ENH: Add armv7l wheel (manylinux/musllinux)

[Lauszus]

Proposed new feature or change:

I would like to add support for building armv7l wheels (manylinux/musllinux) to numpy.

Building manylinux/musllinux using cibuildwheel has been available for some time backed by the manylinux project.

I have created two PRs: #31348 and numpy/numpy-release#45 with the required changes. I have changed them to draft for now.

My use case is that I have several products using Raspberry Pi compute module 4 deployed running in 32-bit mode. For now I have been compiling numpy in CI using the manylinux_2_31 Docker image for armv7l. Adding armv7l wheels would speed up my CI, but also help a lot of people stuck on 32-bit mode using Raspberry Pis.

I have read: https://numpy.org/neps/nep-0057-numpy-platform-support.html and understand your concern about long-term support. I can maintain it if needed.

[rgommers]

Thanks @Lauszus. Do you actually use the musllinux variant? That seems to be a niche build for an already niche platform.

[rgommers]

I think we can consider armv7l in one CI job, if that helps coverage. It seems pretty clear that we don't want to support armv7l wheels long-term, because it's a legacy platform that has been declining in popularity quite a lot over the past years, and that will continue. Also, any Raspberry Pi users who still need this (fewer as well today) can use Piwheels - which also actively recommends against uploading wheels to PyPI. From https://www.piwheels.org/faq.html: "We don't recommend that package maintainers upload Raspberry Pi Arm wheels to PyPI in case they don't work on other Arm platforms. Raspberry Pi users have access to piwheels, so that should suffice."

I'll leave gh-31348 open, since that's for regular CI. But I'll close this one as rejected, as well as numpy/numpy-release#45.

[Lauszus]

I think we can consider armv7l in one CI job, if that helps coverage. It seems pretty clear that we don't want to support armv7l wheels long-term, because it's a legacy platform that has been declining in popularity quite a lot over the past years, and that will continue. Also, any Raspberry Pi users who still need this (fewer as well today) can use Piwheels - which also actively recommends against uploading wheels to PyPI. From https://www.piwheels.org/faq.html: "We don't recommend that package maintainers upload Raspberry Pi Arm wheels to PyPI in case they don't work on other Arm platforms. Raspberry Pi users have access to piwheels, so that should suffice."

I'll leave gh-31348 open, since that's for regular CI. But I'll close this one as rejected, as well as numpy/numpy-release#45.

Okay makes sense. Thanks for the reply.