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Merged
merged 27 commits into from
Dec 24, 2020
Merged

bpo-41559: Implement PEP 612 - Add ParamSpec and Concatenate to typing #23702

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219b4ee
Add ParamSpec and Concatenate
Fidget-Spinner Dec 8, 2020
a1c0d0a
support ParamSpec in generics
Fidget-Spinner Dec 8, 2020
7b3beab
Add typing tests, disallow Concatenate in other types
Fidget-Spinner Dec 9, 2020
5dd3b44
Add news
Fidget-Spinner Dec 9, 2020
59c0b20
Address some of Guido's review comments
Fidget-Spinner Dec 10, 2020
4c381b3
remove extraneous empty lines
Fidget-Spinner Dec 10, 2020
b36b62d
Support ParamSpec in __parameters__ of typing and builtin GenericAlias
Fidget-Spinner Dec 10, 2020
d09d088
add tests for user defined generics
Fidget-Spinner Dec 10, 2020
0a19f34
Merge remote-tracking branch 'upstream/master' into pep612
Fidget-Spinner Dec 14, 2020
9727e2a
cast list to tuple done, loosened type checks for Generic
Fidget-Spinner Dec 14, 2020
cc7fc1c
loosen generics, allow typevar-like subst, flatten out args if Callable
Fidget-Spinner Dec 15, 2020
3e67f23
fix whitespace issue, cast list to tuple for types.GenericAlias
Fidget-Spinner Dec 15, 2020
d9baa1a
convert list to tuples if substituting paramspecs in types.GenericAlias
Fidget-Spinner Dec 16, 2020
c4155b6
done! flattened __args__ in substitutions for collections.abc.Callable
Fidget-Spinner Dec 16, 2020
2dbf861
fix repr problems, add repr tests
Fidget-Spinner Dec 16, 2020
87c2d19
Add another test for multiple chaining
Fidget-Spinner Dec 16, 2020
2b09de6
fix typo
Fidget-Spinner Dec 16, 2020
d980702
Clean up some comments
Fidget-Spinner Dec 17, 2020
45f7894
Merge remote-tracking branch 'upstream/master' into pep612
Fidget-Spinner Dec 22, 2020
d6f777c
remove stray whitespace
Fidget-Spinner Dec 22, 2020
9a8176b
Address nearly all of Guido's reviews
Fidget-Spinner Dec 23, 2020
fa06838
more reviews; fix some docstrings, clean up code, cast list to tuple …
Fidget-Spinner Dec 23, 2020
b8672cd
remove uneeded tests copied over from typevar
Fidget-Spinner Dec 23, 2020
51a463c
remove unused variable
Fidget-Spinner Dec 23, 2020
6d5b754
Merge remote-tracking branch 'upstream/master' into pep612
Fidget-Spinner Dec 24, 2020
c05d5d7
merge length checking into _has_special_args too
Fidget-Spinner Dec 24, 2020
c49ba30
Update Lib/_collections_abc.py
gvanrossum Dec 24, 2020
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185 changes: 165 additions & 20 deletions Lib/test/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
from typing import Pattern, Match
from typing import Annotated, ForwardRef
from typing import TypeAlias
from typing import ParamSpec, Concatenate
import abc
import typing
import weakref
Expand Down Expand Up @@ -1573,7 +1574,8 @@ class C(B[int]):

def test_subscripted_generics_as_proxies(self):
T = TypeVar('T')
class C(Generic[T]):
P = ParamSpec('T')
class C(Generic[T, P]):
x = 'def'
self.assertEqual(C[int].x, 'def')
self.assertEqual(C[C[int]].x, 'def')
Expand Down Expand Up @@ -1705,11 +1707,12 @@ class Meta(type): ...
self.assertEqual(Callable[..., Meta].__args__, (Ellipsis, Meta))

def test_generic_hashes(self):
class A(Generic[T]):
P = ParamSpec('P')
class A(Generic[T, P]):
...

class B(Generic[T]):
class A(Generic[T]):
class B(Generic[T, P]):
class A(Generic[T, P]):
...

self.assertEqual(A, A)
Expand Down Expand Up @@ -1892,8 +1895,10 @@ def test_all_repr_eq_any(self):
def test_pickle(self):
global C # pickle wants to reference the class by name
T = TypeVar('T')
global P
P = ParamSpec('P')

class B(Generic[T]):
class B(Generic[T, P]):
pass

class C(B[int]):
Expand All @@ -1917,7 +1922,8 @@ class C(B[int]):
x = pickle.loads(z)
self.assertEqual(s, x)
more_samples = [List, typing.Iterable, typing.Type, List[int],
typing.Type[typing.Mapping], typing.AbstractSet[Tuple[int, str]]]
typing.Type[typing.Mapping], typing.AbstractSet[Tuple[int, str]],
Concatenate[int, P]]
for s in more_samples:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
z = pickle.dumps(s, proto)
Expand All @@ -1926,7 +1932,8 @@ class C(B[int]):

def test_copy_and_deepcopy(self):
T = TypeVar('T')
class Node(Generic[T]): ...
P = ParamSpec('P')
class Node(Generic[T, P]): ...
things = [Union[T, int], Tuple[T, int], Callable[..., T], Callable[[int], int],
Tuple[Any, Any], Node[T], Node[int], Node[Any], typing.Iterable[T],
typing.Iterable[Any], typing.Iterable[int], typing.Dict[int, str],
Expand Down Expand Up @@ -1958,7 +1965,10 @@ def test_immutability_by_copy_and_pickle(self):

def test_copy_generic_instances(self):
T = TypeVar('T')
class C(Generic[T]):
P = ParamSpec('P')

class C(Generic[T, P]):
f: Callable[P, int]
def __init__(self, attr: T) -> None:
self.attr = attr

Expand Down Expand Up @@ -1990,7 +2000,9 @@ def test_weakref_all(self):

def test_parameterized_slots(self):
T = TypeVar('T')
class C(Generic[T]):
P = ParamSpec('P')

class C(Generic[T, P]):
__slots__ = ('potato',)

c = C()
Expand All @@ -2009,7 +2021,9 @@ def foo(x: C['C']): ...

def test_parameterized_slots_dict(self):
T = TypeVar('T')
class D(Generic[T]):
P = ParamSpec('P')

class D(Generic[T, P]):
__slots__ = {'banana': 42}

d = D()
Expand All @@ -2030,7 +2044,9 @@ class C(Generic[B]):
pass

def test_repr_2(self):
class C(Generic[T]):
P = ParamSpec('P')

class C(Generic[T, P]):
pass

self.assertEqual(C.__module__, __name__)
Expand Down Expand Up @@ -2066,8 +2082,9 @@ class B(Generic[T]):
self.assertNotEqual(A[T], B[T])

def test_multiple_inheritance(self):
P = ParamSpec('P')

class A(Generic[T, VT]):
class A(Generic[T, VT, P]):
pass

class B(Generic[KT, T]):
Expand All @@ -2080,7 +2097,9 @@ class C(A[T, VT], Generic[VT, T, KT], B[KT, T]):

def test_multiple_inheritance_special(self):
S = TypeVar('S')
class B(Generic[S]): ...
P = ParamSpec('P')

class B(Generic[S, P]): ...
class C(List[int], B): ...
self.assertEqual(C.__mro__, (C, list, B, Generic, object))

Expand All @@ -2094,7 +2113,8 @@ def __init_subclass__(cls, **kwargs) -> None:
if base is not Final and issubclass(base, Final):
raise FinalException(base)
super().__init_subclass__(**kwargs)
class Test(Generic[T], Final):
P = ParamSpec('P')
class Test(Generic[T, P], Final):
pass
with self.assertRaises(FinalException):
class Subclass(Test):
Expand All @@ -2104,10 +2124,10 @@ class Subclass(Test[int]):
pass

def test_nested(self):

P = ParamSpec('P')
G = Generic

class Visitor(G[T]):
class Visitor(G[T, P]):

a = None

Expand Down Expand Up @@ -2135,8 +2155,9 @@ def append(self, x: int):

def test_type_erasure(self):
T = TypeVar('T')
P = ParamSpec('P')

class Node(Generic[T]):
class Node(Generic[T, P]):
def __init__(self, label: T,
left: 'Node[T]' = None,
right: 'Node[T]' = None):
Expand All @@ -2159,8 +2180,9 @@ def foo(x: T):

def test_implicit_any(self):
T = TypeVar('T')
P = ParamSpec('P')

class C(Generic[T]):
class C(Generic[T, P]):
pass

class D(C):
Expand All @@ -2176,8 +2198,9 @@ class D(C):
D[T]

def test_new_with_args(self):
P = ParamSpec('P')

class A(Generic[T]):
class A(Generic[T, P]):
pass

class B:
Expand Down Expand Up @@ -2214,8 +2237,9 @@ def __init__(self, arg):
self.assertEqual(c.from_c, 'foo')

def test_new_no_args(self):
P = ParamSpec('P')

class A(Generic[T]):
class A(Generic[T, P]):
pass

with self.assertRaises(TypeError):
Expand Down Expand Up @@ -4253,6 +4277,127 @@ def test_cannot_subscript(self):
TypeAlias[int]


class ParamSpecTests(BaseTestCase):

def test_basic_plain(self):
P = ParamSpec('P')
self.assertEqual(P, P)
self.assertIsInstance(P, ParamSpec)

def test_valid_uses(self):
P = ParamSpec('P')
T = TypeVar('T')
C1 = Callable[P, int]
self.assertEqual(C1.__args__, (P, int))
self.assertEqual(C1.__parameters__, ())
C2 = Callable[P, T]
self.assertEqual(C2.__args__, (P, T))
self.assertEqual(C2.__parameters__, (T,))
# Test collections.abc.Callable too.
C3 = collections.abc.Callable[P, int]
self.assertEqual(C3.__args__, (P, int))
self.assertEqual(C3.__parameters__, ())
C4 = collections.abc.Callable[P, T]
self.assertEqual(C4.__args__, (P, T))
self.assertEqual(C4.__parameters__, (T,))

# ParamSpec instances should also have args and kwargs attributes.
self.assertIn('args', dir(P))
self.assertIn('kwargs', dir(P))
P.args
P.kwargs

def test_instance_type_error(self):
P = ParamSpec('P')
with self.assertRaises(TypeError):
isinstance(42, P)

def test_instance_type_error(self):
P = ParamSpec('P')
with self.assertRaises(TypeError):
issubclass(int, P)
with self.assertRaises(TypeError):
issubclass(P, int)

def test_union_unique(self):
P1 = ParamSpec('P1')
P2 = ParamSpec('P2')
self.assertNotEqual(P1, P2)
self.assertEqual(Union[P1], P1)
self.assertNotEqual(Union[P1], Union[P1, P2])
self.assertEqual(Union[P1, P1], P1)
self.assertNotEqual(Union[P1, int], Union[P1])
self.assertNotEqual(Union[P1, int], Union[int])
self.assertEqual(Union[P1, int].__args__, (P1, int))
self.assertEqual(Union[P1, int].__parameters__, ())
self.assertIs(Union[P1, int].__origin__, Union)

def test_repr(self):
P = ParamSpec('P')
self.assertEqual(repr(P), '~P')
P_co = ParamSpec('P_co', covariant=True)
self.assertEqual(repr(P_co), '+P_co')
P_contra = ParamSpec('P_contra', contravariant=True)
self.assertEqual(repr(P_contra), '-P_contra')

def test_no_redefinition(self):
self.assertNotEqual(ParamSpec('P'), ParamSpec('P'))
self.assertNotEqual(ParamSpec('P', int, str), ParamSpec('P', int, str))

def test_cannot_subclass_vars(self):
with self.assertRaises(TypeError):
class V(ParamSpec('P')):
pass

def test_cannot_subclass_var_itself(self):
with self.assertRaises(TypeError):
class V(ParamSpec):
pass

def test_cannot_instantiate_vars(self):
with self.assertRaises(TypeError):
ParamSpec('A')()

def test_no_bivariant(self):
with self.assertRaises(ValueError):
ParamSpec('P', covariant=True, contravariant=True)


class ConcatenateTests(BaseTestCase):
def test_basics(self):
P = ParamSpec('P')
class MyClass: ...
c = Concatenate[MyClass, P]
self.assertNotEqual(c, Concatenate)

def test_valid_uses(self):
P = ParamSpec('P')
T = TypeVar('T')
C1 = Callable[Concatenate[int, P], int]
self.assertEqual(C1.__args__, (Concatenate[int, P], int))
self.assertEqual(C1.__parameters__, ())
C2 = Callable[Concatenate[int, P, T], T]
self.assertEqual(C2.__args__, (Concatenate[int, P, T], T))
self.assertEqual(C2.__parameters__, (T,))

# Test collections.abc.Callable too.
C3 = collections.abc.Callable[Concatenate[int, P], int]
self.assertEqual(C3.__args__, (Concatenate[int, P], int))
self.assertEqual(C3.__parameters__, ())
C4 = collections.abc.Callable[Concatenate[int, P, T], T]
self.assertEqual(C4.__args__, (Concatenate[int, P, T], T))
self.assertEqual(C4.__parameters__, (T,))

def test_disallow_in_other_types(self):
P = ParamSpec('P')
C = Concatenate[int, P]
samples = [Any, Union, Tuple, ClassVar, List,
typing.DefaultDict, typing.FrozenSet]
for s in samples:
with self.subTest(f'{s}'):
with self.assertRaises(TypeError):
s[C]

class AllTests(BaseTestCase):
"""Tests for __all__."""

Expand Down
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