[Python-checkins] cpython (3.5): Issue #28790: Fix error when using Generic and slots (Ivan L)

Tue Nov 29 12:47:00 EST 2016

https://hg.python.org/cpython/rev/0bbd29405c9d
changeset: 105392:0bbd29405c9d
branch: 3.5
parent: 105374:40567b8e3478
user: Guido van Rossum <guido at python.org>
date: Tue Nov 29 09:46:21 2016 -0800
summary:
 Issue #28790: Fix error when using Generic and __slots__ (Ivan L)
files:
 Lib/test/test_typing.py | 38 +++++++++++++++++++++++++++++
 Lib/typing.py | 18 +++++++++++--
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -896,6 +896,44 @@
 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]
diff --git a/Lib/typing.py b/Lib/typing.py
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -870,6 +870,17 @@
 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 @@
 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 @@
 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 @@
 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__)
 
-- 
Repository URL: https://hg.python.org/cpython


[Python-checkins] cpython (3.5): Issue #28790: Fix error when using Generic and __slots__ (Ivan L)

[Python-checkins] cpython (3.5): Issue #28790: Fix error when using Generic and slots (Ivan L)