PYTHON-5044 - Successive AsyncMongoClients on a single loop always timeout on server selection

Author: NoahStapp

pymongo/asynchronous/mongo_client.py

@@ -1565,6 +1565,8 @@ async def close(self) -> None:
             # TODO: PYTHON-1921 Encrypted MongoClients cannot be re-opened.
             await self._encrypter.close()
         self._closed = True
+        # Yield to the asyncio event loop so all executor tasks properly exit after cancellation
+        await asyncio.sleep(0)
 
     if not _IS_SYNC:
         # Add support for contextlib.aclosing.

pymongo/periodic_executor.py

@@ -75,6 +75,8 @@ def close(self, dummy: Any = None) -> None:
         callback; see monitor.py.
         """
         self._stopped = True
+        if self._task:
+            self._task.cancel()
 
     async def join(self, timeout: Optional[int] = None) -> None:
         if self._task is not None:

pymongo/synchronous/mongo_client.py

@@ -1559,6 +1559,7 @@ def close(self) -> None:
             # TODO: PYTHON-1921 Encrypted MongoClients cannot be re-opened.
             self._encrypter.close()
         self._closed = True
+        # Yield to the asyncio event loop so all executor tasks properly exit after cancellation
 
     if not _IS_SYNC:
         # Add support for contextlib.closing.