Issue #28790: Fix error when using Generic and __slots__ (Ivan L)

This commit is contained in:
Guido van Rossum 2016-11-29 09:46:21 -08:00
parent 47a9a4beda
commit 61f0a0261f
2 changed files with 53 additions and 3 deletions

View File

@ -896,6 +896,44 @@ class GenericTests(BaseTestCase):
self.assertEqual(t, copy(t))
self.assertEqual(t, deepcopy(t))
def test_parameterized_slots(self):
T = TypeVar('T')
class C(Generic[T]):
__slots__ = ('potato',)
c = C()
c_int = C[int]()
self.assertEqual(C.__slots__, C[str].__slots__)
c.potato = 0
c_int.potato = 0
with self.assertRaises(AttributeError):
c.tomato = 0
with self.assertRaises(AttributeError):
c_int.tomato = 0
def foo(x: C['C']): ...
self.assertEqual(get_type_hints(foo, globals(), locals())['x'], C[C])
self.assertEqual(get_type_hints(foo, globals(), locals())['x'].__slots__,
C.__slots__)
self.assertEqual(copy(C[int]), deepcopy(C[int]))
def test_parameterized_slots_dict(self):
T = TypeVar('T')
class D(Generic[T]):
__slots__ = {'banana': 42}
d = D()
d_int = D[int]()
self.assertEqual(D.__slots__, D[str].__slots__)
d.banana = 'yes'
d_int.banana = 'yes'
with self.assertRaises(AttributeError):
d.foobar = 'no'
with self.assertRaises(AttributeError):
d_int.foobar = 'no'
def test_errors(self):
with self.assertRaises(TypeError):
B = SimpleMapping[XK, Any]

View File

@ -870,6 +870,17 @@ def _make_subclasshook(cls):
return __extrahook__
def _no_slots_copy(dct):
"""Internal helper: copy class __dict__ and clean slots class variables.
(They will be re-created if necessary by normal class machinery.)
"""
dict_copy = dict(dct)
if '__slots__' in dict_copy:
for slot in dict_copy['__slots__']:
dict_copy.pop(slot, None)
return dict_copy
class GenericMeta(TypingMeta, abc.ABCMeta):
"""Metaclass for generic types."""
@ -967,7 +978,7 @@ class GenericMeta(TypingMeta, abc.ABCMeta):
return self
return self.__class__(self.__name__,
self.__bases__,
dict(self.__dict__),
_no_slots_copy(self.__dict__),
tvars=_type_vars(ev_args) if ev_args else None,
args=ev_args,
origin=ev_origin,
@ -1043,7 +1054,7 @@ class GenericMeta(TypingMeta, abc.ABCMeta):
args = params
return self.__class__(self.__name__,
self.__bases__,
dict(self.__dict__),
_no_slots_copy(self.__dict__),
tvars=tvars,
args=args,
origin=self,
@ -1059,7 +1070,8 @@ class GenericMeta(TypingMeta, abc.ABCMeta):
return issubclass(instance.__class__, self)
def __copy__(self):
return self.__class__(self.__name__, self.__bases__, dict(self.__dict__),
return self.__class__(self.__name__, self.__bases__,
_no_slots_copy(self.__dict__),
self.__parameters__, self.__args__, self.__origin__,
self.__extra__, self.__orig_bases__)