The pants default also needs to be updated to None (https://github.com/pantsbuild/pants/blob/50544b9318aa945b0cf5323f971b14e28790947d/src/python/pants/backend/python/subsystems/python_setup.py#L59) and unfortunately I don’t have a working pants checkout at the moment, and today is hellish schedule; I can take a stab at it over the weekend.