Is it a bug of python protobuf v2.6.1?

[wpc062]

I am using dynamic reflection functionality of python protobuf v2.6.1, and have a function like below:

# initilization code

        des_db_ = descriptor_database.DescriptorDatabase()
        des_pool_ = descriptor_pool.DescriptorPool(des_db_)


        fdp = descriptor_pb2.FileDescriptorProto.FromString(
            a_pb_module.DESCRIPTOR.serialized_pb)
        des_db_.Add(fdp)


def unpack_PB_msg(type_name, pb_msg_str)
        factory = message_factory.MessageFactory(des_pool_)
        msg_class = factory.GetPrototype(des_pool_.FindMessageTypeByName(type_name))

        pb_msg = msg_class()
        pb_msg.ParseFromString(pb_msg_str)

       return pb_msg

But following client code will fail

    hello = Hello_msg()
    hello_str = hello.SerializeToString()
    hello2 = unpack_PB_msg(Hello_msg.DESCRIPTOR.full_name, hello_str)

    hello3 = Hello_msg()
    hello3.CopyFrom(hello2)# failed here!!!

The error message is:

hello3.CopyFrom(hello2)

  File "C:\Localdata\Python27\lib\site-packages\google\protobuf\message.py", line 119, in CopyFrom

    self.MergeFrom(other_msg)

  File "C:\Localdata\Python27\lib\site-packages\google\protobuf\internal\python_message.py", line 971, in MergeFrom

    "expected %s got %s." % (cls.__name__, type(msg).__name__))

TypeError: Parameter to MergeFrom() must be instance of same class: expected Hello_msg got Hello_msg.

It seems CopyFrom fails because isinstance fails.

  def MergeFrom(self, msg):
    if not isinstance(msg, cls):
      raise TypeError(
          "Parameter to MergeFrom() must be instance of same class: "
          "expected %s got %s." % (cls.__name__, type(msg).__name__))

Is this a protobuf bug?

Thanks,

[Lokman Dz]

Did you manage to solve the problem? I am running into similar situation.

Thanks