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Close issue20653: allow Enum subclasses to override __reduce_ex__

This commit is contained in:
Ethan Furman 2014-02-18 12:37:12 -08:00
parent e3e786c963
commit dc87052c0c
2 changed files with 73 additions and 14 deletions
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26
Lib/enum.py
View File

@ -116,12 +116,14 @@ class EnumMeta(type):
enum_class._value2member_map_ = {}
# check for a supported pickle protocols, and if not present sabotage
# pickling, since it won't work anyway
if member_type is not object:
methods = ('__getnewargs_ex__', '__getnewargs__',
'__reduce_ex__', '__reduce__')
if not any(map(member_type.__dict__.get, methods)):
_make_class_unpicklable(enum_class)
# pickling, since it won't work anyway.
# if new class implements its own __reduce_ex__, do not sabotage
if classdict.get('__reduce_ex__') is None:
if member_type is not object:
methods = ('__getnewargs_ex__', '__getnewargs__',
'__reduce_ex__', '__reduce__')
if not any(map(member_type.__dict__.get, methods)):
_make_class_unpicklable(enum_class)
# instantiate them, checking for duplicates as we go
# we instantiate first instead of checking for duplicates first in case
@ -167,7 +169,7 @@ class EnumMeta(type):
# double check that repr and friends are not the mixin's or various
# things break (such as pickle)
for name in ('__repr__', '__str__', '__format__', '__getnewargs__', '__reduce_ex__'):
for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
class_method = getattr(enum_class, name)
obj_method = getattr(member_type, name, None)
enum_method = getattr(first_enum, name, None)
@ -192,8 +194,9 @@ class EnumMeta(type):
(i.e. Color = Enum('Color', names='red green blue')).
When used for the functional API: `module`, if set, will be stored in
the new class' __module__ attribute; `type`, if set, will be mixed in
as the first base class.
the new class' __module__ attribute; `qualname`, if set, will be stored
in the new class' __qualname__ attribute; `type`, if set, will be mixed
in as the first base class.
Note: if `module` is not set this routine will attempt to discover the
calling module by walking the frame stack; if this is unsuccessful
@ -465,14 +468,11 @@ class Enum(metaclass=EnumMeta):
val = self.value
return cls.__format__(val, format_spec)
def __getnewargs__(self):
return (self._value_, )
def __hash__(self):
return hash(self._name_)
def __reduce_ex__(self, proto):
return self.__class__, self.__getnewargs__()
return self.__class__, (self._value_, )
# DynamicClassAttribute is used to provide access to the `name` and
# `value` properties of enum members while keeping some measure of

61
Lib/test/test_enum.py
View File

@ -956,6 +956,7 @@ class TestEnum(unittest.TestCase):
test_pickle_dump_load(self.assertEqual, NI5, 5)
self.assertEqual(NEI.y.value, 2)
test_pickle_dump_load(self.assertIs, NEI.y)
test_pickle_dump_load(self.assertIs, NEI)
def test_subclasses_with_getnewargs_ex(self):
class NamedInt(int):
@ -1012,6 +1013,7 @@ class TestEnum(unittest.TestCase):
test_pickle_dump_load(self.assertEqual, NI5, 5, protocol=(4, 4))
self.assertEqual(NEI.y.value, 2)
test_pickle_dump_load(self.assertIs, NEI.y, protocol=(4, 4))
test_pickle_dump_load(self.assertIs, NEI)
def test_subclasses_with_reduce(self):
class NamedInt(int):
@ -1068,6 +1070,7 @@ class TestEnum(unittest.TestCase):
test_pickle_dump_load(self.assertEqual, NI5, 5)
self.assertEqual(NEI.y.value, 2)
test_pickle_dump_load(self.assertIs, NEI.y)
test_pickle_dump_load(self.assertIs, NEI)
def test_subclasses_with_reduce_ex(self):
class NamedInt(int):
@ -1124,8 +1127,9 @@ class TestEnum(unittest.TestCase):
test_pickle_dump_load(self.assertEqual, NI5, 5)
self.assertEqual(NEI.y.value, 2)
test_pickle_dump_load(self.assertIs, NEI.y)
test_pickle_dump_load(self.assertIs, NEI)
def test_subclasses_without_getnewargs(self):
def test_subclasses_without_direct_pickle_support(self):
class NamedInt(int):
__qualname__ = 'NamedInt'
def __new__(cls, *args):
@ -1178,6 +1182,61 @@ class TestEnum(unittest.TestCase):
test_pickle_exception(self.assertRaises, TypeError, NEI.x)
test_pickle_exception(self.assertRaises, PicklingError, NEI)
def test_subclasses_without_direct_pickle_support_using_name(self):
class NamedInt(int):
__qualname__ = 'NamedInt'
def __new__(cls, *args):
_args = args
name, *args = args
if len(args) == 0:
raise TypeError("name and value must be specified")
self = int.__new__(cls, *args)
self._intname = name
self._args = _args
return self
@property
def __name__(self):
return self._intname
def __repr__(self):
# repr() is updated to include the name and type info
return "{}({!r}, {})".format(type(self).__name__,
self.__name__,
int.__repr__(self))
def __str__(self):
# str() is unchanged, even if it relies on the repr() fallback
base = int
base_str = base.__str__
if base_str.__objclass__ is object:
return base.__repr__(self)
return base_str(self)
# for simplicity, we only define one operator that
# propagates expressions
def __add__(self, other):
temp = int(self) + int( other)
if isinstance(self, NamedInt) and isinstance(other, NamedInt):
return NamedInt(
'({0} + {1})'.format(self.__name__, other.__name__),
temp )
else:
return temp
class NEI(NamedInt, Enum):
__qualname__ = 'NEI'
x = ('the-x', 1)
y = ('the-y', 2)
def __reduce_ex__(self, proto):
return getattr, (self.__class__, self._name_)
self.assertIs(NEI.__new__, Enum.__new__)
self.assertEqual(repr(NEI.x + NEI.y), "NamedInt('(the-x + the-y)', 3)")
globals()['NamedInt'] = NamedInt
globals()['NEI'] = NEI
NI5 = NamedInt('test', 5)
self.assertEqual(NI5, 5)
self.assertEqual(NEI.y.value, 2)
test_pickle_dump_load(self.assertIs, NEI.y)
test_pickle_dump_load(self.assertIs, NEI)
def test_tuple_subclass(self):
class SomeTuple(tuple, Enum):
__qualname__ = 'SomeTuple' # needed for pickle protocol 4