@hurricane-voronin Can you explain the problem you face in more detail? What do you try to solve and why does it not work?

@hurricane-voronin any feedback?

Hi there,
I have validation rules that stored in the database and could be configured dynamically, e.g I am able to create additional entities, configure/add fields and validation rules for them from the application UI. To load these configs I needed to add a custom validator loader that allow me to do this.

That explains what you are trying to do. But it's still not clear to me how you tried to solve your issue and where you were stuck or what did not work.

Before 9b204c93544532ebac27e6b500de22a2599fab7e changes there was a possibility to add custom validator loader to \Symfony\Component\Validator\Mapping\Loader\LoaderChain through compiler pass, as it was declared as service.

For now as a workaround, the easiest way is to override ValidatorBuilder, that is not a good approach.
Is it valid changes in 9b204c93544532ebac27e6b500de22a2599fab7e , may some changes should be reverted or I have to find a different way to resolve my problem?

There is indeed to other way than replacing the validator.builder service. However, I do not think the use case is common enough to justify its own extension point.

Well, the fact that we use this ValidatorBuilder to instantiate loaders instead of using the DIC means we don't allow using the container extension points (compiler passes) to hook into this. That's the only component where we do this.

ValidatorBuilder::addLoader() is part of #28210