Function is not valid as a type

Hi,

Thank you for this wonderful project. I’m integrating mypy with a codebase that uses protobufs and feel that this will be quite helpful in doing so!

I’m able to generate the *.pyi type stub files along with the other definitions by invoking the following command:

$ python -m grpc_tools.protoc -I=github.com/gogo/protobuf/gogoproto -I=. \
    --python_out=generated/python \
    --grpc_python_out=generated/python \
    --mypy_out=generated/python

The generated *.pyi files look correct, however when I try to run mypy over modules that import these definitions, I receive error messages like the following (names/line #s scrubbed):

generated/python/foo_pb2.pyi:123: error: Function "Foo" is not valid as a type
generated/python/foo_pb2.pyi:123: note: Perhaps you need "Callable[...]" or a callback protocol?

Inside of foo_pb2.py, Foo is defined like follows:

Foo = _reflection.GeneratedProtocolMessageType('Foo', (_message.Message,), {
  'DESCRIPTOR' : _FOO,
  '__module__' : 'path.to.foo'
  # @@protoc_insertion_point(class_scope:Foo)
  })
_sym_db.RegisterMessage(Foo)

Is there something obvious I’m doing wrong? I’m using the following versions for my dependencies:

• mypy 0.761
• mypy-protobuf 1.18
• Python 3.6.5
• python-protobuf 3.11.3

$ python -m grpc_tools.protoc --version
libprotoc 3.8.0

Thanks!

[nipunn1313]

@forestbelton - mind taking a look at #112 to see if it handles the case you’ve brought up here (There are tests which should help illustrate).

[forestbelton]

@nipunn1313, #112 looks like it will cover these above cases. Thanks for the quick turnaround!