feat: option to build directly with uv

[henryiii]

Adding an option to build directly with uv. Will conflict with #2321, so probably will rebase after that one.

[jake-arkinstall]

I have a question on this.

UV supports workspaces, and a 'uv build' of a workspace may result in more than one wheel. I currently have a project which builds ~10 wheels per target platform, and I'd love to be able to do this with a single invocation of CIBuildWheel. Is that something that could be made possible (or something that is already possible)?

The reason I'm asking is that I haven't been able to get build[uv] to be able to work with uv workspace projects, but invoking uv directly could make that possible.

[henryiii]

That's interesting, probably! We might/will need to handle pure-Python output wheels, but other than that I think it should work. Nice to know this will enable something (especially since it's been annoying to make work due to astral-sh/uv#12639). I'll try to test that.

[henryiii]

I'm happy to push this off to 3.1 for now in interests of getting a 3.0 out. This is just a new option, not a change.

[trim21]

Looks like now we get all naitve building works, the only failing tests are cross-build for iOS and Android.

I'm not sure how python or uv works on these platforms, I'll take a look on Android because I don't have a macos machine.

[trim21]

Nevermind, uv can't do corss build, we should skip using uv on Android or iOS just like what we did for pip

astral-sh/uv#7957

[trim21]

you forget to enable test_failed_build_with_so_files for uv, it's still skipped

[trim21]

tested this locally, musllinux docker image doesn't have uv installed

[henryiii]

uv is on musllinux, at least for common archs: https://manylinuxinspector.joerick.me/#/

This predates the update to Android, so not surprising that it wasn't skipped here. :)

[Copilot]

Pull request overview

Adds support for selecting uv directly as the build frontend (in addition to existing build, build[uv], and pip) and updates validation + tests accordingly.

Changes:

• Extend BuildFrontendName and config/schema parsing to accept uv.
• Implement uv build invocation paths across platforms (Linux/macOS/Windows) and update troubleshooting detection.
• Expand test matrix/fixtures and add config parsing coverage for build-frontend = "uv".

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
unit_test/options_test.py	Adds unit test coverage for parsing build-frontend = "uv".
test/test_android.py	Expands Android negative frontend test to include uv.
test/conftest.py	Adds uv to build-frontend fixture params and adjusts skips for unsupported platforms.
cibuildwheel/platforms/windows.py	Treats uv as a build frontend and adds a uv build execution path.
cibuildwheel/platforms/macos.py	Treats uv as a build frontend; installs needed tools and adds uv build path.
cibuildwheel/platforms/linux.py	Adds uv build execution path in containers and updates troubleshoot matching.
cibuildwheel/platforms/ios.py	Explicitly rejects uv frontend on iOS (matching existing uv limitations).
cibuildwheel/frontend.py	Extends BuildFrontendName literal to include uv.
bin/generate_schema.py	Updates JSON schema generation to document/validate uv as a build frontend.

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[trim21]

looks like the ci is failed on a network error, not our code

Do we still missing something in this PR? Except uv workspace support. I think it need a seprated pr to support multiple wheels output in single build

[henryiii]

Yes, workspace support can be a followup PR, and I also would like to see if we can support uv for android; I don't see why build[uv] would work but not uv, but for this PR to move forward I just skipped the test instead of removing the conditional check. But I'd like to try that.