Is this to be expected?
Yes, and it is also not a limit to array/list/sequence sizes in the message format (as your question seems to imply), but a usability feature.
The ROS 2 rostopic
CLI tool by default will not print full length arrays for lists/arrays/sequences longer than 128
elements to prevent "runaway" terminals (where you are waiting 5 minutes for rostopic
to quit after having rostopic echo
d a topic carrying PointCloud
msgs fi).
You can disable/change this behaviour in two ways:
- provide an alternative value with the
--truncate-length
option (here) - add
--full-length
to your echo
invocation (here)
Note that this is similar to rostopic echo
's --noarr
in ROS 1 (although that didn't allow you to specify a limit to the nr of elements it did print).