>> I don't see that error message - where are you seeing it?


You need to search for it in the full log:


stderr:
---
Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/test/test_importlib/partial/pool_in_threads.py", line 9, in t
    with multiprocessing.Pool(1):
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/context.py", line 119, in Pool
    return Pool(processes, initializer, initargs, maxtasksperchild,
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/pool.py", line 212, in __init__
    self._repopulate_pool()
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/pool.py", line 303, in _repopulate_pool
    return self._repopulate_pool_static(self._ctx, self.Process,
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/pool.py", line 326, in _repopulate_pool_static
    w.start()
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/process.py", line 121, in start
    self._popen = self._Popen(self)
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/context.py", line 284, in _Popen
    return Popen(process_obj)
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/popen_spawn_posix.py", line 32, in __init__
    super().__init__(process_obj)
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/popen_fork.py", line 19, in __init__
    self._launch(process_obj)
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/popen_spawn_posix.py", line 42, in _launch
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "/Users/buildbot/buildarea/3.x.billenstein-macos/build/Lib/multiprocessing/spawn.py", line 176, in get_preparation_data
    dir=os.getcwd(),
OSError: [Errno 24] Too many open files