homepage

Using PR 3138 of bpo-31234, I noticed that test_concurrent_futures leaks dangling threads:
haypo@selma$ ./python -u -m test --fail-env-changed test_concurrent_futures -v -m ThreadPoolWaitTests
== CPython 3.7.0a0 (heads/master:0267128, Aug 21 2017, 17:23:11) [GCC 6.4.1 20170727 (Red Hat 6.4.1-1)]
(...)
test_all_completed (test.test_concurrent_futures.ThreadPoolWaitTests) ... Warning -- threading_cleanup() detected 0 leaked threads (count: 0, dangling: 6)
0.11s ok
test_first_completed (test.test_concurrent_futures.ThreadPoolWaitTests) ... 1.60s ok
test_first_completed_some_already_completed (test.test_concurrent_futures.ThreadPoolWaitTests) ... 1.60s ok
test_first_exception (test.test_concurrent_futures.ThreadPoolWaitTests) ... Warning -- threading_cleanup() detected 0 leaked threads (count: 0, dangling: 6)
3.11s ok
test_first_exception_one_already_failed (test.test_concurrent_futures.ThreadPoolWaitTests) ... 2.10s ok
test_first_exception_some_already_complete (test.test_concurrent_futures.ThreadPoolWaitTests) ... Warning -- threading_cleanup() detected 0 leaked threads (count: 0, dangling: 6)
1.60s ok
test_pending_calls_race (test.test_concurrent_futures.ThreadPoolWaitTests) ... 0.12s ok
test_timeout (test.test_concurrent_futures.ThreadPoolWaitTests) ... 6.11s ok
(...)

New changeset 489d91c61d02f401551966f1558ee2dc87fc0ad9 by Victor Stinner in branch 'master':
bpo-31249: test_concurrent_futures checks dangling threads (#3167)
https://github.com/python/cpython/commit/489d91c61d02f401551966f1558ee2dc87fc0ad9

New changeset bc61315377056fe362b744d9c44e17cd3178ce54 by Victor Stinner in branch 'master':
bpo-31249: Fix ref cycle in ThreadPoolExecutor (#3178)
https://github.com/python/cpython/commit/bc61315377056fe362b744d9c44e17cd3178ce54

New changeset 60f3f1fb5cbf5354c3081138be806c56cb04153f by Victor Stinner in branch '3.6':
bpo-31249: Fix ref cycle in ThreadPoolExecutor (#3253)
https://github.com/python/cpython/commit/60f3f1fb5cbf5354c3081138be806c56cb04153f

I still see the warning sometimes:
0:04:09 load avg: 7.03 [185/405/1] test_concurrent_futures failed (env changed) (68 sec) -- running: test_multiprocessing_spawn (160 sec), test_gdb (53 sec), test_lib2to3 (195 sec)
test_cancel (test.test_concurrent_futures.FutureTests) ... ok
test_cancelled (test.test_concurrent_futures.FutureTests) ... ok
test_done (test.test_concurrent_futures.FutureTests) ... ok
test_done_callback_already_cancelled (test.test_concurrent_futures.FutureTests) ... ok
test_done_callback_already_failed (test.test_concurrent_futures.FutureTests) ... ok
test_done_callback_already_successful (test.test_concurrent_futures.FutureTests) ... ok
test_done_callback_raises (test.test_concurrent_futures.FutureTests) ... ok
test_done_callback_with_cancel (test.test_concurrent_futures.FutureTests) ... ok
test_done_callback_with_exception (test.test_concurrent_futures.FutureTests) ... ok
test_done_callback_with_result (test.test_concurrent_futures.FutureTests) ... ok
test_exception_with_success (test.test_concurrent_futures.FutureTests) ... ok
test_exception_with_timeout (test.test_concurrent_futures.FutureTests) ... ok
test_repr (test.test_concurrent_futures.FutureTests) ... ok
test_result_with_cancel (test.test_concurrent_futures.FutureTests) ... ok
test_result_with_success (test.test_concurrent_futures.FutureTests) ... ok
test_result_with_timeout (test.test_concurrent_futures.FutureTests) ... ok
test_running (test.test_concurrent_futures.FutureTests) ... ok
test_correct_timeout_exception_msg (test.test_concurrent_futures.ProcessPoolAsCompletedTests) ... 0.15s ok
test_duplicate_futures (test.test_concurrent_futures.ProcessPoolAsCompletedTests) ... 2.16s ok
test_free_reference_yielded_future (test.test_concurrent_futures.ProcessPoolAsCompletedTests) ... 0.15s ok
test_no_timeout (test.test_concurrent_futures.ProcessPoolAsCompletedTests) ... 0.15s ok
test_zero_timeout (test.test_concurrent_futures.ProcessPoolAsCompletedTests) ... 2.15s ok
test_free_reference (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.17s ok
test_killed_child (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.15s ok
test_map (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.18s ok
test_map_chunksize (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.17s ok
test_map_exception (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.17s ok
test_map_timeout (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 6.16s ok
test_max_workers_negative (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.14s ok
test_no_stale_references (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.14s ok
test_shutdown_race_issue12456 (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.15s ok
test_submit (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.14s ok
test_submit_keyword (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.13s ok
test_traceback (test.test_concurrent_futures.ProcessPoolExecutorTest) ... 0.15s ok
test_context_manager_shutdown (test.test_concurrent_futures.ProcessPoolShutdownTest) ... 0.07s ok
test_del_shutdown (test.test_concurrent_futures.ProcessPoolShutdownTest) ... 0.05s Warning -- threading_cleanup() detected 1 leaked threads (count: 1, dangling: 2)
ok
test_hang_issue12364 (test.test_concurrent_futures.ProcessPoolShutdownTest) ... 1.09s ok
test_interpreter_shutdown (test.test_concurrent_futures.ProcessPoolShutdownTest) ... 2.67s ok
test_processes_terminate (test.test_concurrent_futures.ProcessPoolShutdownTest) ... 0.05s ok
test_run_after_shutdown (test.test_concurrent_futures.ProcessPoolShutdownTest) ... 0.00s ok
test_all_completed (test.test_concurrent_futures.ProcessPoolWaitTests) ... 0.16s ok
test_first_completed (test.test_concurrent_futures.ProcessPoolWaitTests) ... 1.64s ok
test_first_completed_some_already_completed (test.test_concurrent_futures.ProcessPoolWaitTests) ... 1.65s ok
test_first_exception (test.test_concurrent_futures.ProcessPoolWaitTests) ... 3.15s ok
test_first_exception_one_already_failed (test.test_concurrent_futures.ProcessPoolWaitTests) ... 2.15s ok
test_first_exception_some_already_complete (test.test_concurrent_futures.ProcessPoolWaitTests) ... 1.65s ok
test_timeout (test.test_concurrent_futures.ProcessPoolWaitTests) ... 6.15s ok
test_correct_timeout_exception_msg (test.test_concurrent_futures.ThreadPoolAsCompletedTests) ... 0.16s ok
test_duplicate_futures (test.test_concurrent_futures.ThreadPoolAsCompletedTests) ... 2.15s ok
test_free_reference_yielded_future (test.test_concurrent_futures.ThreadPoolAsCompletedTests) ... 0.15s ok
test_no_timeout (test.test_concurrent_futures.ThreadPoolAsCompletedTests) ... 0.16s ok
test_zero_timeout (test.test_concurrent_futures.ThreadPoolAsCompletedTests) ... 2.15s ok
test_default_workers (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.15s ok
test_free_reference (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.14s ok
test_map (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.15s ok
test_map_exception (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.16s ok
test_map_submits_without_iteration (test.test_concurrent_futures.ThreadPoolExecutorTest)
Tests verifying issue 11777. ... 0.15s ok
test_map_timeout (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 6.13s ok
test_max_workers_negative (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.14s ok
test_no_stale_references (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.14s ok
test_shutdown_race_issue12456 (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.16s ok
test_submit (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.14s ok
test_submit_keyword (test.test_concurrent_futures.ThreadPoolExecutorTest) ... 0.14s ok
test_context_manager_shutdown (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 0.07s ok
test_del_shutdown (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 0.04s ok
test_hang_issue12364 (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 1.07s ok
test_interpreter_shutdown (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 1.65s ok
test_run_after_shutdown (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 0.00s ok
test_thread_names_assigned (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 0.05s ok
test_thread_names_default (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 0.04s ok
test_threads_terminate (test.test_concurrent_futures.ThreadPoolShutdownTest) ... 0.02s ok
test_all_completed (test.test_concurrent_futures.ThreadPoolWaitTests) ... 0.14s ok
test_first_completed (test.test_concurrent_futures.ThreadPoolWaitTests) ... 1.65s ok
test_first_completed_some_already_completed (test.test_concurrent_futures.ThreadPoolWaitTests) ... 1.65s ok
test_first_exception (test.test_concurrent_futures.ThreadPoolWaitTests) ... 3.14s ok
test_first_exception_one_already_failed (test.test_concurrent_futures.ThreadPoolWaitTests) ... 2.16s ok
test_first_exception_some_already_complete (test.test_concurrent_futures.ThreadPoolWaitTests) ... 1.62s ok
test_pending_calls_race (test.test_concurrent_futures.ThreadPoolWaitTests) ... 0.16s ok
test_timeout (test.test_concurrent_futures.ThreadPoolWaitTests) ... 6.13s ok
----------------------------------------------------------------------
Ran 79 tests in 68.182s
OK

New changeset 3bcf157c115ba3e48bce62ac8cb13c703475a113 by Victor Stinner in branch 'master':
bpo-31249: Fix test_concurrent_futures dangling thread (#3521)
https://github.com/python/cpython/commit/3bcf157c115ba3e48bce62ac8cb13c703475a113

New changeset 94eb2d5b73d07bc447f1fe19923b4c3259734b9c by Victor Stinner (Miss Islington (bot)) in branch '3.6':
[3.6] bpo-31249: Fix test_concurrent_futures dangling thread (GH-3521) (#3522)
https://github.com/python/cpython/commit/94eb2d5b73d07bc447f1fe19923b4c3259734b9c

Ok, the issue should now be fixed in Python 3.6 and master (future 3.7).