test_stress_different_keys_threadsafe hangs when run on a single core

[bdrung]

Running the test case test_stress_different_keys_threadsafe on just one core causes the test case to hang:

$ taskset -c 0 python3 -m pytest --pyargs zict
============================= test session starts ==============================
platform linux -- Python 3.11.5, pytest-7.4.0, pluggy-1.2.0 -- /usr/bin/python3.11
cachedir: .pytest_cache
rootdir: /tmp/autopkgtest.r5brBZ/autopkgtest_tmp
configfile: setup.cfg
plugins: timeout-2.1.0
timeout: 180.0s
timeout method: thread
timeout func_only: False
collecting ... collected 539 items

[...]
tests/test_lru.py::test_stress_different_keys_threadsafe 
+++++++++++++++++++++++++++++++++++ Timeout ++++++++++++++++++++++++++++++++++++

~~~~~~~~~~~~~ Stack of ThreadPoolExecutor-174_1 (140600758003392) ~~~~~~~~~~~~~~
  File "/usr/lib/python3.11/threading.py", line 995, in _bootstrap
    self._bootstrap_inner()
  File "/usr/lib/python3.11/threading.py", line 1038, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.11/threading.py", line 975, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib/python3.11/concurrent/futures/thread.py", line 83, in _worker
    work_item.run()
  File "/usr/lib/python3.11/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/lib/python3/dist-packages/zict/tests/utils_test.py", line 173, in worker
    z[key] = value
  File "/usr/lib/python3/dist-packages/zict/lru.py", line 138, in __setitem__
    self.evict_until_below_target()
  File "/usr/lib/python3/dist-packages/zict/lru.py", line 180, in evict_until_below_target
    self.evict()
  File "/usr/lib/python3/dist-packages/zict/common.py", line 127, in wrapper
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/zict/lru.py", line 224, in evict
    with self.unlock():
  File "/usr/lib/python3.11/contextlib.py", line 144, in __exit__
    next(self.gen)
  File "/usr/lib/python3/dist-packages/zict/common.py", line 91, in unlock
    self.lock.acquire()

~~~~~~~~~~~~~ Stack of ThreadPoolExecutor-174_0 (140600766428864) ~~~~~~~~~~~~~~
  File "/usr/lib/python3.11/threading.py", line 995, in _bootstrap
    self._bootstrap_inner()
  File "/usr/lib/python3.11/threading.py", line 1038, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.11/threading.py", line 975, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib/python3.11/concurrent/futures/thread.py", line 83, in _worker
    work_item.run()
  File "/usr/lib/python3.11/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/lib/python3/dist-packages/zict/tests/utils_test.py", line 173, in worker
    z[key] = value
  File "/usr/lib/python3/dist-packages/zict/lru.py", line 138, in __setitem__
    self.evict_until_below_target()
  File "/usr/lib/python3/dist-packages/zict/lru.py", line 180, in evict_until_below_target
    self.evict()
  File "/usr/lib/python3/dist-packages/zict/common.py", line 127, in wrapper
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/zict/lru.py", line 184, in evict
    @locked

~~~~~~~~~~~~~~~~~~~~ Stack of MainThread (140600811225152) ~~~~~~~~~~~~~~~~~~~~~
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/usr/lib/python3/dist-packages/pytest/__main__.py", line 5, in <module>
    raise SystemExit(pytest.console_main())
  File "/usr/lib/python3/dist-packages/_pytest/config/__init__.py", line 189, in console_main
    code = main()
  File "/usr/lib/python3/dist-packages/_pytest/config/__init__.py", line 166, in main
    ret: Union[ExitCode, int] = config.hook.pytest_cmdline_main(
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 433, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 112, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 80, in _multicall
    res = hook_impl.function(*args)
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 317, in pytest_cmdline_main
    return wrap_session(config, _main)
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 270, in wrap_session
    session.exitstatus = doit(config, session) or 0
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 324, in _main
    config.hook.pytest_runtestloop(session=session)
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 433, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 112, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 80, in _multicall
    res = hook_impl.function(*args)
  File "/usr/lib/python3/dist-packages/_pytest/main.py", line 349, in pytest_runtestloop
    item.config.hook.pytest_runtest_protocol(item=item, nextitem=nextitem)
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 433, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 112, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 80, in _multicall
    res = hook_impl.function(*args)
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 114, in pytest_runtest_protocol
    runtestprotocol(item, nextitem=nextitem)
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 133, in runtestprotocol
    reports.append(call_and_report(item, "call", log))
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 222, in call_and_report
    call = call_runtest_hook(item, when, **kwds)
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 261, in call_runtest_hook
    return CallInfo.from_call(
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 341, in from_call
    result: Optional[TResult] = func()
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 262, in <lambda>
    lambda: ihook(item=item, **kwds), when=when, reraise=reraise
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 433, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 112, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 80, in _multicall
    res = hook_impl.function(*args)
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 169, in pytest_runtest_call
    item.runtest()
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 1788, in runtest
    self.ihook.pytest_pyfunc_call(pyfuncitem=self)
  File "/usr/lib/python3/dist-packages/pluggy/_hooks.py", line 433, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_manager.py", line 112, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
  File "/usr/lib/python3/dist-packages/pluggy/_callers.py", line 80, in _multicall
    res = hook_impl.function(*args)
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 194, in pytest_pyfunc_call
    result = testfunction(**testargs)
  File "/usr/lib/python3/dist-packages/zict/tests/test_lru.py", line 440, in test_stress_different_keys_threadsafe
    utils_test.check_different_keys_threadsafe(lru, allow_keyerror=True)
  File "/usr/lib/python3/dist-packages/zict/tests/utils_test.py", line 193, in check_different_keys_threadsafe
    f1.result()
  File "/usr/lib/python3.11/concurrent/futures/_base.py", line 451, in result
    self._condition.wait(timeout)
  File "/usr/lib/python3.11/threading.py", line 320, in wait
    waiter.acquire()

+++++++++++++++++++++++++++++++++++ Timeout ++++++++++++++++++++++++++++++++++++

Ubuntu bug: https://bugs.launchpad.net/ubuntu/+source/zict/+bug/2033759

Environment:

• Zict version: 3.0.0-2
• Python version: 3.11.5
• Operating System: Ubuntu 23.10 (mantic)
• Install method (conda, pip, source): Debian package

[jrbourbeau]

cc @crusaderky