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Commit d911e40e authored by Ivan Levkivskyi's avatar Ivan Levkivskyi Committed by GitHub
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bpo-32226: PEP 560: improve typing module (#4906) 

This PR re-designs the internal typing API using the new PEP 560 features.
However, there are only few minor changes in the public API.
parent d57f26c7
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Showing with 804 additions and 1673 deletions
Lib/dataclasses.py
View file @ d911e40e
......@@ -389,7 +389,8 @@ def _get_field(cls, a_name, a_type):
if typing is not None:
# This test uses a typing internal class, but it's the best
# way to test if this is a ClassVar.
if type(a_type) is typing._ClassVar:
if (type(a_type) is typing._GenericAlias and
a_type.__origin__ is typing.ClassVar):
# This field is a ClassVar, so it's not a field.
f._field_type = _FIELD_CLASSVAR
......
Lib/test/libregrtest/refleak.py
View file @ d911e40e
......@@ -135,11 +135,6 @@ def dash_R_cleanup(fs, ps, pic, zdc, abcs):
# Clear ABC registries, restoring previously saved ABC registries.
abs_classes = [getattr(collections.abc, a) for a in collections.abc.__all__]
abs_classes = filter(isabstract, abs_classes)
if 'typing' in sys.modules:
t = sys.modules['typing']
# These classes require special treatment because they do not appear
# in direct subclasses of collections.abc classes
abs_classes = list(abs_classes) + [t.ChainMap, t.Counter, t.DefaultDict]
for abc in abs_classes:
for obj in abc.__subclasses__() + [abc]:
obj._abc_registry = abcs.get(obj, WeakSet()).copy()
......
Lib/test/test_pydoc.py
View file @ d911e40e
......@@ -827,7 +827,7 @@ class TestDescriptions(unittest.TestCase):
'f\x08fo\x08oo\x08o(data: List[Any], x: int)'
' -> Iterator[Tuple[int, Any]]')
self.assertEqual(pydoc.render_doc(C).splitlines()[2],
'class C\x08C(typing.Mapping)')
'class C\x08C(collections.abc.Mapping, typing.Generic)')
def test_builtin(self):
for name in ('str', 'str.translate', 'builtins.str',
......
Lib/test/test_typing.py
View file @ d911e40e
......@@ -12,7 +12,7 @@ from typing import T, KT, VT # Not in __all__.
from typing import Union, Optional
from typing import Tuple, List, MutableMapping
from typing import Callable
from typing import Generic, ClassVar, GenericMeta
from typing import Generic, ClassVar
from typing import cast
from typing import get_type_hints
from typing import no_type_check, no_type_check_decorator
......@@ -24,20 +24,8 @@ from typing import Pattern, Match
import abc
import typing
import weakref
try:
import collections.abc as collections_abc
except ImportError:
import collections as collections_abc # Fallback for PY3.2.
try:
import mod_generics_cache
except ImportError:
# try to use the builtin one, Python 3.5+
from test import mod_generics_cache
PY36 = sys.version_info[:2] >= (3, 6)
from test import mod_generics_cache
class BaseTestCase(TestCase):
......@@ -606,7 +594,10 @@ class GenericTests(BaseTestCase):
Y[str]
with self.assertRaises(TypeError):
Y[str, str]
self.assertIsSubclass(SimpleMapping[str, int], SimpleMapping)
SM1 = SimpleMapping[str, int]
with self.assertRaises(TypeError):
issubclass(SM1, SimpleMapping)
self.assertIsInstance(SM1(), SimpleMapping)
def test_generic_errors(self):
T = TypeVar('T')
......@@ -617,6 +608,8 @@ class GenericTests(BaseTestCase):
Generic[T][T]
with self.assertRaises(TypeError):
Generic[T][S]
with self.assertRaises(TypeError):
class C(Generic[T], Generic[T]): ...
with self.assertRaises(TypeError):
isinstance([], List[int])
with self.assertRaises(TypeError):
......@@ -636,7 +629,6 @@ class GenericTests(BaseTestCase):
with self.assertRaises(TypeError):
Generic[T, S, T]
@skipUnless(PY36, "__init_subclass__ support required")
def test_init_subclass(self):
class X(typing.Generic[T]):
def __init_subclass__(cls, **kwargs):
......@@ -659,9 +651,9 @@ class GenericTests(BaseTestCase):
def test_repr(self):
self.assertEqual(repr(SimpleMapping),
__name__ + '.' + 'SimpleMapping')
"<class 'test.test_typing.SimpleMapping'>")
self.assertEqual(repr(MySimpleMapping),
__name__ + '.' + 'MySimpleMapping')
"<class 'test.test_typing.MySimpleMapping'>")
def test_chain_repr(self):
T = TypeVar('T')
......@@ -713,7 +705,7 @@ class GenericTests(BaseTestCase):
def test_new_repr_bare(self):
T = TypeVar('T')
self.assertEqual(repr(Generic[T]), 'typing.Generic[~T]')
self.assertEqual(repr(typing._Protocol[T]), 'typing.Protocol[~T]')
self.assertEqual(repr(typing._Protocol[T]), 'typing._Protocol[~T]')
class C(typing.Dict[Any, Any]): ...
# this line should just work
repr(C.__mro__)
......@@ -764,11 +756,13 @@ class GenericTests(BaseTestCase):
def test_abc_registry_kept(self):
T = TypeVar('T')
class C(Generic[T]): ...
class C(collections.abc.Mapping, Generic[T]): ...
C.register(int)
self.assertIsInstance(1, C)
C[int]
self.assertIsInstance(1, C)
C._abc_registry.clear()
C._abc_cache.clear() # To keep refleak hunting mode clean
def test_false_subclasses(self):
class MyMapping(MutableMapping[str, str]): pass
......@@ -789,18 +783,17 @@ class GenericTests(BaseTestCase):
return 0
# this should just work
MM().update()
self.assertIsInstance(MM(), collections_abc.MutableMapping)
self.assertIsInstance(MM(), collections.abc.MutableMapping)
self.assertIsInstance(MM(), MutableMapping)
self.assertNotIsInstance(MM(), List)
self.assertNotIsInstance({}, MM)
def test_multiple_bases(self):
class MM1(MutableMapping[str, str], collections_abc.MutableMapping):
class MM1(MutableMapping[str, str], collections.abc.MutableMapping):
pass
with self.assertRaises(TypeError):
# consistent MRO not possible
class MM2(collections_abc.MutableMapping, MutableMapping[str, str]):
pass
class MM2(collections.abc.MutableMapping, MutableMapping[str, str]):
pass
self.assertEqual(MM2.__bases__, (collections.abc.MutableMapping, Generic))
def test_orig_bases(self):
T = TypeVar('T')
......@@ -855,16 +848,17 @@ class GenericTests(BaseTestCase):
self.assertEqual(D[int].__parameters__, ())
self.assertEqual(C[int].__args__, (int,))
self.assertEqual(D[int].__args__, (int,))
self.assertEqual(C.__bases__, (List,))
self.assertEqual(D.__bases__, (C, List))
self.assertEqual(C.__bases__, (list, Generic))
self.assertEqual(D.__bases__, (C, list, Generic))
self.assertEqual(C.__orig_bases__, (List[T][U][V],))
self.assertEqual(D.__orig_bases__, (C, List[T][U][V]))
def test_subscript_meta(self):
T = TypeVar('T')
self.assertEqual(Type[GenericMeta], Type[GenericMeta])
self.assertEqual(Union[T, int][GenericMeta], Union[GenericMeta, int])
self.assertEqual(Callable[..., GenericMeta].__args__, (Ellipsis, GenericMeta))
class Meta(type): ...
self.assertEqual(Type[Meta], Type[Meta])
self.assertEqual(Union[T, int][Meta], Union[Meta, int])
self.assertEqual(Callable[..., Meta].__args__, (Ellipsis, Meta))
def test_generic_hashes(self):
class A(Generic[T]):
......@@ -939,7 +933,7 @@ class GenericTests(BaseTestCase):
self.assertEqual(repr(Union[Tuple, Callable]).replace('typing.', ''),
'Union[Tuple, Callable]')
self.assertEqual(repr(Union[Tuple, Tuple[int]]).replace('typing.', ''),
'Tuple')
'Union[Tuple, Tuple[int]]')
self.assertEqual(repr(Callable[..., Optional[T]][int]).replace('typing.', ''),
'Callable[..., Union[int, NoneType]]')
self.assertEqual(repr(Callable[[], List[T]][int]).replace('typing.', ''),
......@@ -980,13 +974,15 @@ class GenericTests(BaseTestCase):
self.assertEqual(repr(C1[int]).split('.')[-1], 'C1[int]')
self.assertEqual(C2.__parameters__, ())
self.assertIsInstance(C2(), collections_abc.Callable)
self.assertIsSubclass(C2, collections_abc.Callable)
self.assertIsSubclass(C1, collections_abc.Callable)
self.assertIsInstance(C2(), collections.abc.Callable)
self.assertIsSubclass(C2, collections.abc.Callable)
self.assertIsSubclass(C1, collections.abc.Callable)
self.assertIsInstance(T1(), tuple)
self.assertIsSubclass(T2, tuple)
self.assertIsSubclass(Tuple[int, ...], typing.Sequence)
self.assertIsSubclass(Tuple[int, ...], typing.Iterable)
with self.assertRaises(TypeError):
issubclass(Tuple[int, ...], typing.Sequence)
with self.assertRaises(TypeError):
issubclass(Tuple[int, ...], typing.Iterable)
def test_fail_with_bare_union(self):
with self.assertRaises(TypeError):
......@@ -1006,8 +1002,6 @@ class GenericTests(BaseTestCase):
Tuple[Generic[T]]
with self.assertRaises(TypeError):
List[typing._Protocol]
with self.assertRaises(TypeError):
isinstance(1, Generic)
def test_type_erasure_special(self):
T = TypeVar('T')
......@@ -1044,21 +1038,6 @@ class GenericTests(BaseTestCase):
self.assertNotEqual(repr(base), '')
self.assertEqual(base, base)
def test_substitution_helper(self):
T = TypeVar('T')
KT = TypeVar('KT')
VT = TypeVar('VT')
class Map(Generic[KT, VT]):
def meth(self, k: KT, v: VT): ...
StrMap = Map[str, T]
obj = StrMap[int]()
new_args = typing._subs_tree(obj.__orig_class__)
new_annots = {k: typing._replace_arg(v, type(obj).__parameters__, new_args)
for k, v in obj.meth.__annotations__.items()}
self.assertEqual(new_annots, {'k': str, 'v': int})
def test_pickle(self):
global C # pickle wants to reference the class by name
T = TypeVar('T')
......@@ -1078,12 +1057,20 @@ class GenericTests(BaseTestCase):
self.assertEqual(x.foo, 42)
self.assertEqual(x.bar, 'abc')
self.assertEqual(x.__dict__, {'foo': 42, 'bar': 'abc'})
simples = [Any, Union, Tuple, Callable, ClassVar, List, typing.Iterable]
for s in simples:
samples = [Any, Union, Tuple, Callable, ClassVar]
for s in samples:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
z = pickle.dumps(s, proto)
x = pickle.loads(z)
self.assertEqual(s, x)
more_samples = [List, typing.Iterable, typing.Type]
for s in more_samples:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
z = pickle.dumps(s, proto)
x = pickle.loads(z)
self.assertEqual(repr(s), repr(x)) # TODO: fix this
# see also comment in test_copy_and_deepcopy
# the issue is typing/#512
def test_copy_and_deepcopy(self):
T = TypeVar('T')
......@@ -1095,14 +1082,7 @@ class GenericTests(BaseTestCase):
Union['T', int], List['T'], typing.Mapping['T', int]]
for t in things + [Any]:
self.assertEqual(t, copy(t))
self.assertEqual(t, deepcopy(t))
if sys.version_info >= (3, 3):
# From copy module documentation:
# It does "copy" functions and classes (shallow and deeply), by returning
# the original object unchanged; this is compatible with the way these
# are treated by the pickle module.
self.assertTrue(t is copy(t))
self.assertTrue(t is deepcopy(t))
self.assertEqual(repr(t), repr(deepcopy(t))) # Use repr() because of TypeVars
def test_copy_generic_instances(self):
T = TypeVar('T')
......@@ -1143,7 +1123,6 @@ class GenericTests(BaseTestCase):
c = C()
c_int = C[int]()
self.assertEqual(C.__slots__, C[str].__slots__)
c.potato = 0
c_int.potato = 0
......@@ -1154,8 +1133,6 @@ class GenericTests(BaseTestCase):
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):
......@@ -1165,7 +1142,6 @@ class GenericTests(BaseTestCase):
d = D()
d_int = D[int]()
self.assertEqual(D.__slots__, D[str].__slots__)
d.banana = 'yes'
d_int.banana = 'yes'
......@@ -1182,30 +1158,22 @@ class GenericTests(BaseTestCase):
pass
def test_repr_2(self):
PY32 = sys.version_info[:2] < (3, 3)
class C(Generic[T]):
pass
self.assertEqual(C.__module__, __name__)
if not PY32:
self.assertEqual(C.__qualname__,
'GenericTests.test_repr_2.<locals>.C')
self.assertEqual(repr(C).split('.')[-1], 'C')
self.assertEqual(C.__qualname__,
'GenericTests.test_repr_2.<locals>.C')
X = C[int]
self.assertEqual(X.__module__, __name__)
if not PY32:
self.assertTrue(X.__qualname__.endswith('.<locals>.C'))
self.assertEqual(repr(X).split('.')[-1], 'C[int]')
class Y(C[int]):
pass
self.assertEqual(Y.__module__, __name__)
if not PY32:
self.assertEqual(Y.__qualname__,
'GenericTests.test_repr_2.<locals>.Y')
self.assertEqual(repr(Y).split('.')[-1], 'Y')
self.assertEqual(Y.__qualname__,
'GenericTests.test_repr_2.<locals>.Y')
def test_eq_1(self):
self.assertEqual(Generic, Generic)
......@@ -1238,6 +1206,12 @@ class GenericTests(BaseTestCase):
self.assertEqual(C.__parameters__, (VT, T, KT))
def test_multiple_inheritance_special(self):
S = TypeVar('S')
class B(Generic[S]): ...
class C(List[int], B): ...
self.assertEqual(C.__mro__, (C, list, B, Generic, object))
def test_nested(self):
G = Generic
......@@ -1408,22 +1382,22 @@ class ForwardRefTests(BaseTestCase):
self.assertEqual(right_hints['node'], Optional[Node[T]])
def test_forwardref_instance_type_error(self):
fr = typing._ForwardRef('int')
fr = typing.ForwardRef('int')
with self.assertRaises(TypeError):
isinstance(42, fr)
def test_forwardref_subclass_type_error(self):
fr = typing._ForwardRef('int')
fr = typing.ForwardRef('int')
with self.assertRaises(TypeError):
issubclass(int, fr)
def test_forward_equality(self):
fr = typing._ForwardRef('int')
self.assertEqual(fr, typing._ForwardRef('int'))
fr = typing.ForwardRef('int')
self.assertEqual(fr, typing.ForwardRef('int'))
self.assertNotEqual(List['int'], List[int])
def test_forward_repr(self):
self.assertEqual(repr(List['int']), "typing.List[_ForwardRef('int')]")
self.assertEqual(repr(List['int']), "typing.List[ForwardRef('int')]")
def test_union_forward(self):
......@@ -1579,8 +1553,6 @@ class OverloadTests(BaseTestCase):
blah()
ASYNCIO = sys.version_info[:2] >= (3, 5)
ASYNCIO_TESTS = """
import asyncio
......@@ -1618,17 +1590,15 @@ class ACM:
return None
"""
if ASYNCIO:
try:
exec(ASYNCIO_TESTS)
except ImportError:
ASYNCIO = False
try:
exec(ASYNCIO_TESTS)
except ImportError:
ASYNCIO = False # multithreading is not enabled
else:
# fake names for the sake of static analysis
asyncio = None
AwaitableWrapper = AsyncIteratorWrapper = ACM = object
ASYNCIO = True
# Definitions needed for features introduced in Python 3.6
PY36_TESTS = """
from test import ann_module, ann_module2, ann_module3
from typing import AsyncContextManager
......@@ -1681,15 +1651,6 @@ try:
g_with(ACM()).send(None)
except StopIteration as e:
assert e.args[0] == 42
"""
if PY36:
exec(PY36_TESTS)
else:
# fake names for the sake of static analysis
ann_module = ann_module2 = ann_module3 = None
A = B = CSub = G = CoolEmployee = CoolEmployeeWithDefault = object
XMeth = XRepr = NoneAndForward = object
gth = get_type_hints
......@@ -1704,14 +1665,12 @@ class GetTypeHintTests(BaseTestCase):
with self.assertRaises(TypeError):
gth(None)
@skipUnless(PY36, 'Python 3.6 required')
def test_get_type_hints_modules(self):
ann_module_type_hints = {1: 2, 'f': Tuple[int, int], 'x': int, 'y': str}
self.assertEqual(gth(ann_module), ann_module_type_hints)
self.assertEqual(gth(ann_module2), {})
self.assertEqual(gth(ann_module3), {})
@skipUnless(PY36, 'Python 3.6 required')
@expectedFailure
def test_get_type_hints_modules_forwardref(self):
# FIXME: This currently exposes a bug in typing. Cached forward references
......@@ -1721,7 +1680,6 @@ class GetTypeHintTests(BaseTestCase):
'default_b': Optional[mod_generics_cache.B]}
self.assertEqual(gth(mod_generics_cache), mgc_hints)
@skipUnless(PY36, 'Python 3.6 required')
def test_get_type_hints_classes(self):
self.assertEqual(gth(ann_module.C), # gth will find the right globalns
{'y': Optional[ann_module.C]})
......@@ -1744,7 +1702,6 @@ class GetTypeHintTests(BaseTestCase):
'my_inner_a2': mod_generics_cache.B.A,
'my_outer_a': mod_generics_cache.A})
@skipUnless(PY36, 'Python 3.6 required')
def test_respect_no_type_check(self):
@no_type_check
class NoTpCheck:
......@@ -1783,7 +1740,6 @@ class GetTypeHintTests(BaseTestCase):
b.__annotations__ = {'x': 'A'}
self.assertEqual(gth(b, locals()), {'x': A})
@skipUnless(PY36, 'Python 3.6 required')
def test_get_type_hints_ClassVar(self):
self.assertEqual(gth(ann_module2.CV, ann_module2.__dict__),
{'var': typing.ClassVar[ann_module2.CV]})
......@@ -2082,7 +2038,6 @@ class CollectionsAbcTests(BaseTestCase):
with self.assertRaises(TypeError):
typing.Generator[int, int, int]()
@skipUnless(PY36, 'Python 3.6 required')
def test_async_generator(self):
ns = {}
exec("async def f():\n"
......@@ -2090,7 +2045,6 @@ class CollectionsAbcTests(BaseTestCase):
g = ns['f']()
self.assertIsSubclass(type(g), typing.AsyncGenerator)
@skipUnless(PY36, 'Python 3.6 required')
def test_no_async_generator_instantiation(self):
with self.assertRaises(TypeError):
typing.AsyncGenerator()
......@@ -2147,13 +2101,14 @@ class CollectionsAbcTests(BaseTestCase):
self.assertIsSubclass(MMC, typing.Mapping)
self.assertIsInstance(MMB[KT, VT](), typing.Mapping)
self.assertIsInstance(MMB[KT, VT](), collections_abc.Mapping)
self.assertIsInstance(MMB[KT, VT](), collections.abc.Mapping)
self.assertIsSubclass(MMA, collections_abc.Mapping)
self.assertIsSubclass(MMB, collections_abc.Mapping)
self.assertIsSubclass(MMC, collections_abc.Mapping)
self.assertIsSubclass(MMA, collections.abc.Mapping)
self.assertIsSubclass(MMB, collections.abc.Mapping)
self.assertIsSubclass(MMC, collections.abc.Mapping)
self.assertIsSubclass(MMB[str, str], typing.Mapping)
with self.assertRaises(TypeError):
issubclass(MMB[str, str], typing.Mapping)
self.assertIsSubclass(MMC, MMA)
class I(typing.Iterable): ...
......@@ -2163,12 +2118,10 @@ class CollectionsAbcTests(BaseTestCase):
def g(): yield 0
self.assertIsSubclass(G, typing.Generator)
self.assertIsSubclass(G, typing.Iterable)
if hasattr(collections_abc, 'Generator'):
self.assertIsSubclass(G, collections_abc.Generator)
self.assertIsSubclass(G, collections_abc.Iterable)
self.assertIsSubclass(G, collections.abc.Generator)
self.assertIsSubclass(G, collections.abc.Iterable)
self.assertNotIsSubclass(type(g), G)
@skipUnless(PY36, 'Python 3.6 required')
def test_subclassing_async_generator(self):
class G(typing.AsyncGenerator[int, int]):
def asend(self, value):
......@@ -2181,15 +2134,15 @@ class CollectionsAbcTests(BaseTestCase):
g = ns['g']
self.assertIsSubclass(G, typing.AsyncGenerator)
self.assertIsSubclass(G, typing.AsyncIterable)
self.assertIsSubclass(G, collections_abc.AsyncGenerator)
self.assertIsSubclass(G, collections_abc.AsyncIterable)
self.assertIsSubclass(G, collections.abc.AsyncGenerator)
self.assertIsSubclass(G, collections.abc.AsyncIterable)
self.assertNotIsSubclass(type(g), G)
instance = G()
self.assertIsInstance(instance, typing.AsyncGenerator)
self.assertIsInstance(instance, typing.AsyncIterable)
self.assertIsInstance(instance, collections_abc.AsyncGenerator)
self.assertIsInstance(instance, collections_abc.AsyncIterable)
self.assertIsInstance(instance, collections.abc.AsyncGenerator)
self.assertIsInstance(instance, collections.abc.AsyncIterable)
self.assertNotIsInstance(type(g), G)
self.assertNotIsInstance(g, G)
......@@ -2226,23 +2179,23 @@ class CollectionsAbcTests(BaseTestCase):
self.assertIsSubclass(D, B)
class M(): ...
collections_abc.MutableMapping.register(M)
collections.abc.MutableMapping.register(M)
self.assertIsSubclass(M, typing.Mapping)
def test_collections_as_base(self):
class M(collections_abc.Mapping): ...
class M(collections.abc.Mapping): ...
self.assertIsSubclass(M, typing.Mapping)
self.assertIsSubclass(M, typing.Iterable)
class S(collections_abc.MutableSequence): ...
class S(collections.abc.MutableSequence): ...
self.assertIsSubclass(S, typing.MutableSequence)
self.assertIsSubclass(S, typing.Iterable)
class I(collections_abc.Iterable): ...
class I(collections.abc.Iterable): ...
self.assertIsSubclass(I, typing.Iterable)
class A(collections_abc.Mapping, metaclass=abc.ABCMeta): ...
class A(collections.abc.Mapping, metaclass=abc.ABCMeta): ...
class B: ...
A.register(B)
self.assertIsSubclass(B, typing.Mapping)
......@@ -2363,7 +2316,6 @@ class NamedTupleTests(BaseTestCase):
class NotYet(NamedTuple):
whatever = 0
@skipUnless(PY36, 'Python 3.6 required')
def test_annotation_usage(self):
tim = CoolEmployee('Tim', 9000)
self.assertIsInstance(tim, CoolEmployee)
......@@ -2376,7 +2328,6 @@ class NamedTupleTests(BaseTestCase):
collections.OrderedDict(name=str, cool=int))
self.assertIs(CoolEmployee._field_types, CoolEmployee.__annotations__)
@skipUnless(PY36, 'Python 3.6 required')
def test_annotation_usage_with_default(self):
jelle = CoolEmployeeWithDefault('Jelle')
self.assertIsInstance(jelle, CoolEmployeeWithDefault)
......@@ -2398,7 +2349,6 @@ class NonDefaultAfterDefault(NamedTuple):
y: int
""")
@skipUnless(PY36, 'Python 3.6 required')
def test_annotation_usage_with_methods(self):
self.assertEqual(XMeth(1).double(), 2)
self.assertEqual(XMeth(42).x, XMeth(42)[0])
......@@ -2421,7 +2371,6 @@ class XMethBad2(NamedTuple):
return 'no chance for this as well'
""")
@skipUnless(PY36, 'Python 3.6 required')
def test_namedtuple_keyword_usage(self):
LocalEmployee = NamedTuple("LocalEmployee", name=str, age=int)
nick = LocalEmployee('Nick', 25)
......@@ -2506,15 +2455,8 @@ class RETests(BaseTestCase):
self.assertNotEqual(Pattern[str], str)
def test_errors(self):
with self.assertRaises(TypeError):
# Doesn't fit AnyStr.
Pattern[int]
with self.assertRaises(TypeError):
# Can't change type vars?
Match[T]
m = Match[Union[str, bytes]]
with self.assertRaises(TypeError):
# Too complicated?
m[str]
with self.assertRaises(TypeError):
# We don't support isinstance().
......@@ -2524,12 +2466,12 @@ class RETests(BaseTestCase):
issubclass(Pattern[bytes], Pattern[str])
def test_repr(self):
self.assertEqual(repr(Pattern), 'Pattern[~AnyStr]')
self.assertEqual(repr(Pattern[str]), 'Pattern[str]')
self.assertEqual(repr(Pattern[bytes]), 'Pattern[bytes]')
self.assertEqual(repr(Match), 'Match[~AnyStr]')
self.assertEqual(repr(Match[str]), 'Match[str]')
self.assertEqual(repr(Match[bytes]), 'Match[bytes]')
self.assertEqual(repr(Pattern), 'typing.Pattern')
self.assertEqual(repr(Pattern[str]), 'typing.Pattern[str]')
self.assertEqual(repr(Pattern[bytes]), 'typing.Pattern[bytes]')
self.assertEqual(repr(Match), 'typing.Match')
self.assertEqual(repr(Match[str]), 'typing.Match[str]')
self.assertEqual(repr(Match[bytes]), 'typing.Match[bytes]')
def test_re_submodule(self):
from typing.re import Match, Pattern, __all__, __name__
......@@ -2545,7 +2487,7 @@ class RETests(BaseTestCase):
pass
self.assertEqual(str(ex.exception),
"Cannot subclass typing._TypeAlias")
"type 're.Match' is not an acceptable base type")
class AllTests(BaseTestCase):
......
Lib/typing.py
View file @ d911e40e
"""
The typing module: Support for gradual typing as defined by PEP 484.
At large scale, the structure of the module is following:
* Imports and exports, all public names should be explicitelly added to __all__.
* Internal helper functions: these should never be used in code outside this module.
* _SpecialForm and its instances (special forms): Any, NoReturn, ClassVar, Union, Optional
* Two classes whose instances can be type arguments in addition to types: ForwardRef and TypeVar
* The core of internal generics API: _GenericAlias and _VariadicGenericAlias, the latter is
currently only used by Tuple and Callable. All subscripted types like X[int], Union[int, str],
etc., are instances of either of these classes.
* The public counterpart of the generics API consists of two classes: Generic and Protocol
(the latter is currently private, but will be made public after PEP 544 acceptance).
* Public helper functions: get_type_hints, overload, cast, no_type_check,
no_type_check_decorator.
* Generic aliases for collections.abc ABCs and few additional protocols.
* Special types: NewType, NamedTuple, TypedDict (may be added soon).
* Wrapper submodules for re and io related types.
"""
import abc
from abc import abstractmethod, abstractproperty
import collections
import collections.abc
import contextlib
import functools
import re as stdlib_re # Avoid confusion with the re we export.
import sys
import types
try:
import collections.abc as collections_abc
except ImportError:
import collections as collections_abc # Fallback for PY3.2.
if sys.version_info[:2] >= (3, 6):
import _collections_abc # Needed for private function _check_methods # noqa
try:
from types import WrapperDescriptorType, MethodWrapperType, MethodDescriptorType
except ImportError:
WrapperDescriptorType = type(object.__init__)
MethodWrapperType = type(object().__str__)
MethodDescriptorType = type(str.join)
from types import WrapperDescriptorType, MethodWrapperType, MethodDescriptorType
# Please keep __all__ alphabetized within each category.
__all__ = [
......@@ -35,8 +44,6 @@ __all__ = [
# ABCs (from collections.abc).
'AbstractSet', # collections.abc.Set.
'GenericMeta', # subclass of abc.ABCMeta and a metaclass
# for 'Generic' and ABCs below.
'ByteString',
'Container',
'ContextManager',
......@@ -53,15 +60,13 @@ __all__ = [
'Sequence',
'Sized',
'ValuesView',
# The following are added depending on presence
# of their non-generic counterparts in stdlib:
# Awaitable,
# AsyncIterator,
# AsyncIterable,
# Coroutine,
# Collection,
# AsyncGenerator,
# AsyncContextManager
'Awaitable',
'AsyncIterator',
'AsyncIterable',
'Coroutine',
'Collection',
'AsyncGenerator',
'AsyncContextManager',
# Structural checks, a.k.a. protocols.
'Reversible',
......@@ -100,70 +105,199 @@ __all__ = [
# legitimate imports of those modules.
def _qualname(x):
if sys.version_info[:2] >= (3, 3):
return x.__qualname__
else:
# Fall back to just name.
return x.__name__
def _type_check(arg, msg):
"""Check that the argument is a type, and return it (internal helper).
As a special case, accept None and return type(None) instead. Also wrap strings
into ForwardRef instances. Consider several corner cases, for example plain
special forms like Union are not valid, while Union[int, str] is OK, etc.
The msg argument is a human-readable error message, e.g::
def _trim_name(nm):
whitelist = ('_TypeAlias', '_ForwardRef', '_TypingBase', '_FinalTypingBase')
if nm.startswith('_') and nm not in whitelist:
nm = nm[1:]
return nm
"Union[arg, ...]: arg should be a type."
We append the repr() of the actual value (truncated to 100 chars).
"""
if arg is None:
return type(None)
if isinstance(arg, str):
return ForwardRef(arg)
if (isinstance(arg, _GenericAlias) and
arg.__origin__ in (Generic, _Protocol, ClassVar)):
raise TypeError(f"{arg} is not valid as type argument")
if (isinstance(arg, _SpecialForm) and arg is not Any or
arg in (Generic, _Protocol)):
raise TypeError(f"Plain {arg} is not valid as type argument")
if isinstance(arg, (type, TypeVar, ForwardRef)):
return arg
if not callable(arg):
raise TypeError(f"{msg} Got {arg!r:.100}.")
return arg
class TypingMeta(type):
"""Metaclass for most types defined in typing module
(not a part of public API).
This overrides __new__() to require an extra keyword parameter
'_root', which serves as a guard against naive subclassing of the
typing classes. Any legitimate class defined using a metaclass
derived from TypingMeta must pass _root=True.
def _type_repr(obj):
"""Return the repr() of an object, special-casing types (internal helper).
This also defines a dummy constructor (all the work for most typing
constructs is done in __new__) and a nicer repr().
If obj is a type, we return a shorter version than the default
type.__repr__, based on the module and qualified name, which is
typically enough to uniquely identify a type. For everything
else, we fall back on repr(obj).
"""
if isinstance(obj, type):
if obj.__module__ == 'builtins':
return obj.__qualname__
return f'{obj.__module__}.{obj.__qualname__}'
if obj is ...:
return('...')
if isinstance(obj, types.FunctionType):
return obj.__name__
return repr(obj)
_is_protocol = False
def __new__(cls, name, bases, namespace, *, _root=False):
if not _root:
raise TypeError("Cannot subclass %s" %
(', '.join(map(_type_repr, bases)) or '()'))
return super().__new__(cls, name, bases, namespace)
def _collect_type_vars(types):
"""Collect all type variable contained in types in order of
first appearance (lexicographic order). For example::
def __init__(self, *args, **kwds):
pass
_collect_type_vars((T, List[S, T])) == (T, S)
"""
tvars = []
for t in types:
if isinstance(t, TypeVar) and t not in tvars:
tvars.append(t)
if isinstance(t, _GenericAlias) and not t._special:
tvars.extend([t for t in t.__parameters__ if t not in tvars])
return tuple(tvars)
def _eval_type(self, globalns, localns):
"""Override this in subclasses to interpret forward references.
For example, List['C'] is internally stored as
List[_ForwardRef('C')], which should evaluate to List[C],
where C is an object found in globalns or localns (searching
localns first, of course).
"""
return self
def _subs_tvars(tp, tvars, subs):
"""Substitute type variables 'tvars' with substitutions 'subs'.
These two must have the same length.
"""
if not isinstance(tp, _GenericAlias):
return tp
new_args = list(tp.__args__)
for a, arg in enumerate(tp.__args__):
if isinstance(arg, TypeVar):
for i, tvar in enumerate(tvars):
if arg == tvar:
new_args[a] = subs[i]
else:
new_args[a] = _subs_tvars(arg, tvars, subs)
if tp.__origin__ is Union:
return Union[tuple(new_args)]
return tp.copy_with(tuple(new_args))
def _get_type_vars(self, tvars):
pass
def __repr__(self):
qname = _trim_name(_qualname(self))
return '%s.%s' % (self.__module__, qname)
def _check_generic(cls, parameters):
"""Check correct count for parameters of a generic cls (internal helper).
This gives a nice error message in case of count mismatch.
"""
if not cls.__parameters__:
raise TypeError(f"{cls} is not a generic class")
alen = len(parameters)
elen = len(cls.__parameters__)
if alen != elen:
raise TypeError(f"Too {'many' if alen > elen else 'few'} parameters for {cls};"
f" actual {alen}, expected {elen}")
def _remove_dups_flatten(parameters):
"""An internal helper for Union creation and substitution: flatten Union's
among parameters, then remove duplicates and strict subclasses.
"""
# Flatten out Union[Union[...], ...].
params = []
for p in parameters:
if isinstance(p, _GenericAlias) and p.__origin__ is Union:
params.extend(p.__args__)
elif isinstance(p, tuple) and len(p) > 0 and p[0] is Union:
params.extend(p[1:])
else:
params.append(p)
# Weed out strict duplicates, preserving the first of each occurrence.
all_params = set(params)
if len(all_params) < len(params):
new_params = []
for t in params:
if t in all_params:
new_params.append(t)
all_params.remove(t)
params = new_params
assert not all_params, all_params
# Weed out subclasses.
# E.g. Union[int, Employee, Manager] == Union[int, Employee].
# If object is present it will be sole survivor among proper classes.
# Never discard type variables.
# (In particular, Union[str, AnyStr] != AnyStr.)
all_params = set(params)
for t1 in params:
if not isinstance(t1, type):
continue
if any((isinstance(t2, type) or
isinstance(t2, _GenericAlias) and t2._special) and issubclass(t1, t2)
for t2 in all_params - {t1}):
all_params.remove(t1)
return tuple(t for t in params if t in all_params)
_cleanups = []
def _tp_cache(func):
"""Internal wrapper caching __getitem__ of generic types with a fallback to
original function for non-hashable arguments.
"""
cached = functools.lru_cache()(func)
_cleanups.append(cached.cache_clear)
@functools.wraps(func)
def inner(*args, **kwds):
try:
return cached(*args, **kwds)
except TypeError:
pass # All real errors (not unhashable args) are raised below.
return func(*args, **kwds)
return inner
def _eval_type(t, globalns, localns):
"""Evaluate all forward reverences in the given type t.
For use of globalns and localns see the docstring for get_type_hints().
"""
if isinstance(t, ForwardRef):
return t._evaluate(globalns, localns)
if isinstance(t, _GenericAlias):
ev_args = tuple(_eval_type(a, globalns, localns) for a in t.__args__)
if ev_args == t.__args__:
return t
res = t.copy_with(ev_args)
res._special = t._special
return res
return t
class _TypingBase(metaclass=TypingMeta, _root=True):
"""Internal indicator of special typing constructs."""
class _Final:
"""Mixin to prohibit subclassing"""
__slots__ = ('__weakref__',)
def __init__(self, *args, **kwds):
pass
def __init_subclass__(self, *args, **kwds):
if '_root' not in kwds:
raise TypeError("Cannot subclass special typing classes")
class _SpecialForm(_Final, _root=True):
"""Internal indicator of special typing constructs.
See _doc instance attribute for specific docs.
"""
__slots__ = ('_name', '_doc')
def __getstate__(self):
return {'name': self._name, 'doc': self._doc}
def __setstate__(self, state):
self._name = state['name']
self._doc = state['doc']
def __new__(cls, *args, **kwds):
"""Constructor.
......@@ -175,65 +309,166 @@ class _TypingBase(metaclass=TypingMeta, _root=True):
isinstance(args[0], str) and
isinstance(args[1], tuple)):
# Close enough.
raise TypeError("Cannot subclass %r" % cls)
raise TypeError(f"Cannot subclass {cls!r}")
return super().__new__(cls)
# Things that are not classes also need these.
def _eval_type(self, globalns, localns):
return self
def __init__(self, name, doc):
self._name = name
self._doc = doc
def _get_type_vars(self, tvars):
pass
def __eq__(self, other):
if not isinstance(other, _SpecialForm):
return NotImplemented
return self._name == other._name
def __hash__(self):
return hash((self._name,))
def __repr__(self):
cls = type(self)
qname = _trim_name(_qualname(cls))
return '%s.%s' % (cls.__module__, qname)
return 'typing.' + self._name
def __copy__(self):
return self # Special forms are immutable.
def __call__(self, *args, **kwds):
raise TypeError("Cannot instantiate %r" % type(self))
raise TypeError(f"Cannot instantiate {self!r}")
def __instancecheck__(self, obj):
raise TypeError(f"{self} cannot be used with isinstance()")
class _FinalTypingBase(_TypingBase, _root=True):
"""Internal mix-in class to prevent instantiation.
def __subclasscheck__(self, cls):
raise TypeError(f"{self} cannot be used with issubclass()")
Prevents instantiation unless _root=True is given in class call.
It is used to create pseudo-singleton instances Any, Union, Optional, etc.
"""
@_tp_cache
def __getitem__(self, parameters):
if self._name == 'ClassVar':
item = _type_check(parameters, 'ClassVar accepts only single type.')
return _GenericAlias(self, (item,))
if self._name == 'Union':
if parameters == ():
raise TypeError("Cannot take a Union of no types.")
if not isinstance(parameters, tuple):
parameters = (parameters,)
msg = "Union[arg, ...]: each arg must be a type."
parameters = tuple(_type_check(p, msg) for p in parameters)
parameters = _remove_dups_flatten(parameters)
if len(parameters) == 1:
return parameters[0]
return _GenericAlias(self, parameters)
if self._name == 'Optional':
arg = _type_check(parameters, "Optional[t] requires a single type.")
return Union[arg, type(None)]
raise TypeError(f"{self} is not subscriptable")
__slots__ = ()
def __new__(cls, *args, _root=False, **kwds):
self = super().__new__(cls, *args, **kwds)
if _root is True:
return self
raise TypeError("Cannot instantiate %r" % cls)
Any = _SpecialForm('Any', doc=
"""Special type indicating an unconstrained type.
- Any is compatible with every type.
- Any assumed to have all methods.
- All values assumed to be instances of Any.
Note that all the above statements are true from the point of view of
static type checkers. At runtime, Any should not be used with instance
or class checks.
""")
NoReturn = _SpecialForm('NoReturn', doc=
"""Special type indicating functions that never return.
Example::
from typing import NoReturn
def stop() -> NoReturn:
raise Exception('no way')
This type is invalid in other positions, e.g., ``List[NoReturn]``
will fail in static type checkers.
""")
ClassVar = _SpecialForm('ClassVar', doc=
"""Special type construct to mark class variables.
An annotation wrapped in ClassVar indicates that a given
attribute is intended to be used as a class variable and
should not be set on instances of that class. Usage::
class Starship:
stats: ClassVar[Dict[str, int]] = {} # class variable
damage: int = 10 # instance variable
ClassVar accepts only types and cannot be further subscribed.
Note that ClassVar is not a class itself, and should not
be used with isinstance() or issubclass().
""")
Union = _SpecialForm('Union', doc=
"""Union type; Union[X, Y] means either X or Y.
To define a union, use e.g. Union[int, str]. Details:
- The arguments must be types and there must be at least one.
- None as an argument is a special case and is replaced by
type(None).
- Unions of unions are flattened, e.g.::
Union[Union[int, str], float] == Union[int, str, float]
- Unions of a single argument vanish, e.g.::
Union[int] == int # The constructor actually returns int
- Redundant arguments are skipped, e.g.::
Union[int, str, int] == Union[int, str]
- When comparing unions, the argument order is ignored, e.g.::
Union[int, str] == Union[str, int]
- When two arguments have a subclass relationship, the least
derived argument is kept, e.g.::
class Employee: pass
class Manager(Employee): pass
Union[int, Employee, Manager] == Union[int, Employee]
Union[Manager, int, Employee] == Union[int, Employee]
Union[Employee, Manager] == Employee
- Similar for object::
Union[int, object] == object
- You cannot subclass or instantiate a union.
- You can use Optional[X] as a shorthand for Union[X, None].
""")
def __reduce__(self):
return _trim_name(type(self).__name__)
Optional = _SpecialForm('Optional', doc=
"""Optional type.
Optional[X] is equivalent to Union[X, None].
""")
class _ForwardRef(_TypingBase, _root=True):
class ForwardRef(_Final, _root=True):
"""Internal wrapper to hold a forward reference."""
__slots__ = ('__forward_arg__', '__forward_code__',
'__forward_evaluated__', '__forward_value__')
def __init__(self, arg):
super().__init__(arg)
if not isinstance(arg, str):
raise TypeError('Forward reference must be a string -- got %r' % (arg,))
raise TypeError(f"Forward reference must be a string -- got {arg!r}")
try:
code = compile(arg, '<string>', 'eval')
except SyntaxError:
raise SyntaxError('Forward reference must be an expression -- got %r' %
(arg,))
raise SyntaxError(f"Forward reference must be an expression -- got {arg!r}")
self.__forward_arg__ = arg
self.__forward_code__ = code
self.__forward_evaluated__ = False
self.__forward_value__ = None
def _eval_type(self, globalns, localns):
def _evaluate(self, globalns, localns):
if not self.__forward_evaluated__ or localns is not globalns:
if globalns is None and localns is None:
globalns = localns = {}
......@@ -248,7 +483,7 @@ class _ForwardRef(_TypingBase, _root=True):
return self.__forward_value__
def __eq__(self, other):
if not isinstance(other, _ForwardRef):
if not isinstance(other, ForwardRef):
return NotImplemented
return (self.__forward_arg__ == other.__forward_arg__ and
self.__forward_value__ == other.__forward_value__)
......@@ -256,249 +491,57 @@ class _ForwardRef(_TypingBase, _root=True):
def __hash__(self):
return hash((self.__forward_arg__, self.__forward_value__))
def __instancecheck__(self, obj):
raise TypeError("Forward references cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Forward references cannot be used with issubclass().")
def __repr__(self):
return '_ForwardRef(%r)' % (self.__forward_arg__,)
class _TypeAlias(_TypingBase, _root=True):
"""Internal helper class for defining generic variants of concrete types.
Note that this is not a type; let's call it a pseudo-type. It cannot
be used in instance and subclass checks in parameterized form, i.e.
``isinstance(42, Match[str])`` raises ``TypeError`` instead of returning
``False``.
"""
__slots__ = ('name', 'type_var', 'impl_type', 'type_checker')
return f'ForwardRef({self.__forward_arg__!r})'
def __init__(self, name, type_var, impl_type, type_checker):
"""Initializer.
Args:
name: The name, e.g. 'Pattern'.
type_var: The type parameter, e.g. AnyStr, or the
specific type, e.g. str.
impl_type: The implementation type.
type_checker: Function that takes an impl_type instance.
and returns a value that should be a type_var instance.
"""
assert isinstance(name, str), repr(name)
assert isinstance(impl_type, type), repr(impl_type)
assert not isinstance(impl_type, TypingMeta), repr(impl_type)
assert isinstance(type_var, (type, _TypingBase)), repr(type_var)
self.name = name
self.type_var = type_var
self.impl_type = impl_type
self.type_checker = type_checker
def __repr__(self):
return "%s[%s]" % (self.name, _type_repr(self.type_var))
def __getitem__(self, parameter):
if not isinstance(self.type_var, TypeVar):
raise TypeError("%s cannot be further parameterized." % self)
if self.type_var.__constraints__ and isinstance(parameter, type):
if not issubclass(parameter, self.type_var.__constraints__):
raise TypeError("%s is not a valid substitution for %s." %
(parameter, self.type_var))
if isinstance(parameter, TypeVar) and parameter is not self.type_var:
raise TypeError("%s cannot be re-parameterized." % self)
return self.__class__(self.name, parameter,
self.impl_type, self.type_checker)
def __eq__(self, other):
if not isinstance(other, _TypeAlias):
return NotImplemented
return self.name == other.name and self.type_var == other.type_var
class TypeVar(_Final, _root=True):
"""Type variable.
def __hash__(self):
return hash((self.name, self.type_var))
Usage::
def __instancecheck__(self, obj):
if not isinstance(self.type_var, TypeVar):
raise TypeError("Parameterized type aliases cannot be used "
"with isinstance().")
return isinstance(obj, self.impl_type)
T = TypeVar('T') # Can be anything
A = TypeVar('A', str, bytes) # Must be str or bytes
def __subclasscheck__(self, cls):
if not isinstance(self.type_var, TypeVar):
raise TypeError("Parameterized type aliases cannot be used "
"with issubclass().")
return issubclass(cls, self.impl_type)
Type variables exist primarily for the benefit of static type
checkers. They serve as the parameters for generic types as well
as for generic function definitions. See class Generic for more
information on generic types. Generic functions work as follows:
def repeat(x: T, n: int) -> List[T]:
'''Return a list containing n references to x.'''
return [x]*n
def _get_type_vars(types, tvars):
for t in types:
if isinstance(t, TypingMeta) or isinstance(t, _TypingBase):
t._get_type_vars(tvars)
def longest(x: A, y: A) -> A:
'''Return the longest of two strings.'''
return x if len(x) >= len(y) else y
The latter example's signature is essentially the overloading
of (str, str) -> str and (bytes, bytes) -> bytes. Also note
that if the arguments are instances of some subclass of str,
the return type is still plain str.
def _type_vars(types):
tvars = []
_get_type_vars(types, tvars)
return tuple(tvars)
At runtime, isinstance(x, T) and issubclass(C, T) will raise TypeError.
Type variables defined with covariant=True or contravariant=True
can be used do declare covariant or contravariant generic types.
See PEP 484 for more details. By default generic types are invariant
in all type variables.
def _eval_type(t, globalns, localns):
if isinstance(t, TypingMeta) or isinstance(t, _TypingBase):
return t._eval_type(globalns, localns)
return t
Type variables can be introspected. e.g.:
T.__name__ == 'T'
T.__constraints__ == ()
T.__covariant__ == False
T.__contravariant__ = False
A.__constraints__ == (str, bytes)
"""
def _type_check(arg, msg):
"""Check that the argument is a type, and return it (internal helper).
As a special case, accept None and return type(None) instead.
Also, _TypeAlias instances (e.g. Match, Pattern) are acceptable.
The msg argument is a human-readable error message, e.g.
"Union[arg, ...]: arg should be a type."
We append the repr() of the actual value (truncated to 100 chars).
"""
if arg is None:
return type(None)
if isinstance(arg, str):
arg = _ForwardRef(arg)
if (
isinstance(arg, _TypingBase) and type(arg).__name__ == '_ClassVar' or
not isinstance(arg, (type, _TypingBase)) and not callable(arg)
):
raise TypeError(msg + " Got %.100r." % (arg,))
# Bare Union etc. are not valid as type arguments
if (
type(arg).__name__ in ('_Union', '_Optional') and
not getattr(arg, '__origin__', None) or
isinstance(arg, TypingMeta) and arg._gorg in (Generic, _Protocol)
):
raise TypeError("Plain %s is not valid as type argument" % arg)
return arg
def _type_repr(obj):
"""Return the repr() of an object, special-casing types (internal helper).
If obj is a type, we return a shorter version than the default
type.__repr__, based on the module and qualified name, which is
typically enough to uniquely identify a type. For everything
else, we fall back on repr(obj).
"""
if isinstance(obj, type) and not isinstance(obj, TypingMeta):
if obj.__module__ == 'builtins':
return _qualname(obj)
return '%s.%s' % (obj.__module__, _qualname(obj))
if obj is ...:
return('...')
if isinstance(obj, types.FunctionType):
return obj.__name__
return repr(obj)
class _Any(_FinalTypingBase, _root=True):
"""Special type indicating an unconstrained type.
- Any is compatible with every type.
- Any assumed to have all methods.
- All values assumed to be instances of Any.
Note that all the above statements are true from the point of view of
static type checkers. At runtime, Any should not be used with instance
or class checks.
"""
__slots__ = ()
def __instancecheck__(self, obj):
raise TypeError("Any cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Any cannot be used with issubclass().")
Any = _Any(_root=True)
class _NoReturn(_FinalTypingBase, _root=True):
"""Special type indicating functions that never return.
Example::
from typing import NoReturn
def stop() -> NoReturn:
raise Exception('no way')
This type is invalid in other positions, e.g., ``List[NoReturn]``
will fail in static type checkers.
"""
__slots__ = ()
def __instancecheck__(self, obj):
raise TypeError("NoReturn cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("NoReturn cannot be used with issubclass().")
NoReturn = _NoReturn(_root=True)
class TypeVar(_TypingBase, _root=True):
"""Type variable.
Usage::
T = TypeVar('T') # Can be anything
A = TypeVar('A', str, bytes) # Must be str or bytes
Type variables exist primarily for the benefit of static type
checkers. They serve as the parameters for generic types as well
as for generic function definitions. See class Generic for more
information on generic types. Generic functions work as follows:
def repeat(x: T, n: int) -> List[T]:
'''Return a list containing n references to x.'''
return [x]*n
def longest(x: A, y: A) -> A:
'''Return the longest of two strings.'''
return x if len(x) >= len(y) else y
The latter example's signature is essentially the overloading
of (str, str) -> str and (bytes, bytes) -> bytes. Also note
that if the arguments are instances of some subclass of str,
the return type is still plain str.
At runtime, isinstance(x, T) and issubclass(C, T) will raise TypeError.
Type variables defined with covariant=True or contravariant=True
can be used do declare covariant or contravariant generic types.
See PEP 484 for more details. By default generic types are invariant
in all type variables.
Type variables can be introspected. e.g.:
T.__name__ == 'T'
T.__constraints__ == ()
T.__covariant__ == False
T.__contravariant__ = False
A.__constraints__ == (str, bytes)
"""
__slots__ = ('__name__', '__bound__', '__constraints__',
'__covariant__', '__contravariant__')
__slots__ = ('__name__', '__bound__', '__constraints__',
'__covariant__', '__contravariant__')
def __init__(self, name, *constraints, bound=None,
covariant=False, contravariant=False):
super().__init__(name, *constraints, bound=bound,
covariant=covariant, contravariant=contravariant)
self.__name__ = name
if covariant and contravariant:
raise ValueError("Bivariant types are not supported.")
......@@ -515,9 +558,19 @@ class TypeVar(_TypingBase, _root=True):
else:
self.__bound__ = None
def _get_type_vars(self, tvars):
if self not in tvars:
tvars.append(self)
def __getstate__(self):
return {'name': self.__name__,
'bound': self.__bound__,
'constraints': self.__constraints__,
'co': self.__covariant__,
'contra': self.__contravariant__}
def __setstate__(self, state):
self.__name__ = state['name']
self.__bound__ = state['bound']
self.__constraints__ = state['constraints']
self.__covariant__ = state['co']
self.__contravariant__ = state['contra']
def __repr__(self):
if self.__covariant__:
......@@ -528,44 +581,6 @@ class TypeVar(_TypingBase, _root=True):
prefix = '~'
return prefix + self.__name__
def __instancecheck__(self, instance):
raise TypeError("Type variables cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Type variables cannot be used with issubclass().")
# Some unconstrained type variables. These are used by the container types.
# (These are not for export.)
T = TypeVar('T') # Any type.
KT = TypeVar('KT') # Key type.
VT = TypeVar('VT') # Value type.
T_co = TypeVar('T_co', covariant=True) # Any type covariant containers.
V_co = TypeVar('V_co', covariant=True) # Any type covariant containers.
VT_co = TypeVar('VT_co', covariant=True) # Value type covariant containers.
T_contra = TypeVar('T_contra', contravariant=True) # Ditto contravariant.
# A useful type variable with constraints. This represents string types.
# (This one *is* for export!)
AnyStr = TypeVar('AnyStr', bytes, str)
def _replace_arg(arg, tvars, args):
"""An internal helper function: replace arg if it is a type variable
found in tvars with corresponding substitution from args or
with corresponding substitution sub-tree if arg is a generic type.
"""
if tvars is None:
tvars = []
if hasattr(arg, '_subs_tree') and isinstance(arg, (GenericMeta, _TypingBase)):
return arg._subs_tree(tvars, args)
if isinstance(arg, TypeVar):
for i, tvar in enumerate(tvars):
if arg == tvar:
return args[i]
return arg
# Special typing constructs Union, Optional, Generic, Callable and Tuple
# use three special attributes for internal bookkeeping of generic types:
......@@ -576,849 +591,285 @@ def _replace_arg(arg, tvars, args):
# * __args__ is a tuple of all arguments used in subscripting,
# e.g., Dict[T, int].__args__ == (T, int).
def _is_dunder(attr):
return attr.startswith('__') and attr.endswith('__')
def _subs_tree(cls, tvars=None, args=None):
"""An internal helper function: calculate substitution tree
for generic cls after replacing its type parameters with
substitutions in tvars -> args (if any).
Repeat the same following __origin__'s.
Return a list of arguments with all possible substitutions
performed. Arguments that are generic classes themselves are represented
as tuples (so that no new classes are created by this function).
For example: _subs_tree(List[Tuple[int, T]][str]) == [(Tuple, int, str)]
"""
class _GenericAlias(_Final, _root=True):
"""The central part of internal API.
if cls.__origin__ is None:
return cls
# Make of chain of origins (i.e. cls -> cls.__origin__)
current = cls.__origin__
orig_chain = []
while current.__origin__ is not None:
orig_chain.append(current)
current = current.__origin__
# Replace type variables in __args__ if asked ...
tree_args = []
for arg in cls.__args__:
tree_args.append(_replace_arg(arg, tvars, args))
# ... then continue replacing down the origin chain.
for ocls in orig_chain:
new_tree_args = []
for arg in ocls.__args__:
new_tree_args.append(_replace_arg(arg, ocls.__parameters__, tree_args))
tree_args = new_tree_args
return tree_args
def _remove_dups_flatten(parameters):
"""An internal helper for Union creation and substitution: flatten Union's
among parameters, then remove duplicates and strict subclasses.
This represents a generic version of type 'origin' with type arguments 'params'.
There are two kind of these aliases: user defined and special. The special ones
are wrappers around builtin collections and ABCs in collections.abc. These must
have 'name' always set. If 'inst' is False, then the alias can't be instantiated,
this is used by e.g. typing.List and typing.Dict.
"""
# Flatten out Union[Union[...], ...].
params = []
for p in parameters:
if isinstance(p, _Union) and p.__origin__ is Union:
params.extend(p.__args__)
elif isinstance(p, tuple) and len(p) > 0 and p[0] is Union:
params.extend(p[1:])
else:
params.append(p)
# Weed out strict duplicates, preserving the first of each occurrence.
all_params = set(params)
if len(all_params) < len(params):
new_params = []
for t in params:
if t in all_params:
new_params.append(t)
all_params.remove(t)
params = new_params
assert not all_params, all_params
# Weed out subclasses.
# E.g. Union[int, Employee, Manager] == Union[int, Employee].
# If object is present it will be sole survivor among proper classes.
# Never discard type variables.
# (In particular, Union[str, AnyStr] != AnyStr.)
all_params = set(params)
for t1 in params:
if not isinstance(t1, type):
continue
if any(isinstance(t2, type) and issubclass(t1, t2)
for t2 in all_params - {t1}
if not (isinstance(t2, GenericMeta) and
t2.__origin__ is not None)):
all_params.remove(t1)
return tuple(t for t in params if t in all_params)
def _check_generic(cls, parameters):
# Check correct count for parameters of a generic cls (internal helper).
if not cls.__parameters__:
raise TypeError("%s is not a generic class" % repr(cls))
alen = len(parameters)
elen = len(cls.__parameters__)
if alen != elen:
raise TypeError("Too %s parameters for %s; actual %s, expected %s" %
("many" if alen > elen else "few", repr(cls), alen, elen))
_cleanups = []
def _tp_cache(func):
"""Internal wrapper caching __getitem__ of generic types with a fallback to
original function for non-hashable arguments.
"""
cached = functools.lru_cache()(func)
_cleanups.append(cached.cache_clear)
@functools.wraps(func)
def inner(*args, **kwds):
try:
return cached(*args, **kwds)
except TypeError:
pass # All real errors (not unhashable args) are raised below.
return func(*args, **kwds)
return inner
class _Union(_FinalTypingBase, _root=True):
"""Union type; Union[X, Y] means either X or Y.
To define a union, use e.g. Union[int, str]. Details:
- The arguments must be types and there must be at least one.
- None as an argument is a special case and is replaced by
type(None).
- Unions of unions are flattened, e.g.::
Union[Union[int, str], float] == Union[int, str, float]
- Unions of a single argument vanish, e.g.::
Union[int] == int # The constructor actually returns int
- Redundant arguments are skipped, e.g.::
Union[int, str, int] == Union[int, str]
- When comparing unions, the argument order is ignored, e.g.::
Union[int, str] == Union[str, int]
- When two arguments have a subclass relationship, the least
derived argument is kept, e.g.::
class Employee: pass
class Manager(Employee): pass
Union[int, Employee, Manager] == Union[int, Employee]
Union[Manager, int, Employee] == Union[int, Employee]
Union[Employee, Manager] == Employee
- Similar for object::
Union[int, object] == object
- You cannot subclass or instantiate a union.
- You can use Optional[X] as a shorthand for Union[X, None].
"""
__slots__ = ('__parameters__', '__args__', '__origin__', '__tree_hash__')
def __new__(cls, parameters=None, origin=None, *args, _root=False):
self = super().__new__(cls, parameters, origin, *args, _root=_root)
if origin is None:
self.__parameters__ = None
self.__args__ = None
self.__origin__ = None
self.__tree_hash__ = hash(frozenset(('Union',)))
return self
if not isinstance(parameters, tuple):
raise TypeError("Expected parameters=<tuple>")
if origin is Union:
parameters = _remove_dups_flatten(parameters)
# It's not a union if there's only one type left.
if len(parameters) == 1:
return parameters[0]
self.__parameters__ = _type_vars(parameters)
self.__args__ = parameters
def __init__(self, origin, params, *, inst=True, special=False, name=None):
self._inst = inst
self._special = special
if special and name is None:
orig_name = origin.__name__
name = orig_name[0].title() + orig_name[1:]
self._name = name
if not isinstance(params, tuple):
params = (params,)
self.__origin__ = origin
# Pre-calculate the __hash__ on instantiation.
# This improves speed for complex substitutions.
subs_tree = self._subs_tree()
if isinstance(subs_tree, tuple):
self.__tree_hash__ = hash(frozenset(subs_tree))
else:
self.__tree_hash__ = hash(subs_tree)
return self
def _eval_type(self, globalns, localns):
if self.__args__ is None:
return self
ev_args = tuple(_eval_type(t, globalns, localns) for t in self.__args__)
ev_origin = _eval_type(self.__origin__, globalns, localns)
if ev_args == self.__args__ and ev_origin == self.__origin__:
# Everything is already evaluated.
return self
return self.__class__(ev_args, ev_origin, _root=True)
def _get_type_vars(self, tvars):
if self.__origin__ and self.__parameters__:
_get_type_vars(self.__parameters__, tvars)
def __repr__(self):
if self.__origin__ is None:
return super().__repr__()
tree = self._subs_tree()
if not isinstance(tree, tuple):
return repr(tree)
return tree[0]._tree_repr(tree)
def _tree_repr(self, tree):
arg_list = []
for arg in tree[1:]:
if not isinstance(arg, tuple):
arg_list.append(_type_repr(arg))
else:
arg_list.append(arg[0]._tree_repr(arg))
return super().__repr__() + '[%s]' % ', '.join(arg_list)
@_tp_cache
def __getitem__(self, parameters):
if parameters == ():
raise TypeError("Cannot take a Union of no types.")
if not isinstance(parameters, tuple):
parameters = (parameters,)
if self.__origin__ is None:
msg = "Union[arg, ...]: each arg must be a type."
else:
msg = "Parameters to generic types must be types."
parameters = tuple(_type_check(p, msg) for p in parameters)
if self is not Union:
_check_generic(self, parameters)
return self.__class__(parameters, origin=self, _root=True)
def _subs_tree(self, tvars=None, args=None):
if self is Union:
return Union # Nothing to substitute
tree_args = _subs_tree(self, tvars, args)
tree_args = _remove_dups_flatten(tree_args)
if len(tree_args) == 1:
return tree_args[0] # Union of a single type is that type
return (Union,) + tree_args
def __eq__(self, other):
if isinstance(other, _Union):
return self.__tree_hash__ == other.__tree_hash__
elif self is not Union:
return self._subs_tree() == other
else:
return self is other
def __hash__(self):
return self.__tree_hash__
def __instancecheck__(self, obj):
raise TypeError("Unions cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Unions cannot be used with issubclass().")
Union = _Union(_root=True)
class _Optional(_FinalTypingBase, _root=True):
"""Optional type.
Optional[X] is equivalent to Union[X, None].
"""
__slots__ = ()
@_tp_cache
def __getitem__(self, arg):
arg = _type_check(arg, "Optional[t] requires a single type.")
return Union[arg, type(None)]
Optional = _Optional(_root=True)
def _next_in_mro(cls):
"""Helper for Generic.__new__.
Returns the class after the last occurrence of Generic or
Generic[...] in cls.__mro__.
"""
next_in_mro = object
# Look for the last occurrence of Generic or Generic[...].
for i, c in enumerate(cls.__mro__[:-1]):
if isinstance(c, GenericMeta) and c._gorg is Generic:
next_in_mro = cls.__mro__[i + 1]
return next_in_mro
def _make_subclasshook(cls):
"""Construct a __subclasshook__ callable that incorporates
the associated __extra__ class in subclass checks performed
against cls.
"""
if isinstance(cls.__extra__, abc.ABCMeta):
# The logic mirrors that of ABCMeta.__subclasscheck__.
# Registered classes need not be checked here because
# cls and its extra share the same _abc_registry.
def __extrahook__(subclass):
res = cls.__extra__.__subclasshook__(subclass)
if res is not NotImplemented:
return res
if cls.__extra__ in subclass.__mro__:
return True
for scls in cls.__extra__.__subclasses__():
if isinstance(scls, GenericMeta):
continue
if issubclass(subclass, scls):
return True
return NotImplemented
else:
# For non-ABC extras we'll just call issubclass().
def __extrahook__(subclass):
if cls.__extra__ and issubclass(subclass, cls.__extra__):
return True
return NotImplemented
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.
This is a metaclass for typing.Generic and generic ABCs defined in
typing module. User defined subclasses of GenericMeta can override
__new__ and invoke super().__new__. Note that GenericMeta.__new__
has strict rules on what is allowed in its bases argument:
* plain Generic is disallowed in bases;
* Generic[...] should appear in bases at most once;
* if Generic[...] is present, then it should list all type variables
that appear in other bases.
In addition, type of all generic bases is erased, e.g., C[int] is
stripped to plain C.
"""
def __new__(cls, name, bases, namespace,
tvars=None, args=None, origin=None, extra=None, orig_bases=None):
"""Create a new generic class. GenericMeta.__new__ accepts
keyword arguments that are used for internal bookkeeping, therefore
an override should pass unused keyword arguments to super().
"""
if tvars is not None:
# Called from __getitem__() below.
assert origin is not None
assert all(isinstance(t, TypeVar) for t in tvars), tvars
else:
# Called from class statement.
assert tvars is None, tvars
assert args is None, args
assert origin is None, origin
# Get the full set of tvars from the bases.
tvars = _type_vars(bases)
# Look for Generic[T1, ..., Tn].
# If found, tvars must be a subset of it.
# If not found, tvars is it.
# Also check for and reject plain Generic,
# and reject multiple Generic[...].
gvars = None
for base in bases:
if base is Generic:
raise TypeError("Cannot inherit from plain Generic")
if (isinstance(base, GenericMeta) and
base.__origin__ is Generic):
if gvars is not None:
raise TypeError(
"Cannot inherit from Generic[...] multiple types.")
gvars = base.__parameters__
if gvars is None:
gvars = tvars
else:
tvarset = set(tvars)
gvarset = set(gvars)
if not tvarset <= gvarset:
raise TypeError(
"Some type variables (%s) "
"are not listed in Generic[%s]" %
(", ".join(str(t) for t in tvars if t not in gvarset),
", ".join(str(g) for g in gvars)))
tvars = gvars
initial_bases = bases
if extra is not None and type(extra) is abc.ABCMeta and extra not in bases:
bases = (extra,) + bases
bases = tuple(b._gorg if isinstance(b, GenericMeta) else b for b in bases)
# remove bare Generic from bases if there are other generic bases
if any(isinstance(b, GenericMeta) and b is not Generic for b in bases):
bases = tuple(b for b in bases if b is not Generic)
namespace.update({'__origin__': origin, '__extra__': extra,
'_gorg': None if not origin else origin._gorg})
self = super().__new__(cls, name, bases, namespace, _root=True)
super(GenericMeta, self).__setattr__('_gorg',
self if not origin else origin._gorg)
self.__parameters__ = tvars
# Be prepared that GenericMeta will be subclassed by TupleMeta
# and CallableMeta, those two allow ..., (), or [] in __args___.
self.__args__ = tuple(... if a is _TypingEllipsis else
() if a is _TypingEmpty else
a for a in args) if args else None
# Speed hack (https://github.com/python/typing/issues/196).
self.__next_in_mro__ = _next_in_mro(self)
# Preserve base classes on subclassing (__bases__ are type erased now).
if orig_bases is None:
self.__orig_bases__ = initial_bases
# This allows unparameterized generic collections to be used
# with issubclass() and isinstance() in the same way as their
# collections.abc counterparts (e.g., isinstance([], Iterable)).
if (
'__subclasshook__' not in namespace and extra or
# allow overriding
getattr(self.__subclasshook__, '__name__', '') == '__extrahook__'
):
self.__subclasshook__ = _make_subclasshook(self)
if isinstance(extra, abc.ABCMeta):
self._abc_registry = extra._abc_registry
self._abc_cache = extra._abc_cache
elif origin is not None:
self._abc_registry = origin._abc_registry
self._abc_cache = origin._abc_cache
if origin and hasattr(origin, '__qualname__'): # Fix for Python 3.2.
self.__qualname__ = origin.__qualname__
self.__tree_hash__ = (hash(self._subs_tree()) if origin else
super(GenericMeta, self).__hash__())
return self
# _abc_negative_cache and _abc_negative_cache_version
# realised as descriptors, since GenClass[t1, t2, ...] always
# share subclass info with GenClass.
# This is an important memory optimization.
@property
def _abc_negative_cache(self):
if isinstance(self.__extra__, abc.ABCMeta):
return self.__extra__._abc_negative_cache
return self._gorg._abc_generic_negative_cache
@_abc_negative_cache.setter
def _abc_negative_cache(self, value):
if self.__origin__ is None:
if isinstance(self.__extra__, abc.ABCMeta):
self.__extra__._abc_negative_cache = value
else:
self._abc_generic_negative_cache = value
@property
def _abc_negative_cache_version(self):
if isinstance(self.__extra__, abc.ABCMeta):
return self.__extra__._abc_negative_cache_version
return self._gorg._abc_generic_negative_cache_version
@_abc_negative_cache_version.setter
def _abc_negative_cache_version(self, value):
if self.__origin__ is None:
if isinstance(self.__extra__, abc.ABCMeta):
self.__extra__._abc_negative_cache_version = value
else:
self._abc_generic_negative_cache_version = value
def _get_type_vars(self, tvars):
if self.__origin__ and self.__parameters__:
_get_type_vars(self.__parameters__, tvars)
def _eval_type(self, globalns, localns):
ev_origin = (self.__origin__._eval_type(globalns, localns)
if self.__origin__ else None)
ev_args = tuple(_eval_type(a, globalns, localns) for a
in self.__args__) if self.__args__ else None
if ev_origin == self.__origin__ and ev_args == self.__args__:
return self
return self.__class__(self.__name__,
self.__bases__,
_no_slots_copy(self.__dict__),
tvars=_type_vars(ev_args) if ev_args else None,
args=ev_args,
origin=ev_origin,
extra=self.__extra__,
orig_bases=self.__orig_bases__)
def __repr__(self):
if self.__origin__ is None:
return super().__repr__()
return self._tree_repr(self._subs_tree())
def _tree_repr(self, tree):
arg_list = []
for arg in tree[1:]:
if arg == ():
arg_list.append('()')
elif not isinstance(arg, tuple):
arg_list.append(_type_repr(arg))
else:
arg_list.append(arg[0]._tree_repr(arg))
return super().__repr__() + '[%s]' % ', '.join(arg_list)
def _subs_tree(self, tvars=None, args=None):
if self.__origin__ is None:
return self
tree_args = _subs_tree(self, tvars, args)
return (self._gorg,) + tuple(tree_args)
def __eq__(self, other):
if not isinstance(other, GenericMeta):
return NotImplemented
if self.__origin__ is None or other.__origin__ is None:
return self is other
return self.__tree_hash__ == other.__tree_hash__
def __hash__(self):
return self.__tree_hash__
a for a in params)
self.__parameters__ = _collect_type_vars(params)
self.__slots__ = None # This is not documented.
if not name:
self.__module__ = origin.__module__
@_tp_cache
def __getitem__(self, params):
if self.__origin__ in (Generic, _Protocol):
# Can't subscript Generic[...] or _Protocol[...].
raise TypeError(f"Cannot subscript already-subscripted {self}")
if not isinstance(params, tuple):
params = (params,)
if not params and self._gorg is not Tuple:
raise TypeError(
"Parameter list to %s[...] cannot be empty" % _qualname(self))
msg = "Parameters to generic types must be types."
params = tuple(_type_check(p, msg) for p in params)
if self is Generic:
# Generic can only be subscripted with unique type variables.
if not all(isinstance(p, TypeVar) for p in params):
raise TypeError(
"Parameters to Generic[...] must all be type variables")
if len(set(params)) != len(params):
raise TypeError(
"Parameters to Generic[...] must all be unique")
tvars = params
args = params
elif self in (Tuple, Callable):
tvars = _type_vars(params)
args = params
elif self is _Protocol:
# _Protocol is internal, don't check anything.
tvars = params
args = params
elif self.__origin__ in (Generic, _Protocol):
# Can't subscript Generic[...] or _Protocol[...].
raise TypeError("Cannot subscript already-subscripted %s" %
repr(self))
else:
# Subscripting a regular Generic subclass.
_check_generic(self, params)
tvars = _type_vars(params)
args = params
prepend = (self,) if self.__origin__ is None else ()
return self.__class__(self.__name__,
prepend + self.__bases__,
_no_slots_copy(self.__dict__),
tvars=tvars,
args=args,
origin=self,
extra=self.__extra__,
orig_bases=self.__orig_bases__)
def __subclasscheck__(self, cls):
if self.__origin__ is not None:
if sys._getframe(1).f_globals['__name__'] not in ['abc', 'functools']:
raise TypeError("Parameterized generics cannot be used with class "
"or instance checks")
return False
if self is Generic:
raise TypeError("Class %r cannot be used with class "
"or instance checks" % self)
return super().__subclasscheck__(cls)
def __instancecheck__(self, instance):
# Since we extend ABC.__subclasscheck__ and
# ABC.__instancecheck__ inlines the cache checking done by the
# latter, we must extend __instancecheck__ too. For simplicity
# we just skip the cache check -- instance checks for generic
# classes are supposed to be rare anyways.
return issubclass(instance.__class__, self)
def __setattr__(self, attr, value):
# We consider all the subscripted generics as proxies for original class
if (
attr.startswith('__') and attr.endswith('__') or
attr.startswith('_abc_') or
self._gorg is None # The class is not fully created, see #typing/506
):
super(GenericMeta, self).__setattr__(attr, value)
else:
super(GenericMeta, self._gorg).__setattr__(attr, value)
_check_generic(self, params)
return _subs_tvars(self, self.__parameters__, params)
def copy_with(self, params):
# We don't copy self._special.
return _GenericAlias(self.__origin__, params, name=self._name, inst=self._inst)
# Prevent checks for Generic to crash when defining Generic.
Generic = None
def __repr__(self):
if (self._name != 'Callable' or
len(self.__args__) == 2 and self.__args__[0] is Ellipsis):
if self._name:
name = 'typing.' + self._name
else:
name = _type_repr(self.__origin__)
if not self._special:
args = f'[{", ".join([_type_repr(a) for a in self.__args__])}]'
else:
args = ''
return (f'{name}{args}')
if self._special:
return 'typing.Callable'
return (f'typing.Callable'
f'[[{", ".join([_type_repr(a) for a in self.__args__[:-1]])}], '
f'{_type_repr(self.__args__[-1])}]')
def __eq__(self, other):
if not isinstance(other, _GenericAlias):
return NotImplemented
if self.__origin__ != other.__origin__:
return False
if self.__origin__ is Union and other.__origin__ is Union:
return frozenset(self.__args__) == frozenset(other.__args__)
return self.__args__ == other.__args__
def _generic_new(base_cls, cls, *args, **kwds):
# Assure type is erased on instantiation,
# but attempt to store it in __orig_class__
if cls.__origin__ is None:
return base_cls.__new__(cls)
else:
origin = cls._gorg
obj = base_cls.__new__(origin)
def __hash__(self):
if self.__origin__ is Union:
return hash((Union, frozenset(self.__args__)))
return hash((self.__origin__, self.__args__))
def __call__(self, *args, **kwargs):
if not self._inst:
raise TypeError(f"Type {self._name} cannot be instantiated; "
f"use {self._name.lower()}() instead")
result = self.__origin__(*args, **kwargs)
try:
obj.__orig_class__ = cls
result.__orig_class__ = self
except AttributeError:
pass
obj.__init__(*args, **kwds)
return obj
class Generic(metaclass=GenericMeta):
"""Abstract base class for generic types.
A generic type is typically declared by inheriting from
this class parameterized with one or more type variables.
For example, a generic mapping type might be defined as::
class Mapping(Generic[KT, VT]):
def __getitem__(self, key: KT) -> VT:
...
# Etc.
This class can then be used as follows::
def lookup_name(mapping: Mapping[KT, VT], key: KT, default: VT) -> VT:
try:
return mapping[key]
except KeyError:
return default
"""
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Generic:
raise TypeError("Type Generic cannot be instantiated; "
"it can be used only as a base class")
return _generic_new(cls.__next_in_mro__, cls, *args, **kwds)
class _TypingEmpty:
"""Internal placeholder for () or []. Used by TupleMeta and CallableMeta
to allow empty list/tuple in specific places, without allowing them
to sneak in where prohibited.
"""
class _TypingEllipsis:
"""Internal placeholder for ... (ellipsis)."""
class TupleMeta(GenericMeta):
"""Metaclass for Tuple (internal)."""
@_tp_cache
def __getitem__(self, parameters):
if self.__origin__ is not None or self._gorg is not Tuple:
# Normal generic rules apply if this is not the first subscription
# or a subscription of a subclass.
return super().__getitem__(parameters)
if parameters == ():
return super().__getitem__((_TypingEmpty,))
if not isinstance(parameters, tuple):
parameters = (parameters,)
if len(parameters) == 2 and parameters[1] is ...:
msg = "Tuple[t, ...]: t must be a type."
p = _type_check(parameters[0], msg)
return super().__getitem__((p, _TypingEllipsis))
msg = "Tuple[t0, t1, ...]: each t must be a type."
parameters = tuple(_type_check(p, msg) for p in parameters)
return super().__getitem__(parameters)
return result
def __mro_entries__(self, bases):
if self._name: # generic version of an ABC or built-in class
res = []
if self.__origin__ not in bases:
res.append(self.__origin__)
i = bases.index(self)
if not any(isinstance(b, _GenericAlias) or issubclass(b, Generic)
for b in bases[i+1:]):
res.append(Generic)
return tuple(res)
if self.__origin__ is Generic:
i = bases.index(self)
for b in bases[i+1:]:
if isinstance(b, _GenericAlias) and b is not self:
return ()
return (self.__origin__,)
def __getattr__(self, attr):
# We are carefull for copy and pickle.
# Also for simplicity we just don't relay all dunder names
if '__origin__' in self.__dict__ and not _is_dunder(attr):
return getattr(self.__origin__, attr)
raise AttributeError(attr)
def __setattr__(self, attr, val):
if _is_dunder(attr) or attr in ('_name', '_inst', '_special'):
super().__setattr__(attr, val)
else:
setattr(self.__origin__, attr, val)
def __instancecheck__(self, obj):
if self.__args__ is None:
return isinstance(obj, tuple)
raise TypeError("Parameterized Tuple cannot be used "
"with isinstance().")
return self.__subclasscheck__(type(obj))
def __subclasscheck__(self, cls):
if self.__args__ is None:
return issubclass(cls, tuple)
raise TypeError("Parameterized Tuple cannot be used "
"with issubclass().")
class Tuple(tuple, extra=tuple, metaclass=TupleMeta):
"""Tuple type; Tuple[X, Y] is the cross-product type of X and Y.
Example: Tuple[T1, T2] is a tuple of two elements corresponding
to type variables T1 and T2. Tuple[int, float, str] is a tuple
of an int, a float and a string.
To specify a variable-length tuple of homogeneous type, use Tuple[T, ...].
if self._special:
if not isinstance(cls, _GenericAlias):
return issubclass(cls, self.__origin__)
if cls._special:
return issubclass(cls.__origin__, self.__origin__)
raise TypeError("Subscripted generics cannot be used with"
" class and instance checks")
class _VariadicGenericAlias(_GenericAlias, _root=True):
"""Same as _GenericAlias above but for variadic aliases. Currently,
this is used only by special internal aliases: Tuple and Callable.
"""
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Tuple:
raise TypeError("Type Tuple cannot be instantiated; "
"use tuple() instead")
return _generic_new(tuple, cls, *args, **kwds)
class CallableMeta(GenericMeta):
"""Metaclass for Callable (internal)."""
def __repr__(self):
if self.__origin__ is None:
return super().__repr__()
return self._tree_repr(self._subs_tree())
def _tree_repr(self, tree):
if self._gorg is not Callable:
return super()._tree_repr(tree)
# For actual Callable (not its subclass) we override
# super()._tree_repr() for nice formatting.
arg_list = []
for arg in tree[1:]:
if not isinstance(arg, tuple):
arg_list.append(_type_repr(arg))
else:
arg_list.append(arg[0]._tree_repr(arg))
if arg_list[0] == '...':
return repr(tree[0]) + '[..., %s]' % arg_list[1]
return (repr(tree[0]) +
'[[%s], %s]' % (', '.join(arg_list[:-1]), arg_list[-1]))
def __getitem__(self, parameters):
"""A thin wrapper around __getitem_inner__ to provide the latter
with hashable arguments to improve speed.
"""
if self.__origin__ is not None or self._gorg is not Callable:
return super().__getitem__(parameters)
if not isinstance(parameters, tuple) or len(parameters) != 2:
def __getitem__(self, params):
if self._name != 'Callable' or not self._special:
return self.__getitem_inner__(params)
if not isinstance(params, tuple) or len(params) != 2:
raise TypeError("Callable must be used as "
"Callable[[arg, ...], result].")
args, result = parameters
args, result = params
if args is Ellipsis:
parameters = (Ellipsis, result)
params = (Ellipsis, result)
else:
if not isinstance(args, list):
raise TypeError("Callable[args, result]: args must be a list."
" Got %.100r." % (args,))
parameters = (tuple(args), result)
return self.__getitem_inner__(parameters)
raise TypeError(f"Callable[args, result]: args must be a list."
f" Got {args}")
params = (tuple(args), result)
return self.__getitem_inner__(params)
@_tp_cache
def __getitem_inner__(self, parameters):
args, result = parameters
msg = "Callable[args, result]: result must be a type."
result = _type_check(result, msg)
if args is Ellipsis:
return super().__getitem__((_TypingEllipsis, result))
msg = "Callable[[arg, ...], result]: each arg must be a type."
args = tuple(_type_check(arg, msg) for arg in args)
parameters = args + (result,)
return super().__getitem__(parameters)
class Callable(extra=collections_abc.Callable, metaclass=CallableMeta):
"""Callable type; Callable[[int], str] is a function of (int) -> str.
The subscription syntax must always be used with exactly two
values: the argument list and the return type. The argument list
must be a list of types or ellipsis; the return type must be a single type.
There is no syntax to indicate optional or keyword arguments,
such function types are rarely used as callback types.
"""
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Callable:
raise TypeError("Type Callable cannot be instantiated; "
"use a non-abstract subclass instead")
return _generic_new(cls.__next_in_mro__, cls, *args, **kwds)
class _ClassVar(_FinalTypingBase, _root=True):
"""Special type construct to mark class variables.
def __getitem_inner__(self, params):
if self.__origin__ is tuple and self._special:
if params == ():
return self.copy_with((_TypingEmpty,))
if not isinstance(params, tuple):
params = (params,)
if len(params) == 2 and params[1] is ...:
msg = "Tuple[t, ...]: t must be a type."
p = _type_check(params[0], msg)
return self.copy_with((p, _TypingEllipsis))
msg = "Tuple[t0, t1, ...]: each t must be a type."
params = tuple(_type_check(p, msg) for p in params)
return self.copy_with(params)
if self.__origin__ is collections.abc.Callable and self._special:
args, result = params
msg = "Callable[args, result]: result must be a type."
result = _type_check(result, msg)
if args is Ellipsis:
return self.copy_with((_TypingEllipsis, result))
msg = "Callable[[arg, ...], result]: each arg must be a type."
args = tuple(_type_check(arg, msg) for arg in args)
params = args + (result,)
return self.copy_with(params)
return super().__getitem__(params)
class Generic:
"""Abstract base class for generic types.
An annotation wrapped in ClassVar indicates that a given
attribute is intended to be used as a class variable and
should not be set on instances of that class. Usage::
A generic type is typically declared by inheriting from
this class parameterized with one or more type variables.
For example, a generic mapping type might be defined as::
class Starship:
stats: ClassVar[Dict[str, int]] = {} # class variable
damage: int = 10 # instance variable
class Mapping(Generic[KT, VT]):
def __getitem__(self, key: KT) -> VT:
...
# Etc.
ClassVar accepts only types and cannot be further subscribed.
This class can then be used as follows::
Note that ClassVar is not a class itself, and should not
be used with isinstance() or issubclass().
def lookup_name(mapping: Mapping[KT, VT], key: KT, default: VT) -> VT:
try:
return mapping[key]
except KeyError:
return default
"""
__slots__ = ()
__slots__ = ('__type__',)
def __init__(self, tp=None, **kwds):
self.__type__ = tp
def __getitem__(self, item):
cls = type(self)
if self.__type__ is None:
return cls(_type_check(item,
'{} accepts only single type.'.format(cls.__name__[1:])),
_root=True)
raise TypeError('{} cannot be further subscripted'
.format(cls.__name__[1:]))
def __new__(cls, *args, **kwds):
if cls is Generic:
raise TypeError("Type Generic cannot be instantiated; "
"it can be used only as a base class")
return super().__new__(cls)
def _eval_type(self, globalns, localns):
new_tp = _eval_type(self.__type__, globalns, localns)
if new_tp == self.__type__:
return self
return type(self)(new_tp, _root=True)
@_tp_cache
def __class_getitem__(cls, params):
if not isinstance(params, tuple):
params = (params,)
if not params and cls is not Tuple:
raise TypeError(
f"Parameter list to {cls.__qualname__}[...] cannot be empty")
msg = "Parameters to generic types must be types."
params = tuple(_type_check(p, msg) for p in params)
if cls is Generic:
# Generic can only be subscripted with unique type variables.
if not all(isinstance(p, TypeVar) for p in params):
raise TypeError(
"Parameters to Generic[...] must all be type variables")
if len(set(params)) != len(params):
raise TypeError(
"Parameters to Generic[...] must all be unique")
elif cls is _Protocol:
# _Protocol is internal at the moment, just skip the check
pass
else:
# Subscripting a regular Generic subclass.
_check_generic(cls, params)
return _GenericAlias(cls, params)
def __repr__(self):
r = super().__repr__()
if self.__type__ is not None:
r += '[{}]'.format(_type_repr(self.__type__))
return r
def __init_subclass__(cls, *args, **kwargs):
tvars = []
if '__orig_bases__' in cls.__dict__:
error = Generic in cls.__orig_bases__
else:
error = Generic in cls.__bases__ and cls.__name__ != '_Protocol'
if error:
raise TypeError("Cannot inherit from plain Generic")
if '__orig_bases__' in cls.__dict__:
tvars = _collect_type_vars(cls.__orig_bases__)
# Look for Generic[T1, ..., Tn].
# If found, tvars must be a subset of it.
# If not found, tvars is it.
# Also check for and reject plain Generic,
# and reject multiple Generic[...].
gvars = None
for base in cls.__orig_bases__:
if (isinstance(base, _GenericAlias) and
base.__origin__ is Generic):
if gvars is not None:
raise TypeError(
"Cannot inherit from Generic[...] multiple types.")
gvars = base.__parameters__
if gvars is None:
gvars = tvars
else:
tvarset = set(tvars)
gvarset = set(gvars)
if not tvarset <= gvarset:
s_vars = ', '.join(str(t) for t in tvars if t not in gvarset)
s_args = ', '.join(str(g) for g in gvars)
raise TypeError(f"Some type variables ({s_vars}) are"
f" not listed in Generic[{s_args}]")
tvars = gvars
cls.__parameters__ = tuple(tvars)
def __hash__(self):
return hash((type(self).__name__, self.__type__))
def __eq__(self, other):
if not isinstance(other, _ClassVar):
return NotImplemented
if self.__type__ is not None:
return self.__type__ == other.__type__
return self is other
class _TypingEmpty:
"""Internal placeholder for () or []. Used by TupleMeta and CallableMeta
to allow empty list/tuple in specific places, without allowing them
to sneak in where prohibited.
"""
ClassVar = _ClassVar(_root=True)
class _TypingEllipsis:
"""Internal placeholder for ... (ellipsis)."""
def cast(typ, val):
......@@ -1503,7 +954,7 @@ def get_type_hints(obj, globalns=None, localns=None):
if value is None:
value = type(None)
if isinstance(value, str):
value = _ForwardRef(value)
value = ForwardRef(value)
value = _eval_type(value, base_globals, localns)
hints[name] = value
return hints
......@@ -1531,7 +982,7 @@ def get_type_hints(obj, globalns=None, localns=None):
if value is None:
value = type(None)
if isinstance(value, str):
value = _ForwardRef(value)
value = ForwardRef(value)
value = _eval_type(value, globalns, localns)
if name in defaults and defaults[name] is None:
value = Optional[value]
......@@ -1619,7 +1070,7 @@ def overload(func):
return _overload_dummy
class _ProtocolMeta(GenericMeta):
class _ProtocolMeta(type):
"""Internal metaclass for _Protocol.
This exists so _Protocol classes can be generic without deriving
......@@ -1687,7 +1138,7 @@ class _ProtocolMeta(GenericMeta):
return attrs
class _Protocol(metaclass=_ProtocolMeta):
class _Protocol(Generic, metaclass=_ProtocolMeta):
"""Internal base class for protocol classes.
This implements a simple-minded structural issubclass check
......@@ -1699,47 +1150,111 @@ class _Protocol(metaclass=_ProtocolMeta):
_is_protocol = True
def __class_getitem__(cls, params):
return super().__class_getitem__(params)
# Various ABCs mimicking those in collections.abc.
# A few are simply re-exported for completeness.
Hashable = collections_abc.Hashable # Not generic.
# Some unconstrained type variables. These are used by the container types.
# (These are not for export.)
T = TypeVar('T') # Any type.
KT = TypeVar('KT') # Key type.
VT = TypeVar('VT') # Value type.
T_co = TypeVar('T_co', covariant=True) # Any type covariant containers.
V_co = TypeVar('V_co', covariant=True) # Any type covariant containers.
VT_co = TypeVar('VT_co', covariant=True) # Value type covariant containers.
T_contra = TypeVar('T_contra', contravariant=True) # Ditto contravariant.
# Internal type variable used for Type[].
CT_co = TypeVar('CT_co', covariant=True, bound=type)
if hasattr(collections_abc, 'Awaitable'):
class Awaitable(Generic[T_co], extra=collections_abc.Awaitable):
__slots__ = ()
__all__.append('Awaitable')
# A useful type variable with constraints. This represents string types.
# (This one *is* for export!)
AnyStr = TypeVar('AnyStr', bytes, str)
if hasattr(collections_abc, 'Coroutine'):
class Coroutine(Awaitable[V_co], Generic[T_co, T_contra, V_co],
extra=collections_abc.Coroutine):
__slots__ = ()
# Various ABCs mimicking those in collections.abc.
def _alias(origin, params, inst=True):
return _GenericAlias(origin, params, special=True, inst=inst)
Hashable = _alias(collections.abc.Hashable, ()) # Not generic.
Awaitable = _alias(collections.abc.Awaitable, T_co)
Coroutine = _alias(collections.abc.Coroutine, (T_co, T_contra, V_co))
AsyncIterable = _alias(collections.abc.AsyncIterable, T_co)
AsyncIterator = _alias(collections.abc.AsyncIterator, T_co)
Iterable = _alias(collections.abc.Iterable, T_co)
Iterator = _alias(collections.abc.Iterator, T_co)
Reversible = _alias(collections.abc.Reversible, T_co)
Sized = _alias(collections.abc.Sized, ()) # Not generic.
Container = _alias(collections.abc.Container, T_co)
Collection = _alias(collections.abc.Collection, T_co)
Callable = _VariadicGenericAlias(collections.abc.Callable, (), special=True)
Callable.__doc__ = \
"""Callable type; Callable[[int], str] is a function of (int) -> str.
__all__.append('Coroutine')
The subscription syntax must always be used with exactly two
values: the argument list and the return type. The argument list
must be a list of types or ellipsis; the return type must be a single type.
There is no syntax to indicate optional or keyword arguments,
such function types are rarely used as callback types.
"""
AbstractSet = _alias(collections.abc.Set, T_co)
MutableSet = _alias(collections.abc.MutableSet, T)
# NOTE: Mapping is only covariant in the value type.
Mapping = _alias(collections.abc.Mapping, (KT, VT_co))
MutableMapping = _alias(collections.abc.MutableMapping, (KT, VT))
Sequence = _alias(collections.abc.Sequence, T_co)
MutableSequence = _alias(collections.abc.MutableSequence, T)
ByteString = _alias(collections.abc.ByteString, ()) # Not generic
Tuple = _VariadicGenericAlias(tuple, (), inst=False, special=True)
Tuple.__doc__ = \
"""Tuple type; Tuple[X, Y] is the cross-product type of X and Y.
if hasattr(collections_abc, 'AsyncIterable'):
Example: Tuple[T1, T2] is a tuple of two elements corresponding
to type variables T1 and T2. Tuple[int, float, str] is a tuple
of an int, a float and a string.
class AsyncIterable(Generic[T_co], extra=collections_abc.AsyncIterable):
__slots__ = ()
To specify a variable-length tuple of homogeneous type, use Tuple[T, ...].
"""
List = _alias(list, T, inst=False)
Deque = _alias(collections.deque, T)
Set = _alias(set, T, inst=False)
FrozenSet = _alias(frozenset, T_co, inst=False)
MappingView = _alias(collections.abc.MappingView, T_co)
KeysView = _alias(collections.abc.KeysView, KT)
ItemsView = _alias(collections.abc.ItemsView, (KT, VT_co))
ValuesView = _alias(collections.abc.ValuesView, VT_co)
ContextManager = _alias(contextlib.AbstractContextManager, T_co)
AsyncContextManager = _alias(contextlib.AbstractAsyncContextManager, T_co)
Dict = _alias(dict, (KT, VT), inst=False)
DefaultDict = _alias(collections.defaultdict, (KT, VT))
Counter = _alias(collections.Counter, T)
ChainMap = _alias(collections.ChainMap, (KT, VT))
Generator = _alias(collections.abc.Generator, (T_co, T_contra, V_co))
AsyncGenerator = _alias(collections.abc.AsyncGenerator, (T_co, T_contra))
Type = _alias(type, CT_co, inst=False)
Type.__doc__ = \
"""A special construct usable to annotate class objects.
class AsyncIterator(AsyncIterable[T_co],
extra=collections_abc.AsyncIterator):
__slots__ = ()
For example, suppose we have the following classes::
__all__.append('AsyncIterable')
__all__.append('AsyncIterator')
class User: ... # Abstract base for User classes
class BasicUser(User): ...
class ProUser(User): ...
class TeamUser(User): ...
And a function that takes a class argument that's a subclass of
User and returns an instance of the corresponding class::
class Iterable(Generic[T_co], extra=collections_abc.Iterable):
__slots__ = ()
U = TypeVar('U', bound=User)
def new_user(user_class: Type[U]) -> U:
user = user_class()
# (Here we could write the user object to a database)
return user
joe = new_user(BasicUser)
class Iterator(Iterable[T_co], extra=collections_abc.Iterator):
__slots__ = ()
At this point the type checker knows that joe has type BasicUser.
"""
class SupportsInt(_Protocol):
......@@ -1790,316 +1305,6 @@ class SupportsRound(_Protocol[T_co]):
pass
if hasattr(collections_abc, 'Reversible'):
class Reversible(Iterable[T_co], extra=collections_abc.Reversible):
__slots__ = ()
else:
class Reversible(_Protocol[T_co]):
__slots__ = ()
@abstractmethod
def __reversed__(self) -> 'Iterator[T_co]':
pass
Sized = collections_abc.Sized # Not generic.
class Container(Generic[T_co], extra=collections_abc.Container):
__slots__ = ()
if hasattr(collections_abc, 'Collection'):
class Collection(Sized, Iterable[T_co], Container[T_co],
extra=collections_abc.Collection):
__slots__ = ()
__all__.append('Collection')
# Callable was defined earlier.
if hasattr(collections_abc, 'Collection'):
class AbstractSet(Collection[T_co],
extra=collections_abc.Set):
__slots__ = ()
else:
class AbstractSet(Sized, Iterable[T_co], Container[T_co],
extra=collections_abc.Set):
__slots__ = ()
class MutableSet(AbstractSet[T], extra=collections_abc.MutableSet):
__slots__ = ()
# NOTE: It is only covariant in the value type.
if hasattr(collections_abc, 'Collection'):
class Mapping(Collection[KT], Generic[KT, VT_co],
extra=collections_abc.Mapping):
__slots__ = ()
else:
class Mapping(Sized, Iterable[KT], Container[KT], Generic[KT, VT_co],
extra=collections_abc.Mapping):
__slots__ = ()
class MutableMapping(Mapping[KT, VT], extra=collections_abc.MutableMapping):
__slots__ = ()
if hasattr(collections_abc, 'Reversible'):
if hasattr(collections_abc, 'Collection'):
class Sequence(Reversible[T_co], Collection[T_co],
extra=collections_abc.Sequence):
__slots__ = ()
else:
class Sequence(Sized, Reversible[T_co], Container[T_co],
extra=collections_abc.Sequence):
__slots__ = ()
else:
class Sequence(Sized, Iterable[T_co], Container[T_co],
extra=collections_abc.Sequence):
__slots__ = ()
class MutableSequence(Sequence[T], extra=collections_abc.MutableSequence):
__slots__ = ()
class ByteString(Sequence[int], extra=collections_abc.ByteString):
__slots__ = ()
class List(list, MutableSequence[T], extra=list):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is List:
raise TypeError("Type List cannot be instantiated; "
"use list() instead")
return _generic_new(list, cls, *args, **kwds)
class Deque(collections.deque, MutableSequence[T], extra=collections.deque):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Deque:
return collections.deque(*args, **kwds)
return _generic_new(collections.deque, cls, *args, **kwds)
class Set(set, MutableSet[T], extra=set):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Set:
raise TypeError("Type Set cannot be instantiated; "
"use set() instead")
return _generic_new(set, cls, *args, **kwds)
class FrozenSet(frozenset, AbstractSet[T_co], extra=frozenset):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is FrozenSet:
raise TypeError("Type FrozenSet cannot be instantiated; "
"use frozenset() instead")
return _generic_new(frozenset, cls, *args, **kwds)
class MappingView(Sized, Iterable[T_co], extra=collections_abc.MappingView):
__slots__ = ()
class KeysView(MappingView[KT], AbstractSet[KT],
extra=collections_abc.KeysView):
__slots__ = ()
class ItemsView(MappingView[Tuple[KT, VT_co]],
AbstractSet[Tuple[KT, VT_co]],
Generic[KT, VT_co],
extra=collections_abc.ItemsView):
__slots__ = ()
class ValuesView(MappingView[VT_co], extra=collections_abc.ValuesView):
__slots__ = ()
if hasattr(contextlib, 'AbstractContextManager'):
class ContextManager(Generic[T_co], extra=contextlib.AbstractContextManager):
__slots__ = ()
else:
class ContextManager(Generic[T_co]):
__slots__ = ()
def __enter__(self):
return self
@abc.abstractmethod
def __exit__(self, exc_type, exc_value, traceback):
return None
@classmethod
def __subclasshook__(cls, C):
if cls is ContextManager:
# In Python 3.6+, it is possible to set a method to None to
# explicitly indicate that the class does not implement an ABC
# (https://bugs.python.org/issue25958), but we do not support
# that pattern here because this fallback class is only used
# in Python 3.5 and earlier.
if (any("__enter__" in B.__dict__ for B in C.__mro__) and
any("__exit__" in B.__dict__ for B in C.__mro__)):
return True
return NotImplemented
if hasattr(contextlib, 'AbstractAsyncContextManager'):
class AsyncContextManager(Generic[T_co],
extra=contextlib.AbstractAsyncContextManager):
__slots__ = ()
__all__.append('AsyncContextManager')
elif sys.version_info[:2] >= (3, 5):
exec("""
class AsyncContextManager(Generic[T_co]):
__slots__ = ()
async def __aenter__(self):
return self
@abc.abstractmethod
async def __aexit__(self, exc_type, exc_value, traceback):
return None
@classmethod
def __subclasshook__(cls, C):
if cls is AsyncContextManager:
if sys.version_info[:2] >= (3, 6):
return _collections_abc._check_methods(C, "__aenter__", "__aexit__")
if (any("__aenter__" in B.__dict__ for B in C.__mro__) and
any("__aexit__" in B.__dict__ for B in C.__mro__)):
return True
return NotImplemented
__all__.append('AsyncContextManager')
""")
class Dict(dict, MutableMapping[KT, VT], extra=dict):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Dict:
raise TypeError("Type Dict cannot be instantiated; "
"use dict() instead")
return _generic_new(dict, cls, *args, **kwds)
class DefaultDict(collections.defaultdict, MutableMapping[KT, VT],
extra=collections.defaultdict):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is DefaultDict:
return collections.defaultdict(*args, **kwds)
return _generic_new(collections.defaultdict, cls, *args, **kwds)
class Counter(collections.Counter, Dict[T, int], extra=collections.Counter):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Counter:
return collections.Counter(*args, **kwds)
return _generic_new(collections.Counter, cls, *args, **kwds)
if hasattr(collections, 'ChainMap'):
# ChainMap only exists in 3.3+
__all__.append('ChainMap')
class ChainMap(collections.ChainMap, MutableMapping[KT, VT],
extra=collections.ChainMap):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is ChainMap:
return collections.ChainMap(*args, **kwds)
return _generic_new(collections.ChainMap, cls, *args, **kwds)
# Determine what base class to use for Generator.
if hasattr(collections_abc, 'Generator'):
# Sufficiently recent versions of 3.5 have a Generator ABC.
_G_base = collections_abc.Generator
else:
# Fall back on the exact type.
_G_base = types.GeneratorType
class Generator(Iterator[T_co], Generic[T_co, T_contra, V_co],
extra=_G_base):
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls._gorg is Generator:
raise TypeError("Type Generator cannot be instantiated; "
"create a subclass instead")
return _generic_new(_G_base, cls, *args, **kwds)
if hasattr(collections_abc, 'AsyncGenerator'):
class AsyncGenerator(AsyncIterator[T_co], Generic[T_co, T_contra],
extra=collections_abc.AsyncGenerator):
__slots__ = ()
__all__.append('AsyncGenerator')
# Internal type variable used for Type[].
CT_co = TypeVar('CT_co', covariant=True, bound=type)
# This is not a real generic class. Don't use outside annotations.
class Type(Generic[CT_co], extra=type):
"""A special construct usable to annotate class objects.
For example, suppose we have the following classes::
class User: ... # Abstract base for User classes
class BasicUser(User): ...
class ProUser(User): ...
class TeamUser(User): ...
And a function that takes a class argument that's a subclass of
User and returns an instance of the corresponding class::
U = TypeVar('U', bound=User)
def new_user(user_class: Type[U]) -> U:
user = user_class()
# (Here we could write the user object to a database)
return user
joe = new_user(BasicUser)
At this point the type checker knows that joe has type BasicUser.
"""
__slots__ = ()
def _make_nmtuple(name, types):
msg = "NamedTuple('Name', [(f0, t0), (f1, t1), ...]); each t must be a type"
types = [(n, _type_check(t, msg)) for n, t in types]
......@@ -2114,8 +1319,6 @@ def _make_nmtuple(name, types):
return nm_tpl
_PY36 = sys.version_info[:2] >= (3, 6)
# attributes prohibited to set in NamedTuple class syntax
_prohibited = ('__new__', '__init__', '__slots__', '__getnewargs__',
'_fields', '_field_defaults', '_field_types',
......@@ -2129,9 +1332,6 @@ class NamedTupleMeta(type):
def __new__(cls, typename, bases, ns):
if ns.get('_root', False):
return super().__new__(cls, typename, bases, ns)
if not _PY36:
raise TypeError("Class syntax for NamedTuple is only supported"
" in Python 3.6+")
types = ns.get('__annotations__', {})
nm_tpl = _make_nmtuple(typename, types.items())
defaults = []
......@@ -2186,9 +1386,6 @@ class NamedTuple(metaclass=NamedTupleMeta):
_root = True
def __new__(self, typename, fields=None, **kwargs):
if kwargs and not _PY36:
raise TypeError("Keyword syntax for NamedTuple is only supported"
" in Python 3.6+")
if fields is None:
fields = kwargs.items()
elif kwargs:
......@@ -2384,12 +1581,8 @@ class io:
io.__name__ = __name__ + '.io'
sys.modules[io.__name__] = io
Pattern = _TypeAlias('Pattern', AnyStr, type(stdlib_re.compile('')),
lambda p: p.pattern)
Match = _TypeAlias('Match', AnyStr, type(stdlib_re.match('', '')),
lambda m: m.re.pattern)
Pattern = _alias(stdlib_re.Pattern, AnyStr)
Match = _alias(stdlib_re.Match, AnyStr)
class re:
"""Wrapper namespace for re type aliases."""
......
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