Calling typing.get_type_hints with a class or instance method with PEP 695 type parameters fails if PEP 563 is enabled
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Since Sep 14, 2024.
3.12
3.13
3.14
stdlib
topic-typing
type-bug
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Description
Bug report
Bug description:
from __future__ import annotations
import typing
class Test[M]:
def foo(self, arg: M) -> None:
pass
print(typing.get_type_hints(Test.foo))
$ python3.12 pep_695_pep_563.py
Traceback (most recent call last):
File "/run/host/tmp/test/pep_695_pep_563.py", line 9, in <module>
print(typing.get_type_hints(Test.foo))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib64/python3.12/typing.py", line 2310, in get_type_hints
hints[name] = _eval_type(value, globalns, localns, type_params)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib64/python3.12/typing.py", line 415, in _eval_type
return t._evaluate(globalns, localns, type_params, recursive_guard=recursive_guard)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib64/python3.12/typing.py", line 947, in _evaluate
eval(self.__forward_code__, globalns, localns),
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "<string>", line 1, in <module>
NameError: name 'M' is not defined
This seems very similar to #114053, but with class methods (or instance methods, the result is the same) instead of classes themselves.
Removing the from __future__ import annotations import works fine:
import typing
class Test[M]:
def foo(self, arg: M) -> None:
pass
print(typing.get_type_hints(Test.foo))
$ python3.12 pep_695_no_563.py
{'arg': M, 'return': <class 'NoneType'>}
Using the pre PEP-695 syntax, with or without from __future__ import annotations, works fine as well:
from __future__ import annotations
import typing
M = typing.TypeVar("M")
class Test(typing.Generic[M]):
def foo(self, arg: M) -> None:
pass
print(typing.get_type_hints(Test.foo))
$ python3.12 no_695_pep_563.py
{'arg': ~M, 'return': <class 'NoneType'>}
import typing
M = typing.TypeVar("M")
class Test(typing.Generic[M]):
def foo(self, arg: M) -> None:
pass
print(typing.get_type_hints(Test.foo))
$ python3.12 no_695_no_563.py
{'arg': ~M, 'return': <class 'NoneType'>}
This happens on both 3.12.5 and 3.13.0rc2
CPython versions tested on:
3.12, 3.13
Operating systems tested on:
Linux
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