Close #18635: Move class level private attribute from instance to class.

Lib/enum.py

@@ -127,6 +127,7 @@ class EnumMeta(type):
         enum_class = super().__new__(metacls, cls, bases, classdict)
         enum_class._member_names_ = []               # names in definition order
         enum_class._member_map_ = OrderedDict()      # name->value map
+        enum_class._member_type_ = member_type
 
         # Reverse value->name map for hashable values.
         enum_class._value2member_map_ = {}
@@ -159,7 +160,6 @@ class EnumMeta(type):
                 if not hasattr(enum_member, '_value_'):
                     enum_member._value_ = member_type(*args)
             value = enum_member._value_
-            enum_member._member_type_ = member_type
             enum_member._name_ = member_name
             enum_member.__init__(*args)
             # If another member with the same value was already defined, the

Lib/test/test_enum.py

@@ -583,6 +583,24 @@ class TestEnum(unittest.TestCase):
             option3 = 3
         self.assertEqual(int(MailManOptions.option1), 1)
 
+    def test_introspection(self):
+        class Number(IntEnum):
+            one = 100
+            two = 200
+        self.assertIs(Number.one._member_type_, int)
+        self.assertIs(Number._member_type_, int)
+        class String(str, Enum):
+            yarn = 'soft'
+            rope = 'rough'
+            wire = 'hard'
+        self.assertIs(String.yarn._member_type_, str)
+        self.assertIs(String._member_type_, str)
+        class Plain(Enum):
+            vanilla = 'white'
+            one = 1
+        self.assertIs(Plain.vanilla._member_type_, object)
+        self.assertIs(Plain._member_type_, object)
+
     def test_no_such_enum_member(self):
         class Color(Enum):
             red = 1