Fallback to stdlib distutils if setuptools._distutils is missing

_distutils_hack/__init__.py

@@ -33,12 +33,43 @@ def clear_distutils():
  del sys.modules[name]
 
 
+def get_local_distutils():
+ import importlib
+
+ try:
+ return importlib.import_module('setuptools._distutils')
+ except Exception:
+ # There are a couple of cases where setuptools._distutils
+ # may not be present:
+ # - An older Setuptools without a local distutils is
+ # taking precedence. Ref #2957.
+ # - Path manipulation during sitecustomize removes
+ # setuptools from the path but only after the hook
+ # has been loaded. Ref #2980.
+ # - setuptools._distutils has been removed, either by the user
+ # or by packaging / distribution.
+ # In either case, fall back to stdlib behavior.
+ return None
+
+
 def enabled():
  """
  Allow selection of distutils by environment variable.
  """
  which = os.environ.get('SETUPTOOLS_USE_DISTUTILS', 'local')
- return which == 'local'
+ if which != 'local':
+ return False
+
+ if sys.version_info < (3, 12) and not get_local_distutils():
+ import warnings
+
+ warnings.warn(
+ "environment variable SETUPTOOLS_USE_DISTUTILS is set to 'local' or None, "
+ + "but `setuptools._distutils` could not be imported. Falling back to stdlib "
+ + "distutils. This will lead to an error in Python 3.12 and above."
+ )
+ return False
+ return True
 
 
 def ensure_local_distutils():
@@ -97,17 +128,8 @@ def spec_for_distutils(self):
  import importlib.abc
  import importlib.util
 
- try:
- mod = importlib.import_module('setuptools._distutils')
- except Exception:
- # There are a couple of cases where setuptools._distutils
- # may not be present:
- # - An older Setuptools without a local distutils is
- # taking precedence. Ref #2957.
- # - Path manipulation during sitecustomize removes
- # setuptools from the path but only after the hook
- # has been loaded. Ref #2980.
- # In either case, fall back to stdlib behavior.
+ mod = get_local_distutils()
+ if not mod:
  return None
 
  class DistutilsLoader(importlib.abc.Loader):

newsfragments/4441.bugfix.rst

@@ -0,0 +1 @@
+Added a fallback to stdlib `distutils` if ``setuptools._distutils`` is missing on Python 3.11 or below, even with ``SETUPTOOLS_USE_DISTUTILS=local``. -- by :user:`Avasam`