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[3.7] bpo-33217: deprecate non-Enum lookups in Enums (GH-6392)
deprecate non-Enum lookups in Enums Lookups such as `1 in Color` and `2 in SomeFlag()` will raise TypeError in 3.8+.
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Lines changed: 78 additions & 5 deletions

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‎Doc/library/enum.rst‎

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@@ -976,7 +976,7 @@ Enum Classes
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The :class:`EnumMeta` metaclass is responsible for providing the
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:meth:`__contains__`, :meth:`__dir__`, :meth:`__iter__` and other methods that
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allow one to do things with an :class:`Enum` class that fail on a typical
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class, such as `list(Color)` or `some_var in Color`. :class:`EnumMeta` is
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class, such as `list(Color)` or `some_enum_var in Color`. :class:`EnumMeta` is
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responsible for ensuring that various other methods on the final :class:`Enum`
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class are correct (such as :meth:`__new__`, :meth:`__getnewargs__`,
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:meth:`__str__` and :meth:`__repr__`).

‎Doc/whatsnew/3.7.rst‎

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@@ -1041,6 +1041,12 @@ Deprecated
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:meth:`ssl.SSLContext.wrap_socket` instead.
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(Contributed by Christian Heimes in :issue:`28124`.)
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- In Python 3.8, attempting to check for non-Enum objects in :class:`Enum`
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classes will raise a :exc:`TypeError` (e.g. ``1 in Color``); similarly,
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attempting to check for non-Flag objects in a :class:`Flag` member will
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raise :exc:`TypeError` (e.g. ``1 in Perm.RW``); currently, both operations
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return :const:`False` instead.
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10441050

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Windows Only
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------------

‎Lib/enum.py‎

Lines changed: 12 additions & 1 deletion
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@@ -309,6 +309,12 @@ def __call__(cls, value, names=None, *, module=None, qualname=None, type=None, s
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return cls._create_(value, names, module=module, qualname=qualname, type=type, start=start)
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def __contains__(cls, member):
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if not isinstance(member, Enum):
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import warnings
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warnings.warn(
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"using non-Enums in containment checks will raise "
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"TypeError in Python 3.8",
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DeprecationWarning, 2)
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return isinstance(member, cls) and member._name_ in cls._member_map_
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def __delattr__(cls, attr):
@@ -713,7 +719,12 @@ def _create_pseudo_member_(cls, value):
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714720
def __contains__(self, other):
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if not isinstance(other, self.__class__):
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return NotImplemented
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import warnings
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warnings.warn(
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"using non-Flags in containment checks will raise "
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"TypeError in Python 3.8",
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DeprecationWarning, 2)
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return False
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return other._value_ & self._value_ == other._value_
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def __repr__(self):

‎Lib/test/test_enum.py‎

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Original file line numberDiff line numberDiff line change
@@ -325,7 +325,10 @@ class IntLogic(int, Enum):
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def test_contains(self):
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Season = self.Season
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self.assertIn(Season.AUTUMN, Season)
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self.assertNotIn(3, Season)
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with self.assertWarns(DeprecationWarning):
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self.assertNotIn(3, Season)
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with self.assertWarns(DeprecationWarning):
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self.assertNotIn('AUTUMN', Season)
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val = Season(3)
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self.assertIn(val, Season)
@@ -334,6 +337,11 @@ class OtherEnum(Enum):
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one = 1; two = 2
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self.assertNotIn(OtherEnum.two, Season)
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def test_member_contains(self):
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self.assertRaises(TypeError, lambda: 'test' in self.Season.AUTUMN)
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self.assertRaises(TypeError, lambda: 3 in self.Season.AUTUMN)
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self.assertRaises(TypeError, lambda: 'AUTUMN' in self.Season.AUTUMN)
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def test_comparisons(self):
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Season = self.Season
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with self.assertRaises(TypeError):
@@ -1745,6 +1753,13 @@ class TestFlag(unittest.TestCase):
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class Perm(Flag):
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R, W, X = 4, 2, 1
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class Color(Flag):
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BLACK = 0
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RED = 1
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GREEN = 2
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BLUE = 4
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PURPLE = RED|BLUE
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class Open(Flag):
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RO = 0
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WO = 1
@@ -1954,7 +1969,21 @@ def test_pickle(self):
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test_pickle_dump_load(self.assertIs, FlagStooges.CURLY|FlagStooges.MOE)
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test_pickle_dump_load(self.assertIs, FlagStooges)
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1957-
def test_containment(self):
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def test_contains(self):
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Open = self.Open
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Color = self.Color
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self.assertFalse(Color.BLACK in Open)
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self.assertFalse(Open.RO in Color)
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with self.assertWarns(DeprecationWarning):
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self.assertFalse('BLACK' in Color)
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with self.assertWarns(DeprecationWarning):
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self.assertFalse('RO' in Open)
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with self.assertWarns(DeprecationWarning):
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self.assertFalse(1 in Color)
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with self.assertWarns(DeprecationWarning):
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self.assertFalse(1 in Open)
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def test_member_contains(self):
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Perm = self.Perm
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R, W, X = Perm
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RW = R | W
@@ -2065,6 +2094,13 @@ class Perm(IntFlag):
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W = 1 << 1
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R = 1 << 2
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2097+
class Color(IntFlag):
2098+
BLACK = 0
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RED = 1
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GREEN = 2
2101+
BLUE = 4
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PURPLE = RED|BLUE
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class Open(IntFlag):
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RO = 0
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WO = 1
@@ -2340,7 +2376,23 @@ def test_programatic_function_from_empty_tuple(self):
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self.assertEqual(len(lst), len(Thing))
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self.assertEqual(len(Thing), 0, Thing)
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2343-
def test_containment(self):
2379+
def test_contains(self):
2380+
Color = self.Color
2381+
Open = self.Open
2382+
self.assertTrue(Color.GREEN in Color)
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self.assertTrue(Open.RW in Open)
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self.assertFalse(Color.GREEN in Open)
2385+
self.assertFalse(Open.RW in Color)
2386+
with self.assertWarns(DeprecationWarning):
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self.assertFalse('GREEN' in Color)
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with self.assertWarns(DeprecationWarning):
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self.assertFalse('RW' in Open)
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with self.assertWarns(DeprecationWarning):
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self.assertFalse(2 in Color)
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with self.assertWarns(DeprecationWarning):
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self.assertFalse(2 in Open)
2394+
2395+
def test_member_contains(self):
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Perm = self.Perm
23452397
R, W, X = Perm
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RW = R | W
@@ -2359,6 +2411,8 @@ def test_containment(self):
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self.assertFalse(R in WX)
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self.assertFalse(W in RX)
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self.assertFalse(X in RW)
2414+
with self.assertWarns(DeprecationWarning):
2415+
self.assertFalse('swallow' in RW)
23622416

23632417
def test_bool(self):
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Perm = self.Perm

‎Misc/NEWS.d/next/Library/2018-04-05-13-36-09.bpo-33217.FfOKDI.rst‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,2 @@
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Deprecate looking up non-Enum objects in Enum classes and Enum members (will
2+
raise :exc:`TypeError` in 3.8+).

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