Fixed issue 119946 - Enum with ABC mixin

Lib/enum.py

@@ -1,6 +1,7 @@
 import sys
 import builtins as bltns
 from types import MappingProxyType, DynamicClassAttribute
+from abc import ABCMeta
 
 
 __all__ = [
@@ -466,7 +467,7 @@ def update(self, members, **more_members):
 _EnumDict = EnumDict        # keep private name for backwards compatibility
 
 
-class EnumType(type):
+class EnumType(ABCMeta):
     """
     Metaclass for Enum
     """
@@ -1773,7 +1774,7 @@ def convert_class(cls):
             body['__rand__'] = Flag.__rand__
             body['__invert__'] = Flag.__invert__
         for name, obj in cls.__dict__.items():
-            if name in ('__dict__', '__weakref__'):
+            if name in ('__dict__', '__weakref__', '_abc_impl'):
                 continue
             if _is_dunder(name) or _is_private(cls_name, name) or _is_sunder(name) or _is_descriptor(obj):
                 body[name] = obj
@@ -2038,7 +2039,7 @@ def _test_simple_enum(checked_enum, simple_enum):
                 )
         for key in set(checked_keys + simple_keys):
             if key in ('__module__', '_member_map_', '_value2member_map_', '__doc__',
-                       '__static_attributes__', '__firstlineno__'):
+                       '__static_attributes__', '__firstlineno__', '_abc_impl'):
                 # keys known to be different, or very long
                 continue
             elif key in member_names:

Lib/test/test_enum.py

@@ -21,6 +21,7 @@
 from test.support import ALWAYS_EQ, REPO_ROOT
 from test.support import threading_helper
 from datetime import timedelta
+from abc import ABC, abstractmethod
 
 python_version = sys.version_info[:2]
 
@@ -3910,6 +3911,23 @@ class Color(StrMixin, AllMixin, Flag):
         self.assertEqual(Color.ALL.value, 7)
         self.assertEqual(str(Color.BLUE), 'blue')
 
+    def test_abstract_mixin(self):
+        class HasColor(ABC):
+            @abstractmethod
+            def color(self):
+                ...
+        class Flowers(HasColor, Enum):
+            ROSES = 1
+            VIOLETS = 2
+            def color(self):
+                match self:
+                    case self.ROSES:
+                        return 'red'
+                    case self.VIOLETS:
+                        return 'blue'
+        self.assertEqual(Flowers.ROSES.color(), 'red')
+        self.assertEqual(Flowers.VIOLETS.color(), 'blue')
+
     @threading_helper.reap_threads
     @threading_helper.requires_working_threading()
     def test_unique_composite(self):
@@ -5221,7 +5239,33 @@ def __new__(cls, value, label):
             VEST = 1, 'uppert half'
             PANTS = 2, 'lower half'
         _test_simple_enum(CheckedComplexFlag, ComplexFlag)
-
+        #
+        #
+        class HasColor(ABC):
+            @abstractmethod
+            def color(self):
+                ...
+        class CheckedABCMixin(HasColor, Enum):
+            ROSES = 1
+            VIOLETS = 2
+            def color(self):
+                match self:
+                    case self.ROSES:
+                        return 'red'
+                    case self.VIOLETS:
+                        return 'blue'
+        #
+        @_simple_enum(Enum)
+        class ABCMixin(HasColor):
+            ROSES = 1
+            VIOLETS = 2
+            def color(self):
+                match self:
+                    case self.ROSES:
+                        return 'red'
+                    case self.VIOLETS:
+                        return 'blue'
+        _test_simple_enum(CheckedABCMixin, ABCMixin)
 
 class MiscTestCase(unittest.TestCase):
 

Misc/NEWS.d/next/Library/2024-06-02-19-26-01.gh-issue-119946.g8wtLh.rst

@@ -0,0 +1 @@
+Allow Enum classes to have mixins derived from an abstract base class (ABC).