René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Regression in multiprocessing example using venv on Windows in 3.11rc2","articleBody":"I'm programming in PyCharm in Virtual Environment on Win11 on a 12900k\r\n\r\nI use 2 modules:\r\n• mp_tst_all.py\r\n• mp_tst_a.py\r\n\r\n\u003cdetails\u003e\r\n\r\n# mp_tst_all.py\r\n```\r\nimport multiprocessing\r\nimport platform\r\n\r\nimport mp_tst_a\r\n\r\n\r\ndef run_my_multi():\r\n    p_xyz = multiprocessing.Process(\r\n        target=mp_tst_a.run_main,\r\n        args=())\r\n\r\n    # p_... = ...\r\n\r\n    p_xyz.start()\r\n    # p_... .start()\r\n\r\n    p_xyz.join()\r\n    # p_... .join()\r\n\r\n    return\r\n\r\n\r\nif __name__ == '__main__':\r\n\r\n    print('py:', platform.python_version())\r\n\r\n    run_my_multi()\r\n\r\n```\r\n\r\n# mp_tst_a.py\r\n```\r\nimport multiprocessing\r\nimport time\r\nimport platform\r\n\r\nmain_queue = multiprocessing.Queue()\r\n\r\n\r\ndef load_directory(def_queue):\r\n\r\n    content_def = def_queue.get()\r\n    content_def['load_directory_is_alive'] = True\r\n    def_queue.put(content_def)\r\n\r\n    # ---- do something ... --------\r\n    print('\\n' + 'LOAD DIRECTORY:')\r\n    for x in range(3):\r\n        time.sleep(.6)\r\n        print('do something ...')\r\n    print('\\n' + 'LOAD ok' + '\\n')\r\n\r\n\r\n    content_def = def_queue.get()\r\n    content_def['load_directory_is_alive'] = False\r\n    content_def['run_load_file'] = True\r\n    def_queue.put(content_def)\r\n\r\n    return\r\n\r\n\r\ndef load_files(def_queue):\r\n\r\n    content_def = def_queue.get()\r\n    run_load_file_i = content_def['run_load_file']\r\n    def_queue.put(content_def)\r\n\r\n    # ---- do something ... --------\r\n    print('LOAD FILE:')\r\n    if run_load_file_i:\r\n        for x in range(3):\r\n            time.sleep(.6)\r\n            print('FILE ' + str(x))\r\n    print('\\n' + 'LOAD ok' + '\\n')\r\n\r\n    return\r\n\r\n\r\ndef run_main():\r\n\r\n    global main_queue\r\n\r\n    content = {\r\n        'load_directory_is_alive': None,\r\n        'run_load_file': None,\r\n        'last_download_date': None\r\n        }\r\n\r\n    main_queue.put(content)\r\n\r\n    rest = 0.2  # for test, try different values\r\n    time.sleep(rest)\r\n\r\n    jobs = []\r\n\r\n    content = main_queue.get()\r\n    content['last_download_date'] = 'xx.xx.xxxx'\r\n    main_queue.put(content)\r\n    time.sleep(rest)\r\n\r\n\r\n    # ---- process_1.1: load_directory -----------------------------------\r\n    process_1_1 = multiprocessing.Process(\r\n        target=load_directory, name='load_directory',\r\n        args=(main_queue, ))\r\n\r\n    jobs.append(process_1_1)\r\n    process_1_1.start()\r\n    time.sleep(rest)\r\n\r\n\r\n    # ---- do not begin process_2 before process_1.1: load_directory exits\r\n    while process_1_1.is_alive():\r\n        pass\r\n        time.sleep(rest)\r\n\r\n\r\n    # ---- process_2: load_files -----------------------------------------\r\n    process_2 = multiprocessing.Process(\r\n        target=load_files, name='load_files',\r\n        args=(main_queue, ))\r\n\r\n    jobs.append(process_2)\r\n    process_2.start()\r\n\r\n\r\n    process_1_1.join()\r\n    process_2.join()\r\n\r\n    return\r\n\r\n\r\nif __name__ == \"__main__\":\r\n\r\n    print('py:', platform.python_version())\r\n    run_main()\r\n```\r\n\r\n\u003c/details\u003e\r\n\r\n\r\n# Bug\r\n\r\n**first:  with PyCharm**\r\n\r\nmp_tst_a.py works in py 3.11.0_rc2 and in py 3.10(.7)\r\n\r\n**but**\r\n\r\n**when mp_tst_a.py is called from mp_tst_all.py there is an error in py 3.11.0_rc2,**\r\nhowever, in py 3.10(.7) it works\r\n\r\nthe error message varies depending on the 'rest' variable (mp_tst_a.py -\u003e def run_main)\r\n\r\n```\r\nProcess load_directory:\r\nTraceback (most recent call last):\r\n  File \"C:\\...\\Python311\\Lib\\multiprocessing\\process.py\", line 314, in _bootstrap\r\n    self.run()\r\n  File \"C:\\...Python311\\Lib\\multiprocessing\\process.py\", line 108, in run\r\n    self._target(*self._args, **self._kwargs)\r\n  File \"C:\\...\\mp_test_single_a.py\", line 10, in load_directory\r\n    content_def = def_queue.get()\r\n                  ^^^^^^^^^^^^^^^\r\n  File \"C:\\...\\Python311\\Lib\\multiprocessing\\queues.py\", line 102, in get\r\n    with self._rlock:\r\n  File \"C:\\...\\Python311\\Lib\\multiprocessing\\synchronize.py\", line 95, in __enter__\r\n    return self._semlock.__enter__()\r\n           ^^^^^^^^^^^^^^^^^^^^^^^^^\r\n**PermissionError: [WinError 5]** Zugriff verweigert\r\n```\r\n\r\n\r\n```\r\nProcess load_directory:\r\nTraceback (most recent call last):\r\n  File \"C:\\...\\Python311\\Lib\\multiprocessing\\process.py\", line 314, in _bootstrap\r\n    self.run()\r\n  File \"C:\\...\\Python311\\Lib\\multiprocessing\\process.py\", line 108, in run\r\n    self._target(*self._args, **self._kwargs)\r\n  File \"C:\\...\\mp_test_single_a.py\", line 10, in load_directory\r\n    content_def = def_queue.get()\r\n                  ^^^^^^^^^^^^^^^\r\n  File \"C:\\...\\Python311\\Lib\\multiprocessing\\queues.py\", line 102, in get\r\n    with self._rlock:\r\n  File \"C:\\...\\Python311\\Lib\\multiprocessing\\synchronize.py\", line 98, in __exit__\r\n    return self._semlock.__exit__(*args)\r\n           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\r\n**OSError: [WinError 6]** Das Handle ist ungültig\r\n```\r\n\r\n\r\n\r\n**secondly: in Command Prompt Window (cmd) it runs:**\r\n\r\n```\r\nC:\\...\\Python311\\Lib\\site-packages\u003emp_tst_all.py\r\npy: 3.11.0rc2\r\n\r\nLOAD DIRECTORY:\r\ndo something ...\r\ndo something ...\r\ndo something ...\r\n\r\nLOAD ok\r\n\r\nLOAD FILE:\r\nFILE 0\r\nFILE 1\r\nFILE 2\r\n\r\nLOAD ok\r\n\r\n\r\nC:\\...\\Python311\\Lib\\site-packages\u003e\r\n```\r\n\r\n\r\n\r\n**_is it a bug in 3.11.0_rc2 or do i need to change something in the code ?_**\r\n**Thank you**\r\n","author":{"url":"https://github.com/edge-python","@type":"Person","name":"edge-python"},"datePublished":"2022-10-17T17:03:28.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/98360/cpython/issues/98360"}