Merge with 3.4; Closes #22315

Lib/distutils/dir_util.py

@@ -125,12 +125,11 @@ def copy_tree(src, dst, preserve_mode=1, preserve_times=1,
     try:
         names = os.listdir(src)
     except OSError as e:
-        (errno, errstr) = e
         if dry_run:
             names = []
         else:
             raise DistutilsFileError(
-                  "error listing files in '%s': %s" % (src, errstr))
+                  "error listing files in '%s': %s" % (src, e.strerror))
 
     if not dry_run:
         mkpath(dst, verbose=verbose)

Lib/distutils/tests/test_dir_util.py

@@ -3,7 +3,9 @@ import unittest
 import os
 import stat
 import sys
+from unittest.mock import patch
 
+from distutils import dir_util, errors
 from distutils.dir_util import (mkpath, remove_tree, create_tree, copy_tree,
                                 ensure_relative)
 
@@ -11,6 +13,7 @@ from distutils import log
 from distutils.tests import support
 from test.support import run_unittest
 
+
 class DirUtilTestCase(support.TempdirManager, unittest.TestCase):
 
     def _log(self, msg, *args):
@@ -119,6 +122,16 @@ class DirUtilTestCase(support.TempdirManager, unittest.TestCase):
             self.assertEqual(ensure_relative('c:\\home\\foo'), 'c:home\\foo')
             self.assertEqual(ensure_relative('home\\foo'), 'home\\foo')
 
+    @patch('os.listdir', side_effect=OSError())
+    def test_copy_tree_exception_in_listdir(self, listdir):
+        """
+        An exception in listdir should raise a DistutilsFileError
+        """
+        with self.assertRaises(errors.DistutilsFileError):
+            src = self.tempdirs[-1]
+            dir_util.copy_tree(src, None)
+
+
 def test_suite():
     return unittest.makeSuite(DirUtilTestCase)