Невозможно передать multiprocessing.Manager для обработки при использовании forkserver: невозможно выбрать объект «weakr ⇐ Python

[Anonymous]

Пример кода:
import multiprocessing

def main():
multiprocessing.set_start_method('forkserver')
with multiprocessing.Manager() as manager:
proc = multiprocessing.Process(target=fun, args=('p1', manager))
proc.start()
proc.join()

def fun(name, manager):
print('fun:', name, manager)

if __name__ == '__main__':
main()

Ошибка:
$ /opt/python3.12.6/bin/python3 ./demo_mp_manager_forkserver.py
Traceback (most recent call last):
File "/home/.../demo_mp_manager_forkserver.py", line 14, in
main()
File "/home/.../demo_mp_manager_forkserver.py", line 7, in main
proc.start()
File "/opt/python3.12.6/lib/python3.12/multiprocessing/process.py", line 121, in start
self._popen = self._Popen(self)
^^^^^^^^^^^^^^^^^
File "/opt/python3.12.6/lib/python3.12/multiprocessing/context.py", line 224, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/python3.12.6/lib/python3.12/multiprocessing/context.py", line 301, in _Popen
return Popen(process_obj)
^^^^^^^^^^^^^^^^^^
File "/opt/python3.12.6/lib/python3.12/multiprocessing/popen_forkserver.py", line 35, in __init__
super().__init__(process_obj)
File "/opt/python3.12.6/lib/python3.12/multiprocessing/popen_fork.py", line 19, in __init__
self._launch(process_obj)
File "/opt/python3.12.6/lib/python3.12/multiprocessing/popen_forkserver.py", line 47, in _launch
reduction.dump(process_obj, buf)
File "/opt/python3.12.6/lib/python3.12/multiprocessing/reduction.py", line 60, in dump
ForkingPickler(file, protocol).dump(obj)
TypeError: cannot pickle 'weakref.ReferenceType' object


Подробнее здесь: https://stackoverflow.com/questions/790 ... cannot-pic