Executable file produces infinite count of processed with "multiprocessing" if "spawn" mode is selected. Ubuntu 18.04.

[Yuriy-Leonov]

Hello.
I faced with following issue:

Env:

Ubuntu - 18.04
Python - 3.6.6
cx_Freeze - 6.1

Code base:

https://github.com/Yuriy-Leonov/cython_multiprocessing_issue

There is a simple main_script.py:

import multiprocessing


if __name__ == '__main__':
    print("step-1")
    multiprocessing.set_start_method("spawn")
    print("step-2")
    multiprocessing.freeze_support()
    print("step-3")
    manager = multiprocessing.Manager()
    print("step-4")
    s_dict = manager.dict()
    print("finish")

If run it with command python main_script.py expected things will happen - 5 print.

But If "make executable file" with following script and command python setup.py build:

import cx_Freeze

executables = [cx_Freeze.Executable("main_script.py")]

cx_Freeze.setup(
    name="Example",
    options={
        "build_exe": {
            "replace_paths": [("*", "")]
        },
    },
    executables=executables
)

and then run it from folder build/exe.linux-x86_64-3.6 like ./main_script it produces following log and infinite count of processes:

step-1
step-2
step-3
step-1
step-2
step-3
step-1
step-2
step-3
...

I'm not sure, did I do all in a right way, but it looks very unexpected from my sight. Therefore I've created this ticket.

[marcelotduarte]

The most important info from the code base:
###NOTE! Be careful, it could spawn infinite processes.
Prepare following command pkill -9 -f main_script and use it right after Ctrl + C on executable file

[marcelotduarte]

You can test the patch in the latest development build:
pip install --upgrade --pre --extra-index-url https://marcelotduarte.github.io/packages/ cx_Freeze

I tested the PR in Ubuntu 20.04 Python 3.10.6 but I expect that it should work from Python 3.8 to 3.12.

[marcelotduarte]

Release 6.15.4 is out!