Currently, if we want to exclude classes from registering as services in the container, we can add their namespace(s) in the app configuration, or use the #[Exclude]/#[When('never')] attributes on each of the classes.

When it comes to certain types of classes, eg. entities, they can be placed all around the apps in many different folders, which can result in many entries under the exclude configuration. It is also usual for us to have many entity classes, so adding the attribute to each of them can be error-prone.

However, classes of a same type may already have a common attribute declared on them - such as Doctrine\ORM\Mapping\Entity.

Because of that, I'm proposing a new way for excluding classes by making it possible to register any attribute for exclusion.

Underneath, this is just extending the functionality for handling the classes with #[Exclude] attribute by additionally checking the list of attributes marked for exclusion.

Usage:

To exclude all classes with the #[Entity] attribute:

use Doctrine\ORM\Mapping\Entity;
use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\HttpKernel\Kernel as BaseKernel;

class Kernel extends BaseKernel
{
    use MicroKernelTrait;

    protected function build(ContainerBuilder $container)
    {
        $container->registerAttributeForExclusion(Entity::class);
    }
}