feat: Allow importing action feedback message types (backport #1108) (#1112)

Author: bjsowa

rosbridge_library/src/rosbridge_library/internal/ros_loader.py

@@ -231,6 +231,11 @@ def _load_class(
         raise InvalidModuleException(modname, subname, exc) from exc
 
     try:
+        # Special case for action feedback messages
+        if subname == "action" and classname.endswith("_FeedbackMessage"):
+            action_name, name = classname.rsplit("_", 1)
+            return getattr(getattr(pypkg, action_name).Impl, name)
+
         return getattr(pypkg, classname)
     except Exception as exc:
         raise InvalidClassException(modname, subname, classname, exc) from exc

rosbridge_library/test/internal/test_ros_loader.py

@@ -143,6 +143,7 @@ def test_assorted_msg_names(self) -> None:
             "visualization_msgs/InteractiveMarkerUpdate",
             "nav_msgs/GridCells",
             "sensor_msgs/PointCloud2",
+            "example_interfaces/action/Fibonacci_FeedbackMessage",
         ]
         for x in assortedmsgs:
             self.assertNotEqual(ros_loader.get_message_class(x), None)