Description

mhils

opened on Aug 13, 2024

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Bug report

Bug description:

In Python 3.13rc1, inspect.getsource() sometimes returns a "random" line for some objects.
For example, here's ssl.AlertDescription:

$ docker run --rm python:3.13-rc python -c "import inspect, ssl; print(inspect.getsource(ssl.AlertDescription))"
        super().shutdown(how)

This line is likely https://github.com/python/cpython/blob/v3.13.0rc1/Lib/ssl.py#L1334.

In contrast, on 3.12 and below, this raises an OSError (not ideal but also not wrong):

$ docker run --rm python:3.12-rc python -c "import inspect, ssl; print(inspect.getsource(ssl.AlertDescription))"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/local/lib/python3.12/inspect.py", line 1285, in getsource
    lines, lnum = getsourcelines(object)
                  ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/inspect.py", line 1267, in getsourcelines
    lines, lnum = findsource(object)
                  ^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/inspect.py", line 1112, in findsource
    raise OSError('could not find class definition')
OSError: could not find class definition

I'm not sure why this is happening, but it also affects pytest.PytestAssertRewriteWarning and pluggy.PluggyTeardownRaisedWarning, which both extend custom classes that override __module__.

CPython versions tested on:

3.8, 3.9, 3.10, 3.11, 3.12, 3.13

Operating systems tested on:

Linux

Linked PRs

• gh-122981: Fix inspect.getsource() for generated classes with Python base classes #123001
• [3.13] gh-122981: Fix inspect.getsource() for generated classes with Python base classes (GH-123001) #123182

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1. mhils

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Aug 13, 2024
2. devdanzin commented on Aug 14, 2024

   

   devdanzin

   on Aug 14, 2024

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   Bisected to 153b3f7, introduced by #118475.

   It happens because class ssl.AlertDescription now has a __firstlineno__ attribute, and that is erroneously interpreted as a line number in ssl.py. It shares the same line number (1334) with other classes, like SSLErrorNumber, created via IntEnum._convert_. This line number corresponds to IntEnum's line number in enum.py instead.

   So ISTM the issue is that the construction of __firstlineno__ for these classes is capturing the line number of the class generator definition instead of the class creation site.

   cc @serhiy-storchaka
3. serhiy-storchaka

   added a commit that references this issue on Aug 14, 2024

   pythongh-122981: Fix inspect.getsource() for generated classes with P…

   6ee8a73
4. serhiy-storchaka commented on Aug 14, 2024

   

   serhiy-storchaka

   on Aug 14, 2024

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   Thank you for your report @mhils. I agree with @devdanzin analysis. __firstlineno__ is not set for these enum classes, but inherited from the base class. There is a test for generated class, but it does not have a base class that has __firstlineno__.

   #123001 should fix this.
5. serhiy-storchaka

   added

   3.13only security fixesonly security fixes

   3.14bugs and security fixesbugs and security fixes

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   on Aug 14, 2024
6. serhiy-storchaka

   added this to Inspect issues 🔍on Aug 14, 2024
7. serhiy-storchaka

   moved this to In Progress in Inspect issues 🔍on Aug 14, 2024
8. serhiy-storchaka

   added a commit that references this issue on Aug 14, 2024

   pythongh-122981: Fix inspect.getsource() for generated classes with P…

   36e96ba
9. mhils commented on Aug 14, 2024

   

   mhils

   on Aug 14, 2024

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   Awesome - thank you two for getting to the bottom of this with lightning speed! ⚡🍰 😃
10. serhiy-storchaka

    added a commit that references this issue on Aug 20, 2024

    gh-122981: Fix inspect.getsource() for generated classes with Python …

    f88c14d
11. miss-islington

    added a commit that references this issue on Aug 20, 2024

    pythongh-122981: Fix inspect.getsource() for generated classes with P…

    f19222e
12. blhsing

    added a commit that references this issue on Aug 22, 2024

    pythongh-122981: Fix inspect.getsource() for generated classes with P…

    7fb2041
13. Yhg1s

    added a commit that references this issue on Sep 2, 2024

    [3.13] gh-122981: Fix inspect.getsource() for generated classes with …

    2b4c31d
14. mhils commented on Sep 10, 2024

    

    mhils

    on Sep 10, 2024

    ContributorAuthor

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    Thank you two again! I can confirm that the issue is fixed now for ssl.AlertDescription with 3.13rc2. Unfortunately our smoke tests still show a very similar error in this case here:

    $ docker run --rm python:3.13.0rc2 bash -c \
        'pip install pluggy==1.5.0; python -c "import inspect, pluggy; print(inspect.getsource(pluggy.PluggyTeardownRaisedWarning))"'
    [...]
        "PluginManager",

    docker run --rm python:3.12 bash -c \
        'pip install pluggy==1.5.0; python -c "import inspect, pluggy; print(inspect.getsource(pluggy.PluggyTeardownRaisedWarning))"'
    [...]
    OSError: could not find class definition

    (https://github.com/mitmproxy/pdoc/actions/runs/10772390037/job/29935976461?pr=730)

    Would you like me to file a new issue, or do we keep it here?

    Thanks! 😃
15. serhiy-storchaka commented on Sep 11, 2024

    

    serhiy-storchaka

    on Sep 11, 2024

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    pluggy.PluggyTeardownRaisedWarning is not the part of the stdlib, so I cannot say what exactly happened, but this may be related to #123339.
16. serhiy-storchaka

    closed this as completedon Sep 11, 2024
17. github-project-automation

    moved this from In Progress to Done in Inspect issues 🔍on Sep 11, 2024

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