Switch cibuildwheel to the uv build frontend (#12595)

Author: bdraco

.github/workflows/ci-cd.yml

@@ -627,6 +627,12 @@ jobs:
         make cythonize
     - name: Build wheels
       uses: pypa/cibuildwheel@v3.4.1
+      with:
+        # `build-frontend = "build[uv]"` (pyproject.toml) requires uv to be
+        # available on the runner for Windows and macOS. Installing
+        # cibuildwheel with the `uv` extra bundles uv with it; Linux
+        # already has uv inside the manylinux/musllinux container.
+        extras: uv
       env:
         CIBW_SKIP: pp* ${{ matrix.musl == 'musllinux' && '*manylinux*' || '*musllinux*' }}
         CIBW_ARCHS_MACOS: x86_64 arm64 universal2

CHANGES/12595.contrib.rst

@@ -0,0 +1,5 @@
+Switched the ``cibuildwheel`` build frontend to ``build[uv]`` so
+that ``uv`` provisions every build-isolation virtual environment
+in the wheel matrix, replacing the per-ABI ``pip`` resolve with a
+roughly sub-second ``uv`` resolve
+-- by :user:`bdraco`.

docs/spelling_wordlist.txt

@@ -1,4 +1,5 @@
 abc
+ABI
 addons
 aiodns
 aioes

pyproject.toml

@@ -159,6 +159,13 @@ include = [
 
 
 [tool.cibuildwheel]
+# `build[uv]` makes cibuildwheel use `uv` for every venv it provisions,
+# both on the build side (passed to `python -m build` as `--installer=uv`)
+# and when materializing the build isolation environment. uv resolves and
+# installs the build requirements in roughly a second; the previous
+# pip-based path took noticeably longer per ABI and ran once per matrix
+# cell.
+build-frontend = "build[uv]"
 test-command = ""
 # don't build PyPy wheels, install from source instead
 skip = "pp*"