[New-bugs-announce] [issue25654] test_multiprocessing_spawn ResourceWarning with -Werror

[Martin Panter]

New submission from Martin Panter:

Running the test suite with -Werror enabled causes test_multiprocessing_spawn to print out lots of unhandled errors from the garbage collector, and one of these causes a test failure. It looks like there are lots of files that should be explicitly closed rather than leaving them for the garbage collector.

Also, one error occurred _after_ the test command had exiting. That can’t be a good thing, though I have never used the multiprocessing module so maybe this is unavoidable.

$ ./python -Werror -m unittest -v test.test_multiprocessing_spawn
. . .
======================================================================
FAIL: test_sys_exit (test.test_multiprocessing_spawn.WithProcessesTestSubclassingProcess)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/media/disk/home/proj/python/cpython/Lib/test/_test_multiprocessing.py", line 483, in test_sys_exit
    self.assertEqual(f.read().rstrip(), str(reason))
AssertionError: "[1, 2, 3]\nException ignored in: <_io.Fi[136 chars]-8'>" != '[1, 2, 3]'
- [1, 2, 3]
?          -
+ [1, 2, 3]- Exception ignored in: <_io.FileIO name='/dev/null' mode='rb' closefd=True>
- ResourceWarning: unclosed file <_io.TextIOWrapper name='/dev/null' mode='r' encoding='UTF-8'>

----------------------------------------------------------------------
Ran 265 tests in 151.904s

FAILED (failures=1, skipped=15)
[Exit 1]
$ Exception ignored in: <_io.FileIO name='/dev/null' mode='rb' closefd=True>
ResourceWarning: unclosed file <_io.TextIOWrapper name='/dev/null' mode='r' encoding='UTF-8'>

----------
components: Tests
messages: 254834
nosy: martin.panter
priority: normal
severity: normal
status: open
title: test_multiprocessing_spawn ResourceWarning with -Werror
type: behavior
versions: Python 3.6

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue25654>
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