Fix Windows codegen target ABI and respect CMAKE_GENERATOR

src/osqp/codegen/pywrapper/setup.py.jinja

@@ -33,11 +33,13 @@ class CmdCMakeBuild(build_ext):
             build_args += [f'--config={cfg}']
 
         if system() == "Windows":
-            cmake_args += ['-G', 'Visual Studio 17 2022']
+            generator = os.environ.get('CMAKE_GENERATOR', 'Visual Studio 17 2022')
+            cmake_args += ['-G', generator]
             cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{}={}'.format(cfg.upper(), extdir)]
-            if sys.maxsize > 2 ** 32:
-                cmake_args += ['-A', 'x64']
-            build_args += ['--', '/m']
+            if generator.startswith('Visual Studio'):
+                platform = {'win32': 'Win32', 'win-amd64': 'x64', 'win-arm64': 'ARM64'}[self.plat_name]
+                cmake_args += ['-A', platform]
+            build_args += ['--parallel', '2']
         else:
             cmake_args += ['-DCMAKE_BUILD_TYPE=' + cfg]
             build_args += ['--', '-j2']

src/osqp/tests/codegen_platform_test.py

@@ -0,0 +1,63 @@
+import os
+from pathlib import Path
+import tempfile
+import unittest
+from unittest.mock import Mock, patch
+from typing import Any
+
+from setuptools import Distribution
+
+
+class codegen_platform_tests(unittest.TestCase):
+    def configure(self, platform, generator=None):
+        template = Path(__file__).parents[1] / 'codegen' / 'pywrapper' / 'setup.py.jinja'
+        namespace: dict[str, Any] = {'__file__': str(template)}
+        source = template.read_text().replace('{{extension_name}}', 'test_ext').replace('{{embedded_mode}}', '1')
+        with patch('setuptools.setup'):
+            exec(compile(source, str(template), 'exec'), namespace)
+        command = namespace['CmdCMakeBuild'](Distribution())
+        command.plat_name = platform
+        command.debug = False
+        extension = namespace['CMakeExtension']('test_ext')
+        env = dict(os.environ)
+        env.pop('CMAKE_GENERATOR', None)
+        if generator is not None:
+            env['CMAKE_GENERATOR'] = generator
+        with tempfile.TemporaryDirectory() as directory:
+            command.build_temp = str(Path(directory) / 'build')
+            command.build_lib = str(Path(directory) / 'lib')
+            with patch.dict(os.environ, env, clear=True), patch.dict(namespace, {'system': lambda: 'Windows'}):
+                with patch.dict(namespace, {'check_call': Mock()}) as mocked:
+                    command.build_extension(extension)
+                    return [call.args[0] for call in mocked['check_call'].call_args_list]
+
+    def test_native_arm64_visual_studio(self):
+        configure, build = self.configure('win-arm64')
+        self.assertEqual(configure[configure.index('-A') + 1], 'ARM64')
+        self.assertNotIn('/m', build)
+
+    def test_emulated_amd64_interpreter(self):
+        configure, _ = self.configure('win-amd64')
+        self.assertEqual(configure[configure.index('-A') + 1], 'x64')
+
+    def test_win32_interpreter(self):
+        configure, _ = self.configure('win32')
+        self.assertEqual(configure[configure.index('-A') + 1], 'Win32')
+
+    def test_explicit_visual_studio_generator(self):
+        configure, _ = self.configure('win-arm64', 'Visual Studio 18 2026')
+        self.assertEqual(configure[configure.index('-G') + 1], 'Visual Studio 18 2026')
+        self.assertEqual(configure[configure.index('-A') + 1], 'ARM64')
+
+    def test_ninja_does_not_receive_visual_studio_options(self):
+        for generator in ('Ninja', 'Ninja Multi-Config'):
+            with self.subTest(generator=generator):
+                configure, build = self.configure('win-arm64', generator)
+                self.assertEqual(configure[configure.index('-G') + 1], generator)
+                self.assertNotIn('-A', configure)
+                self.assertNotIn('/m', build)
+                self.assertIn('--parallel', build)
+
+
+if __name__ == '__main__':
+    unittest.main()