I believe Azure Pipelines and GitHub Actions essentially use the same infra, and Azure Pipelines is also dropping macOS Intel x86-64:
I don't think that is correct. They use the same *runner images* and the macos-13 image is indeed deprecated for Azure as well, but there's a large difference in the hardware offered. Azure only just started giving preview access to macOS arm64 runners, and macos-14/15 images still run on x86-64 hardware by default.
That said, I'm really not a fan of trying to move to Azure, for multiple reasons:
1. It's a lot of work for a temporary extension of the support window only
2. Azure is pretty awful to work with, and we have never done any release builds on Azure. Starting now is very unappealing.
3. Release process wise there are both new opportunities for mistakes, and also we'd not be able to do synchronized uploads so Chuck would have to upload the macOS x86-64 wheels manually before starting the trusted publishing process (to avoid sdist becoming visible to users first).
4. It indeed would prevent from fully moving to trusted publishing and no longer doing manual uploads (however, the security aspect is not the most important to me here, we only delay an improvement, it's not really a regression).
The case for doing the extra work isn't all that compelling, since NumPy is quite easy to build on macOS - it's the easiest platform by some distance, even easier than Linux because it's the only platform where a BLAS library is always available (unless a user is still on macOS <=12, which is a really small fraction of users). So it's very easy to build compared to SciPy, Matplotlib, etc. - and I very much doubt that those projects will be building on Azure.
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What Andrew suggests would be the more reasonable route: if testing with cibuildwheel for x86-64 on arm64 through Rosetta works, we can decide to accept that some features are not as well tested as they should be, but at least most functionality is tested, and for the rest we rely on it not changing.
I'm not as convinced as Andrew that this will work, but I also don't know that it won't. So let's see if we can move to macos-15 on arm64 and get this to work? If it works well enough, then keep support for one more year (and if not, then not)?
