ObjectiveC build fails when using dynamic framework and oneof

[sercand]

I have modified the HelloRequest at grpc helloworld.proto by adding oneof fileds.

message HelloRequest {
    string name = 1;    
    oneof data{
        string text = 2;
        int32 integer = 3;
        bool boolean = 4;
    }
}

As a result, building fails with following error

Undefined symbols for architecture x86_64:
  "_OBJC_IVAR_$_GPBDescriptor.oneofs_", referenced from:
      _HLWHelloRequest_ClearDataOneOfCase in Hello.pbobjc.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

My guess is this line is only accessible within framework (because @package directive), so when using dynamic framework it fails.