fix population of recursive message fields

[dirk-thomas]

Fixes #22.

Ready for review.

[dhood]

confirm this fixes #22

[dhood]

remove debug print?

[dirk-thomas]

Good point. Gone.

[dhood]

I recommend catching exceptions here and saying which field failed, otherwise here's an example of giving 35 elements to Covariance instead of 36:

$ ros2 topic pub asdf geometry_msgs/PoseWithCovariance "pose:
  position: {x: 0.0, y: 0.0, z: 0.0}
  orientation: {x: 0.0, y: 0.0, z: 0.0, w: 0.0}
covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
  0.0, 0.0, 0.0, 0.0, 0.0]" 
covariance [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
Traceback (most recent call last):
  File "/home/dhood/ros2_ws/install_isolated/ros2cli/bin/ros2", line 11, in <module>
    load_entry_point('ros2cli==0.0.0', 'console_scripts', 'ros2')()
  File "/home/dhood/ros2_ws/install_isolated/ros2cli/lib/python3.5/site-packages/ros2cli/cli.py", line 64, in main
    rc = extension.main(parser=parser, args=args)
  File "/home/dhood/ros2_ws/install_isolated/ros2topic/lib/python3.5/site-packages/ros2topic/command/topic.py", line 38, in main
    return extension.main(args=args)
  File "/home/dhood/ros2_ws/install_isolated/ros2topic/lib/python3.5/site-packages/ros2topic/verb/pub.py", line 43, in main
    return main(args)
  File "/home/dhood/ros2_ws/install_isolated/ros2topic/lib/python3.5/site-packages/ros2topic/verb/pub.py", line 47, in main
    publisher(args.message_type, args.topic_name, args.values)
  File "/home/dhood/ros2_ws/install_isolated/ros2topic/lib/python3.5/site-packages/ros2topic/verb/pub.py", line 67, in publisher
    set_msg_fields(msg, values_dictionary)
  File "/home/dhood/ros2_ws/install_isolated/ros2topic/lib/python3.5/site-packages/ros2topic/verb/pub.py", line 86, in set_msg_fields
    setattr(msg, field_name, value)
  File "/home/dhood/ros2_ws/install_isolated/geometry_msgs/lib/python3.5/site-packages/geometry_msgs/msg/_pose_with_covariance.py", line 102, in covariance
    True)
AssertionError

[dirk-thomas]

Please see the updated patch. Can you try it with an even more nested message?

[dirk-thomas]

If the assert would contain a reasonable message (which I added for this manually) I get the following now:

Failed to populate field 'covariance': The 'covariance' field must be a seq or list with length 36 and float values

[dirk-thomas]

See ros2/rosidl#224 for adding assert messages to all cases in the Python generator.

[dhood]

Tested with PoseWithCovarianceStamped which has 3 or 4 levels of nesting and this works well, thanks:

ros2 topic pub initialpose geometry_msgs/PoseWithCovarianceStamped "header:
  stamp:
    sec: 0
    nanosec: 0
  frame_id: 'map'   
pose:
  pose:
    position: {x: 5.5, y: 4.5, z: 0.0}
    orientation: {x: 0.0, y: 0.0, z: 0.0, w: 1.0}
  covariance: [0.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0,    0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0, 0.0, 0.0]"
publisher: beginning loop
publishing geometry_msgs.msg.PoseWithCovarianceStamped(header=std_msgs.msg.Header(stamp=builtin_interfaces.msg.Time(sec=0, nanosec=0), frame_id='map'), pose=geometry_msgs.msg.PoseWithCovariance(pose=geometry_msgs.msg.Pose(position=geometry_msgs.msg.Point(x=5.5, y=4.5, z=0.0), orientation=geometry_msgs.msg.Quaternion(x=0.0, y=0.0, z=0.0, w=1.0)), covariance=[0.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]))

[dirk-thomas]

See #27 for another improvement when passing wrong types.