Skip to content

bpo-43224: Implement substitution of unpacked TypeVarTuple #31800

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
serhiy-storchaka merged 5 commits into from
Mar 11, 2022
Merged

bpo-43224: Implement substitution of unpacked TypeVarTuple #31800

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
4fab260
bpo-43224: Implement substitution of unpacked TypeVarTuple
serhiy-storchaka Mar 10, 2022
8a8cf5d
Support multiple type variables
serhiy-storchaka Mar 11, 2022
a376210
Add tests for Tuple.
serhiy-storchaka Mar 11, 2022
b0412ec
Merge branch 'main' into typevartuple-subst
serhiy-storchaka Mar 11, 2022
425d779
Simplify.
serhiy-storchaka Mar 11, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
93 changes: 35 additions & 58 deletions Lib/test/test_typing.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -390,6 +390,10 @@ def test_cannot_be_called(self):

class TypeVarTupleTests(BaseTestCase):

def assertEndsWith(self, string, tail):
if not string.endswith(tail):
self.fail(f"String {string!r} does not end with {tail!r}")

def test_instance_is_equal_to_itself(self):
Ts = TypeVarTuple('Ts')
self.assertEqual(Ts, Ts)
Expand Down Expand Up @@ -449,78 +453,51 @@ def test_variadic_class_repr_is_correct(self):
Ts = TypeVarTuple('Ts')
class A(Generic[Unpack[Ts]]): pass

self.assertTrue(repr(A[()]).endswith('A[()]'))
self.assertTrue(repr(A[float]).endswith('A[float]'))
self.assertTrue(repr(A[float, str]).endswith('A[float, str]'))
self.assertTrue(repr(
A[Unpack[tuple[int, ...]]]
).endswith(
'A[*tuple[int, ...]]'
))
self.assertTrue(repr(
A[float, Unpack[tuple[int, ...]]]
).endswith(
'A[float, *tuple[int, ...]]'
))
self.assertTrue(repr(
A[Unpack[tuple[int, ...]], str]
).endswith(
'A[*tuple[int, ...], str]'
))
self.assertTrue(repr(
A[float, Unpack[tuple[int, ...]], str]
).endswith(
'A[float, *tuple[int, ...], str]'
))
self.assertEndsWith(repr(A[()]), 'A[()]')
self.assertEndsWith(repr(A[float]), 'A[float]')
self.assertEndsWith(repr(A[float, str]), 'A[float, str]')
self.assertEndsWith(repr(A[Unpack[tuple[int, ...]]]),
'A[*tuple[int, ...]]')
self.assertEndsWith(repr(A[float, Unpack[tuple[int, ...]]]),
'A[float, *tuple[int, ...]]')
self.assertEndsWith(repr(A[Unpack[tuple[int, ...]], str]),
'A[*tuple[int, ...], str]')
self.assertEndsWith(repr(A[float, Unpack[tuple[int, ...]], str]),
'A[float, *tuple[int, ...], str]')

def test_variadic_class_alias_repr_is_correct(self):
Ts = TypeVarTuple('Ts')
class A(Generic[Unpack[Ts]]): pass

B = A[Unpack[Ts]]
self.assertTrue(repr(B).endswith('A[*Ts]'))
with self.assertRaises(NotImplementedError):
B[()]
with self.assertRaises(NotImplementedError):
B[float]
with self.assertRaises(NotImplementedError):
B[float, str]
self.assertEndsWith(repr(B), 'A[*Ts]')
self.assertEndsWith(repr(B[()]), 'A[()]')
self.assertEndsWith(repr(B[float]), 'A[float]')
self.assertEndsWith(repr(B[float, str]), 'A[float, str]')

C = A[Unpack[Ts], int]
self.assertTrue(repr(C).endswith('A[*Ts, int]'))
with self.assertRaises(NotImplementedError):
C[()]
with self.assertRaises(NotImplementedError):
C[float]
with self.assertRaises(NotImplementedError):
C[float, str]
self.assertEndsWith(repr(C), 'A[*Ts, int]')
self.assertEndsWith(repr(C[()]), 'A[int]')
self.assertEndsWith(repr(C[float]), 'A[float, int]')
self.assertEndsWith(repr(C[float, str]), 'A[float, str, int]')

D = A[int, Unpack[Ts]]
self.assertTrue(repr(D).endswith('A[int, *Ts]'))
with self.assertRaises(NotImplementedError):
D[()]
with self.assertRaises(NotImplementedError):
D[float]
with self.assertRaises(NotImplementedError):
D[float, str]
self.assertEndsWith(repr(D), 'A[int, *Ts]')
self.assertEndsWith(repr(D[()]), 'A[int]')
self.assertEndsWith(repr(D[float]), 'A[int, float]')
self.assertEndsWith(repr(D[float, str]), 'A[int, float, str]')

E = A[int, Unpack[Ts], str]
self.assertTrue(repr(E).endswith('A[int, *Ts, str]'))
with self.assertRaises(NotImplementedError):
E[()]
with self.assertRaises(NotImplementedError):
E[float]
with self.assertRaises(NotImplementedError):
E[float, bool]
self.assertEndsWith(repr(E), 'A[int, *Ts, str]')
self.assertEndsWith(repr(E[()]), 'A[int, str]')
self.assertEndsWith(repr(E[float]), 'A[int, float, str]')
self.assertEndsWith(repr(E[float, str]), 'A[int, float, str, str]')

F = A[Unpack[Ts], Unpack[tuple[str, ...]]]
self.assertTrue(repr(F).endswith('A[*Ts, *tuple[str, ...]]'))
with self.assertRaises(NotImplementedError):
F[()]
with self.assertRaises(NotImplementedError):
F[float]
with self.assertRaises(NotImplementedError):
F[float, int]
self.assertEndsWith(repr(F), 'A[*Ts, *tuple[str, ...]]')
self.assertEndsWith(repr(F[()]), 'A[*tuple[str, ...]]')
self.assertEndsWith(repr(F[float]), 'A[float, *tuple[str, ...]]')
self.assertEndsWith(repr(F[float, str]), 'A[float, str, *tuple[str, ...]]')

def test_cannot_subclass_class(self):
with self.assertRaises(TypeError):
Expand Down
6 changes: 2 additions & 4 deletions Lib/typing.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1281,10 +1281,8 @@ def _determine_new_args(self, args):
# anything more exotic than a plain `TypeVar`, we need to consider
# edge cases.

if any(isinstance(p, TypeVarTuple) for p in self.__parameters__):
raise NotImplementedError(
"Type substitution for TypeVarTuples is not yet implemented"
)
if len(self.__parameters__) == 1 and isinstance(self.__parameters__[0], TypeVarTuple):
Copy link
Contributor

@mrahtz mrahtz Mar 10, 2022

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not sure it's sufficient to only check for the case where len(self.__parameters__) == 1 - we could have e.g.:

T1 = TypeVar('T1')
T2 = TypeVar('T2')
Ts = TypeVarTuple('Ts')
class A(Generic[T1, T2, Unpack[Ts]]): pass
B = A[int, T2, Unpack[Ts]]
C = B[str, float]
print(C)

There, B.__parameters__ is (T2, Ts), causing a TypeError later on in the code.

Copy link
Member Author

@serhiy-storchaka serhiy-storchaka Mar 11, 2022

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

You are right. The previous code only worked with existing tests. New code adds tests for generics with multiple type variables.

args = args,
# In the example above, this would be {T3: str}
new_arg_by_param = dict(zip(self.__parameters__, args))

Expand Down