Impossible to tell which parameters were gotten if some don't exist #490
Description
Bug report
Required Info:
- Operating System:
- Ubuntu 16.04
- Installation type:
- source
- Version or commit hash:
- DDS implementation:
- Fast-RTPS
- Client library (if applicable):
- rclcpp
Steps to reproduce issue
ros2 run demo_nodes_cpp listener
In another terminal
ros2 param set listener bool_param1 true
ros2 param set listener bool_param2 true
ros2 service call /listener/get_parameters rcl_interfaces/GetParameters "{'names': ['bool_param1', 'does_not_exist', 'bool_param2']}"
Expected behavior
I would expect the returned output from the service call to indicate which parameter did not exist
Actual behavior
Response to service call has 2 values, but no indication of which of the 3 requested parameters were returned.
rcl_interfaces.srv.GetParameters_Response(values=[rcl_interfaces.msg.ParameterValue(type=1, bool_value=True, integer_value=0, double_value=0.0, string_value='', byte_array_value=[], bool_array_value=[], integer_array_value=[], double_array_value=[], string_array_value=[]), rcl_interfaces.msg.ParameterValue(type=1, bool_value=True, integer_value=0, double_value=0.0, string_value='', byte_array_value=[], bool_array_value=[], integer_array_value=[], double_array_value=[], string_array_value=[])])
Additional information
The cause seems to be this code that only adds a result if the parameter exists. One solution might be to add an else case adding a parameter value with type NOT_SET to the result.
rclcpp/rclcpp/src/rclcpp/node_interfaces/node_parameters.cpp
Lines 126 to 132 in 2a17232