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Weird int.__str__ behaviour inside sub-interpreters #117482

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Weird int.__str__ behaviour inside sub-interpreters#117482
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3.12only security fixes3.13only security fixes3.14bugs and security fixestopic-subinterpreterstype-bugAn unexpected behavior, bug, or error

Description

@mliezun
mliezun
opened on Apr 2, 2024

Bug report

Bug description:

Hi Python maintainers!

I noticed something weird when using subinterpreters, while converting an Enum to string I get an unexpected result. This occurs in Python 3.12 and 3.13.

Here's an script to reproduce it:

import _xxsubinterpreters as interpreters


script = """from enum import _simple_enum, IntEnum

@_simple_enum(IntEnum)
class MyEnum:
    DATA = 1
    
print(str(MyEnum.DATA))
"""

exec(script)
# Output: 1

interp_id = interpreters.create(isolated=False)
interpreters.run_string(interp_id, script)
# Output: <MyEnum.DATA: 1>, Expected: 1

In all python versions previous to 3.12 this prints "1" two times, on newer versions I get <MyEnum.DATA: 1> when running inside a subinterpreter. For some reason, the __str__ function being used is different on new Python versions.

I also noticed that the function pointed by __str__ is different inside and outside the subinterpreter.

Outside:

...
print(MyEnum.DATA.__str__)
# Output: <method-wrapper '__repr__' of MyEnum object at 0x7f9a09a2e910>

Inside:

...
print(MyEnum.DATA.__str__)
# Output: <method-wrapper '__str__' of MyEnum object at 0x7f9a099a5e90>

NOTE: I'm creating subinterpreters passing the isolated=False flag, which uses the Legacy init config.
I first noticed the error on MacOS, then reproduced using Docker with various Python versions.

I hope this is enough to get to the source of the issue.

Appreciate all your work and effort on building Python, thank you!

CPython versions tested on:

3.8, 3.9, 3.10, 3.11, 3.12, 3.13

Operating systems tested on:

Linux, macOS

Linked PRs

Activity

  1. mliezun
    added
    type-bugAn unexpected behavior, bug, or error
    on Apr 2, 2024
  2. Eclips4
    added
    topic-subinterpreters
    on Apr 2, 2024
  3. github-project-automation
    added this to Subinterpreterson Apr 2, 2024
  4. github-project-automation
    moved this to Todo in Subinterpreterson Apr 2, 2024

  5. Eclips4 commented on Apr 2, 2024

    @Eclips4
    Eclips4
    on Apr 2, 2024
    Member

    Bisected to de64e75

  6. Elchinchel commented on Apr 2, 2024

    @Elchinchel
    Elchinchel
    on Apr 2, 2024

    I think i've got a shorter MRE, i believe this issue is not related to enums.

    import _xxsubinterpreters as interpreters

script = """print(int.__str__)"""


exec(script)
# Output: <slot wrapper '__str__' of 'object' objects>

interp_id = interpreters.create()
interpreters.run_string(interp_id, script)
# Output: <slot wrapper '__str__' of 'int' objects>

  7. Eclips4 commented on Apr 2, 2024

    @Eclips4
    Eclips4
    on Apr 2, 2024
    Member

    I think i've got a shorter MRE, i believe this issue is not related to enums.

    import _xxsubinterpreters as interpreters

script = """print(int.__str__)"""


exec(script)
# Output: <slot wrapper '__str__' of 'object' objects>

interp_id = interpreters.create()
interpreters.run_string(interp_id, script)
# Output: <slot wrapper '__str__' of 'int' objects>

    This sheds light on what is going on. Thanks, @Elchinchel!

  8. Eclips4
    changed the title [-]Weird Enum behaviour inside Subinterpreter[/-] [+]Weird `int.__str__` behaviour inside sub-interpreters[/+] on Apr 2, 2024

  9. mliezun commented on Apr 3, 2024

    @mliezun
    mliezun
    on Apr 3, 2024
    Author

    Awesome! Thanks for looking into this @Eclips4 and @Elchinchel.

    By running the simplified script, I noticed that other base types have the same issue: bool, float, complex.

    The commit de64e75 you mentioned seems to change how the MRO works for base-types. I think that's probably related to the problem.

  10. ericsnowcurrently commented on Jul 10, 2024

    @ericsnowcurrently
    ericsnowcurrently
    on Jul 10, 2024
    Member

    FTR, #117660 (comment) provides further analysis.

  11. ericsnowcurrently
    added
    3.12only security fixes
    3.13only security fixes
    3.14bugs and security fixes
    on Jul 10, 2024
  12. ericsnowcurrently
    added a commit that references this issue on Jul 11, 2024

    gh-117482: Fix Builtin Types Slot Wrappers (gh-121602)

    5250a03
  13. miss-islington
    added a commit that references this issue on Jul 11, 2024

    pythongh-117482: Fix Builtin Types Slot Wrappers (pythongh-121602)

    4b5e638

  14. 8 remaining items

  15. ericsnowcurrently
    added 6 commits that reference this issue on Jul 23, 2024

    [3.13] gh-117482: Expand Tests for Slot Wrappers of Inherited Slots o…

    1d601a1

    pythongh-117482: Expand Tests for Slot Wrappers of Inherited Slots of…

    34cb17d

    [3.12] gh-117482: Expand Tests for Slot Wrappers of Inherited Slots o…

    d7c67e0

    [3.13] gh-117482: Simplify the Fix For Builtin Types Slot Wrappers (g…

    716c677

    [3.13] pythongh-117482: Simplify the Fix For Builtin Types Slot Wrapp…

    a2210ca

    [3.12] gh-117482: Simplify the Fix For Builtin Types Slot Wrappers (g…

    dd4c8ac
  16. nohlson
    added 2 commits that reference this issue on Jul 24, 2024

    pythongh-117482: Expand Tests for Slot Wrappers of Inherited Slots of…

    dac02c1

    pythongh-117482: Expand Tests for Slot Wrappers of Inherited Slots of…

    6568455
  17. ericsnowcurrently
    added 3 commits that reference this issue on Jul 29, 2024

    gh-117482: Fix the Slot Wrapper Inheritance Tests (gh-122248)

    490e0ad

    [3.13] gh-117482: Fix the Slot Wrapper Inheritance Tests (gh-122249)

    10cf7d6

    [3.12] gh-117482: Fix the Slot Wrapper Inheritance Tests (gh-122250)

    5bd2ea2
  18. ericsnowcurrently
    added a commit that references this issue on Aug 12, 2024

    gh-117482: Make the Slot Wrapper Inheritance Tests Much More Thorough (…

    503af8f
  19. blhsing
    added a commit that references this issue on Aug 22, 2024

    pythongh-117482: Make the Slot Wrapper Inheritance Tests Much More Th…

    c10a778
  20. encukou
    added a commit that references this issue on Sep 9, 2024

    gh-117482: Simplify the Fix For Builtin Types Slot Wrappers (GH-122865)

    d8f3c1e

  21. encukou commented on Sep 9, 2024

    @encukou
    encukou
    on Sep 9, 2024
    Member

    Note that current PRs are closed, the issue should stay open. @ericsnowcurrently said in #122865:

    I'll circle back to it in the future, particularly after I've improved
    the tests so no corner cases slip through the cracks.

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