AutoRegister no longer needs to return a metaclass

[todofixthis]

Thanks to https://peps.python.org/pep-0487/ we now have __init_subclass__ which can (amongst other things) be used to automatically add classes to a registry. As a result, AutoRegister no longer needs to return a metaclass, which would substantially improve its interoperability with other libraries (e.g., Pydantic).

I think something more-or-less like this should work nicely:

def AutoRegister(registry: ClassRegistry):
    class _Base(ABC):
        def __init_subclass__(cls, **kwargs):
            super().__init_subclass__(**kwargs)
            if not isabstract(cls):
                registry.register(cls)
    return _Base

Also, I think AutoRegister can drop its base_type parameter, as developers could achieve the same outcome with multiple inheritance, e.g.:

class IDToken(BaseModel, AutoRegister(registry)):
    ...

An alternative would be to make registry a kwarg for __init_subclass__, so that AutoRegister becomes an actual class instead of a function that returns same...but that feels brittle to me, as it could potentially cause conflicts if another base class is expecting a kwarg with the same name.

class AutoRegister(ABC):
    def __init_subclass__(cls, /, registry, **kwargs):
        ...

class IDToken(BaseModel, AutoRegister, registry=registry):
    ...

But then, I've never been comfortable with this style, so maybe I'm the problem 😅

[todofixthis]

Need to think about how to deprecate the existing AutoRegister gracefully.

Maybe keep the existing AutoRegister but add a DeprecationWarning when it's called. Then add a new AutoRegister to class_registry.base maybe?

After a few releases I can then remove the old AutoRegister, or maybe just keep it but rename to AutoRegisterMeta? This would be a good use case for adding telemetry, but that's against my religion, so.... 😅

[todofixthis]

Maybe do a quick survey of public projects that use phx-class-registry in GitHub, GitLab, Bitbucket and see if anyone is using AutoRegister 🤔

I'm not sure if I'm hoping that people are using it, or that people aren't using it 😹