Bypass distutils loader when setuptools module is no longer available on sys.path. Fixes #2980.

1 files changed, 7 insertions, 0 deletions

diff --git a/_distutils_hack/__init__.py b/_distutils_hack/__init__.py
index 85a51370..55ea0825 100644
--- a/_distutils_hack/__init__.py
+++ b/_distutils_hack/__init__.py
@@ -86,6 +86,13 @@ class DistutilsMetaFinder:
         import importlib.abc
         import importlib.util
 
+        # In cases of path manipulation during sitecustomize,
+        # Setuptools might actually not be present even though
+        # the hook has been loaded. Allow the caller to fall
+        # back to stdlib behavior. See #2980.
+        if not importlib.util.find_spec('setuptools'):
+            return
+
         class DistutilsLoader(importlib.abc.Loader):
 
             def create_module(self, spec):