Fix the PATH computation in GHA on windows, and require uv on PATH

action.yml

@@ -47,8 +47,6 @@ runs:
         from subprocess import run
 
         EXTRAS = set(e.strip() for e in "${{ inputs.extras }}".split(",") if e.strip())
-        if sys.platform == "linux":
-            EXTRAS.discard("uv")
 
 
         class EnvBuilder(venv.EnvBuilder):
@@ -73,47 +71,41 @@ runs:
             shutil.rmtree(venv_path)
         builder = EnvBuilder()
         builder.create(venv_path)
-        exposed_binaries = {"cibuildwheel"}
-        if "uv" in EXTRAS:
-            exposed_binaries.add("uv")
-        clean_bin_path = builder.bin_path.parent / f"{builder.bin_path.name}.clean"
-        clean_bin_path.mkdir()
-        for path in list(builder.bin_path.iterdir()):
-            if path.stem in exposed_binaries:
-                try:
-                    os.symlink(path, clean_bin_path / path.name)
-                except OSError:
-                    import shutil
+        cibw_bin = [p for p in builder.bin_path.glob("cibuildwheel*") if p.stem == "cibuildwheel"][0]
 
-                    shutil.copy2(path, clean_bin_path / path.name)
-        full_path = f"{clean_bin_path}{os.pathsep}{os.environ['PATH']}"
         with open(os.environ["GITHUB_OUTPUT"], "at") as f:
-            f.write(f"updated-path={full_path}\n")
+            f.write(f"cibw-bin={cibw_bin}\n")
+            f.write(f"prepend-path={builder.bin_path if 'uv' in EXTRAS else ''}\n")
+
         print("::endgroup::")
         EOF
       shell: bash
 
     # Redirecting stderr to stdout to fix interleaving issue in Actions.
-    - run: >
-        cibuildwheel
-        "${{ inputs.package-dir }}"
-        ${{ inputs.output-dir != ''  && format('--output-dir "{0}"', inputs.output-dir) || ''}}
-        ${{ inputs.config-file != '' && format('--config-file "{0}"', inputs.config-file) || ''}}
-        ${{ inputs.only != ''        && format('--only "{0}"', inputs.only) || ''}}
-        2>&1
-      env:
-        PATH: "${{ steps.cibw.outputs.updated-path }}"
+    - run: |
+        prepend_path="${{ steps.cibw.outputs.prepend-path }}"
+        if [ -n "$prepend_path" ]; then
+            export PATH="$prepend_path:$PATH"
+        fi
+        "${{ steps.cibw.outputs.cibw-bin }}" \
+          "${{ inputs.package-dir }}" \
+          ${{ inputs.output-dir != ''  && format('--output-dir "{0}"', inputs.output-dir) || ''}} \
+          ${{ inputs.config-file != '' && format('--config-file "{0}"', inputs.config-file) || ''}} \
+          ${{ inputs.only != ''        && format('--only "{0}"', inputs.only) || ''}} \
+          2>&1
       shell: bash
       if: runner.os != 'Windows'
 
     # Windows needs powershell to interact nicely with Meson
-    - run: >
-        cibuildwheel
-        "${{ inputs.package-dir }}"
-        ${{ inputs.output-dir != ''  && format('--output-dir "{0}"', inputs.output-dir) || ''}}
-        ${{ inputs.config-file != '' && format('--config-file "{0}"', inputs.config-file) || ''}}
-        ${{ inputs.only != ''        && format('--only "{0}"', inputs.only) || ''}}
-      env:
-        PATH: "${{ steps.cibw.outputs.updated-path }}"
+    - run: |
+        $PrependPath = "${{ steps.cibw.outputs.prepend-path }}"
+        if ($PrependPath) {
+            $env:PATH = "$PrependPath;$env:PATH"
+        }
+        & "${{ steps.cibw.outputs.cibw-bin }}" `
+          "${{ inputs.package-dir }}" `
+          ${{ inputs.output-dir != ''  && format('--output-dir "{0}"', inputs.output-dir) || ''}} `
+          ${{ inputs.config-file != '' && format('--config-file "{0}"', inputs.config-file) || ''}} `
+          ${{ inputs.only != ''        && format('--only "{0}"', inputs.only) || ''}}
       shell: pwsh
       if: runner.os == 'Windows'

cibuildwheel/platforms/android.py

@@ -34,7 +34,7 @@
 from ..util.helpers import prepare_command
 from ..util.packaging import find_compatible_wheel
 from ..util.python_build_standalone import create_python_build_standalone_environment
-from ..venv import constraint_flags, find_uv, virtualenv
+from ..venv import constraint_flags, ensure_uv, virtualenv
 
 ANDROID_TRIPLET = {
     "arm64_v8a": "aarch64-linux-android",
@@ -191,11 +191,9 @@ def setup_env(
     log.step("Setting up build environment...")
     build_frontend = build_options.build_frontend.name
     use_uv = build_frontend == "build[uv]"
-    uv_path = find_uv()
-    if use_uv and uv_path is None:
-        msg = "uv not found"
-        raise AssertionError(msg)
-    pip = ["pip"] if not use_uv else [str(uv_path), "pip"]
+    if use_uv:
+        ensure_uv()
+    pip = ["pip"] if not use_uv else ["uv", "pip"]
 
     # Create virtual environment
     python_exe = create_python_build_standalone_environment(
@@ -578,11 +576,9 @@ def test_wheel(state: BuildState, wheel: Path, *, build_frontend: str) -> None:
 
     log.step("Testing wheel...")
     use_uv = build_frontend == "build[uv]"
-    uv_path = find_uv()
-    if use_uv and uv_path is None:
-        msg = "uv not found"
-        raise AssertionError(msg)
-    pip = ["pip"] if not use_uv else [str(uv_path), "pip"]
+    if use_uv:
+        ensure_uv()
+    pip = ["pip"] if not use_uv else ["uv", "pip"]
 
     native_arch = arch_synonym(platform.machine(), platforms.native_platform(), "android")
     if state.config.arch != native_arch:

cibuildwheel/platforms/macos.py

@@ -33,7 +33,7 @@
 )
 from ..util.helpers import prepare_command, unwrap
 from ..util.packaging import find_compatible_wheel, get_pip_version
-from ..venv import constraint_flags, find_uv, virtualenv
+from ..venv import constraint_flags, ensure_uv, virtualenv
 
 
 @functools.cache
@@ -217,8 +217,9 @@ def setup_python(
     environment: ParsedEnvironment,
     build_frontend: BuildFrontendName,
 ) -> tuple[Path, dict[str, str]]:
-    uv_path = find_uv()
     use_uv = build_frontend == "build[uv]"
+    if use_uv:
+        ensure_uv()
 
     tmp.mkdir()
     implementation_id = python_configuration.identifier.split("-")[0]
@@ -370,14 +371,13 @@ def setup_python(
                 env=env,
             )
         case "build[uv]":
-            assert uv_path is not None
             call(
-                uv_path,
+                "uv",
                 "pip",
                 "install",
                 "--upgrade",
                 "delocate",
-                "build[virtualenv, uv]",
+                "build",
                 *constraint_flags(dependency_constraint),
                 env=env,
             )
@@ -414,11 +414,9 @@ def build(options: Options, tmp_path: Path) -> None:
             build_options = options.build_options(config.identifier)
             build_frontend = build_options.build_frontend
             use_uv = build_frontend.name == "build[uv]"
-            uv_path = find_uv()
-            if use_uv and uv_path is None:
-                msg = "uv not found"
-                raise AssertionError(msg)
-            pip = ["pip"] if not use_uv else [str(uv_path), "pip"]
+            if use_uv:
+                ensure_uv()
+            pip = ["pip"] if not use_uv else ["uv", "pip"]
             log.build_start(config.identifier)
 
             identifier_tmp_dir = tmp_path / config.identifier

cibuildwheel/platforms/windows.py

@@ -24,7 +24,7 @@
 from ..util.file import CIBW_CACHE_PATH, copy_test_sources, download, extract_zip, move_file
 from ..util.helpers import prepare_command, unwrap
 from ..util.packaging import find_compatible_wheel, get_pip_version
-from ..venv import constraint_flags, find_uv, virtualenv
+from ..venv import constraint_flags, ensure_uv, virtualenv
 
 
 def get_nuget_args(
@@ -272,7 +272,8 @@ def setup_python(
         build_frontend = "build"
 
     use_uv = build_frontend == "build[uv]"
-    uv_path = find_uv()
+    if use_uv:
+        ensure_uv()
 
     log.step("Setting up build environment...")
     venv_path = tmp / "venv"
@@ -323,13 +324,12 @@ def setup_python(
                 env=env,
             )
         case "build[uv]":
-            assert uv_path is not None
             call(
-                uv_path,
+                "uv",
                 "pip",
                 "install",
                 "--upgrade",
-                "build[virtualenv]",
+                "build",
                 *constraint_flags(dependency_constraint),
                 env=env,
             )

cibuildwheel/venv.py

@@ -1,4 +1,3 @@
-import contextlib
 import functools
 import os
 import shutil
@@ -108,6 +107,7 @@ def virtualenv(
     assert python.exists()
 
     if use_uv:
+        ensure_uv()
         call("uv", "venv", venv_path, "--python", python)
     else:
         virtualenv_app, virtualenv_version = _ensure_virtualenv(version)
@@ -156,12 +156,17 @@ def virtualenv(
     return venv_env
 
 
-def find_uv() -> Path | None:
-    # Prefer uv in our environment
-    with contextlib.suppress(ImportError, FileNotFoundError):
-        from uv import find_uv_bin  # noqa: PLC0415
-
-        return Path(find_uv_bin())
+def ensure_uv() -> None:
+    """
+    Ensures uv is available on PATH. Raises an error with a helpful message if not found.
 
-    uv_on_path = shutil.which("uv")
-    return Path(uv_on_path) if uv_on_path else None
+    When using build-frontend=build[uv], callers must ensure uv is available
+    on PATH before invoking cibuildwheel.
+    """
+    if shutil.which("uv") is None:
+        msg = (
+            "uv not found on PATH. When using build-frontend=build[uv], "
+            "ensure uv is installed and available on PATH. "
+            "You can install it with 'pip install uv' or see https://docs.astral.sh/uv/getting-started/installation/"
+        )
+        raise FileNotFoundError(msg)

docs/ci-services.md

@@ -25,7 +25,7 @@ To build Linux, macOS, and Windows wheels using GitHub Actions, create a `.githu
     `package-dir: .`, `output-dir: wheelhouse` and `config-file: ''`
     locations (those values are the defaults). You can also pass a
     comma-separated list of extras to install additional packages.
-    For example, `extras: "uv"` to install UV into the virtual environment.
+    For example, `extras: "uv"` to make uv available for cibuildwheel to use.
 
 !!! tab "pipx"
     The GitHub Actions runners have pipx installed, so you can easily build in

docs/options.md

@@ -470,13 +470,19 @@ Default: `build`
 
 Choose which build frontend to use.
 
-You can use "build\[uv\]", which will use an external [uv][] everywhere
-possible, both through `--installer=uv` passed to build, as well as when making
-all build and test environments. This will generally speed up cibuildwheel.
-Make sure you have an external uv on Windows and macOS, either by
-pre-installing it, or installing cibuildwheel with the `uv` extra, which is
-possible by manually passing `cibuildwheel[uv]` to installers or by using the
-`extras` option in the [cibuildwheel action](ci-services.md#github-actions).
+You can use "build\[uv\]", which will use [uv][] everywhere possible, both
+through `--installer=uv` passed to build, as well as when making all build and
+test environments. This will generally speed up cibuildwheel.
+
+When using `build[uv]`, ensure uv is available on PATH. You can do this by:
+
+- Pre-installing uv (e.g., via `pip install uv` or using `astral-sh/setup-uv`
+  in GitHub Actions)
+- Installing cibuildwheel with the `uv` extra by manually passing
+  `cibuildwheel[uv]` to installers
+- Using the `extras: "uv"` option in the [cibuildwheel action](ci-services.md#github-actions),
+  which installs uv in an isolated environment
+
 uv currently does not support iOS or musllinux on s390x, ppc64le and riscv64.
 
 On Android and Pyodide, the "pip" frontend is not supported.

test/conftest.py

@@ -1,5 +1,6 @@
 import json
 import os
+import shutil
 import subprocess
 from collections.abc import Generator
 
@@ -11,7 +12,6 @@
 from cibuildwheel.options import CommandLineArguments, Options
 from cibuildwheel.selector import EnableGroup
 from cibuildwheel.typing import PLATFORMS
-from cibuildwheel.venv import find_uv
 
 from .utils import DEFAULT_CIBW_ENABLE, EMULATED_ARCHS, get_platform
 
@@ -180,10 +180,10 @@ def build_frontend_env(request: pytest.FixtureRequest) -> dict[str, str]:
         pytest.skip(f"Can't use pip as build frontend for {platform}")
     if platform == "pyodide" and frontend == "build[uv]":
         pytest.skip("Can't use uv with pyodide yet")
-    uv_path = find_uv()
-    if uv_path is None and frontend == "build[uv]":
+    uv_available = shutil.which("uv") is not None
+    if not uv_available and frontend == "build[uv]":
         pytest.skip("Can't find uv, so skipping uv tests")
-    if uv_path is not None and frontend == "build" and platform not in {"android", "ios"}:
+    if uv_available and frontend == "build" and platform not in {"android", "ios"}:
         pytest.skip("No need to check build when uv is present")
 
     return {"CIBW_BUILD_FRONTEND": frontend}