Virtualenv 20.31.0 breaks cibuildwheel testing

[jeremyleung521]

Description

I was in a unique position where my CI (https://github.com/westpa/westpa/actions/runs/14840584129/attempts/1) ran slightly before and after the release of virtualenv 20.31.0.

From my investigation, it seems like virtualenv v20.31.0 no longer bundles/supports wheel directly and that leads to virtualenv: error: unrecognized arguments: --wheel=embed during testing, where it would somehow pull the newest virtualenv version (?). This suggests that there needs to be some changes in cibuildwheel workflow.

EDIT: Seems like related to this: #2329

Build log

https://github.com/westpa/westpa/actions/runs/14840584129/job/41665220582#step:4:288

CI config

https://github.com/westpa/westpa/actions/runs/14840584129/workflow

[henryiii]

I assume (hope) you hit this due to CIBW_DEPENDENCY_VERSIONS: latest?

[jeremyleung521]

I assume (hope) you hit this due to CIBW_DEPENDENCY_VERSIONS: latest?

That seems to be the case:
https://github.com/jeremyleung521/westpa/actions/runs/14843565224 (working, 'pinned')
https://github.com/jeremyleung521/westpa/actions/runs/14843629528 (failing, 'latest')

[henryiii]

We do need to remove --no-wheel, but I don't see a --wheel=embed, do you know where that's coming from? Upstream discussion is at pypa/virtualenv#2868. Maybe Poetry? I think that might get turned into a warning in a future version of virtualenv.

[jeremyleung521]

We do need to remove --no-wheel, but I don't see a --wheel=embed, do you know where that's coming from? Upstream discussion is at pypa/virtualenv#2868. Maybe Poetry? I think that might get turned into a warning in a future version of virtualenv.

Yea, no clue where that's coming from. Maybe the --no-wheel got translated to --wheel=embed here?

Anyhow, virtualenv is in the process of reintroducing the --wheel flag, so that might eventually solve it.
pypa/virtualenv#2884

[henryiii]

I expect a package you are using has this in it somewhere, it's easy to hit it, for example older Poetry runs into this (and Poetry recommends capping 🤣).

We should conditionally remove the --no-wheel though.

[mayeut]

We do need to remove --no-wheel, but I don't see a --wheel=embed, do you know where that's coming from?

we're still using wheel=embed in v2.x

cibuildwheel/cibuildwheel/linux.py

Lines 364 to 366 in faf86a6

	# In Python<3.12, setuptools & wheel are installed as well
	if Version(config.version) < Version("3.12"):
	venv_args.extend(("--setuptools=embed", "--wheel=embed"))

[jeremyleung521]

Seems like the virtualenv v20.31.2 release fixed this. And with --no-wheel removed in future cibuildwheel (v3?) versions, it's probably be fine to close this. Thanks @henryiii for your help and quick response, @mayeut for finding that code snippet.

https://github.com/jeremyleung521/westpa/actions/runs/14843629528/job/42069809562#step:4:383