Test faliure on 3.14

[limburgher]

See: https://bugzilla.redhat.com/show_bug.cgi?id=2326933

=================================== FAILURES ===================================
____ TestBaseManager.test_can_provide_signal_handler_initializers_to_start _____

self = <tests.unit.test_compat.TestBaseManager testMethod=test_can_provide_signal_handler_initializers_to_start>

@skip_if_windows('os.kill() with SIGINT not supported on Windows')
def test_can_provide_signal_handler_initializers_to_start(self):
    manager = self.create_pid_manager()

  manager.start(signal.signal, (signal.SIGINT, signal.SIG_IGN))

tests/unit/test_compat.py:97:

---

/usr/lib64/python3.14/multiprocessing/managers.py:565: in start
self._process.start()
/usr/lib64/python3.14/multiprocessing/process.py:121: in start
self._popen = self._Popen(self)
/usr/lib64/python3.14/multiprocessing/context.py:300: in _Popen
return Popen(process_obj)
/usr/lib64/python3.14/multiprocessing/popen_forkserver.py:35: in init
super().init(process_obj)
/usr/lib64/python3.14/multiprocessing/popen_fork.py:20: in init
self._launch(process_obj)
/usr/lib64/python3.14/multiprocessing/popen_forkserver.py:47: in _launch
reduction.dump(process_obj, buf)

---

obj =
file = <_io.BytesIO object at 0x7f2b60580630>, protocol = None

def dump(obj, file, protocol=None):
    '''Replacement for pickle.dump() using ForkingPickler.'''

  ForkingPickler(file, protocol).dump(obj)

E _pickle.PicklingError: Can't pickle local object <class 'tests.unit.test_compat.TestBaseManager.create_pid_manager..PIDManager'>
E when serializing tuple item 0
E when serializing method reconstructor arguments
E when serializing method object
E when serializing dict item '_target'
E when serializing multiprocessing.context.ForkServerProcess state
E when serializing multiprocessing.context.ForkServerProcess object

/usr/lib64/python3.14/multiprocessing/reduction.py:60: PicklingError

According to https://docs.python.org/dev/whatsnew/3.14.html#multiprocessing

The default start method (see Contexts and start methods) changed from fork to forkserver on platforms other than macOS & Windows where it was already spawn. If you require the threading incompatible fork start method you must explicitly request it using a context from multiprocessing.get_context() (preferred) or change the default via multiprocessing.set_start_method(). (Contributed by Gregory P. Smith in gh-84559.)

[nateprewitt]

Thanks for the issue @limburgher. The 3.14 alpha is still relatively new (<1 month old). We generally will not start looking at work to resolve compatibility issues until the build is at least in beta. We can keep this to track the issue for later work.

[limburgher]

Sounds good. If neither of us have fixed this by the time we start building Fedora with 3.14, I'll just skip that test.