[ros2topic] 'The passed message type is invalid'

[jacobperron]

Bug report

Required Info:

• Operating System:
  • Ubuntu 18.04 (and presumably all other platforms)
• Installation type:
  • source
• Version or commit hash:
  • tag 0.7.2 (8f41966)
• DDS implementation:
  • Fast-RTPS
• Client library (if applicable):
  • rclpy

Steps to reproduce issue

Start publishing to a topic:

ros2 topic pub /chatter std_msgs/Empty

Try using the verbs bw, hz, and delay. E.g.

ros2 topic bw /chatter

Expected behavior

The tools work (e.g. echo bandwidth for bw).

Actual behavior

All tools log the message "The passed message type is invalid" and exit.

Additional information

It's likely this is a bug introduced by ros2/ros2#677.

[cottsay]

I'm using this slightly hacky change to work around this issue for now:

--- a/ros2topic/ros2topic/api/__init__.py
+++ b/ros2topic/ros2topic/api/__init__.py
@@ -57,9 +57,11 @@ class TopicNameCompleter:
 def import_message_type(topic_name, message_type):
     # TODO(dirk-thomas) this logic should come from a rosidl related package
     try:
-        package_name, message_name = message_type.split('/', 2)
+        package_name, message_name = message_type.split('/', 1)
         if not package_name or not message_name:
             raise ValueError()
+        if message_name.startswith('msg/'):
+            message_name = message_name[4:]
     except ValueError:
         raise RuntimeError('The passed message type is invalid')

I think the maxsplit value should always have been 1, even before the regression.

[jacobperron]

Thanks. Yeah, I think maxplit should have been one.