encode ignores __getstate__ returning empty dict

[sitnarf]

I have a custom __getstate__ which excludes attributes that are not seriazable. However if there are no other attributes and __getstate__ therefore returns an empty dict, jsonpickle.encode ignores __getstate__, resulting in an error.

The problem is here (line 627):

jsonpickle/jsonpickle/pickler.py

Lines 618 to 628 in ef95ebc

	if has_own_getstate:
	try:
	state = obj.__getstate__()
	except TypeError:
	# Has getstate but it cannot be called, e.g. file descriptors
	# in Python3
	self._pickle_warning(obj)
	return None
	else:
	if state:
	return self._getstate(state, data)

Just for clarity, this is my code:

class Serializable:
    def __getstate__(self):
        state = copy(self.__dict__)
        exclude = getattr(self, "__exclude__", [])

        for name in exclude:
            state.pop(name, None)
 
       return state

class ServerConnection(Serializable):
    client_ws: WebSocketClientProtocol
    websocket_server: WebSocketClientProtocol

    __exclude__ = ["websocket_server", "client_ws"]

   ...

[Theelx]

Thanks for reporting this! I'm unsure how to properly handle this while maintaining backwards-compatibility though, since this seems like behavior that some people would rely on. I know that the project for which I use jsonpickle actually does rely on this behavior. Would a feature flag be an acceptable solution for this use case?

[sitnarf]

A feature flag sounds good to me.