Zombie/orphan processes with piped shim executables from entry points, when using editable flag under PowerShell Core

Environment

• pip version: 20.2.4
• setuptools version: 50.3.2
• Python version: 3.9.0 (tags/v3.9.0:9cf6752, Oct 5 2020, 15:34:40) [MSC v.1927 64 bit (AMD64)] on win32
• PowerShell Core version: 7.0.3
• OS: Windows 10 Pro 1909 Build: 18363.1139

Description

Some piped shim executables created with pip install --editable . command, seem to hang/morph into zombie/orphan processes under PowerShell Core, when interrupted with Ctrl-C.

This issue doesn’t exist under CMD/Cygwin or if the install is done without the --editable flag. This is why I report the issue here, but it might be a problem with third-party/upstream package or the PowerShell Core machinery itself. Please advise/close if pip is not the source for this issue.

Expected behavior

I expect piped shim executables to exit cleanly/properly upon interruption and not leaving hanging zombie processes.

How to Reproduce

1. Setup:

Folder structure:

$ tree
t
├── baz
│   ├── __init__.py
│   ├── foo.py
│   └── bar.py
└── setup.py

Example minimal setup.py file:

from setuptools import setup, find_packages

setup(
    name='t',
    version='1.0.0',
    url='https://example.com',
    author='Author Name',
    author_email='[e-mail]',
    description='Description',
    packages=find_packages(),
    entry_points = {
        'console_scripts': ['foo=baz.foo:main', 'bar=baz.bar:main'],
    },
    install_requires = ['aioconsole>=0.3.1'],
)

Example script foo.py:

from asyncio import run
from asyncio import sleep
from aioconsole.stream import aprint


async def _main():
    while True:
        await aprint('a')
        await sleep(5)


def main():
    run(_main())


if __name__ == '__main__':
    exit(main())

Example script bar.py:

from asyncio import run

from aioconsole.stream import aprint
from aioconsole.stream import get_standard_streams


async def _main():
    reader, _ = await get_standard_streams()
    async for line in reader:
        await aprint(line)


def main():
    run(_main())


if __name__ == '__main__':
    exit(main())

Archive with all example files: t.zip

1. Create virtualenv and install the package with:

virtualenv venv
. .\venv\Scripts\activate
pip install --editable .

1. Run the two shim executables with pipe and interrupt the command after a couple of seconds with Ctrl+C.

foo | bar

1. Check for any zombie/hanging processes - example:

Output Incorrect output under PowerShell Core:

(venv) PS D:\t> foo | bar
b'a\n'
b'a\n'
Traceback (most recent call last):
  File "D:\t\venv\Scripts\foo-script.py", line 33, in <module>
    sys.exit(load_entry_point('t', 'console_scripts', 'foo')())
  File "d:\t\baz\foo.py", line 13, in main
    run(_main())
  File "C:\Program Files\Python39\lib\asyncio\runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 629, in run_until_complete
    self.run_forever()
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 316, in run_forever
    super().run_forever()
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 596, in run_forever
    self._run_once()
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 1854, in _run_once
    event_list = self._selector.select(timeout)
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 434, in select
    self._poll(timeout)
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 783, in _poll
    status = _overlapped.GetQueuedCompletionStatus(self._iocp, ms)
KeyboardInterrupt

Correct output under CMD (notice the two tracebacks):

(venv) D:\t>foo | bar
b'a\n'
b'a\n'
Traceback (most recent call last):
  File "D:\t\venv\Scripts\foo-script.py", line 33, in <module>
    sys.exit(load_entry_point('t', 'console_scripts', 'foo')())
  File "d:\t\baz\foo.py", line 13, in main
    run(_main())
  File "C:\Program Files\Python39\lib\asyncio\runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 629, in run_until_complete
    self.run_forever()
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 316, in run_forever
    super().run_forever()
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 596, in run_forever
    self._run_once()
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 1854, in _run_once
    event_list = self._selector.select(timeout)
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 434, in select
    self._poll(timeout)
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 783, in _poll
    status = _overlapped.GetQueuedCompletionStatus(self._iocp, ms)
KeyboardInterrupt
^Traceback (most recent call last):
C  File "D:\t\venv\Scripts\bar-script.py", line 33, in <module>
    sys.exit(load_entry_point('t', 'console_scripts', 'bar')())
  File "d:\t\baz\bar.py", line 14, in main
    run(_main())
  File "C:\Program Files\Python39\lib\asyncio\runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 629, in run_until_complete
    self.run_forever()
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 316, in run_forever
    super().run_forever()
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 596, in run_forever
    self._run_once()
  File "C:\Program Files\Python39\lib\asyncio\base_events.py", line 1854, in _run_once
    event_list = self._selector.select(timeout)
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 434, in select
    self._poll(timeout)
  File "C:\Program Files\Python39\lib\asyncio\windows_events.py", line 783, in _poll
    status = _overlapped.GetQueuedCompletionStatus(self._iocp, ms)
KeyboardInterrupt
^C

[pfmoore]

Yeah, I’m pretty confident this isn’t a pip issue. Feel free to @-ping me on the setuptools issue if anything I’ve said here needs clarification.

[int3l]

Closing this one for now.