PYTHON-4021 Fix previous topologyDescription published when closing a client (mongodb#1769)

Author: ShaneHarvey

pymongo/asynchronous/topology.py

@@ -645,6 +645,7 @@ async def close(self) -> None:
         :exc:`~.errors.InvalidOperation`.
         """
         async with self._lock:
+            old_td = self._description
             for server in self._servers.values():
                 await server.close()
 
@@ -664,7 +665,6 @@ async def close(self) -> None:
         # Publish only after releasing the lock.
         if self._publish_tp:
             assert self._events is not None
-            old_td = self._description
             self._description = TopologyDescription(
                 TOPOLOGY_TYPE.Unknown,
                 {},

pymongo/synchronous/topology.py

@@ -643,6 +643,7 @@ def close(self) -> None:
         :exc:`~.errors.InvalidOperation`.
         """
         with self._lock:
+            old_td = self._description
             for server in self._servers.values():
                 server.close()
 
@@ -662,7 +663,6 @@ def close(self) -> None:
         # Publish only after releasing the lock.
         if self._publish_tp:
             assert self._events is not None
-            old_td = self._description
             self._description = TopologyDescription(
                 TOPOLOGY_TYPE.Unknown,
                 {},