rosapi tries to parse IDL files as msg files and errors

[russkel]

Description

If there is no msg files get_interface_path will return an idl path. This is then fed into the parse_message_string function for msg files. This ends up with a lot of errors spamming in the log.

https://github.com/RobotWebTools/rosbridge_suite/blob/ros2/rosapi/src/rosapi/stringify_field_types.py#L20

https://github.com/RobotWebTools/rosbridge_suite/blob/ros2/rosapi/src/rosapi/stringify_field_types.py#L24

• Library Version: main
• ROS Version: Iron release
• Platform / OS: Linux

Steps To Reproduce

Expected Behavior

Either parses IDL using the rosidl parser or errors once it detects the IDL extension and doesn't try to load it again.

Actual Behavior

[rosapi_node-19] Error processing '// generated from nmea0183_adapter/resource/msg_definition.idl.em' of 'nmea0183_msgs/UtcDateTime': '//'