test_asyncio.test_subprocess: test_stdin_broken_pipe() failed on GHA Windows x64 CI

[vstinner]

test_stdin_broken_pipe (test.test_asyncio.test_subprocess.SubprocessProactorTests.test_stdin_broken_pipe) ... FAIL

FAIL: test_stdin_broken_pipe (test.test_asyncio.test_subprocess.SubprocessProactorTests.test_stdin_broken_pipe)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\cpython\cpython\Lib\test\test_asyncio\test_subprocess.py", line 298, in test_stdin_broken_pipe
    self.assertRaises((BrokenPipeError, ConnectionResetError),
AssertionError: (<class 'BrokenPipeError'>, <class 'ConnectionResetError'>) not raised by run_until_complete

build: https://github.com/python/cpython/actions/runs/6268408487/job/17024556425?pr=109701

cc @sorcio

Linked PRs

• gh-109709: Fix asyncio test_stdin_broken_pipe() #109710
• [3.12] gh-109709: Fix asyncio test_stdin_broken_pipe() (GH-109710) #109731
• [3.11] gh-109709: Fix asyncio test_stdin_broken_pipe() (#109710) #109735

[vstinner]

I already saw this bug in the past:

• 2017: issue test_stdin_broken_pipe() of test_asyncio failed randomly on AMD64 FreeBSD CURRENT Non-Debug 3.x #74567
• 2018: issue test_asyncio: test_subprocess test_stdin_broken_pipe() failure on Travis CI #77712
• 2019: issue test_asyncio: test_stdin_broken_pipe() failed on AMD64 FreeBSD CURRENT Shared 3.x #81336

[vstinner]

The issue can be reproduced on FreeBSD with:

vstinner@freebsd$ ./python -m test test_asyncio.test_subprocess -m test_stdin_broken_pipe -v -j25 --forever
(...)
0:00:07 load avg: 7.48 [ 20/1] test_asyncio.test_subprocess failed (1 failure)
test_stdin_broken_pipe (test.test_asyncio.test_subprocess.SubprocessFastWatcherTests.test_stdin_broken_pipe) ... ok
test_stdin_broken_pipe (test.test_asyncio.test_subprocess.SubprocessPidfdWatcherTests.test_stdin_broken_pipe) ... skipped 'operating system does not support pidfds'
test_stdin_broken_pipe (test.test_asyncio.test_subprocess.SubprocessSafeWatcherTests.test_stdin_broken_pipe) ... ok
test_stdin_broken_pipe (test.test_asyncio.test_subprocess.SubprocessThreadedWatcherTests.test_stdin_broken_pipe) ... FAIL

======================================================================
FAIL: test_stdin_broken_pipe (test.test_asyncio.test_subprocess.SubprocessThreadedWatcherTests.test_stdin_broken_pipe)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/home/vstinner/python/main/Lib/test/test_asyncio/test_subprocess.py", line 298, in test_stdin_broken_pipe
    self.assertRaises((BrokenPipeError, ConnectionResetError),
AssertionError: (<class 'BrokenPipeError'>, <class 'ConnectionResetError'>) not raised by run_until_complete

----------------------------------------------------------------------
Ran 4 tests in 2.170s

FAILED (failures=1, skipped=1)
/usr/home/vstinner/python/main/Lib/asyncio/base_subprocess.py:125: ResourceWarning: unclosed transport <_UnixSubprocessTransport pid=2131 running stdin=<_UnixWritePipeTransport closed fd=7 closed>>
  _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
ResourceWarning: Enable tracemalloc to get the object allocation traceback
test test_asyncio.test_subprocess failed