JointGroupPositionController fails to initialize on Rolling due to rclcpp "undeclare_parameter" API change

[schornakj]

There have already been some fixes to other controllers for the rclcpp parameter API changes. Currently (as of 0.4.1) the JointGroupPositionController fails to initialize because it tries to undeclare a statically-typed parameter at these lines, which produces an error:

[ros2_control_node-1] [INFO] [1628693935.184140389] [controller_manager]: Loading controller 'position_controller'
[ros2_control_node-1] Exception thrown during init stage with message: parameter 'interface_name' has invalid type: cannot undeclare an statically typed parameter 
[ros2_control_node-1] [ERROR] [1628693935.194137855] [controller_manager]: Could not initialize the controller named 'position_controller'

I wanted to get some additional context and input before I try to fix this myself: why is it necessary to undeclare the interface_name parameter declared by ForwardCommandController, and does anyone else already have a fix in mind?

[gc-robotics]

I am facing the same issue.

Exception thrown from the following line:

// undeclare interface parameter used in the general forward_command_controller
get_node()->undeclare_parameter("interface_name");

Checking undeclare_parameter, I see the check below is failing:

  if (!parameter_info->second.descriptor.dynamic_typing) {
    throw rclcpp::exceptions::InvalidParameterTypeException{
            name, "cannot undeclare an statically typed parameter"};
  }

I believe the parameter is "interface_name". Not sure where that is added or defined, as I don't have it in my YAML controller definition.

Anyone actively working on this?

[gc-robotics]

Have just seen the PR. Will wait for the approval. Thanks @schornakj .