Bug report

Bug description:

Exception encountered during attempt to upgrade a C++ wrapper using the C API from Python 3.9 to 3.13.3.

Exception trace:

_abc_impl is set to a wrong type<FrameSummary file python/3.13.3/lib/python3.13/traceback.py, line 155 in format_exception><FrameSummary file python/3.13.3/lib/python3.13/traceback.py, line 1406 in format><FrameSummary file python/3.13.3/lib/python3.13/traceback.py, line 993 in emit><FrameSummary file python/3.13.3/lib/python3.13/traceback.py, line 1259 in format_exception_only><FrameSummary file <frozen abc>, line 119 in __instancecheck__>

Details:
Exception is seen on attempt to use format_exception from the traceback module.
Previously we were using PyErr_Fetch to get type, value and traceback of the Exception.
We note the signature change of format_exception requires an Exception object.
We switched to use PyErr_GetRaisedException and pass this to format_exception.
We have a class that stores the exception reference object from PyErr_GetRaisedException which is then used to rethrow the exception to be caught in our code.
The catch then uses a callable function to the imported traceback module to invoke format_exception with the exception object. We then see the above exception stack.format_exception(py::make_tuple(e.getException())); Where getException returns the Exception object reference stored.

We have been unable to reproduce this in a Python script yet.

Checked the callable and is as expected<function format_exception at 0x7fda88878720>.
Checked the initial caught exception object and can print the 'what' asException('Thrown exception from static init').
Checked the initial caught exception is of type<class 'Exception'>.
Confirmed signature of format_exception using the inspect module and parameters confirmed asexc, value, tb, limit, chain, kwargs

We are running in a sub-interpreter with the GIL taken prior to the try, catch that sees this exception.

We are hoping the above is enough to spot a potential issue or anti-pattern.

CPython versions tested on:

3.13

Operating systems tested on:

Linux