fix: review from @joerick

cibuildwheel/__main__.py

@@ -257,6 +257,11 @@ def main() -> None:
 
     print_preamble(platform, build_options)
 
+    if not identifiers:
+        print(f'cibuildwheel: No build identifiers selected: {build_selector}', file=sys.stderr)
+        if not args.allow_empty:
+            sys.exit(3)
+
     if not output_dir.exists():
         output_dir.mkdir(parents=True)
 
@@ -269,11 +274,6 @@ def main() -> None:
     else:
         assert_never(platform)
 
-    if not identifiers:
-        print(f'cibuildwheel: No build identifiers selected: {build_selector}', file=sys.stderr)
-        if not args.allow_empty:
-            sys.exit(3)
-
 
 def detect_obsolete_options() -> None:
     # Check the old 'MANYLINUX1_*_IMAGE' options

test/test_cpp_standards.py

@@ -202,7 +202,7 @@ def test_cpp17_py27_modern_msvc_workaround(tmp_path):
     add_env_x64['CIBW_BUILD'] = 'cp27-win_amd64'
     actual_wheels += utils.cibuildwheel_run(project_dir, add_env=add_env_x64)
 
-    expected_wheels = [w for w in utils.expected_wheels('spam', '0.1.0', filter_27=False)
+    expected_wheels = [w for w in utils.expected_wheels('spam', '0.1.0', exclude_27=False)
                        if 'cp27-cp27m-win' in w
                        or 'pp27-pypy_73-win32' in w]
 

test/utils.py

@@ -77,7 +77,7 @@ def cibuildwheel_run(project_path, package_dir='.', env=None, add_env=None, outp
 
 def expected_wheels(package_name, package_version, manylinux_versions=None,
                     macosx_deployment_target='10.9', machine_arch=None, *,
-                    filter_27=IS_WINDOWS_RUNNING_ON_TRAVIS):
+                    exclude_27=IS_WINDOWS_RUNNING_ON_TRAVIS):
     '''
     Returns a list of expected wheels from a run of cibuildwheel.
     '''
@@ -135,8 +135,9 @@ def expected_wheels(package_name, package_version, manylinux_versions=None,
         for platform_tag in platform_tags:
             wheels.append(f'{package_name}-{package_version}-{python_abi_tag}-{platform_tag}.whl')
 
-    if filter_27:
+    # Travis on Windows does not support using the default Python 2.7 compiler,
-        # Python 2.7 isn't supported on Travis.
+    # so we support skipping here.
+    if exclude_27:
         wheels = [w for w in wheels if '-cp27-' not in w and '-pp2' not in w]
 
     return wheels

unit_test/main_tests/main_platform_test.py

@@ -1,4 +1,3 @@
-import platform as platform_module
 import sys
 
 import pytest
@@ -68,7 +67,6 @@ def test_platform_environment(platform, intercepted_build_args, monkeypatch):
 
 
 def test_archs_default(platform, intercepted_build_args, monkeypatch):
-    monkeypatch.setattr(platform_module, 'machine', lambda: 'AMD64' if platform == 'windows' else 'x86_64')
 
     main()
     build_options = intercepted_build_args.args[0]
@@ -86,7 +84,6 @@ def test_archs_argument(platform, intercepted_build_args, monkeypatch, use_env_v
     if platform == 'windows':
         pytest.skip('Will have empty build selectors on Windows')
 
-    monkeypatch.setattr(platform_module, 'machine', lambda: 'x86_64')
     if use_env_var:
         monkeypatch.setenv('CIBW_ARCHS', 'ppc64le')
     else:
@@ -100,7 +97,6 @@ def test_archs_argument(platform, intercepted_build_args, monkeypatch, use_env_v
 
 
 def test_archs_platform_specific(platform, intercepted_build_args, monkeypatch):
-    monkeypatch.setattr(platform_module, 'machine', lambda: 'x86_64')
     monkeypatch.setenv('CIBW_ARCHS', 'unused')
     monkeypatch.setenv('CIBW_ARCHS_LINUX', 'ppc64le')
     monkeypatch.setenv('CIBW_ARCHS_WINDOWS', 'x86')
@@ -118,7 +114,6 @@ def test_archs_platform_specific(platform, intercepted_build_args, monkeypatch):
 
 
 def test_archs_platform_native(platform, intercepted_build_args, monkeypatch):
-    monkeypatch.setattr(platform_module, 'machine', lambda: 'AMD64' if platform == 'windows' else 'x86_64')
     monkeypatch.setenv('CIBW_ARCHS', 'native')
 
     main()
@@ -133,7 +128,6 @@ def test_archs_platform_native(platform, intercepted_build_args, monkeypatch):
 
 
 def test_archs_platform_all(platform, intercepted_build_args, monkeypatch):
-    monkeypatch.setattr(platform_module, 'machine', lambda: 'x86_64')
     monkeypatch.setenv('CIBW_ARCHS', 'all')
 
     main()