You shoud not inject App\Repository\AttachmentRepository into App\Listeners\PostListener，the EntityMangaer is included into Doctrine\ORM\Event\PreUpdateEventArgs:

<?php

namespace App\Listeners;

use App\Entity\Post;
use App\Entity\Attachment;
use Doctrine\ORM\Event\PreUpdateEventArgs;

class PostListener
{
    public function preUpdate(Post $post, PreUpdateEventArgs $args)
    {
        $attachmentRepository = $args->getEntityManager()->getRepository(Attachment::class);
        dump($attachmentRepository->findAll());
    }
}

Hey there mate, thank you for the response,

Yes using the EntityManager that's in $args would work ,but the problem is i have the same exact code where i inject the AttachmentRepository in PostListener's construcor and it worksm which makes me think this is a bug with the new version because i can find any chnages log reporting any changes in terms of injecting Repositories in Listeners.

@konshensx16 thanks for reporting this issue. You said that this works in 4.1.6 but not in 4.2.1. In order to debug this faster, we'd need to know the first version which breaks your app. Could you please try with 4.1.7, 4.1.8, 4.1.9 and 4.2.0 and tell us which is the first version that breaks your app? Thanks!

Maybe caused by the same change that causes #29637? Can you check if the commit mentioned there made the difference in your application too?

Hello @javiereguiluz and @xabbuh thanks for replying to this, i just want to address one weird thing i just noticed like 5 minutes ago when i was doing more tests, the code i posted above isn't working obviously and throwing the exception, but this one WORKS and i cannot seem to undertand why:

<?php

namespace App\Listeners;

use App\Entity\Attachment;
use App\Entity\Post; 
use App\Repository\AttachmentRepository; 
use Doctrine\ORM\EntityManagerInterface;
use Doctrine\ORM\Event\LifecycleEventArgs;
use Doctrine\ORM\Event\PreUpdateEventArgs;
use Symfony\Component\Security\Core\Security;

class PostListener
{
    // i need to get the current logged in user
    /**
     * @var Security
     */
    private $security;
    /**
     * @var EntityManagerInterface
     */
    private $entityManager; 
    /**
     * @var AttachmentRepository
     */
    private $attachmentRepository;
    
    public function __construct(Security $security,
                                EntityManagerInterface $entityManager,
                                AttachmentRepository $attachmentRepository
    )
    {
        $this->security = $security;
        $this->entityManager = $entityManager;
        $this->attachmentRepository = $attachmentRepository;
    }

    public function preUpdate(Post $post, PreUpdateEventArgs $args)
    {
    	dump($this->attachmentRepository->findAll()); die;
    }

}

You guys have any idea why this would work and the other one (the code in the issue) won't? Does injecting the EntityManagerInterface has something to do with it ?

Edit

Removing the EntityManagerInterface will result in the exception being throw, and this is for the 4.1.6 which i intially said works fine, but when removing the EntityManagerInterface it throws the exception as well, i'm sorry as i was not aware of this.

Did to try lazy services https://symfony.com/doc/current/service_container/lazy_services.html ?

This should do the trick but if not, try injecting repository with @required annotation: https://symfony.com/doc/current/service_container/autowiring.html#autowiring-other-methods-e-g-setters