ROS Basics project feedback - Trigger.srv - service structure does not match what's in the code

In the instructions you list the Trigger.srv structure as

# request, Empty because no data is needed
bool movement_successfull
string extra_data

The actual structure is:

bool success   # indicate successful run of triggered service
string message # informational, e.g. for error messages

I’m guessing you weren’t trying to be misleading intentionally, but can’t really figure why you listed this the way you did. It caused me (and I suspect others) a lot of frustration. If you’re going to give a hint, you shouldn’t give a misleading one.


Thank you for the feedback. We’re not trying to be intentionally misleading, we just didn’t expect the code to be copied hook, line, sinker. But we’ll review this nonetheless, providing further clarifications as needed.

I didn’t copy the code, but I did use it as a reference for the message format. If you just want to give a hint to check out the Trigger message as an appropriate existing message, better to just make that suggestion and leave finding the format as an exercise for the student.

If you include code snippets you have to expect the students to copy it. In fact in many lessons that’s exactly what you tell the student to do. So you shouldn’t mix working code with non-working code unless you make it VERY clear that a specific example is incomplete. Otherwise the distinction may not be obvious to a beginner (i.e. the very people taking your classes).

One other suggestion (instead of opening a new topic). As I worked on my quiz I realized you don’t have an example of an action client dealing with the actual result message (as opposed to the result state). Maybe it’s not something used much in practice, but perhaps it’s worth including. Otherwise it’s unclear why the result message even exists.

Overall the course has been very helpful and I’ve been happy with it. In a way it’s your overall high quality that makes the occasional lapses more frustrating, because I just assume everything is correct. I also appreciate your responsiveness to feedback. Looking forward to working my way through more courses.

Happy holidays,

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Thanks for your comprehensive clarification and further feedback. We’ll definitely look into them.

Happy holidays too!