this looks weird, as it does not look like the service is configured as lazy here, and so I don't see why we would validate a proxy class.

And RepackedApplication is also not overriding anything.

/cc @nicolas-grekas

this looks weird, as it does not look like the service is configured as lazy here, and so I don't see why we would validate a proxy class.

The application is marked as Lazy

And RepackedApplication is also not overriding anything.

Indeed, I tried to make the reproducer as small as possible !

This code used to work. I suspect the issue comes from PHP!

I may have found the culprit. When I dumped the compiled compiler I get

    "App\Application" => Symfony\Component\DependencyInjection\Definition^ {#32                                                                                                             
      -class: "RepackedApplication"                                                                                                                                                         
      #arguments: array:1 [
        0 => Symfony\Component\DependencyInjection\TypedReference^ {#147
          -id: "App\Foo"
          -invalidBehavior: 1
          -name: null
          -type: "App\Foo"
          -attributes: []
        }
      ]
    }
    "App\Foo" => Symfony\Component\DependencyInjection\Definition^ {#44
      -class: "App\Foo"
      #arguments: array:1 [
        0 => Symfony\Component\DependencyInjection\Reference^ {#149
          -id: ".lazy.App\Application"
          -invalidBehavior: 1
        }
      ]
    }
    ".lazy.App\Application" => Symfony\Component\DependencyInjection\Definition^ {#148
      -class: "App\Application"
      #arguments: array:1 [
        0 => array:1 [
          0 => Symfony\Component\DependencyInjection\TypedReference^ {#150 …5}
        ]
      ]
    }
  ]

• Service App\Application => has class RepackedApplication ✅
• Service App\Foo => has argument .lazy.App\Application ✅
• Service .lazy.App\Application => has class App\Application ❌ This is wrong here.

So I suspect two things

• Symfony has always been broken here
• PHP added a check somewhere that break castor

I manage to make a reproducer as smaller as possible (I guess)

<?php

class Application
{
    public function __construct(
        private string $name = 'my-app',
    ) {}

    public function getName(): string
    {
        return $this->name;
    }
}

class RepackedApplication extends Application
{
}

$application = new ReflectionClass(Application::class)->newLazyProxy(fn () => new RepackedApplication());

$application->getName();

I ran it on https://3v4l.org/TfgGE, and it's always the same error. So PHP may have not changed?!
So maybe it was Symfony? This is strange, the issue has popped on castor while we didn't updated our vendor (composer.lock is commited)

Should I open an issue on PHP.net too ?

this is because you don't make the service lazy. You make only the autowired argument lazy, which creates a lazy proxy based on the autowired type (which is the application type).