[issue43944] Processes in Python 3.9 exiting with code 1 when It's created inside a ThreadPoolExecutor

Genaro Camele added the comment: Hi @jack__d, thanks for your answer and time. Unfortunately, It's still a regression, as in Python < 3.9 my example works as expected -- ___ Python tracker <https://bugs.python.org

[issue43944] Processes in Python 3.9 exiting with code 1 when It's created inside a ThreadPoolExecutor

New submission from Genaro Camele : I've a piece of code that submits a task to a [ThreadPoolExecutor][1] which starts a [Process][2]. I've realised that in Python 3.8 that Process finished with exit code `0`. But I've updated Python to the 3.9 version and this started to fini