build arm64 wheels on windows

[wjakob]

No description provided.

[wjakob]

@henryiii I don't think this worked following the change to give precedence to SKBUILD_SOABI and SKBUILD_SOSABI in nanobind. Looking into the transcript for the windows-latest arm64 builds, the generated shared libraries have amd64 in their filename.

[wjakob]

Another unrelated question: CIBW generates a warning about arm64 Python 3.8 wheels (which I think should probably be removed from the build matrix in any case, that's a weird combination). Attempting to do so within pyproject.toml did not seem to do anything: https://github.com/wjakob/nanobind_example/blob/master/pyproject.toml#L41. Did I get something wrong?

[henryiii]

No colon, that's only for tests - universal wheels needed a way to skip the either of the two possibilities when testing, so there's a colon for test-skip (and only for universal wheels). If you want to silence the warning, then you should use test-skip. 3.8 was rather important for macOS Apple Silicon, as it was the default version installed for quite a while (still?). But it's barely supported officially, so it's a little tricky to build for it.

I'll look at the issue soon, currently on paternity leave so am a bit slow.

[henryiii]

Could you add:

[tool.scikit-build]
cmake.verbose = true
logging.level = "INFO"

So we can see a bit more about what's happening?

[wjakob]

done.

[henryiii]

It won’t build with conflicts, unfortunately.

[wjakob]

oops, rebased.

[henryiii]

Suggested change

	logging.level = "INFO"
	logging.level = "DEBUG"

Sorry, a bit more info would be helpful.

[wjakob]

No worries, I committed this change just now.

[wjakob]

@henryiii did the more detailed log message offer any useful info?

[henryiii]

Yes, looks like a bug on my end:

    2024-03-21 14:54:34,003 - scikit_build_core - DEBUG - Windows ARM targeted via SETUPTOOLS_EXT_SUFFIX
    2024-03-21 14:54:34,003 - scikit_build_core - INFO - Reading DIST_EXTRA_CONFIG:build_ext.library_dirs=C:\Users\runneradmin\AppData\Local\pypa\cibuildwheel\Cache\nuget-cpython\pythonarm64.3.11.8\tools\libs
...
set(SKBUILD_SOABI [===[cp311-win_arm64]===] CACHE STRING "" FORCE)

Also, I want to look at pybind/pybind11#5083; the official word from FindPython is you shouldn't find_python(... Interpreter) when cross-compiling; if you don't, then you can set some of these values. But I do need to fix the bug first.

[henryiii]

No, wait, that does say arm. Not sure why I thought it said amd or something. But I think that's the wrong form, I think it should be cpython-312-win_arm64.

[wjakob]

@henryiii does anything change here now that we have arm64 windows builders? (https://github.blog/2024-06-03-arm64-on-github-actions-powering-faster-more-efficient-build-systems/)

[henryiii]

Wow, I knew the linux ones were coming, a bit of a surprise the Windows ones came too. That’s great. Going to be a little tricky to test though until open source ones are available (“by end of year”).

I can do some extra testing on my local windows arm machine, but I think everything should just work if you’re not cross compiling.