Rosbridge error when using Ros2 Parameter Extension

[wouterio]

We're running Foxglove Studio with the Ros2 Parameter Extension connected to a platform with Ros2 Foxy and Rosbridge. Sometimes it looks like we get this Rosbridge error when we run the extension and open the drop down menu to select a node.

[rosapi_node-2] Traceback (most recent call last):
[rosapi_node-2]   File "/opt/ros/foxy/lib/rosapi/rosapi_node", line 329, in <module>
[rosapi_node-2]     main()
[rosapi_node-2]   File "/opt/ros/foxy/lib/rosapi/rosapi_node", line 321, in main
[rosapi_node-2]     rclpy.spin(node)
[rosapi_node-2]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/__init__.py", line 191, in spin
[rosapi_node-2]     executor.spin_once()
[rosapi_node-2]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 718, in spin_once
[rosapi_node-2]     raise handler.exception()
[rosapi_node-2]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/task.py", line 239, in __call__
[rosapi_node-2]     self._handler.send(None)
[rosapi_node-2]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 429, in handler
[rosapi_node-2]     await call_coroutine(entity, arg)
[rosapi_node-2]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 383, in _execute_service
[rosapi_node-2]     response = await await_or_execute(srv.callback, request, srv.srv_type.Response())
[rosapi_node-2]   File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/executors.py", line 118, in await_or_execute
[rosapi_node-2]     return callback(*args)
[rosapi_node-2]   File "/opt/ros/foxy/lib/rosapi/rosapi_node", line 171, in get_node_details
[rosapi_node-2]     (
[rosapi_node-2] TypeError: cannot unpack non-iterable NoneType object

The error refers to this method in rosapi:

    def get_node_details(self, request, response):
        """Called by the rosapi/Nodes service. Returns a node description"""
        (
            response.subscribing,
            response.publishing,
            response.services,
        ) = proxy.get_node_info(request.node)
        return response

It looks like proxy.get_node_info(request.node) return None. The drop down menu stays empty too. I am not entirely sure, but it seems the extension and this rosbridge error are related.