grpc.aio.ServerInterceptor is incompatible with async RPC methods

The grpc.aio.ServerInterceptor is currently annotated using grpc.RpcMethodHandler. However the interface for grpc.RpcMethodHandler is not compatible with async RPC methods. The correct stub for an async version would make use of Awaitable and AsyncIterator:

class RpcMethodHandler(abc.ABC, Generic[_TRequest, _TResponse]):
    request_streaming: bool
    response_streaming: bool

    # XXX: not clear from docs whether this is optional or not
    request_deserializer: _Deserializer[_TRequest] | None

    # XXX: not clear from docs whether this is optional or not
    response_serializer: _Serializer[_TResponse] | None

    unary_unary: Callable[[_TRequest, ServicerContext], Awaitable[_TResponse]] | None

    unary_stream: Callable[[_TRequest, ServicerContext], AsyncIterator[_TResponse]] | None

    stream_unary: Callable[[Iterator[_TRequest], ServicerContext], Awaitable[_TResponse]] | None

    stream_stream: Callable[[Iterator[_TRequest], ServicerContext], AsyncIterator[_TResponse]] | None

Esamina stubs/grpcio/grpc/aio/init.pyi intorno alle righe 374-383 e confronta l’annotazione dell’interceptor con la forma di async RpcMethodHandler descritta nell’issue. Esamina la pull request aperta #15497; il lavoro è concluso quando lo stub accetta metodi RPC asincroni che usano Awaitable e AsyncIterator senza entrare in conflitto con l’interfaccia handler esistente.