderInterface $userProvider)
{
$username = $credentials['_username'];
return $this->em->getRepository('AppBundle:User')
->findOneBy(['email' => $username]);
}
public function checkCredentials($credentials, UserInterface $user)
{
$password = $credentials['_password'];
if($password == 'iliketurtles'){
return true;
}
return false;
}
protected function getLoginUrl()
{
return $this->router->generate('security_login');
}
}
My services.yml:
services:
# default configuration for services in *this* file
_defaults:
# automatically injects dependencies in your services
autowire: true
# automatically registers your services as commands, event subscribers, etc.
autoconfigure: true
# this means you cannot fetch services directly from the container via $container->get()
# if you need to do this, you can override this setting on individual services
public: false
# makes classes in src/AppBundle available to be used as services
# this creates a service per class whose id is the fully-qualified class name
AppBundle\:
resource: '../../src/AppBundle/*'
# you can exclude directories or files
# but if a service is unused, it's removed anyway
exclude: '../../src/AppBundle/{Entity,Repository,Tests}'
# controllers are imported separately to make sure they're public
# and have a tag that allows actions to type-hint services
AppBundle\Controller\:
resource: '../../src/AppBundle/Controller'
public: true
tags: ['controller.service_arguments']
# add more services, or override services that need manual wiring
# AppBundle\Service\ExampleService:
# arguments:
# $someArgument: 'some_value'
app.security.login_form_authenticator:
class: AppBundle\Security\LoginFormAuthenticator
autowire: true
Am a complete novice in Symfony so apologies if I'm missing something obvious.

Answer 1

As noted by #Cerad in the comments, you should change EntityManager to EntityManagerInterface in your constructor.
Change the line
use Doctrine\ORM\EntityManager;
to
use Doctrine\ORM\EntityManagerInterface;
And also change the line
public function __construct(FormFactoryInterface $formFactory, EntityManager $em, RouterInterface $router)
to
public function __construct(FormFactoryInterface $formFactory, EntityManagerInterface $em, RouterInterface $router)

Answer 2

The Doctrine\Common\Persistence\ObjectManager interface is no longer aliased to the doctrine.orm.entity_manager service, use Doctrine\ORM\EntityManagerInterface instead.