Python future 0.15.2 provides a configparser alias that exists on py2 but not on py3 installations. Py3 already has it. When EUPS loads the Python3 variant, it finds it in the Python2 installation of python-future that has been added to the PYTHONPATH. This then upsets future because Py3 is never meant to load the Py2 compatibility code. Hence the error above.
The real problem here is that the stack's PYTHONPATH contains code that is specifically installed as a Py2-only variant and exists purely to override builtins. This is probably going to be flaky. The safe thing is to control the python for everything as you are doing in
I also don't understand why this install is using such an old future? 0.16.0 was installed 2 months ago in