Sphinx v7.3.7: AttributeError: 'Symbol' object has no attribute '_children'

[sphuber]

Describe the bug

The example Python source file (see in how to reproduce) excepts when compiled with Sphinx 7.3.7. Any other older version works just fine. It excepts with the following error:

Exception occurred:
  File "/home/sph/.mambaforge/envs/aiida-py311/lib/python3.11/site-packages/sphinx/domains/c/_symbol.py", line 179, in get_all_symbols
    for sChild in self._children:
                  ^^^^^^^^^^^^^^                                                                                                                                                                                 AttributeError: 'Symbol' object has no attribute '_children'

How to Reproduce

conf.py

import os
import sys
sys.path.insert(0, os.path.abspath('../src'))

extensions = ['sphinx.ext.autodoc']

index.rst

.. automodule:: thing
   :members:

import typing as t

P = t.ParamSpec('P')
R_co = t.TypeVar('R_co', covariant=True)
N = t.TypeVar('N', bound=str)


class ProcessFunctionType(t.Protocol, t.Generic[P, R_co, N]):
    """Protocol type."""

    def run(self, *args: P.args, **kwargs: P.kwargs) -> R_co:
        """Some method."""

build it Sphinx v7.3.7

Environment Information

sphinx==7.3.7

Sphinx extensions

sphinx.ext.autodoc

Additional context

No response

[AA-Turner]

@sphuber please can you provide the index.rst and the conf.py for the minimal example?

[sphuber]

@AA-Turner done

[AA-Turner]

@sphuber with the patch from #12581 I'm unable to reproduce -- I'd expect a C or C++ domain directive given that the error is in the C domain. Please could you double check the reproducer?

A

[AA-Turner]

Is Sphinx 7.4.0 also broken for this?

[nortikin]

https://github.com/nortikin/sverchok/actions/runs/9937287904/job/27447450138 also

Running Sphinx v7.4.0

[AA-Turner]

Are you able to create a (minimal) reproducer please @nortikin? This error is a little confusing, as _children_by_docname should always be defined:

sphinx/sphinx/domains/c/_symbol.py

Line 108 in 73dd9fc

self._children_by_docname: dict[str, dict[str, Symbol]] = {}

A

[sphuber]

Is Sphinx 7.4.0 also broken for this?

I don't think so, because I don't get the exception there, just the warning reported in #12579

[sphuber]

It may have to do something with caching of compiled files. If I build clean, it seems to work just fine. The exception seems to crop up if I first compile with v7.4.1, then downgrade to v7.3.7 and build again. If I clean the old build before building again, v7.3.7 seems to work fine. So this may be a non-issue

[AA-Turner]

I came to the same conclusion -- see #12583 for a fix (by invalidating old environments)

[AA-Turner]

Sphinx 7.4.2 has been released with a fix.

A