Re-assign assignment to students -> more clever solution to keep earlier work

[afmoene]

(feature suggestion) In my course I had to re-assign an assignment twice. As a result, some students lost their work, because the name of the backup file is formed from the orginal name, with a tilde ~ added to it (see https://doc.cocalc.com/teaching-tips_and_tricks.html#how-exactly-are-assignments-copied-to-students). So after the second re-assignment, the students' original files are no longer there.

The re-assign with backup now uses rsync --backup. By adding --suffix, the backup files could be uniquely named: rsync --backup --suffix=`date +'.%y%m%d%H%M'

In that case, the students will always be able to access their previous version (from which they might copy prior work to the new version or the other way around).

[williamstein]

Thanks. Quick question: Did they actually really lose work, which they couldn't recover using TimeTravel? I'm not sure how that is possible.

[afmoene]

First, it is relevant to note that I let my students primarily work in classic Jupyter notebooks, so TimeTravel is not directly available.

• Initially, it seemed as if the backup (with tilde) did not happen at all, because it appears that Jupyter notebooks do not show files with a tilde at the end. When I discovered that, we resorted to the explorer in the cocalc interface to find the files.
• After I discovered that a repeated re-assignment did not result in an additional backup, I resorted to the snapshots. For many students I was able to find their last version. However, it was not clear to me what determined the timing of a new snapshot, hence I was also not perfectly sure that this would always work (it could be possible that I re-assign just before a new snapshot is made).

I was contacted by one student (but there might have been more) for whom we were not able to find her edited notebook back in the snapshots. This made sense, as the snapshot was from after I made the double re-assignment.