split out the monkeypatching

Author: mr-c

mypyc/build.py

@@ -41,7 +41,7 @@
 from mypyc.ir.pprint import format_modules
 from mypyc.namegen import exported_name
 from mypyc.options import CompilerOptions
-
+import mypyc.build_setup
 
 class ModDesc(NamedTuple):
     module: str
@@ -122,52 +122,6 @@ class ModDesc(NamedTuple):
 else:
     from distutils import ccompiler, sysconfig
 
-EXTRA_FLAGS_PER_COMPILER_TYPE_PER_PATH_COMPONENT = {
-    "unix": {
-        "base64/arch/ssse3": "-mssse3",
-        "base64/arch/sse41": "-msse4.1",
-        "base64/arch/sse42": "-msse4.2",
-        "base64/arch/avx2": "-mavx2",
-        "base64/arch/avx": "-mavx",
-    },
-    "msvc": {
-        "base64/arch/sse42": "/arch:SSE4.2",
-        "base64/arch/avx2": "/arch:AVX2",
-        "base64/arch/avx": "/arch:AVX",
-    },
-}
-
-__spawn = ccompiler.CCompiler.spawn
-
-
-def spawn(self, cmd, **kwargs):  # type: ignore[no-untyped-def]
-    compiler_type: str = self.compiler_type
-    extra_options = EXTRA_FLAGS_PER_COMPILER_TYPE_PER_PATH_COMPONENT[compiler_type]
-    new_cmd = list(cmd)
-    if extra_options is not None:
-        # filenames are closer to the end of command line
-        for argument in reversed(new_cmd):
-            # Check if argument contains a filename. We must check for all
-            # possible extensions; checking for target extension is faster.
-            if self.obj_extension and not str(argument).endswith(self.obj_extension):
-                continue
-
-            for path in extra_options.keys():
-                if path in str(argument):
-                    if compiler_type == "bcpp":
-                        # Borland accepts a source file name at the end,
-                        # insert the options before it
-                        new_cmd[-1:-1] = extra_options[path]
-                    else:
-                        new_cmd.append(extra_options[path])
-
-                    # path component is found, no need to search any further
-                    break
-    __spawn(self, new_cmd, **kwargs)
-
-
-ccompiler.CCompiler.spawn = spawn  # type: ignore[method-assign]
-
 
 def get_extension() -> type[Extension]:
     # We can work with either setuptools or distutils, and pick setuptools

mypyc/build_setup.py

@@ -0,0 +1,59 @@
+import sys
+
+try:
+    # Import setuptools so that it monkey-patch overrides distutils
+    import setuptools
+except ImportError:
+    pass
+
+if sys.version_info >= (3, 12):
+    # From setuptools' monkeypatch
+    from distutils import ccompiler, sysconfig  # type: ignore[import-not-found]
+else:
+    from distutils import ccompiler, sysconfig
+
+EXTRA_FLAGS_PER_COMPILER_TYPE_PER_PATH_COMPONENT = {
+    "unix": {
+        "base64/arch/ssse3": "-mssse3",
+        "base64/arch/sse41": "-msse4.1",
+        "base64/arch/sse42": "-msse4.2",
+        "base64/arch/avx2": "-mavx2",
+        "base64/arch/avx": "-mavx",
+    },
+    "msvc": {
+        "base64/arch/sse42": "/arch:SSE4.2",
+        "base64/arch/avx2": "/arch:AVX2",
+        "base64/arch/avx": "/arch:AVX",
+    },
+}
+
+ccompiler.CCompiler.__spawn = ccompiler.CCompiler.spawn  # type: ignore[attr-defined]
+
+
+def spawn(self, cmd, **kwargs) -> None:  # type: ignore[no-untyped-def]
+    compiler_type: str = self.compiler_type
+    extra_options = EXTRA_FLAGS_PER_COMPILER_TYPE_PER_PATH_COMPONENT[compiler_type]
+    new_cmd = list(cmd)
+    if extra_options is not None:
+        # filenames are closer to the end of command line
+        for argument in reversed(new_cmd):
+            # Check if argument contains a filename. We must check for all
+            # possible extensions; checking for target extension is faster.
+            if self.obj_extension and not str(argument).endswith(self.obj_extension):
+                continue
+
+            for path in extra_options.keys():
+                if path in str(argument):
+                    if compiler_type == "bcpp":
+                        # Borland accepts a source file name at the end,
+                        # insert the options before it
+                        new_cmd[-1:-1] = extra_options[path]
+                    else:
+                        new_cmd.append(extra_options[path])
+
+                    # path component is found, no need to search any further
+                    break
+    self.__spawn(new_cmd, **kwargs)
+
+
+ccompiler.CCompiler.spawn = spawn  # type: ignore[method-assign]

setup.py

@@ -99,6 +99,7 @@ def run(self) -> None:
         os.path.join("mypyc", "lib-rt", "setup.py"),
         # Uses __file__ at top level https://github.com/mypyc/mypyc/issues/700
         os.path.join("mypyc", "__main__.py"),
+        os.path.join("mypyc", "build_setup.py"),  # for monkeypatching
     )
 
     everything = [os.path.join("mypy", x) for x in find_package_data("mypy", ["*.py"])] + [