added warning messages when unable to remap the interface properly in Joint State Broadcaster.

joint_state_broadcaster/src/joint_state_broadcaster.cpp

@@ -243,11 +243,19 @@ bool JointStateBroadcaster::init_joint_data()
       name_if_value_mapping_[prefix_name] = {};
     }
     // add interface name
+
     std::string interface_name = si->get_interface_name();
     if (map_interface_to_joint_state_.count(interface_name) > 0)
     {
       interface_name = map_interface_to_joint_state_[interface_name];
     }
+    else 
+    {
+      RCLCPP_WARN(
+        get_node()->get_logger(),
+        "Interface '%s' of joint '%s' is not mapped to any joint state field. The default value %s will be used.",
+        interface_name.c_str(), prefix_name.c_str(), interface_name.c_str());
+    }
     name_if_value_mapping_[prefix_name][interface_name] = kUninitializedValue;
 
     // filter state interfaces that have at least one of the joint_states fields,
@@ -265,8 +273,16 @@ bool JointStateBroadcaster::init_joint_data()
           joint_names_.push_back(prefix_name);
         }
       }
+    } else {
+        // Moreover, when there is not even the default interface (position, velocity, effort), 
+        //then it should also print that it is not present and NaN's will be obtained in the respective field.
+        RCLCPP_WARN(
+          get_node()->get_logger(),
+          "Interface '%s' of joint '%s' is not present in JointState message fields. NaN's will be obtained in the respective field.",
+          interface_name.c_str(), prefix_name.c_str());
     }
   }
+
   std::reverse(joint_names_.begin(), joint_names_.end());
   if (is_model_loaded_ && params_.use_urdf_to_filter && params_.joints.empty())
   {