gh-135559: [Enum] dir() on a Flag now shows aliases (GH-136527)

(cherry picked from commit 26757d1)

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>

Author: ethanfurman

Lib/enum.py

@@ -750,12 +750,16 @@ def __delattr__(cls, attr):
         super().__delattr__(attr)
 
     def __dir__(cls):
+        if issubclass(cls, Flag):
+            members = list(cls._member_map_.keys())
+        else:
+            members = cls._member_names_
         interesting = set([
                 '__class__', '__contains__', '__doc__', '__getitem__',
                 '__iter__', '__len__', '__members__', '__module__',
                 '__name__', '__qualname__',
                 ]
-                + cls._member_names_
+                + members
                 )
         if cls._new_member_ is not object.__new__:
             interesting.add('__new__')

Lib/test/test_enum.py

@@ -5492,12 +5492,16 @@ def test_enum_dict_standalone(self):
 # helpers
 
 def enum_dir(cls):
+    if issubclass(cls, Flag):
+        members = list(cls._member_map_.keys())
+    else:
+        members = cls._member_names_
     interesting = set([
             '__class__', '__contains__', '__doc__', '__getitem__',
             '__iter__', '__len__', '__members__', '__module__',
             '__name__', '__qualname__',
             ]
-            + cls._member_names_
+            + members
             )
     if cls._new_member_ is not object.__new__:
         interesting.add('__new__')

Misc/NEWS.d/next/Library/2025-07-10-18-40-11.gh-issue-135559.BMDtYn.rst

@@ -0,0 +1,2 @@
+Flag: a ``dir()`` on a ``Flag`` enumeration now shows non-canonical members.
+(i.e. aliases).