Another performance idea. In a couple places, we have code to robustly handle mixed interpreter constraints in your project, like some Py2 only code and some Py3 only code. We do things like: partition Flake8 so that it runs on each distinct partition w/ the correct interpreter constraints But if you are in a single interpreter-constraints repo, then this is an unnecessary hit to perf, no matter how much we optimize. So, idea: add

[python-setup].allow_mixed_interpreter_constraints

. If false, ban the

interpreter_constraints

field and solely allow for the global

[python-setup].interpreter_constraints

Thoughts?