feat: support uv with Android (#2587)

cibuildwheel/platforms/android.py

@@ -34,14 +34,12 @@ from ..util.file import CIBW_CACHE_PATH, copy_test_sources, download, move_file
 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, virtualenv
+from ..venv import constraint_flags, find_uv, virtualenv
 
-
-def android_triplet(identifier: str) -> str:
-    return {
-        "arm64_v8a": "aarch64-linux-android",
-        "x86_64": "x86_64-linux-android",
-    }[parse_identifier(identifier)[1]]
+ANDROID_TRIPLET = {
+    "arm64_v8a": "aarch64-linux-android",
+    "x86_64": "x86_64-linux-android",
+}
 
 
 def parse_identifier(identifier: str) -> tuple[str, str]:
@@ -53,6 +51,10 @@ def parse_identifier(identifier: str) -> tuple[str, str]:
     return (f"{major}.{minor}", arch)
 
 
+def android_triplet(identifier: str) -> str:
+    return ANDROID_TRIPLET[parse_identifier(identifier)[1]]
+
+
 @dataclass(frozen=True)
 class PythonConfiguration:
     version: str
@@ -147,7 +149,7 @@ def build(options: Options, tmp_path: Path) -> None:
                 built_wheel = build_wheel(state)
                 repaired_wheel = repair_wheel(state, built_wheel)
 
-            test_wheel(state, repaired_wheel)
+            test_wheel(state, repaired_wheel, build_frontend=build_options.build_frontend.name)
 
             output_wheel: Path | None = None
             if compatible_wheel is None:
@@ -187,6 +189,13 @@ def setup_env(
     * android_env, which uses the environment while simulating running on Android.
     """
     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"]
 
     # Create virtual environment
     python_exe = create_python_build_standalone_environment(
@@ -197,14 +206,14 @@ def setup_env(
         version=config.version, tmp_dir=build_path
     )
     build_env = virtualenv(
-        config.version, python_exe, venv_dir, dependency_constraint, use_uv=False
+        config.version, python_exe, venv_dir, dependency_constraint, use_uv=use_uv
     )
     create_cmake_toolchain(config, build_path, python_dir, build_env)
 
     # Apply custom environment variables, and check environment is still valid
     build_env = build_options.environment.as_dictionary(build_env)
     build_env["PIP_DISABLE_PIP_VERSION_CHECK"] = "1"
-    for command in ["python", "pip"]:
+    for command in ["python"] if use_uv else ["python", "pip"]:
         command_path = call("which", command, env=build_env, capture_stdout=True).strip()
         if command_path != f"{venv_dir}/bin/{command}":
             msg = (
@@ -219,11 +228,10 @@ def setup_env(
     android_env = setup_android_env(config, python_dir, venv_dir, build_env)
 
     # Install build tools
-    build_frontend = build_options.build_frontend
-    if build_frontend.name != "build":
+    if build_frontend not in {"build", "build[uv]"}:
         msg = "Android requires the build frontend to be 'build'"
         raise errors.FatalError(msg)
-    call("pip", "install", "build", *constraint_flags(dependency_constraint), env=build_env)
+    call(*pip, "install", "build", *constraint_flags(dependency_constraint), env=build_env)
 
     # Build-time requirements must be queried within android_env, because
     # `get_requires_for_build` can run arbitrary code in setup.py scripts, which may be
@@ -243,13 +251,13 @@ def setup_env(
 
     pb = ProjectBuilder.from_isolated_env(AndroidEnv(), build_options.package_dir)
     if pb.build_system_requires:
-        call("pip", "install", *pb.build_system_requires, env=build_env)
+        call(*pip, "install", *pb.build_system_requires, env=build_env)
 
     requires_for_build = pb.get_requires_for_build(
         "wheel", parse_config_settings(build_options.config_settings)
     )
     if requires_for_build:
-        call("pip", "install", *requires_for_build, env=build_env)
+        call(*pip, "install", *requires_for_build, env=build_env)
 
     return build_env, android_env
 
@@ -559,12 +567,19 @@ def soname_with_hash(src_path: Path) -> str:
         return src_name
 
 
-def test_wheel(state: BuildState, wheel: Path) -> None:
+def test_wheel(state: BuildState, wheel: Path, *, build_frontend: str) -> None:
     test_command = state.options.test_command
     if not (test_command and state.options.test_selector(state.config.identifier)):
         return
 
     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"]
+
     native_arch = arch_synonym(platform.machine(), platforms.native_platform(), "android")
     if state.config.arch != native_arch:
         log.warning(
@@ -580,15 +595,23 @@ def test_wheel(state: BuildState, wheel: Path) -> None:
             env=state.build_env,
         )
 
+    platform_args = (
+        ["--python-platform", android_triplet(state.config.identifier)]
+        if use_uv
+        else [
+            "--platform",
+            sysconfig_print("get_platform()", state.android_env).replace("-", "_"),
+        ]
+    )
+
     # Install the wheel and test-requires.
     site_packages_dir = state.build_path / "site-packages"
     site_packages_dir.mkdir()
     call(
-        "pip",
+        *pip,
         "install",
         "--only-binary=:all:",
-        "--platform",
-        sysconfig_print("get_platform()", state.android_env).replace("-", "_"),
+        *platform_args,
         "--target",
         site_packages_dir,
         f"{wheel}{state.options.test_extras}",

docs/options.md

@@ -470,18 +470,17 @@ Default: `build`
 
 Choose which build frontend to use.
 
-You can use "build\[uv\]", which will use an external [UV][] everywhere
+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
+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).
-UV currently does not support Android, iOS nor musllinux on s390x. Legacy
-dependencies like setuptools on Python < 3.12 and pip are not installed if
-using UV.
+uv currently does not support iOS or musllinux on s390x. Legacy dependencies
+like setuptools on Python < 3.12 and pip are not installed if using uv.
 
-On Android and Pyodide, only "build" is supported.
+On Android and Pyodide, the "pip" frontend is not supported.
 
 You can specify extra arguments to pass to the build frontend using the
 optional `args` option.

test/conftest.py

@@ -154,19 +154,39 @@ def docker_warmup_fixture(
 @pytest.fixture(params=["pip", "build"])
 def build_frontend_env_nouv(request: pytest.FixtureRequest) -> dict[str, str]:
     frontend = request.param
-    if get_platform() == "pyodide" and frontend == "pip":
+    marks = {m.name for m in request.node.iter_markers()}
+
+    platform = "pyodide" if "pyodide" in marks else get_platform()
+    if platform == "pyodide" and frontend == "pip":
         pytest.skip("Can't use pip as build frontend for pyodide platform")
 
     return {"CIBW_BUILD_FRONTEND": frontend}
 
 
-@pytest.fixture
-def build_frontend_env(build_frontend_env_nouv: dict[str, str]) -> dict[str, str]:
-    frontend = build_frontend_env_nouv["CIBW_BUILD_FRONTEND"]
-    if frontend != "build" or get_platform() == "pyodide" or find_uv() is None:
-        return build_frontend_env_nouv
+@pytest.fixture(params=["pip", "build", "build[uv]"])
+def build_frontend_env(request: pytest.FixtureRequest) -> dict[str, str]:
+    frontend = request.param
+    marks = {m.name for m in request.node.iter_markers()}
+    if "android" in marks:
+        platform = "android"
+    elif "ios" in marks:
+        platform = "ios"
+    elif "pyodide" in marks:
+        platform = "pyodide"
+    else:
+        platform = get_platform()
 
-    return {"CIBW_BUILD_FRONTEND": "build[uv]"}
+    if platform in {"pyodide", "ios", "android"} and frontend == "pip":
+        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]":
+        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"}:
+        pytest.skip("No need to check build when uv is present")
+
+    return {"CIBW_BUILD_FRONTEND": frontend}
 
 
 @pytest.fixture

test/test_android.py

@@ -118,16 +118,17 @@ def test_expected_wheels(tmp_path, spam_env):
     )
 
 
-def test_frontend_good(tmp_path):
+@needs_emulator
+def test_frontend_good(tmp_path, build_frontend_env):
     new_c_project().generate(tmp_path)
     wheels = cibuildwheel_run(
         tmp_path,
-        add_env={**cp313_env, "CIBW_BUILD_FRONTEND": "build"},
+        add_env={**cp313_env, **build_frontend_env, "CIBW_TEST_COMMAND": "python -m site"},
     )
     assert wheels == [f"spam-0.1.0-cp313-cp313-android_21_{native_arch.android_abi}.whl"]
 
 
-@pytest.mark.parametrize("frontend", ["build[uv]", "pip"])
+@pytest.mark.parametrize("frontend", ["pip"])
 def test_frontend_bad(frontend, tmp_path, capfd):
     new_c_project().generate(tmp_path)
     with pytest.raises(CalledProcessError):