WIP: Building on Neutrino155 master: debug petsc -3.10 build

[Chiffafox]

Just trying to isolate the problem to 3.10 -- eliminate all other versions, remove serial tests.

[matthewcarbone]

@Chiffafox any ideas here? 😁

[Chiffafox]

Basically the problem is two-fold

• PETSc is (still) not set up to be built using wheels. The way it is supposed to work right now is it tries to build a wheel, fails, then defaults to legacy install mode via setup.py and succeeds.
• At some point, folks behind pip decided to retire the meaning of --no-binary as "default to legacy install mode via setup.py". So that's my guess as to why, in later versions of python, we start to see a problem as pip is no longer dropping to legacy install mode.

I see two possible solutions

• Find a way to force modern versions of pip to default to legacy install mode (working on this now).
• Build PETSc "the right way", i.e. through ./configure and all that. (Much more painful for the user, not excited about this approach.)

I'll see what I can do to make (1) work, hopefully that solves the problem.

[Chiffafox]

Okay, I have localized it to a version change in pip: with pip version 23.0.1, petsc install works no problem. However the version used with python=3.10 appears to be pip version 23.1.2, which does not drop down to legacy install mode: I confirm this locally as well. I imagine the problem is the same for later Python versions.

Tl;DR is we need to version-lock pip to 23.0.1 or lower.

[matthewcarbone]

It's really spooky that some random change somewhere can totally break our installation. That's not supposed to be the way versioning works. Not that I know how to fix it but honestly it should not be this difficult.

@Chiffafox wild idea: any way we can install PETSc from source or something? Would that be easier?