regression when using pytest-forked (infinite recursion)

This test has been working with shiboken 6.4.1, but it stopped working after updating to 6.5.1.1. We need the --forked option since otherwise we get into other troubles while testing the gui, probably due to insufficient isolation of the test cases. The python environment is

$ python --version
Python 3.9.2

$ pip freeze
exceptiongroup==1.1.2
iniconfig==2.0.0
packaging==23.1
pluggy==1.2.0
py==1.11.0
PySide6==6.5.1.1
PySide6-Addons==6.5.1.1
PySide6-Essentials==6.5.1.1
pytest==7.4.0
pytest-forked==1.6.0
shiboken6==6.5.1.1
tomli==2.0.1

and a minimal test case showing the problem is this:

$ cat test_dummy.py  
import pytest
import shiboken6

def test_dummy():
   pass

$ pytest --forked test_dummy.py | head -n 80
============================= test session starts ==============================
platform linux – Python 3.9.2, pytest-7.4.0, pluggy-1.2.0
rootdir: <snip>
plugins: forked-1.6.0
collected 1 item

test_dummy.py  
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/_pytest/main.py", line 270, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/_pytest/main.py", line 324, in _main
INTERNALERROR>     config.hook.pytest_runtestloop(session=session)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/hooks.py", line 433, in __call_
INTERNALERROR>     return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_manager.py", line 112, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_callers.py", line 155, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_result.py", line 108, in get_result
INTERNALERROR>     raise exc.with_traceback(exc.{}traceback{})
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_callers.py", line 80, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/_pytest/main.py", line 349, in pytest_runtestloop
INTERNALERROR>     item.config.hook.pytest_runtest_protocol(item=item, nextitem=nextitem)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/hooks.py", line 433, in __call_
INTERNALERROR>     return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_manager.py", line 112, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_callers.py", line 155, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_result.py", line 108, in get_result
INTERNALERROR>     raise exc.with_traceback(exc.{}traceback{})
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pluggy/_callers.py", line 80, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pytest_forked/{}init{}.py", line 51, in pytest_runtest_protocol
INTERNALERROR>     reports = forked_run_report(item)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/pytest_forked/{}init{}.py", line 73, in forked_run_report
INTERNALERROR>     ff = py.process.ForkedFunc(runforked)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 157, in __makeattr
INTERNALERROR>     result = importobj(modpath, attrname)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 75, in importobj
INTERNALERROR>     module = {}import{}(modpath, None, None, ["__doc__"])
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/_process/forkedfunc.py", line 8, in <module>
INTERNALERROR>     import py
INTERNALERROR>   File "shibokensupport/signature/loader.py", line 61, in feature_imported
INTERNALERROR>   File "shibokensupport/feature.py", line 137, in feature_imported
INTERNALERROR>   File "shibokensupport/feature.py", line 148, in _mod_uses_pyside
INTERNALERROR>   File "/usr/lib/python3.9/inspect.py", line 1024, in getsource
INTERNALERROR>     lines, lnum = getsourcelines(object)
INTERNALERROR>   File "/usr/lib/python3.9/inspect.py", line 1006, in getsourcelines
INTERNALERROR>     lines, lnum = findsource(object)
INTERNALERROR>   File "/usr/lib/python3.9/inspect.py", line 831, in findsource
INTERNALERROR>     lines = linecache.getlines(file, module.{}dict{})
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init.py", line 177, in __dict_
INTERNALERROR>     self.__makeattr(name)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 157, in __makeattr
INTERNALERROR>     result = importobj(modpath, attrname)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 75, in importobj
INTERNALERROR>     module = {}import{}(modpath, None, None, ["__doc__"])
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/__metainfo.py", line 1, in <module>
INTERNALERROR>     import py
INTERNALERROR>   File "shibokensupport/signature/loader.py", line 61, in feature_imported
INTERNALERROR>   File "shibokensupport/feature.py", line 137, in feature_imported
INTERNALERROR>   File "shibokensupport/feature.py", line 148, in _mod_uses_pyside
INTERNALERROR>   File "/usr/lib/python3.9/inspect.py", line 1024, in getsource
INTERNALERROR>     lines, lnum = getsourcelines(object)
INTERNALERROR>   File "/usr/lib/python3.9/inspect.py", line 1006, in getsourcelines
INTERNALERROR>     lines, lnum = findsource(object)
INTERNALERROR>   File "/usr/lib/python3.9/inspect.py", line 831, in findsource
INTERNALERROR>     lines = linecache.getlines(file, module.{}dict{})
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init.py", line 177, in __dict_
INTERNALERROR>     self.__makeattr(name)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 157, in __makeattr
INTERNALERROR>     result = importobj(modpath, attrname)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 75, in importobj
INTERNALERROR>     module = {}import{}(modpath, None, None, ["__doc__"])
INTERNALERROR>   File "shibokensupport/signature/loader.py", line 61, in feature_imported
INTERNALERROR>   File "shibokensupport/feature.py", line 137, in feature_imported
INTERNALERROR>   File "shibokensupport/feature.py", line 148, in _mod_uses_pyside
INTERNALERROR>   File "/usr/lib/python3.9/inspect.py", line 1024, in getsource

.... snip ....

INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init.py", line 177, in __dict_
INTERNALERROR>     self.__makeattr(name)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 157, in __makeattr
INTERNALERROR>     result = importobj(modpath, attrname)
INTERNALERROR>   File "/tmp/venv/lib/python3.9/site-packages/py/vendored_packages/apipkg/init_.py", line 75, in importobj
INTERNALERROR>     module = {}import{}(modpath, None, None, ["__doc__"])
INTERNALERROR>   File "shibokensupport/signature/loader.py", line 54, in feature_import
INTERNALERROR> RecursionError: maximum recursion depth exceeded