Add support for building Android wheels

.pre-commit-config.yaml

@@ -26,8 +26,10 @@ repos:
   - id: mypy
     name: mypy 3.11 on cibuildwheel/
     args: ["--python-version=3.11"]
+    exclude: ^cibuildwheel/resources/_cross_venv.py$  # Requires Python 3.13 or later
     additional_dependencies: &mypy-dependencies
       - bracex
+      - build
       - dependency-groups>=1.2
       - nox>=2025.2.9
       - orjson
@@ -47,7 +49,6 @@ repos:
       - validate-pyproject
   - id: mypy
     name: mypy 3.13
-    exclude: ^cibuildwheel/resources/.*py$
     args: ["--python-version=3.13"]
     additional_dependencies: *mypy-dependencies
 

README.md

@@ -24,19 +24,19 @@ What does it do?
 
 While cibuildwheel itself requires a recent Python version to run (we support the last three releases), it can target the following versions to build wheels:
 
-|                | macOS Intel | macOS Apple Silicon | Windows 64bit | Windows 32bit | Windows Arm64 | manylinux<br/>musllinux x86_64 | manylinux<br/>musllinux i686 | manylinux<br/>musllinux aarch64 | manylinux<br/>musllinux ppc64le | manylinux<br/>musllinux s390x | manylinux<br/>musllinux armv7l | iOS | Pyodide |
-|----------------|----|-----|-----|-----|-----|----|-----|----|-----|-----|---|-----|-----|
-| CPython 3.8    | ✅ | ✅  | ✅  | ✅  | N/A | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A |
-| CPython 3.9    | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅ | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A |
-| CPython 3.10   | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A |
-| CPython 3.11   | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A |
-| CPython 3.12   | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵  | N/A | ✅⁴ |
-| CPython 3.13³  | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵  | ✅ | N/A |
-| PyPy 3.8 v7.3  | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A |
-| PyPy 3.9 v7.3  | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A |
-| PyPy 3.10 v7.3 | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A |
-| PyPy 3.11 v7.3 | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A |
-| GraalPy 24.2   | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | N/A  | ✅¹ | N/A | N/A | N/A | N/A | N/A |
+|                | macOS Intel | macOS Apple Silicon | Windows 64bit | Windows 32bit | Windows Arm64 | manylinux<br/>musllinux x86_64 | manylinux<br/>musllinux i686 | manylinux<br/>musllinux aarch64 | manylinux<br/>musllinux ppc64le | manylinux<br/>musllinux s390x | manylinux<br/>musllinux armv7l | Android | iOS | Pyodide |
+|----------------|----|-----|----|-----|-----|----|-----|----|-----|-----|---|-----|-----|-----|
+| CPython 3.8    | ✅ | ✅  | ✅  | ✅  | N/A | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A | N/A |
+| CPython 3.9    | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅ | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A | N/A |
+| CPython 3.10   | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A | N/A |
+| CPython 3.11   | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵ | N/A | N/A | N/A |
+| CPython 3.12   | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵  | N/A | N/A | ✅⁴ |
+| CPython 3.13³  | ✅ | ✅  | ✅  | ✅  | ✅² | ✅ | ✅  | ✅ | ✅  | ✅  | ✅⁵  | ✅ | ✅ | N/A |
+| PyPy 3.8 v7.3  | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A | N/A |
+| PyPy 3.9 v7.3  | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A | N/A |
+| PyPy 3.10 v7.3 | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A | N/A |
+| PyPy 3.11 v7.3 | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | ✅¹  | ✅¹ | N/A | N/A | N/A | N/A | N/A | N/A |
+| GraalPy 24.2   | ✅ | ✅  | ✅  | N/A | N/A | ✅¹ | N/A  | ✅¹ | N/A | N/A | N/A | N/A | N/A | N/A |
 
 <sup>¹ PyPy & GraalPy are only supported for manylinux wheels.</sup><br>
 <sup>² Windows arm64 support is experimental.</sup><br>
@@ -56,20 +56,20 @@ Usage
 
 `cibuildwheel` runs inside a CI service. Supported platforms depend on which service you're using:
 
-|                 | Linux | macOS | Windows | Linux ARM | macOS ARM | Windows ARM | iOS |
-|-----------------|-------|-------|---------|-----------|-----------|-------------|-----|
-| GitHub Actions  | ✅    | ✅    | ✅       | ✅        | ✅        | ✅²         | ✅³  |
-| Azure Pipelines | ✅    | ✅    | ✅       |           | ✅        | ✅²         | ✅³  |
-| Travis CI       | ✅    |       | ✅      | ✅        |           |             |     |
-| AppVeyor        | ✅    | ✅    | ✅      |           | ✅        | ✅²         | ✅³  |
-| CircleCI        | ✅    | ✅    |         | ✅        | ✅        |             | ✅³  |
-| Gitlab CI       | ✅    | ✅    | ✅      | ✅¹       | ✅        |             | ✅³  |
-| Cirrus CI       | ✅    | ✅    | ✅      | ✅        | ✅        |             | ✅³  |
+|                 | Linux | macOS | Windows | Linux ARM | macOS ARM | Windows ARM | Android | iOS |
+|-----------------|-------|-------|---------|-----------|-----------|-------------|---------|-----|
+| GitHub Actions  | ✅    | ✅    | ✅       | ✅        | ✅        | ✅²         | ✅⁴      | ✅³  |
+| Azure Pipelines | ✅    | ✅    | ✅       |           | ✅        | ✅²         | ✅⁴      | ✅³  |
+| Travis CI       | ✅    |       | ✅      | ✅        |           |             | ✅⁴      |     |
+| AppVeyor        | ✅    | ✅    | ✅      |           | ✅        | ✅²         | ✅⁴      | ✅³  |
+| CircleCI        | ✅    | ✅    |         | ✅        | ✅        |             | ✅⁴      | ✅³  |
+| Gitlab CI       | ✅    | ✅    | ✅      | ✅¹       | ✅        |             | ✅⁴      | ✅³  |
+| Cirrus CI       | ✅    | ✅    | ✅      | ✅        | ✅        |             | ✅⁴      | ✅³  |
 
 <sup>¹ [Requires emulation](https://cibuildwheel.pypa.io/en/stable/faq/#emulation), distributed separately. Other services may also support Linux ARM through emulation or third-party build hosts, but these are not tested in our CI.</sup><br>
 <sup>² [Uses cross-compilation](https://cibuildwheel.pypa.io/en/stable/faq/#windows-arm64). It is not possible to test `arm64` on this CI platform.</sup><br>
-<sup>³ Requires a macOS runner; runs tests on the simulator for the runner's architecture.</sup>
-
+<sup>³ Requires a macOS runner; runs tests on the simulator for the runner's architecture.</sup><br>
+<sup>⁴ Requires runner to be Linux x86_64, macOS ARM64 or macOS x86_64. Runs tests on the emulator for the runner's architecture.</sup><br>
 <!--intro-end-->
 
 Example setup

bin/generate_schema.py

@@ -333,6 +333,7 @@ def as_object(d: dict[str, Any]) -> dict[str, Any]:
     "windows": as_object(not_linux),
     "macos": as_object(not_linux),
     "pyodide": as_object(not_linux),
+    "android": as_object(not_linux),
     "ios": as_object(not_linux),
 }
 

bin/update_pythons.py

@@ -10,6 +10,7 @@
 from collections.abc import Mapping, MutableMapping
 from pathlib import Path
 from typing import Any, Final, Literal, TypedDict
+from xml.etree import ElementTree as ET
 
 import click
 import requests
@@ -20,6 +21,7 @@
 from rich.syntax import Syntax
 
 from cibuildwheel.extra import dump_python_configurations
+from cibuildwheel.platforms.android import android_triplet
 
 log = logging.getLogger("cibw")
 
@@ -57,7 +59,13 @@ class ConfigApple(TypedDict):
     url: str
 
 
-AnyConfig = ConfigWinCP | ConfigWinPP | ConfigWinGP | ConfigApple
+class ConfigAndroid(TypedDict):
+    identifier: str
+    version: str
+    url: str
+
+
+AnyConfig = ConfigWinCP | ConfigWinPP | ConfigWinGP | ConfigApple | ConfigAndroid
 
 
 # The following set of "Versions" classes allow the initial call to the APIs to
@@ -305,6 +313,39 @@ def update_version_macos(
         return None
 
 
+class AndroidVersions:
+    # This should be replaced with official python.org downloads once they're available.
+    MAVEN_URL = "https://repo.maven.apache.org/maven2/com/chaquo/python/python"
+
+    def __init__(self) -> None:
+        response = requests.get(f"{self.MAVEN_URL}/maven-metadata.xml")
+        response.raise_for_status()
+        root = ET.fromstring(response.text)
+
+        self.versions: list[Version] = []
+        for version_elem in root.findall("./versioning/versions/version"):
+            version_str = version_elem.text
+            assert isinstance(version_str, str), version_str
+            self.versions.append(Version(version_str))
+
+    def update_version_android(
+        self, identifier: str, version: Version, spec: Specifier
+    ) -> ConfigAndroid | None:
+        sorted_versions = sorted(spec.filter(self.versions), reverse=True)
+
+        # Return a config using the highest version for the given specifier.
+        if sorted_versions:
+            max_version = sorted_versions[0]
+            triplet = android_triplet(identifier)
+            return ConfigAndroid(
+                identifier=identifier,
+                version=str(version),
+                url=f"{self.MAVEN_URL}/{max_version}/python-{max_version}-{triplet}.tar.gz",
+            )
+        else:
+            return None
+
+
 class CPythonIOSVersions:
     def __init__(self) -> None:
         response = requests.get(
@@ -365,6 +406,7 @@ def __init__(self) -> None:
         self.macos_pypy = PyPyVersions("64")
         self.macos_pypy_arm64 = PyPyVersions("ARM64")
 
+        self.android = AndroidVersions()
         self.ios_cpython = CPythonIOSVersions()
 
         self.graalpy = GraalPyVersions()
@@ -405,6 +447,8 @@ def update_config(self, config: MutableMapping[str, str]) -> None:
             config_update = self.windows_t_arm64.update_version_windows(spec)
         elif "win_arm64" in identifier and identifier.startswith("cp"):
             config_update = self.windows_arm64.update_version_windows(spec)
+        elif "android" in identifier:
+            config_update = self.android.update_version_android(identifier, version, spec)
         elif "ios" in identifier:
             config_update = self.ios_cpython.update_version_ios(identifier, version)
 
@@ -436,14 +480,9 @@ def update_pythons(force: bool, level: str) -> None:
     with toml_file_path.open("rb") as f:
         configs = tomllib.load(f)
 
-    for config in configs["windows"]["python_configurations"]:
-        all_versions.update_config(config)
-
-    for config in configs["macos"]["python_configurations"]:
-        all_versions.update_config(config)
-
-    for config in configs["ios"]["python_configurations"]:
-        all_versions.update_config(config)
+    for platform in ["windows", "macos", "android", "ios"]:
+        for config in configs[platform]["python_configurations"]:
+            all_versions.update_config(config)
 
     result_toml = dump_python_configurations(configs)
 

cibuildwheel/__main__.py

@@ -17,7 +17,7 @@
 import cibuildwheel
 import cibuildwheel.util
 from cibuildwheel import errors
-from cibuildwheel.architecture import Architecture, allowed_architectures_check
+from cibuildwheel.architecture import Architecture, allowed_architectures_check, native_platform
 from cibuildwheel.ci import CIProvider, detect_ci_provider, fix_ansi_codes_for_github_actions
 from cibuildwheel.logger import log
 from cibuildwheel.options import CommandLineArguments, Options, compute_options
@@ -90,14 +90,14 @@ def main_inner(global_options: GlobalOptions) -> None:
 
     parser.add_argument(
         "--platform",
-        choices=["auto", "linux", "macos", "windows", "pyodide", "ios"],
+        choices=["auto", "linux", "macos", "windows", "pyodide", "android", "ios"],
         default=None,
         help="""
             Platform to build for. Use this option to override the auto-detected
             platform. Specifying "macos" or "windows" only works on that
             operating system. "linux" works on any desktop OS, as long as
-            Docker/Podman is installed. "pyodide" only works on linux and macOS.
-            "ios" only work on macOS. Default: auto.
+            Docker/Podman is installed. "pyodide" and "android" only work on
+            Linux and macOS. "ios" only works on macOS. Default: auto.
         """,
     )
 
@@ -238,28 +238,14 @@ def _compute_platform_only(only: str) -> PlatformName:
         return "windows"
     if "pyodide_" in only:
         return "pyodide"
+    if "android_" in only:
+        return "android"
     if "ios_" in only:
         return "ios"
     msg = f"Invalid --only='{only}', must be a build selector with a known platform"
     raise errors.ConfigurationError(msg)
 
 
-def _compute_platform_auto() -> PlatformName:
-    if sys.platform.startswith("linux"):
-        return "linux"
-    elif sys.platform == "darwin":
-        return "macos"
-    elif sys.platform == "win32":
-        return "windows"
-    else:
-        msg = (
-            'Unable to detect platform from "sys.platform". cibuildwheel doesn\'t '
-            "support building wheels for this platform. You might be able to build for a different "
-            "platform using the --platform argument. Check --help output for more information."
-        )
-        raise errors.ConfigurationError(msg)
-
-
 def _compute_platform(args: CommandLineArguments) -> PlatformName:
     platform_option_value = args.platform or os.environ.get("CIBW_PLATFORM", "") or "auto"
 
@@ -279,7 +265,7 @@ def _compute_platform(args: CommandLineArguments) -> PlatformName:
     elif platform_option_value != "auto":
         return typing.cast(PlatformName, platform_option_value)
 
-    return _compute_platform_auto()
+    return native_platform()
 
 
 @contextlib.contextmanager

cibuildwheel/architecture.py

@@ -17,16 +17,41 @@
     "macos": "macOS",
     "windows": "Windows",
     "pyodide": "Pyodide",
+    "android": "Android",
     "ios": "iOS",
 }
 
 ARCH_SYNONYMS: Final[list[dict[PlatformName, str | None]]] = [
-    {"linux": "x86_64", "macos": "x86_64", "windows": "AMD64"},
+    {"linux": "x86_64", "macos": "x86_64", "windows": "AMD64", "android": "x86_64"},
     {"linux": "i686", "macos": None, "windows": "x86"},
-    {"linux": "aarch64", "macos": "arm64", "windows": "ARM64"},
+    {"linux": "aarch64", "macos": "arm64", "windows": "ARM64", "android": "arm64_v8a"},
 ]
 
 
+def arch_synonym(arch: str, from_platform: PlatformName, to_platform: PlatformName) -> str | None:
+    for arch_synonym in ARCH_SYNONYMS:
+        if arch == arch_synonym.get(from_platform):
+            return arch_synonym.get(to_platform, arch)
+
+    return arch
+
+
+def native_platform() -> PlatformName:
+    if sys.platform.startswith("linux"):
+        return "linux"
+    elif sys.platform == "darwin":
+        return "macos"
+    elif sys.platform == "win32":
+        return "windows"
+    else:
+        msg = (
+            'Unable to detect platform from "sys.platform". cibuildwheel doesn\'t '
+            "support building wheels for this platform. You might be able to build for a different "
+            "platform using the --platform argument. Check --help output for more information."
+        )
+        raise errors.ConfigurationError(msg)
+
+
 def _check_aarch32_el0() -> bool:
     """Check if running armv7l natively on aarch64 is supported"""
     if not sys.platform.startswith("linux"):
@@ -42,7 +67,7 @@
 
 @typing.final
 class Architecture(StrEnum):
-    # mac/linux archs
+    # mac/linux/android archs
     x86_64 = auto()
 
     # linux archs
@@ -65,6 +90,9 @@
     # WebAssembly
     wasm32 = auto()
 
+    # android archs
+    arm64_v8a = auto()
+
     # iOS "multiarch" architectures that include both
     # the CPU architecture and the ABI.
     arm64_iphoneos = auto()
@@ -123,15 +151,12 @@
         # we might need to rename the native arch to the machine we're running
         # on, as the same arch can have different names on different platforms
         if host_platform != platform:
-            for arch_synonym in ARCH_SYNONYMS:
-                if native_machine == arch_synonym.get(host_platform):
-                    synonym = arch_synonym[platform]
-
-                    if synonym is None:
-                        # can't build anything on this platform
-                        return None
+            synonym = arch_synonym(native_machine, host_platform, platform)
+            if synonym is None:
+                # can't build anything on this platform
+                return None
 
-                    native_architecture = Architecture(synonym)
+            native_architecture = Architecture(synonym)
 
         return native_architecture
 
@@ -173,6 +198,7 @@
             "macos": {Architecture.x86_64, Architecture.arm64, Architecture.universal2},
             "windows": {Architecture.x86, Architecture.AMD64, Architecture.ARM64},
             "pyodide": {Architecture.wasm32},
+            "android": {Architecture.x86_64, Architecture.arm64_v8a},
             "ios": {
                 Architecture.x86_64_iphonesimulator,
                 Architecture.arm64_iphonesimulator,

cibuildwheel/frontend.py

@@ -58,6 +58,22 @@ def _split_config_settings(config_settings: str) -> list[str]:
     return [f"-C{setting}" for setting in config_settings_list]
 
 
+# Based on build.__main__.main.
+def parse_config_settings(config_settings_str: str) -> dict[str, str | list[str]]:
+    config_settings: dict[str, str | list[str]] = {}
+    for arg in shlex.split(config_settings_str):
+        setting, _, value = arg.partition("=")
+        existing_value = config_settings.get(setting)
+        if existing_value is None:
+            config_settings[setting] = value
+        elif isinstance(existing_value, str):
+            config_settings[setting] = [existing_value]
+        else:
+            existing_value.append(value)
+
+    return config_settings
+
+
 def get_build_frontend_extra_flags(
     build_frontend: BuildFrontendConfig, verbosity_level: int, config_settings: str
 ) -> list[str]:

cibuildwheel/logger.py

@@ -37,6 +37,8 @@
     "macosx_universal2": "macOS Universal 2 - x86_64 and arm64",
     "macosx_arm64": "macOS arm64 - Apple Silicon",
     "pyodide_wasm32": "Pyodide",
+    "android_arm64_v8a": "Android arm64_v8a",
+    "android_x86_64": "Android x86_64",
     "ios_arm64_iphoneos": "iOS Device (ARM64)",
     "ios_arm64_iphonesimulator": "iOS Simulator (ARM64)",
     "ios_x86_64_iphonesimulator": "iOS Simulator (x86_64)",