Intermittent regression in test_asyncio .. test_subprocess_shell since Python 3.11

[fancidev]

Background

I run a daily continuous integration test of python -m test.test_asyncio for Python 3.7 through 3.11 on Linux, MacOS, and Windows on GitHub Actions.

Issue

Since Python 3.11, the following test intermittently fails on MacOS: (see, for example, Python-3.11-PySide6-macos-latest)

python -m test.test_asyncio
  shell: /bin/bash -e {0}
  env:
    pythonLocation: /Users/runner/hostedtoolcache/Python/3.11.1/x64
    PKG_CONFIG_PATH: /Users/runner/hostedtoolcache/Python/3.11.1/x64/lib/pkgconfig
    Python_ROOT_DIR: /Users/runner/hostedtoolcache/Python/3.11.1/x64
    Python2_ROOT_DIR: /Users/runner/hostedtoolcache/Python/3.11.1/x64
    Python3_ROOT_DIR: /Users/runner/hostedtoolcache/Python/3.11.1/x64

...

======================================================================
FAIL: test_subprocess_shell (test.test_asyncio.test_events.SelectEventLoopTests.test_subprocess_shell)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/test/test_asyncio/test_events.py", line 1814, in test_subprocess_shell
    self.assertEqual(proto.data[1].rstrip(b'\r\n'), b'Python')
AssertionError: b'' != b'Python'

----------------------------------------------------------------------
Ran 2339 tests in 75.968s

FAILED (failures=1, skipped=80)

Observations

I note that:

• This error only occurs on MacOS and only occurs with Python 3.11. That is, it never happened on Python 3.7 through 3.10 (regardless of OS), and it never happened on Linux or Windows (regardless of Python version).
• This error can happen with SelectEventLoopTests, KqueueEventLoopTests, and PollEventLoopTests. This indicates the error is not related to the specific polling mechanism, which makes sense because it tests subprocess shell.

Analysis

I see asyncio's subprocess related code is modified in Python 3.11. But I'm unable to tell whether/how those modifications may cause the observed regression.

Impact

I don't use asyncio's subprocess functionality myself. So I report this error just for good order.

I wonder if you have observed similar error in your Continuous Integration tests?

[kumaraditya303]

Duplicate of #100133

The fix is present in 3.11.2. @fancidev You need to upgrade to 3.11.2.