Regression in multiprocessing example using venv on Windows in 3.11rc2 #98360
Description
I'm programming in PyCharm in Virtual Environment on Win11 on a 12900k
I use 2 modules:
• mp_tst_all.py
• mp_tst_a.py
mp_tst_all.py
import multiprocessing
import platform
import mp_tst_a
def run_my_multi():
p_xyz = multiprocessing.Process(
target=mp_tst_a.run_main,
args=())
# p_... = ...
p_xyz.start()
# p_... .start()
p_xyz.join()
# p_... .join()
return
if __name__ == '__main__':
print('py:', platform.python_version())
run_my_multi()
mp_tst_a.py
import multiprocessing
import time
import platform
main_queue = multiprocessing.Queue()
def load_directory(def_queue):
content_def = def_queue.get()
content_def['load_directory_is_alive'] = True
def_queue.put(content_def)
# ---- do something ... --------
print('\n' + 'LOAD DIRECTORY:')
for x in range(3):
time.sleep(.6)
print('do something ...')
print('\n' + 'LOAD ok' + '\n')
content_def = def_queue.get()
content_def['load_directory_is_alive'] = False
content_def['run_load_file'] = True
def_queue.put(content_def)
return
def load_files(def_queue):
content_def = def_queue.get()
run_load_file_i = content_def['run_load_file']
def_queue.put(content_def)
# ---- do something ... --------
print('LOAD FILE:')
if run_load_file_i:
for x in range(3):
time.sleep(.6)
print('FILE ' + str(x))
print('\n' + 'LOAD ok' + '\n')
return
def run_main():
global main_queue
content = {
'load_directory_is_alive': None,
'run_load_file': None,
'last_download_date': None
}
main_queue.put(content)
rest = 0.2 # for test, try different values
time.sleep(rest)
jobs = []
content = main_queue.get()
content['last_download_date'] = 'xx.xx.xxxx'
main_queue.put(content)
time.sleep(rest)
# ---- process_1.1: load_directory -----------------------------------
process_1_1 = multiprocessing.Process(
target=load_directory, name='load_directory',
args=(main_queue, ))
jobs.append(process_1_1)
process_1_1.start()
time.sleep(rest)
# ---- do not begin process_2 before process_1.1: load_directory exits
while process_1_1.is_alive():
pass
time.sleep(rest)
# ---- process_2: load_files -----------------------------------------
process_2 = multiprocessing.Process(
target=load_files, name='load_files',
args=(main_queue, ))
jobs.append(process_2)
process_2.start()
process_1_1.join()
process_2.join()
return
if __name__ == "__main__":
print('py:', platform.python_version())
run_main()
Bug
first: with PyCharm
mp_tst_a.py works in py 3.11.0_rc2 and in py 3.10(.7)
but
when mp_tst_a.py is called from mp_tst_all.py there is an error in py 3.11.0_rc2,
however, in py 3.10(.7) it works
the error message varies depending on the 'rest' variable (mp_tst_a.py -> def run_main)
Process load_directory:
Traceback (most recent call last):
File "C:\...\Python311\Lib\multiprocessing\process.py", line 314, in _bootstrap
self.run()
File "C:\...Python311\Lib\multiprocessing\process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "C:\...\mp_test_single_a.py", line 10, in load_directory
content_def = def_queue.get()
^^^^^^^^^^^^^^^
File "C:\...\Python311\Lib\multiprocessing\queues.py", line 102, in get
with self._rlock:
File "C:\...\Python311\Lib\multiprocessing\synchronize.py", line 95, in __enter__
return self._semlock.__enter__()
^^^^^^^^^^^^^^^^^^^^^^^^^
**PermissionError: [WinError 5]** Zugriff verweigert
Process load_directory:
Traceback (most recent call last):
File "C:\...\Python311\Lib\multiprocessing\process.py", line 314, in _bootstrap
self.run()
File "C:\...\Python311\Lib\multiprocessing\process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "C:\...\mp_test_single_a.py", line 10, in load_directory
content_def = def_queue.get()
^^^^^^^^^^^^^^^
File "C:\...\Python311\Lib\multiprocessing\queues.py", line 102, in get
with self._rlock:
File "C:\...\Python311\Lib\multiprocessing\synchronize.py", line 98, in __exit__
return self._semlock.__exit__(*args)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
**OSError: [WinError 6]** Das Handle ist ungültig
secondly: in Command Prompt Window (cmd) it runs:
C:\...\Python311\Lib\site-packages>mp_tst_all.py
py: 3.11.0rc2
LOAD DIRECTORY:
do something ...
do something ...
do something ...
LOAD ok
LOAD FILE:
FILE 0
FILE 1
FILE 2
LOAD ok
C:\...\Python311\Lib\site-packages>
is it a bug in 3.11.0_rc2 or do i need to change something in the code ?
Thank you