[BUG] [python3] Use of Thread silently crash on Windows 7

[mipicard]

Describe the bug

After installing latest MSYS2 on Windows 7, I update it and install Python 3.8.3.

When trying to run a Thread, it silently crash without any error nor continuing the script.

Steps to Reproduce the Problem

1. Install msys2-x86_64-20200602.exe

2. Update msys2 runtime to latest version (3.1.5)

3. Install python 3.8.3 (in the MSYS2 MSYS console) :

   • python 3.8.3
   • python appdirs 1.4.4
   • python attrs 19.3.0
   • python packaging 20.4
   • python-pip 20.0.2
   • python-pyparsing 2.4.7
   • python-setuptools 47.1.1
   • python-six 1.15.0

4. Run this simple python script :

   
   #!/usr/bin/python3

from concurrent.futures import ThreadPoolExecutor

def f(id): print('hello from thread {}'.format(id), flush=True)

if name == 'main': with ThreadPoolExecutor() as executor: for i in range(10000): executor.submit(f, i) print('Done', flush=True)

Expected behavior: Display all 'hello' message and then 'Done'
Actual behavior : No message at all on Windows 7, working fine on Windows 10

## Additional Context: Operating System, Screenshots

- OS: Windows 7 Enterprise SP1

[mati865]

Is it mingw-w64-*-python or python package? Pip version suggests mingw package.

[mipicard]

It is python package, we haven't install any mingw package.

[miltmobley]

You might want to query the python forums as to whether this recently added feature set (concurrent*) can work on oh-so-old windows7.