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Type:
Build Failure
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Resolution: Done
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Priority:
Unknown
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Affects Version/s: None
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Component/s: None
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Python Drivers
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Name of Failure:
The following five tests in test.test_connection_monitoring.TestCMAP.test_connection_monitoring... are flaky due to their use of concurrent threads and tight timing windows: pool_checkout_custom_maxConnecting_is_enforced, pool_checkout_maxConnecting_is_enforced, pool_checkout_maxConnecting_timeout, pool_checkout_minPoolSize_connection_maxConnecting, and pool_checkout_returned_connection_maxConnecting.
The flakiness is worse on PyPy, PyOpenSSL, and free-threaded runs.
Link to task:
Context of when and why the failure occurred:
See above.
Stack trace:
[2026/08/26 07:14:46.911] FAILURE: AssertionError: Didn't ever find 1 <class 'pymongo.monitoring.ConnectionCheckOutFailedEvent'> event(s) () [2026/08/26 07:14:46.911] self = <test.test_connection_monitoring.TestCMAP testMethod=test_connection_monitoring_pool_checkout_maxConnecting_timeout_waiting_on_maxConnecting_is_limited_by_WaitQueueTimeoutMS> [2026/08/26 07:14:46.911] def run_scenario(self): [2026/08/26 07:14:46.911] > self.run_scenario(scenario_def, test) [2026/08/26 07:14:46.911] test/test_connection_monitoring.py:451: [2026/08/26 07:14:46.911] _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [2026/08/26 07:14:46.911] test/test_connection_monitoring.py:282: in run_scenario [2026/08/26 07:14:46.911] self.run_operations(test["operations"]) [2026/08/26 07:14:46.911] test/test_connection_monitoring.py:172: in run_operations [2026/08/26 07:14:46.911] self.run_operation(op) [2026/08/26 07:14:46.911] test/test_connection_monitoring.py:166: in run_operation [2026/08/26 07:14:46.911] meth(op) [2026/08/26 07:14:46.911] test/test_connection_monitoring.py:120: in wait_for_event [2026/08/26 07:14:46.911] wait_until( [2026/08/26 07:14:46.911] _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [2026/08/26 07:14:46.911] def wait_until(predicate, success_description, timeout=10): [2026/08/26 07:14:46.911] """Wait up to 10 seconds (by default) for predicate to be true. [2026/08/26 07:14:46.911] [2026/08/26 07:14:46.911] E.g.: [2026/08/26 07:14:46.911] [2026/08/26 07:14:46.911] wait_until(lambda: client.primary == ('a', 1), [2026/08/26 07:14:46.911] 'connect to the primary') [2026/08/26 07:14:46.911] [2026/08/26 07:14:46.911] If the lambda-expression isn't true after 10 seconds, we raise [2026/08/26 07:14:46.911] AssertionError("Didn't ever connect to the primary"). [2026/08/26 07:14:46.911] [2026/08/26 07:14:46.911] Returns the predicate's first true value. [2026/08/26 07:14:46.911] """ [2026/08/26 07:14:46.911] start = time.time() [2026/08/26 07:14:46.911] interval = min(float(timeout) / 100, 0.1) [2026/08/26 07:14:46.911] while True: [2026/08/26 07:14:46.911] if iscoroutinefunction(predicate): [2026/08/26 07:14:46.911] retval = predicate() [2026/08/26 07:14:46.911] else: [2026/08/26 07:14:46.911] retval = predicate() [2026/08/26 07:14:46.911] if retval: [2026/08/26 07:14:46.911] return retval [2026/08/26 07:14:46.911] [2026/08/26 07:14:46.911] if time.time() - start > timeout: [2026/08/26 07:14:46.911] > raise AssertionError("Didn't ever %s" % success_description) [2026/08/26 07:14:46.911] E AssertionError: Didn't ever find 1 <class 'pymongo.monitoring.ConnectionCheckOutFailedEvent'> event(s) [2026/08/26 07:14:46.911] test/utils.py:80: AssertionError