Update typing.py: remove isinstance() support (Mark struck it from the PEP).

This commit is contained in:
Guido van Rossum 2015-06-03 19:04:42 -07:00
parent b980c05ef8
commit 43a79cc552
2 changed files with 71 additions and 330 deletions

View File

@ -41,11 +41,9 @@ class ManagingFounder(Manager, Founder):
class AnyTests(TestCase):
def test_any_instance(self):
self.assertIsInstance(Employee(), Any)
self.assertIsInstance(42, Any)
self.assertIsInstance(None, Any)
self.assertIsInstance(object(), Any)
def test_any_instance_type_error(self):
with self.assertRaises(TypeError):
isinstance(42, Any)
def test_any_subclass(self):
self.assertTrue(issubclass(Employee, Any))
@ -109,9 +107,6 @@ class TypeVarTests(TestCase):
def test_basic_plain(self):
T = TypeVar('T')
# Nothing is an instance if T.
with self.assertRaises(TypeError):
isinstance('', T)
# Every class is a subclass of T.
assert issubclass(int, T)
assert issubclass(str, T)
@ -119,12 +114,16 @@ class TypeVarTests(TestCase):
assert T == T
# T is a subclass of itself.
assert issubclass(T, T)
# T is an instance of TypeVar
assert isinstance(T, TypeVar)
def test_typevar_instance_type_error(self):
T = TypeVar('T')
with self.assertRaises(TypeError):
isinstance(42, T)
def test_basic_constrained(self):
A = TypeVar('A', str, bytes)
# Nothing is an instance of A.
with self.assertRaises(TypeError):
isinstance('', A)
# Only str and bytes are subclasses of A.
assert issubclass(str, A)
assert issubclass(bytes, A)
@ -213,8 +212,6 @@ class UnionTests(TestCase):
def test_basics(self):
u = Union[int, float]
self.assertNotEqual(u, Union)
self.assertIsInstance(42, u)
self.assertIsInstance(3.14, u)
self.assertTrue(issubclass(int, u))
self.assertTrue(issubclass(float, u))
@ -247,7 +244,6 @@ class UnionTests(TestCase):
def test_subclass(self):
u = Union[int, Employee]
self.assertIsInstance(Manager(), u)
self.assertTrue(issubclass(Manager, u))
def test_self_subclass(self):
@ -256,7 +252,6 @@ class UnionTests(TestCase):
def test_multiple_inheritance(self):
u = Union[int, Employee]
self.assertIsInstance(ManagingFounder(), u)
self.assertTrue(issubclass(ManagingFounder, u))
def test_single_class_disappears(self):
@ -309,9 +304,6 @@ class UnionTests(TestCase):
o = Optional[int]
u = Union[int, None]
self.assertEqual(o, u)
self.assertIsInstance(42, o)
self.assertIsInstance(None, o)
self.assertNotIsInstance(3.14, o)
def test_empty(self):
with self.assertRaises(TypeError):
@ -321,11 +313,9 @@ class UnionTests(TestCase):
assert issubclass(Union[int, str], Union)
assert not issubclass(int, Union)
def test_isinstance_union(self):
# Nothing is an instance of bare Union.
assert not isinstance(42, Union)
assert not isinstance(int, Union)
assert not isinstance(Union[int, str], Union)
def test_union_instance_type_error(self):
with self.assertRaises(TypeError):
isinstance(42, Union[int, str])
class TypeVarUnionTests(TestCase):
@ -352,22 +342,11 @@ class TypeVarUnionTests(TestCase):
TU = TypeVar('TU', Union[int, float], None)
assert issubclass(int, TU)
assert issubclass(float, TU)
with self.assertRaises(TypeError):
isinstance(42, TU)
with self.assertRaises(TypeError):
isinstance('', TU)
class TupleTests(TestCase):
def test_basics(self):
self.assertIsInstance((42, 3.14, ''), Tuple)
self.assertIsInstance((42, 3.14, ''), Tuple[int, float, str])
self.assertIsInstance((42,), Tuple[int])
self.assertNotIsInstance((3.14,), Tuple[int])
self.assertNotIsInstance((42, 3.14), Tuple[int, float, str])
self.assertNotIsInstance((42, 3.14, 100), Tuple[int, float, str])
self.assertNotIsInstance((42, 3.14, 100), Tuple[int, float])
self.assertTrue(issubclass(Tuple[int, str], Tuple))
self.assertTrue(issubclass(Tuple[int, str], Tuple[int, str]))
self.assertFalse(issubclass(int, Tuple))
@ -382,14 +361,11 @@ class TupleTests(TestCase):
pass
self.assertTrue(issubclass(MyTuple, Tuple))
def test_tuple_ellipsis(self):
t = Tuple[int, ...]
assert isinstance((), t)
assert isinstance((1,), t)
assert isinstance((1, 2), t)
assert isinstance((1, 2, 3), t)
assert not isinstance((3.14,), t)
assert not isinstance((1, 2, 3.14,), t)
def test_tuple_instance_type_error(self):
with self.assertRaises(TypeError):
isinstance((0, 0), Tuple[int, int])
with self.assertRaises(TypeError):
isinstance((0, 0), Tuple)
def test_tuple_ellipsis_subclass(self):
@ -419,18 +395,6 @@ class TupleTests(TestCase):
class CallableTests(TestCase):
def test_basics(self):
c = Callable[[int, float], str]
def flub(a: int, b: float) -> str:
return str(a * b)
def flob(a: int, b: int) -> str:
return str(a * b)
self.assertIsInstance(flub, c)
self.assertNotIsInstance(flob, c)
def test_self_subclass(self):
self.assertTrue(issubclass(Callable[[int], int], Callable))
self.assertFalse(issubclass(Callable, Callable[[int], int]))
@ -453,91 +417,6 @@ class CallableTests(TestCase):
self.assertNotEqual(Callable[[int], int], Callable[[], int])
self.assertNotEqual(Callable[[int], int], Callable)
def test_with_none(self):
c = Callable[[None], None]
def flub(self: None) -> None:
pass
def flab(self: Any) -> None:
pass
def flob(self: None) -> Any:
pass
self.assertIsInstance(flub, c)
self.assertIsInstance(flab, c)
self.assertNotIsInstance(flob, c) # Test contravariance.
def test_with_subclasses(self):
c = Callable[[Employee, Manager], Employee]
def flub(a: Employee, b: Employee) -> Manager:
return Manager()
def flob(a: Manager, b: Manager) -> Employee:
return Employee()
self.assertIsInstance(flub, c)
self.assertNotIsInstance(flob, c)
def test_with_default_args(self):
c = Callable[[int], int]
def flub(a: int, b: float = 3.14) -> int:
return a
def flab(a: int, *, b: float = 3.14) -> int:
return a
def flob(a: int = 42) -> int:
return a
self.assertIsInstance(flub, c)
self.assertIsInstance(flab, c)
self.assertIsInstance(flob, c)
def test_with_varargs(self):
c = Callable[[int], int]
def flub(*args) -> int:
return 42
def flab(*args: int) -> int:
return 42
def flob(*args: float) -> int:
return 42
self.assertIsInstance(flub, c)
self.assertIsInstance(flab, c)
self.assertNotIsInstance(flob, c)
def test_with_method(self):
class C:
def imethod(self, arg: int) -> int:
self.last_arg = arg
return arg + 1
@classmethod
def cmethod(cls, arg: int) -> int:
cls.last_cls_arg = arg
return arg + 1
@staticmethod
def smethod(arg: int) -> int:
return arg + 1
ct = Callable[[int], int]
self.assertIsInstance(C().imethod, ct)
self.assertIsInstance(C().cmethod, ct)
self.assertIsInstance(C.cmethod, ct)
self.assertIsInstance(C().smethod, ct)
self.assertIsInstance(C.smethod, ct)
self.assertIsInstance(C.imethod, Callable[[Any, int], int])
def test_cannot_subclass(self):
with self.assertRaises(TypeError):
@ -556,21 +435,21 @@ class CallableTests(TestCase):
with self.assertRaises(TypeError):
c()
def test_varargs(self):
ct = Callable[..., int]
def test_callable_instance_works(self):
f = lambda: None
assert isinstance(f, Callable)
assert not isinstance(None, Callable)
def foo(a, b) -> int:
return 42
def bar(a=42) -> int:
return a
def baz(*, x, y, z) -> int:
return 100
self.assertIsInstance(foo, ct)
self.assertIsInstance(bar, ct)
self.assertIsInstance(baz, ct)
def test_callable_instance_type_error(self):
f = lambda: None
with self.assertRaises(TypeError):
assert isinstance(f, Callable[[], None])
with self.assertRaises(TypeError):
assert isinstance(f, Callable[[], Any])
with self.assertRaises(TypeError):
assert not isinstance(None, Callable[[], None])
with self.assertRaises(TypeError):
assert not isinstance(None, Callable[[], Any])
def test_repr(self):
ct0 = Callable[[], bool]
@ -659,6 +538,10 @@ class ProtocolTests(TestCase):
assert issubclass(list, typing.Reversible)
assert not issubclass(int, typing.Reversible)
def test_protocol_instance_type_error(self):
with self.assertRaises(TypeError):
isinstance([], typing.Reversible)
class GenericTests(TestCase):
@ -889,6 +772,11 @@ class ForwardRefTests(TestCase):
right_hints = get_type_hints(t.add_right, globals(), locals())
assert right_hints['node'] == Optional[Node[T]]
def test_forwardref_instance_type_error(self):
fr = typing._ForwardRef('int')
with self.assertRaises(TypeError):
isinstance(42, fr)
def test_union_forward(self):
def foo(a: Union['T']):
@ -1069,50 +957,17 @@ class CollectionsAbcTests(TestCase):
def test_list(self):
assert issubclass(list, typing.List)
assert isinstance([], typing.List)
assert not isinstance((), typing.List)
t = typing.List[int]
assert isinstance([], t)
assert isinstance([42], t)
assert not isinstance([''], t)
def test_set(self):
assert issubclass(set, typing.Set)
assert not issubclass(frozenset, typing.Set)
assert isinstance(set(), typing.Set)
assert not isinstance({}, typing.Set)
t = typing.Set[int]
assert isinstance(set(), t)
assert isinstance({42}, t)
assert not isinstance({''}, t)
def test_frozenset(self):
assert issubclass(frozenset, typing.FrozenSet)
assert not issubclass(set, typing.FrozenSet)
assert isinstance(frozenset(), typing.FrozenSet)
assert not isinstance({}, typing.FrozenSet)
t = typing.FrozenSet[int]
assert isinstance(frozenset(), t)
assert isinstance(frozenset({42}), t)
assert not isinstance(frozenset({''}), t)
assert not isinstance({42}, t)
def test_mapping_views(self):
# TODO: These tests are kind of lame.
assert isinstance({}.keys(), typing.KeysView)
assert isinstance({}.items(), typing.ItemsView)
assert isinstance({}.values(), typing.ValuesView)
def test_dict(self):
assert issubclass(dict, typing.Dict)
assert isinstance({}, typing.Dict)
assert not isinstance([], typing.Dict)
t = typing.Dict[int, str]
assert isinstance({}, t)
assert isinstance({42: ''}, t)
assert not isinstance({42: 42}, t)
assert not isinstance({'': 42}, t)
assert not isinstance({'': ''}, t)
def test_no_list_instantiation(self):
with self.assertRaises(TypeError):
@ -1191,8 +1046,6 @@ class CollectionsAbcTests(TestCase):
yield 42
g = foo()
assert issubclass(type(g), typing.Generator)
assert isinstance(g, typing.Generator)
assert not isinstance(foo, typing.Generator)
assert issubclass(typing.Generator[Manager, Employee, Manager],
typing.Generator[Employee, Manager, Employee])
assert not issubclass(typing.Generator[Manager, Manager, Manager],
@ -1228,12 +1081,6 @@ class CollectionsAbcTests(TestCase):
assert len(MMB[str, str]()) == 0
assert len(MMB[KT, VT]()) == 0
def test_recursive_dict(self):
D = typing.Dict[int, 'D'] # Uses a _ForwardRef
assert isinstance({}, D) # Easy
assert isinstance({0: {}}, D) # Touches _ForwardRef
assert isinstance({0: {0: {}}}, D) # Etc...
class NamedTupleTests(TestCase):
@ -1294,8 +1141,6 @@ class RETests(TestCase):
def test_basics(self):
pat = re.compile('[a-z]+', re.I)
assert issubclass(pat.__class__, Pattern)
assert isinstance(pat, Pattern[str])
assert not isinstance(pat, Pattern[bytes])
assert issubclass(type(pat), Pattern)
assert issubclass(type(pat), Pattern[str])
@ -1307,12 +1152,10 @@ class RETests(TestCase):
assert issubclass(type(mat), Match[str])
p = Pattern[Union[str, bytes]]
assert isinstance(pat, p)
assert issubclass(Pattern[str], Pattern)
assert issubclass(Pattern[str], p)
m = Match[Union[bytes, str]]
assert isinstance(mat, m)
assert issubclass(Match[bytes], Match)
assert issubclass(Match[bytes], m)
@ -1327,6 +1170,12 @@ class RETests(TestCase):
with self.assertRaises(TypeError):
# Too complicated?
m[str]
with self.assertRaises(TypeError):
# We don't support isinstance().
isinstance(42, Pattern)
with self.assertRaises(TypeError):
# We don't support isinstance().
isinstance(42, Pattern[str])
def test_repr(self):
assert repr(Pattern) == 'Pattern[~AnyStr]'

View File

@ -176,6 +176,9 @@ class _ForwardRef(TypingMeta):
self.__forward_evaluated__ = True
return self.__forward_value__
def __instancecheck__(self, obj):
raise TypeError("Forward references cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if not self.__forward_evaluated__:
globalns = self.__forward_frame__.f_globals
@ -186,16 +189,6 @@ class _ForwardRef(TypingMeta):
return False # Too early.
return issubclass(cls, self.__forward_value__)
def __instancecheck__(self, obj):
if not self.__forward_evaluated__:
globalns = self.__forward_frame__.f_globals
localns = self.__forward_frame__.f_locals
try:
self._eval_type(globalns, localns)
except NameError:
return False # Too early.
return isinstance(obj, self.__forward_value__)
def __repr__(self):
return '_ForwardRef(%r)' % (self.__forward_arg__,)
@ -259,8 +252,7 @@ class _TypeAlias:
self.impl_type, self.type_checker)
def __instancecheck__(self, obj):
return (isinstance(obj, self.impl_type) and
isinstance(self.type_checker(obj), self.type_var))
raise TypeError("Type aliases cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if cls is Any:
@ -332,8 +324,8 @@ class AnyMeta(TypingMeta):
self = super().__new__(cls, name, bases, namespace, _root=_root)
return self
def __instancecheck__(self, instance):
return True
def __instancecheck__(self, obj):
raise TypeError("Any cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if not isinstance(cls, type):
@ -548,9 +540,8 @@ class UnionMeta(TypingMeta):
def __hash__(self):
return hash(self.__union_set_params__)
def __instancecheck__(self, instance):
return (self.__union_set_params__ is not None and
any(isinstance(instance, t) for t in self.__union_params__))
def __instancecheck__(self, obj):
raise TypeError("Unions cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if cls is Any:
@ -709,18 +700,8 @@ class TupleMeta(TypingMeta):
def __hash__(self):
return hash(self.__tuple_params__)
def __instancecheck__(self, t):
if not isinstance(t, tuple):
return False
if self.__tuple_params__ is None:
return True
if self.__tuple_use_ellipsis__:
p = self.__tuple_params__[0]
return all(isinstance(x, p) for x in t)
else:
return (len(t) == len(self.__tuple_params__) and
all(isinstance(x, p)
for x, p in zip(t, self.__tuple_params__)))
def __instancecheck__(self, obj):
raise TypeError("Tuples cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if cls is Any:
@ -826,57 +807,14 @@ class CallableMeta(TypingMeta):
def __hash__(self):
return hash(self.__args__) ^ hash(self.__result__)
def __instancecheck__(self, instance):
if not callable(instance):
return False
def __instancecheck__(self, obj):
# For unparametrized Callable we allow this, because
# typing.Callable should be equivalent to
# collections.abc.Callable.
if self.__args__ is None and self.__result__ is None:
return True
assert self.__args__ is not None
assert self.__result__ is not None
my_args, my_result = self.__args__, self.__result__
import inspect # TODO: Avoid this import.
# Would it be better to use Signature objects?
try:
(args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults,
annotations) = inspect.getfullargspec(instance)
except TypeError:
return False # We can't find the signature. Give up.
msg = ("When testing isinstance(<callable>, Callable[...], "
"<calleble>'s annotations must be types.")
if my_args is not Ellipsis:
if kwonlyargs and (not kwonlydefaults or
len(kwonlydefaults) < len(kwonlyargs)):
return False
if isinstance(instance, types.MethodType):
# For methods, getfullargspec() includes self/cls,
# but it's not part of the call signature, so drop it.
del args[0]
min_call_args = len(args)
if defaults:
min_call_args -= len(defaults)
if varargs:
max_call_args = 999999999
if len(args) < len(my_args):
args += [varargs] * (len(my_args) - len(args))
else:
max_call_args = len(args)
if not min_call_args <= len(my_args) <= max_call_args:
return False
for my_arg_type, name in zip(my_args, args):
if name in annotations:
annot_type = _type_check(annotations[name], msg)
else:
annot_type = Any
if not issubclass(my_arg_type, annot_type):
return False
# TODO: If mutable type, check invariance?
if 'return' in annotations:
annot_return_type = _type_check(annotations['return'], msg)
# Note contravariance here!
if not issubclass(annot_return_type, my_result):
return False
# Can't find anything wrong...
return True
return isinstance(obj, collections_abc.Callable)
else:
raise TypeError("Callable[] cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if cls is Any:
@ -1073,13 +1011,6 @@ class GenericMeta(TypingMeta, abc.ABCMeta):
return False
return issubclass(cls, self.__extra__)
def __instancecheck__(self, obj):
if super().__instancecheck__(obj):
return True
if self.__extra__ is None:
return False
return isinstance(obj, self.__extra__)
class Generic(metaclass=GenericMeta):
"""Abstract base class for generic types.
@ -1234,6 +1165,9 @@ class _ProtocolMeta(GenericMeta):
from Generic.
"""
def __instancecheck__(self, obj):
raise TypeError("Protocols cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if not self._is_protocol:
# No structural checks since this isn't a protocol.
@ -1399,19 +1333,7 @@ class ByteString(Sequence[int], extra=collections_abc.ByteString):
ByteString.register(type(memoryview(b'')))
class _ListMeta(GenericMeta):
def __instancecheck__(self, obj):
if not super().__instancecheck__(obj):
return False
itemtype = self.__parameters__[0]
for x in obj:
if not isinstance(x, itemtype):
return False
return True
class List(list, MutableSequence[T], metaclass=_ListMeta):
class List(list, MutableSequence[T]):
def __new__(cls, *args, **kwds):
if _geqv(cls, List):
@ -1420,19 +1342,7 @@ class List(list, MutableSequence[T], metaclass=_ListMeta):
return list.__new__(cls, *args, **kwds)
class _SetMeta(GenericMeta):
def __instancecheck__(self, obj):
if not super().__instancecheck__(obj):
return False
itemtype = self.__parameters__[0]
for x in obj:
if not isinstance(x, itemtype):
return False
return True
class Set(set, MutableSet[T], metaclass=_SetMeta):
class Set(set, MutableSet[T]):
def __new__(cls, *args, **kwds):
if _geqv(cls, Set):
@ -1441,7 +1351,7 @@ class Set(set, MutableSet[T], metaclass=_SetMeta):
return set.__new__(cls, *args, **kwds)
class _FrozenSetMeta(_SetMeta):
class _FrozenSetMeta(GenericMeta):
"""This metaclass ensures set is not a subclass of FrozenSet.
Without this metaclass, set would be considered a subclass of
@ -1454,11 +1364,6 @@ class _FrozenSetMeta(_SetMeta):
return False
return super().__subclasscheck__(cls)
def __instancecheck__(self, obj):
if issubclass(obj.__class__, Set):
return False
return super().__instancecheck__(obj)
class FrozenSet(frozenset, AbstractSet[T_co], metaclass=_FrozenSetMeta):
@ -1488,20 +1393,7 @@ class ValuesView(MappingView[VT_co], extra=collections_abc.ValuesView):
pass
class _DictMeta(GenericMeta):
def __instancecheck__(self, obj):
if not super().__instancecheck__(obj):
return False
keytype, valuetype = self.__parameters__
for key, value in obj.items():
if not (isinstance(key, keytype) and
isinstance(value, valuetype)):
return False
return True
class Dict(dict, MutableMapping[KT, VT], metaclass=_DictMeta):
class Dict(dict, MutableMapping[KT, VT]):
def __new__(cls, *args, **kwds):
if _geqv(cls, Dict):