Undescriptive error on building lesson

[jhidding]

The following error is given when building our lesson on Efficient computing with Julia.

> sandpaper::build_lesson()
...
-- Creating Instructor Notes -----------------------------------------
Error: Length of `path` must equal length of `new_path`
...

I couldn't find anything suspicious in the instructor notes, nor any obvious differences with the generated lesson template. I'm not sure how to recreate this from a newly created lesson (after sandpaper::create_lesson("test")).

[froggleston]

Hi @jhidding - I'm wondering if this is because you have overview.md and instructor-notes.md in the instructors folder?

[jhidding]

Yes! that solves it.

[froggleston]

Great! I'll close this issue!

[jhidding]

No don't! Why can there be only one file there? And why is the error so cryptic? Sandpaper has some serious usability issues (don't get me started on the installation). These things should be fixed not ignored.

[froggleston]

Hi @jhidding - apologies, I wasn't intending to stifle any discussion, but keep the issues focused to specific topics. Please do raise issues that are specific to installation so that we can take a look at them. Similarly for usability we would always welcome suggestions for improvements.

I'm unsure why having two files there results in that message. The R traceback is also not very clear why the file copy fails (the error comes from the R fs package, and not the sandpaper code itself), but we're supplying some parameters to that function that seemingly it doesn't like. I can definitely try and add more useful error messaging in there as a first pass solution.

[froggleston]

Hi @jhidding - I've had a chance to look through this some more, and the issue is that you have the overview.md and instructor-notes.md files in your instructors/ folder, but only the overview.md listed in your config.yaml.

If you add the instructor-notes.md entry into your config, it should build:

# Information for Instructors
instructors:
- overview.md
- instructor-notes.md

I appreciate this error message is not useful at all, so now I know what the issue is, I can do a check and improve the error. I hope this helps.