fix(pymongo): add pin type check (#11145)

Small type check fix for expected `Pin` type to unblock #11041

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ddtrace/contrib/internal/pymongo/client.py

@@ -103,7 +103,10 @@ def _trace_topology_select_server(func, args, kwargs):
     # Ensure the pin used on the traced mongo client is passed down to the topology instance
     # This allows us to pass the same pin in traced server objects.
     topology_instance = get_argument_value(args, kwargs, 0, "self")
-    ddtrace.Pin.get_from(topology_instance).onto(server)
+    pin = ddtrace.Pin.get_from(topology_instance)
+
+    if pin is not None:
+        pin.onto(server)
     return server
 
 

releasenotes/notes/pymongo-check-pin-c3cb9d1fbdc82fb3.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    pymongo: add type checking to solve an issue where ``NoneType`` instead of expected ``Pin`` object would throw an error in ``TracedTopology`` method.