[ethantkoenig]

Message can only be instantiated with an argument-less call:

In [1]: from google.protobuf.message import Message

In [2]: Message()
Out[2]: <google.protobuf.message.Message at 0xffffa0b13be0>

In [3]: Message(x=3)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[3], line 1
----> 1 Message(x=3)

TypeError: Message() takes no arguments

The previous __new__(*args, **kwargs) -> Self: annotation also interfere's with ty's ability to infer a ParamSpec from a generated Message subclass's constructor (as of ty verison 0.0.91):

def wrap[**P, T](callable: Callable[P, T]) -> Callable[P, T]:
    return callable


wrap(MyProtoMessage)(
    'ty accepts positional args, which are not accepted by any Message subclass',
    this_is_not_a_valid_field='ty also accepts any kwarg',
)

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

django-stubs (https://github.com/typeddjango/django-stubs)
  error: INTERNAL ERROR -- Please try using mypy master on GitHub: