Capitalized (Title case) package name causes invalid gRPC code generation

[WJCFerguson]

Working with gRPC on v2.0.0b3, if the .proto package name starts with a capital letter, e.g.

package Echo;

Then the generated file becomes significantly different and invalid. Most obviously there is from .. import MessageName as _MessageName__ for the message types and it can't be imported.

For example, take the echo.proto example from the README.md and generate as suggested with python -m grpc_tools.protoc -I . --python_betterproto_out=. echo.proto, it seems fine, but edit it to package Echo; and in Echo/__init__.py you get, among other changes not limited to s/echo/Echo, at the end:

from .. import EchoEchoRequest as _EchoEchoRequest__
from .. import EchoEchoResponse as _EchoEchoResponse__
from .. import EchoEchoStreamResponse as _EchoEchoStreamResponse__

These don't exist, and the package can't be imported.

Found in v2.0.0b3. Thanks!

---

For completeness, here's the problematic .proto

syntax = "proto3";

package Echo;

message EchoRequest {
  string value = 1;
  // Number of extra times to echo
  uint32 extra_times = 2;
}

message EchoResponse {
  repeated string values = 1;
}

message EchoStreamResponse  {
  string value = 1;
}

service Echo {
  rpc Echo(EchoRequest) returns (EchoResponse);
  rpc EchoStream(EchoRequest) returns (stream EchoStreamResponse);
}