gh-94601: [Enum] fix inheritance for __str__ and friends (GH-94942)

1 files changed, 21 insertions, 5 deletions

diff --git a/Lib/enum.py b/Lib/enum.py
index a4f1f09adae..80945c116bf 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -247,7 +247,10 @@ class _proto_member:
         if not enum_class._use_args_:
             enum_member = enum_class._new_member_(enum_class)
             if not hasattr(enum_member, '_value_'):
-                enum_member._value_ = value
+                try:
+                    enum_member._value_ = enum_class._member_type_(*args)
+                except Exception as exc:
+                    enum_member._value_ = value
         else:
             enum_member = enum_class._new_member_(enum_class, *args)
             if not hasattr(enum_member, '_value_'):
@@ -562,7 +565,13 @@ class EnumType(type):
                 classdict['__str__'] = enum_class.__str__
         for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
             if name not in classdict:
-                setattr(enum_class, name, getattr(first_enum, name))
+                # check for mixin overrides before replacing
+                enum_method = getattr(first_enum, name)
+                found_method = getattr(enum_class, name)
+                object_method = getattr(object, name)
+                data_type_method = getattr(member_type, name)
+                if found_method in (data_type_method, object_method):
+                    setattr(enum_class, name, enum_method)
         #
         # for Flag, add __or__, __and__, __xor__, and __invert__
         if Flag is not None and issubclass(enum_class, Flag):
@@ -937,16 +946,18 @@ class EnumType(type):
     @classmethod
     def _find_data_type_(mcls, class_name, bases):
         data_types = set()
+        base_chain = set()
         for chain in bases:
             candidate = None
             for base in chain.__mro__:
+                base_chain.add(base)
                 if base is object:
                     continue
                 elif issubclass(base, Enum):
                     if base._member_type_ is not object:
                         data_types.add(base._member_type_)
                         break
-                elif '__new__' in base.__dict__:
+                elif '__new__' in base.__dict__ or '__init__' in base.__dict__:
                     if issubclass(base, Enum):
                         continue
                     data_types.add(candidate or base)
@@ -1658,7 +1669,13 @@ def _simple_enum(etype=Enum, *, boundary=None, use_args=None):
         enum_class = type(cls_name, (etype, ), body, boundary=boundary, _simple=True)
         for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
             if name not in body:
-                setattr(enum_class, name, getattr(etype, name))
+                # check for mixin overrides before replacing
+                enum_method = getattr(etype, name)
+                found_method = getattr(enum_class, name)
+                object_method = getattr(object, name)
+                data_type_method = getattr(member_type, name)
+                if found_method in (data_type_method, object_method):
+                    setattr(enum_class, name, enum_method)
         gnv_last_values = []
         if issubclass(enum_class, Flag):
             # Flag / IntFlag
@@ -1989,7 +2006,6 @@ def _old_convert_(etype, name, module, filter, source=None, *, boundary=None):
         members.sort(key=lambda t: t[0])
     cls = etype(name, members, module=module, boundary=boundary or KEEP)
     cls.__reduce_ex__ = _reduce_ex_by_global_name
-    cls.__repr__ = global_enum_repr
     return cls
 
 _stdlib_enums = IntEnum, StrEnum, IntFlag