Empty messages in a conversation cause previos messages in the conversations to be muted

[jsorva]

The Jutut changes in summer 2024 have been largely excellent. However, a few things (mostly small ones) don’t quite work. Here’s one of them.

• If a student writes a message to the course staff, that chapter-specific conversation gets placed in the Unread section of the teacher interface. Great.

• But then if the student writes an empty (or very short?!?) message in the same chapter, the entire conversation disappears from the Unread section of the teacher interface.

Here’s an artificial example that I just constructed myself: https://jutut.cs.aalto.fi/manage/60/feedbacks/?student=3&exercise=2601
Note that the second message by the same "student" (me) from the same chapter has an empty message and has been consequently auto-accepted (which is fine). But that has had the additional consequence that the entire conversation (including the original non-empty message) no longer appears here: https://jutut.cs.aalto.fi/manage/60/unread/
Which is bad. Essentially, the original feedback message (just "foo" here, but you get the point) has vanished from the primary channel through which a teacher might see it.

I’ve (through sheer luck) happened to spot this happening a few times already in production, and I think that each time it has not actually been the student’s intention to cancel their earlier feedback message. It’s just that they’ve somehow ended up with their keyboard focus in the more-feedback section ended up leaving it empty after all. But the consequence is that they’ve kinda destroyed their own feedback.

(There are other consequences to this bug as well, but I won’t go into more detail here, since I think the above is reason enough to have this fixed.)