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typing.get_type_hints fails when passed a class with PEP 695 type parameters and PEP 563 is enabled #114053

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typing.get_type_hints fails when passed a class with PEP 695 type parameters and PEP 563 is enabled#114053
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AlexWaygood
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3.12only security fixes3.13only security fixesstdlibStandard Library Python modules in the Lib/ directorytopic-typingtype-bugAn unexpected behavior, bug, or error

Description

@mjog
mjog
opened on Jan 14, 2024

Bug report

Bug description:

from __future__ import annotations

import typing

class Test[M]:
    attr: M

print(typing.get_type_hints(Test))

This fails with a NameError:

$ poetry run python3 pep_695_get_type_hints.py
Traceback (most recent call last):
  File "/home/mjog/pep_695_get_type_hints.py", line 8, in <module>
    print(typing.get_type_hints(Test))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/typing.py", line 2197, in get_type_hints
    value = _eval_type(value, base_globals, base_locals)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/typing.py", line 393, in _eval_type
    return t._evaluate(globalns, localns, recursive_guard)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/typing.py", line 900, in _evaluate
    eval(self.__forward_code__, globalns, localns),
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<string>", line 1, in <module>
NameError: name 'M' is not defined

Although get_type_hints does not work with imported imported type aliases, this is not imported, so I would expect it to work. Further, the documentation for the function indicates using PEP 563 should /help/, but in this case it actually causes an error.

FWIW, removing the PEP 563 import works fine, giving:

{'attr': M}

Python version:

$ poetry run python3 --version
Python 3.12.0

CPython versions tested on:

3.12

Operating systems tested on:

Linux

Linked PRs

Activity

  1. mjog
    added
    type-bugAn unexpected behavior, bug, or error
    on Jan 14, 2024
  2. Eclips4
    added
    topic-typing
    3.12only security fixes
    3.13only security fixes
    on Jan 14, 2024

  3. mjog commented on Jan 14, 2024

    @mjog
    mjog
    on Jan 14, 2024 · Hidden as outdated
    Author
  4. mjog
    changed the title [-]typing.get_type_hints fails when passed a class with PEP 695 type parameters and PEP 563 is enabled[/-] [+]typing.get_type_hints fails when passed a generic class and PEP 563 is enabled[/+] on Jan 14, 2024
  5. mjog
    changed the title [-]typing.get_type_hints fails when passed a generic class and PEP 563 is enabled[/-] [+]typing.get_type_hints fails when passed a class with PEP 695 type parameters and PEP 563 is enabled[/+] on Jan 15, 2024

  6. mjog commented on Jan 15, 2024

    @mjog
    mjog
    on Jan 15, 2024
    Author

    Sorry, my now-hidden comment above is incorrect - it does work fine with pre-695 generic classes, I just had a typo in the code.

    This is only an issue with PEP 695 type parameters in conjunction with PEP 563.

  7. treykeown commented on Jan 19, 2024

    @treykeown
    treykeown
    on Jan 19, 2024

    +1, just ran into this as well.

  8. AlexWaygood commented on Apr 17, 2024

    @AlexWaygood
    AlexWaygood
    on Apr 17, 2024
    Member

    I suppose the problem is probably that get_type_hints looks things up in the global scope but doesn't look things up in the new annotation scopes introduced by PEP-695. The old way of defining TypeVars doesn't suffer from this because TypeVars were defined in the global scope; now they aren't.

  9. AlexWaygood
    added 4 commits that reference this issue on Apr 17, 2024

    pythongh-114053: Fix bad interaction of PEP-695, PEP-563 and ``get_ty…

    c76bfc0

    gh-114053: Fix bad interaction of PEP-695, PEP-563 and ``get_type_hin…

    1e3e7ce

    [3.12] pythongh-114053: Fix bad interaction of PEP-695, PEP-563 and `…

    58a86e5

    [3.12] gh-114053: Fix bad interaction of PEP-695, PEP-563 and ``get_t…

    5430f61
  10. AlexWaygood
    closed this as completedon Apr 19, 2024

  11. 9 remaining items

  12. miss-islington
    added a commit that references this issue on Jun 13, 2024

    pythongh-114053: Fix bad interaction of PEP 695, PEP 563 and `inspect…

    5b88dca
  13. AlexWaygood
    added 2 commits that reference this issue on Jun 13, 2024

    [3.12] gh-114053: Fix bad interaction of PEP 695, PEP 563 and `inspec…

    1834453

    [3.13] gh-114053: Fix bad interaction of PEP 695, PEP 563 and `inspec…

    d4174fa
  14. AlexWaygood
    added a commit that references this issue on Jun 25, 2024

    gh-114053: Fix another edge case involving `get_type_hints`, PEP 695 …

    2d3187b
  15. miss-islington
    added 2 commits that reference this issue on Jun 25, 2024

    pythongh-114053: Fix another edge case involving `get_type_hints`, PE…

    91ed17c

    pythongh-114053: Fix another edge case involving `get_type_hints`, PE…

    62f3c3b
  16. AlexWaygood
    closed this as completedon Jun 25, 2024
  17. AlexWaygood
    added 2 commits that reference this issue on Jun 25, 2024

    [3.13] gh-114053: Fix another edge case involving `get_type_hints`, P…

    f4f8a71

    [3.12] gh-114053: Fix another edge case involving `get_type_hints`, P…

    a85241d
  18. mrahtz
    added 2 commits that reference this issue on Jun 30, 2024

    pythongh-114053: Fix bad interaction of PEP 695, PEP 563 and `inspect…

    6211f9d

    pythongh-114053: Fix another edge case involving `get_type_hints`, PE…

    7357059
  19. noahbkim
    added 2 commits that reference this issue on Jul 11, 2024

    pythongh-114053: Fix bad interaction of PEP 695, PEP 563 and `inspect…

    d87297d

    pythongh-114053: Fix another edge case involving `get_type_hints`, PE…

    7dcc9e0
  20. estyxx
    added 2 commits that reference this issue on Jul 17, 2024

    pythongh-114053: Fix bad interaction of PEP 695, PEP 563 and `inspect…

    6171713

    pythongh-114053: Fix another edge case involving `get_type_hints`, PE…

    f62761c
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3.12only security fixes3.13only security fixesstdlibStandard Library Python modules in the Lib/ directorytopic-typingtype-bugAn unexpected behavior, bug, or error

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