PyObject_VisitManagedDict result ignored in a lot of places

[maxbachmann]

Bug report

Bug description:

There are a lot of places that incorrectly ignore PyObject_VisitManagedDict. This leads to issues during traverse. In our own Python wrapper this did lead to the relation between the dict and it's owning class not getting found

CPython versions tested on:

3.14

Operating systems tested on:

No response

Linked PRs

• gh-148274: Properly handle result from PyObject_VisitManagedDict #148275

[kumaraditya303]

This leads to issues during traverse. In our own Python wrapper this did lead to the relation between the dict and it's owning class not getting found

What is the issue? Ignoring the return value doesn't mean that the object wasn't visited.

[maxbachmann]

I didn't construct a test with the Cpython types but at least for our own inhouse Python wrapper not handling this did lead to

    instance = m.DynamicAttr()
    instance.a = "test"
    assert instance in gc.get_referrers(instance.__dict__)

failing. This was fixed by returning the corresponding return code instead of always returning 0.

This is in line with the Py_VISIT macro which also returns on a visit result != 0.

[maxbachmann]

For pybind11 I did create the fix as well (pybind/pybind11#6032) but there it continues failing for now since the ci is still on 3.14.3 and so doesn't have the fixes from (#130327) yet.