[issue36888] Create a way to check that the parent process is alive for deamonized processes

[STINNER Victor]

STINNER Victor <vstinner at redhat.com> added the comment:

This new test is not reliable, it failed on x86 Gentoo Refleaks 3.8:
https://buildbot.python.org/all/#/builders/223/builds/9

Please fix the test or revert the change. The CI must remain green ;-)


running: test_multiprocessing_spawn (31 min 51 sec), test_multiprocessing_forkserver (3 min 7 ms)
3:20:42 load avg: 6.89 [415/423/1] test_multiprocessing_spawn failed (31 min 30 sec) -- running: test_multiprocessing_forkserver (3 min 7 sec)
beginning 6 repetitions
123456
....Process Process-1588:1:
Traceback (most recent call last):
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/multiprocessing/process.py", line 313, in _bootstrap
    self.run()
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/test/_test_multiprocessing.py", line 326, in _test_report_parent_status
    wconn.send("alive" if parent_process().is_alive() else "not alive")
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/multiprocessing/connection.py", line 206, in send
    self._send_bytes(_ForkingPickler.dumps(obj))
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/multiprocessing/connection.py", line 411, in _send_bytes
    self._send(header + buf)
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/multiprocessing/connection.py", line 368, in _send
    n = write(self._handle, buf)
BrokenPipeError: [Errno 32] Broken pipe
Warning -- Dangling processes: {<Process name='Process-1588' pid=6665 parent=13022 started>}
Warning -- Dangling processes: {<Process name='Process-1588' pid=6665 parent=13022 started>}
Warning -- multiprocessing.process._dangling was modified by test_multiprocessing_spawn
  Before: set()
  After:  {<weakref at 0xb6d7e840; to 'Process' at 0xb4573878>} 
test test_multiprocessing_spawn failed -- Traceback (most recent call last):
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/test/_test_multiprocessing.py", line 305, in test_parent_process
    raise AssertionError("Could not communicate with child process")
AssertionError: Could not communicate with child process

/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/multiprocessing/resource_tracker.py:203: UserWarning: resource_tracker: There appear to be 1 leaked shared_memory objects to clean up at shutdown
  warnings.warn('resource_tracker: There appear to be %d '
/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/multiprocessing/resource_tracker.py:216: UserWarning: resource_tracker: '//psm_b32d1a2f': [Errno 2] No such file or directory: '//psm_b32d1a2f'
  warnings.warn('resource_tracker: %r: %s' % (name, e))

(...)

Re-running test_multiprocessing_spawn in verbose mode

======================================================================
FAIL: test_parent_process (test.test_multiprocessing_spawn.WithProcessesTestProcess)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/buildbot/buildarea/cpython/3.8.ware-gentoo-x86.refleak/build/Lib/test/_test_multiprocessing.py", line 305, in test_parent_process
    raise AssertionError("Could not communicate with child process")
AssertionError: Could not communicate with child process

----------
nosy: +vstinner
resolution: fixed -> 
status: closed -> open

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue36888>
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