`CIBW_BEFORE_BUILD`: Changes do not propagate

[mrmundt]

Description

We recently updated to 2.21.3 in order to start building Python 3.13 wheels for Pyomo. We have always utilized CIBW_BEFORE_BUILD to install some dependencies (pip install cython pybind11), and that step ran; however, as soon as it attempted to actually build the wheels, a failure was hit because it could not find cython and pybind11.

Build log

https://github.com/mrmundt/pyomo/actions/runs/11860593427/job/33056184668

CI config

https://github.com/mrmundt/pyomo/blob/ee0c2b39b9a6663cb33ffeb5fe2f4549ac60a04b/.github/workflows/release_wheel_creation.yml

[Czaki]

Why you do not use pyproject.toml for define build dependencies?

[mrmundt]

We are an old-style Python package and do not use pyproject.toml. Per the tool's documentation, pyproject.toml is not required (and, in fact, it is implied that CIBW_BEFORE_BUILD is meant to help with exactly this).

[Czaki]

Hm. The only change that I see and may have such impact is bumping pip version.

However I see some successfull CI job with most recent cibuildwheel.

[henryiii]

I would highly recommend adding a pyproject.toml. That will allow you to declare you need these, so even SDist builds will benefit. Adding dependencies like cython and pybind11 is why pyproject.toml was developed in the first place. And every version of Python you support (3.8+) should have excellent pyproject.toml support. The only thing you need to watch out for is that setuptools no longer makes the current directory available by default with the modern build backend; if you need to import from the local directory (say to grab a helper), then you'll need to manipulate the path manually, as it's now considered an anti pattern. But otherwise, you should be able to drop a three-line pyproject.toml in and get started.

It looks like you are getting isolated builds for some reason. Not sure why. It's just installing setuptools (since you don't have a pyproject.toml telling it what you do actually require) in an isolated environment.

[henryiii]

I see you added this in CI - is there a reason not to add it to repo and benefit anyone building an SDist? And you should not add "wheel", that's never been required for pyproject.toml, setuptools adds it for you (and now doesn't because it's not used anymore by modern setuptools). And I highly recommend adding the explicit modern build backend setting, build-system.build-backend = "setuptools.build_meta". See https://learn.scientific-python.org/development/guides/packaging-classic/

What was the last version of cibuildwheel you were using? v2.16.5? I didn't see anything in the pip logs that would have been likely to cause isolated builds to start being used, though that's a pretty big jump. I'd recommend using dependabot to keep that a bit more up to date, you can also pin to minor version instead of patch version. Quite a bit happened which makes it harder to pin down what might have changed between the two versions. It would be helpful to know which version this happened in.

[henryiii]

2.17 -> 2.18 is when this started happening.

[henryiii]

We stopped injecting setuptools and wheel in every environment in 2.18. If you add setuptools and wheel to the before-build libraries, it works. https://github.com/henryiii/pyomo/actions/runs/11865436281

I guess pip makes an isolated env of setuptools is missing?

If you used pyproject.toml and put the cibw config there, I could have built these locally much faster.