bpo-44771: Apply changes from importlib_resources 5.2.1 (GH-27436)

* bpo-44771: Apply changes from importlib_resources@3b24bd6307

* Add blurb

* Exclude namespacedata01 from eol conversion.

1 files changed, 7 insertions, 8 deletions

diff --git a/Lib/importlib/readers.py b/Lib/importlib/readers.py
index 41089c071d..b470a2062b 100644
--- a/Lib/importlib/readers.py
+++ b/Lib/importlib/readers.py
@@ -1,8 +1,12 @@
 import collections
-import zipfile
+import operator
 import pathlib
+import zipfile
+
 from . import abc
 
+from ._itertools import unique_everseen
+
 
 def remove_duplicates(items):
     return iter(collections.OrderedDict.fromkeys(items))
@@ -63,13 +67,8 @@ class MultiplexedPath(abc.Traversable):
             raise NotADirectoryError('MultiplexedPath only supports directories')
 
     def iterdir(self):
-        visited = []
-        for path in self._paths:
-            for file in path.iterdir():
-                if file.name in visited:
-                    continue
-                visited.append(file.name)
-                yield file
+        files = (file for path in self._paths for file in path.iterdir())
+        return unique_everseen(files, key=operator.attrgetter('name'))
 
     def read_bytes(self):
         raise FileNotFoundError(f'{self} is not a file')