Move EXT_SUFFIX support to _py39compat, to be removed after support for Python 3.9 is dropped. Fall back to default behavior on Python 3.10. Remove functionality for SO, which has been long deprecated and is untested.

2 files changed, 17 insertions, 9 deletions

diff --git a/distutils/py39compat.py b/distutils/py39compat.py
new file mode 100644
index 00000000..6771f0ff
--- /dev/null
+++ b/distutils/py39compat.py
@@ -0,0 +1,14 @@
+import sys
+import platform
+
+
+def ext_suffix(vars):
+    """
+    Ensure vars contains 'EXT_SUFFIX'. pypa/distutils#130
+    """
+    if sys.version_info < (3, 10):
+        return vars
+    if platform.system() != 'Windows':
+        return vars
+    import _imp
+    vars.update(EXT_SUFFIX=_imp.extension_suffixes()[0])
diff --git a/distutils/sysconfig.py b/distutils/sysconfig.py
index e2a395df..ef554768 100644
--- a/distutils/sysconfig.py
+++ b/distutils/sysconfig.py
@@ -16,6 +16,7 @@ import sys
 import sysconfig
 
 from .errors import DistutilsPlatformError
+from . import py39compat
 
 IS_PYPY = '__pypy__' in sys.builtin_module_names
 
@@ -448,15 +449,8 @@ def get_config_vars(*args):
     """
     global _config_vars
     if _config_vars is None:
-        _config_vars = sysconfig.get_config_vars().copy()
-        if os.name == 'nt':
-            # See https://github.com/pypa/distutils/issues/130
-            _config_vars['EXT_SUFFIX'] = _imp.extension_suffixes()[0]
-            if not IS_PYPY:
-                # For backward compatibility, see issue19555
-                SO = _config_vars.get('EXT_SUFFIX')
-                if SO is not None:
-                    _config_vars['SO'] = SO
+        _config_vars = py39compat.ext_suffix(
+            sysconfig.get_config_vars().copy())
 
     if args:
         vals = []