Use the ARCHS option to select universal2/arm64 builds

cibuildwheel/__main__.py

@@ -312,7 +312,7 @@ def print_build_identifiers(
     elif platform == 'windows':
         python_configurations = cibuildwheel.windows.get_python_configurations(build_selector)
     elif platform == 'macos':
-        python_configurations = cibuildwheel.macos.get_python_configurations(build_selector)
+        python_configurations = cibuildwheel.macos.get_python_configurations(build_selector, architectures)
 
     for config in python_configurations:
         print(config.identifier)

cibuildwheel/macos.py

@@ -46,7 +46,8 @@ class PythonConfiguration(NamedTuple):
     url: str
 
 
-def get_python_configurations(build_selector: BuildSelector) -> List[PythonConfiguration]:
+def get_python_configurations(build_selector: BuildSelector,
+                              architectures: List[Architecture]) -> List[PythonConfiguration]:
     python_configurations = [
         # CPython
         PythonConfiguration(version='2.7', identifier='cp27-macosx_x86_64', url='https://www.python.org/ftp/python/2.7.18/python-2.7.18-macosx10.9.pkg'),
@@ -58,19 +59,22 @@ def get_python_configurations(build_selector: BuildSelector) -> List[PythonConfi
         PythonConfiguration(version='3.9', identifier='cp39-macosx_universal2', url='https://www.python.org/ftp/python/3.9.1/python-3.9.1-macos11.0.pkg'),
         PythonConfiguration(version='3.9', identifier='cp39-macosx_arm64', url='https://www.python.org/ftp/python/3.9.1/python-3.9.1-macos11.0.pkg'),
         # PyPy
-        # TODO: may not support 11.0 yet
         PythonConfiguration(version='2.7', identifier='pp27-macosx_x86_64', url='https://downloads.python.org/pypy/pypy2.7-v7.3.3-osx64.tar.bz2'),
         PythonConfiguration(version='3.6', identifier='pp36-macosx_x86_64', url='https://downloads.python.org/pypy/pypy3.6-v7.3.3-osx64.tar.bz2'),
         PythonConfiguration(version='3.7', identifier='pp37-macosx_x86_64', url='https://downloads.python.org/pypy/pypy3.7-v7.3.3-osx64.tar.bz2'),
     ]
 
-    # skip builds as required
+    # filter out configs that don't match any of the selected architectures
+    python_configurations = [c for c in python_configurations
+                             if any(c.identifier.endswith(a.value) for a in architectures)]
+
+    # skip builds as required by BUILD/SKIP
     python_configurations = [c for c in python_configurations if build_selector(c.identifier)]
 
     if get_macos_version() >= (11, 0):
-        # pypy doesn't work on macOS 11 yet
-        # See https://foss.heptapod.net/pypy/pypy/-/issues/3314
         if any(c.identifier.startswith('pp') for c in python_configurations):
+            # pypy doesn't work on macOS 11 yet
+            # See https://foss.heptapod.net/pypy/pypy/-/issues/3314
             log.warning(wrap_text('''
                 PyPy is currently unsupported when building on macOS 11. To build macOS PyPy wheels,
                 build on an older OS, such as macOS 10.15. To silence this warning, deselect PyPy by
@@ -81,14 +85,12 @@ def get_python_configurations(build_selector: BuildSelector) -> List[PythonConfi
         if any(c.identifier.startswith('cp35') for c in python_configurations):
             # CPython 3.5 doesn't work on macOS 11
             log.warning(wrap_text('''
-                CPython is unsupported when building on macOS 11. To build CPython 3.5 wheels, build
+                CPython 3.5 is unsupported when building on macOS 11. To build CPython 3.5 wheels,
-                on an older OS, such as macOS 10.15. To silence this warning, deselect CPython 3.5
+                build on an older OS, such as macOS 10.15. To silence this warning, deselect CPython
-                by adding "cp35-macosx_x86_64" to your CIBW_SKIP option.
+                3.5 by adding "cp35-macosx_x86_64" to your CIBW_SKIP option.
             '''))
             python_configurations = [c for c in python_configurations if not c.identifier.startswith('cp35')]
 
-        python_configurations = [c for c in python_configurations if not c.identifier.startswith('cp35')]
-
     return python_configurations
 
 
@@ -236,10 +238,11 @@ def setup_python(python_configuration: PythonConfiguration,
 
 
 def build(options: BuildOptions) -> None:
-    if options.architectures != [Architecture.x86_64]:
+    allowed_archs = {Architecture.x86_64, Architecture.universal2, Architecture.arm64}
+    if set(options.architectures) <= allowed_archs:
         raise ValueError(textwrap.dedent(f'''
-            Invalid archs option {options.architectures}. macOS only supports x86_64 for the moment.
+            Invalid archs option {options.architectures}. macOS only supports
-            If you want to set emulation architectures on Linux, use CIBW_ARCHS_LINUX instead.
+            these architectures: {', '.join(a.value for a in allowed_archs)}.
         '''))
 
     temp_dir = Path(tempfile.mkdtemp(prefix='cibuildwheel'))
@@ -253,7 +256,7 @@ def build(options: BuildOptions) -> None:
             before_all_prepared = prepare_command(options.before_all, project='.', package=options.package_dir)
             call([before_all_prepared], shell=True, env=env)
 
-        python_configurations = get_python_configurations(options.build_selector)
+        python_configurations = get_python_configurations(options.build_selector, options.architectures)
 
         for config in python_configurations:
             log.build_start(config.identifier)

cibuildwheel/util.py

@@ -127,11 +127,17 @@ class DependencyConstraints:
 class Architecture(Enum):
     # mac/linux archs
     x86_64 = 'x86_64'
+
+    # linux archs
     i686 = 'i686'
     aarch64 = 'aarch64'
     ppc64le = 'ppc64le'
     s390x = 's390x'
 
+    # mac archs
+    universal2 = 'universal2'
+    arm64 = 'arm64'
+
     # windows archs
     x86 = 'x86'
     AMD64 = 'AMD64'
@@ -150,11 +156,18 @@ class Architecture(Enum):
     def auto_archs(platform: str) -> 'List[Architecture]':
         native_architecture = Architecture(platform_module.machine())
         result = [native_architecture]
+
         if platform == 'linux' and native_architecture == Architecture.x86_64:
             # x86_64 machines can run i686 docker containers
             result.append(Architecture.i686)
+
         if platform == 'windows' and native_architecture == Architecture.AMD64:
             result.append(Architecture.x86)
+
+        if platform == 'macos' and native_architecture == Architecture.arm64:
+            # arm64 can build and test both archs of a universal2 wheel.
+            result.append(Architecture.universal2)
+
         return result
 
 

test/test_macos_archs.py

@@ -0,0 +1,25 @@
+import pytest
+
+from . import test_projects, utils
+
+basic_project = test_projects.new_c_project()
+
+
+def test_cross_compiled_build(tmp_path):
+    if utils.platform != 'macos':
+        pytest.skip('this test is only relevant to macos')
+
+    project_dir = tmp_path / 'project'
+    basic_project.generate(project_dir)
+
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env={
+        'CIBW_ARCHS': 'x86_64, universal2, arm64',
+    })
+
+    expected_wheels = (
+        utils.expected_wheels('spam', '0.1.0', machine_arch='x86_64')
+        + utils.expected_wheels('spam', '0.1.0', machine_arch='arm64')
+    )
+    assert set(actual_wheels) == set(expected_wheels)
+
+# TODO: add a TEST_COMMAND test when using cross-compiling

test/utils.py

@@ -100,9 +100,11 @@ def expected_wheels(package_name, package_version, manylinux_versions=None,
         if platform == 'linux':
             python_abi_tags.append('cp27-cp27mu')  # python 2.7 has 2 different ABI on manylinux
 
-    if platform == 'macos':
+    if platform == 'macos' and get_macos_version() >= (11, 0):
-        # TODO: perhaps drop Python 3.5 across the board?
+        # CPython 3.5 doesn't work on macOS 11.
         python_abi_tags.remove('cp35-cp35m')
+        # pypy not supported on macOS 11.
+        python_abi_tags = [t for t in python_abi_tags if not t.startswith('pp')]
 
     wheels = []
 
@@ -129,11 +131,17 @@ def expected_wheels(package_name, package_version, manylinux_versions=None,
 
         elif platform == 'macos':
             if python_abi_tag == 'cp39-cp39':
-                platform_tags = [
+                if machine_arch == 'x86_64':
-                    f'macosx_{macosx_deployment_target.replace(".", "_")}_x86_64',
+                    platform_tags = [
-                    f'macosx_{macosx_deployment_target.replace(".", "_")}_universal2.macosx_11_0_universal2',
+                        f'macosx_{macosx_deployment_target.replace(".", "_")}_x86_64',
-                    'macosx_11_0_arm64',
+                    ]
-                ]
+                elif machine_arch == 'arm64':
+                    platform_tags = [
+                        f'macosx_{macosx_deployment_target.replace(".", "_")}_universal2.macosx_11_0_universal2',
+                        # macosx_deployment_target is ignored on arm64, because arm64 isn't supported on
+                        # macOS earlier than 11.0
+                        'macosx_11_0_arm64',
+                    ]
             else:
                 platform_tags = [
                     f'macosx_{macosx_deployment_target.replace(".", "_")}_x86_64',
@@ -152,6 +160,18 @@ def expected_wheels(package_name, package_version, manylinux_versions=None,
     return wheels
 
 
+def get_macos_version():
+    '''
+    Returns the macOS major/minor version, as a tuple, e.g. (10, 15) or (11, 0)
+
+    These tuples can be used in comparisons, e.g.
+        (10, 14) <= (11, 0) == True
+        (11, 2) <= (11, 0) != True
+    '''
+    version_str, _, _ = pm.mac_ver()
+    return tuple(map(int, version_str.split(".")[:2]))
+
+
 platform = None
 
 if 'CIBW_PLATFORM' in os.environ: