``test_concurrent_futures.test_init`` raises a ``UserWarning``

[Eclips4]

Bug report

Bug description:

Full trace:

./python.exe -m test -R 3:3 test_concurrent_futures.test_init      
Using random seed: 256345264
0:00:00 load avg: 26.64 Run 1 test sequentially
0:00:00 load avg: 26.64 [1/1] test_concurrent_futures.test_init
beginning 6 repetitions
123456
/Users/admin/Projects/cpython/Lib/multiprocessing/resource_tracker.py:254: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown: {'/mp-sirq4ugj', '/mp-rl_2jbw3', '/mp-xahxrhsh', '/mp-iizqar8w', '/mp-2hsbr18l', '/mp-0l_el3ow'}
  warnings.warn(
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
./Users/admin/Projects/cpython/Lib/multiprocessing/resource_tracker.py:254: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown: {'/mp-lylw1wiw', '/mp-4uiidj6c', '/mp-7_ynxysg', '/mp-fx5syuzw', '/mp-ee8we555', '/mp-txhnr28x'}
  warnings.warn(
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
./Users/admin/Projects/cpython/Lib/multiprocessing/resource_tracker.py:254: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown: {'/mp-mey7u772', '/mp-1vws0viu', '/mp-1afg36e2', '/mp-bjp0f0e8', '/mp-7rpmd8vy', '/mp-95_5xypk'}
  warnings.warn(
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
./Users/admin/Projects/cpython/Lib/multiprocessing/resource_tracker.py:254: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown: {'/mp-618trphi', '/mp-wumuoxh9', '/mp-67c83ehk', '/mp-gv1cs7ab', '/mp-58aupobv', '/mp-70_ec35j'}
  warnings.warn(
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
./Users/admin/Projects/cpython/Lib/multiprocessing/resource_tracker.py:254: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown: {'/mp-micqbsoj', '/mp-t8f_ctlr', '/mp-5ae_spee', '/mp-ukdpimut', '/mp-mzxz9i98', '/mp-z15yhv29'}
  warnings.warn(
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
./Users/admin/Projects/cpython/Lib/multiprocessing/resource_tracker.py:254: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown: {'/mp-hnbdlmxa', '/mp-jrz89bu_', '/mp-aqeivj6m', '/mp-5yqnp8sh', '/mp-ga8p0vrj', '/mp-ugk7l_je'}
  warnings.warn(
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 296, in _run_finalizers
    finalizer()
    ~~~~~~~~~^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/util.py", line 220, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/admin/Projects/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
    ~~~~~~~~~~^^^^^^
FileNotFoundError: [Errno 2] No such file or directory
.

== Tests result: SUCCESS ==

1 test OK.

Total duration: 8.0 sec
Total tests: run=8
Total test files: run=1/1
Result: SUCCESS

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

[Eclips4]

FYI: I'm not able to reproduce it with --forever ( I mean ./python.exe -m test -v test_concurrent_futures.test_init --forever)

[encukou]

This just happened on a Mac free-threading refleaks buildbot. The same test leaked a reference.

[encukou]

Can reproduce consistently on Linux with -R : (that is, ./python -m test test_concurrent_futures.test_init -R:).

[encukou]

Looks like a test-only issue: in multiprocessing.util._cleanup_tests, this happens:

• the ResourceTracker is stopped, and it:
  • emits the one-line warning about “leaked semaphore objects to clean up at shutdown”
  • cleans up the semaphores
• only after that, _run_finalizers runs, cleaning up the semaphores -- but the semaphores are already missing, hence the FileNotFoundError

IMO, it should be fine to switch the order here. Will send a PR after more testing.

[encukou]

... or maybe these are supposed to be cleaned up before atexit finalizers, and the test should catch this?

[encukou]

Oh, this is a duplicate of #104090. There's much more info there.