python json_format.MessageToDict() instead of converting the uint64 field to int, it is converted to str

[leosocy]

What version of protobuf and what language are you using?
Version: 3.9.2
Language: Python

What operating system (Linux, Windows, ...) and version?

MacOS

What runtime / compiler are you using (e.g., python version or gcc version)

python 3.6.5

What did you do?

message User {
    uint64 id=1;
}

s = User(id=1).SerializeToString

json_format.MessageToDict(User.FromString(s))

What did you expect to see

{"id": 1}

What did you see instead?

{"id": "1"}

Make sure you include information that can help us debug (full error message, exception listing, stack trace, logs).

Anything else we should know about your project / environment

[HughKu]

@leosocy
This behavior is specified in proto3 spec and here is another thread discussing about this as well.

[anandolee]

Thank HughKu@ for reply
And {"id": "1"} is the expected behavior as described in proto3 spec