Description

vstinner

opened on Sep 19, 2023

Issue body actions

Windows x86:

FAIL: test_future_times_out (test.test_concurrent_futures.test_as_completed.ThreadPoolAsCompletedTest.test_future_times_out) [0.01]
Test ``futures.as_completed`` timing out before
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\cpython\cpython\Lib\test\test_concurrent_futures\test_as_completed.py", line 60, in test_future_times_out
    self.assertEqual(completed_futures, already_completed)
AssertionError: Items in the first set but not the second:
<Future at 0x5684560 state=finished returned NoneType>

build: https://github.com/python/cpython/actions/runs/6225761937/job/16896880945?pr=108965

The test fails randomly. It passed when re-run in verbose mode in a fresh process:

0:16:02 load avg: 5.55 [2/2/1] test.test_concurrent_futures.test_as_completed passed
Re-running test.test_concurrent_futures.test_as_completed in verbose mode (matching: test_future_times_out)
test_future_times_out (test.test_concurrent_futures.test_as_completed.ProcessPoolForkAsCompletedTest.test_future_times_out)
Test ``futures.as_completed`` timing out before ... skipped 'require unix system'
test_future_times_out (test.test_concurrent_futures.test_as_completed.ProcessPoolForkserverAsCompletedTest.test_future_times_out)
Test ``futures.as_completed`` timing out before ... skipped 'require unix system'
test_future_times_out (test.test_concurrent_futures.test_as_completed.ProcessPoolSpawnAsCompletedTest.test_future_times_out)
Test ``futures.as_completed`` timing out before ... 0.75s ok
test_future_times_out (test.test_concurrent_futures.test_as_completed.ThreadPoolAsCompletedTest.test_future_times_out)
Test ``futures.as_completed`` timing out before ... 0.11s ok

----------------------------------------------------------------------
Ran 4 tests in 0.881s

OK (skipped=2)

Linked PRs

• gh-109565: Fix concurrent.futures test_future_times_out() #109949
• [3.12] gh-109565: Fix concurrent.futures test_future_times_out() (GH-109949) #109952

Activity

1. vstinner

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   testsTests in the Lib/test dirTests in the Lib/test dir

   on Sep 19, 2023
2. vstinner commented on Sep 21, 2023

   

   vstinner

   on Sep 21, 2023

   MemberAuthor

   More actions

   Test also failed on s390x Fedora 3.x: https://buildbot.python.org/all/#/builders/223/builds/4511

     test_future_times_out (test.test_concurrent_futures.test_as_completed.ThreadPoolAsCompletedTest.test_future_times_out) [0]
   Test ``futures.as_completed`` timing out before ... FAIL
   
   Stdout:
   0.35s 
   test_no_timeout (test.test_concurrent_futures.test_as_completed.ThreadPoolAsCompletedTest.test_no_timeout) ... ok
   
   ======================================================================
   FAIL: test_future_times_out (test.test_concurrent_futures.test_as_completed.ThreadPoolAsCompletedTest.test_future_times_out) [0]
   Test ``futures.as_completed`` timing out before
   ----------------------------------------------------------------------
   Traceback (most recent call last):
     File "/home/dje/cpython-buildarea/3.x.edelsohn-fedora-z/build/Lib/test/test_concurrent_futures/test_as_completed.py", line 60, in test_future_times_out
       self.assertEqual(completed_futures, already_completed)
   AssertionError: Items in the first set but not the second:
   <Future at 0x3ff9280f1c0 state=finished returned NoneType>
   
3. elfstrom commented on Sep 27, 2023

   

   elfstrom

   on Sep 27, 2023

   Contributor

   More actions

   I guess this would fix it:

               with self.subTest(timeout):
   
   -               future = self.executor.submit(time.sleep, 0.1)
   +               future = self.executor.submit(time.sleep, 10.0)
                   completed_futures = set()
                   try:

   I don't think the short sleep serves any testing purpose here, it just makes the test more likely to fail if there is any unexpected CPU contention.

   Reacted by Chris Withers
4. vstinner commented on Sep 27, 2023

   

   vstinner

   on Sep 27, 2023

   MemberAuthor

   More actions

   The problem is that the test waits cleanly until the future completes, and so the test takes 10 seconds with your change, instead of 100 ms (100x slower).

   Reacted by JosephSBoyle
5. vstinner

   added 2 commits that reference this issue on Sep 27, 2023

   pythongh-109565: Fix concurrent.futures test_future_times_out()

   bf4ab70

   pythongh-109565: Fix concurrent.futures test_future_times_out()

   afcaa29
6. vstinner commented on Sep 27, 2023

   

   vstinner

   on Sep 27, 2023

   MemberAuthor

   More actions

   I proposed PR #109949 to fix this test.
7. vstinner

   added a commit that references this issue on Sep 27, 2023

   gh-109565: Fix concurrent.futures test_future_times_out() (#109949)

   b1aebf1
8. miss-islington

   added a commit that references this issue on Sep 27, 2023

   pythongh-109565: Fix concurrent.futures test_future_times_out() (pyth…

   62986cb
9. csm10495

   added a commit that references this issue on Sep 28, 2023

   pythongh-109565: Fix concurrent.futures test_future_times_out() (pyth…

   cb42e83
10. Yhg1s

    added a commit that references this issue on Oct 2, 2023

    [3.12] gh-109565: Fix concurrent.futures test_future_times_out() (GH-…

    73ec1e7
11. vstinner

    closed this as completedon Oct 17, 2023
12. Glyphack

    added a commit that references this issue on Sep 2, 2024

    pythongh-109565: Fix concurrent.futures test_future_times_out() (pyth…

    4bb49f3
13. colesbury commented on Mar 1, 2025

    

    colesbury

    on Mar 1, 2025

    Contributor

    More actions

    Seen again in https://github.com/python/cpython/actions/runs/13606703595/job/38039027766?pr=130731:

    FAIL: test_future_times_out (test.test_concurrent_futures.test_as_completed.ThreadPoolAsCompletedTest.test_future_times_out) [0.1]
    Test ``futures.as_completed`` timing out before
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "D:\a\cpython\cpython\Lib\test\test_concurrent_futures\test_as_completed.py", line 63, in test_future_times_out
        self.assertEqual(completed_futures, already_completed)
        ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    AssertionError: Items in the first set but not the second:
    <Future at 0x200006535e0 state=finished returned NoneType>
    ----------------------------------------------------------------------
    
14. colesbury

    reopened this on Mar 1, 2025

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