Grades incorrect in "Students" list and student view for group switchers

[Andreas Abel]

A student alerted me of a problem with the student list view (and the individual student view), which is also the basis for reporting grades.

See https://plt-lp2-17.frs.cse.chalmers.se/admin/students line Hassainia, Mohamed Seddik and even https://plt-lp2-17.frs.cse.chalmers.se/admin/students/[e-mail] :

Fire says that he failed labs 2-4, but following the links one gets to group 79 which he is no longer member of. Instead he is member of a new group 88, and following to the labs from there, I can see he passed. However, I only get to his current group by clicking "Current group" on the student's page.

Something is at odds here. What is the semantics of "passing a lab" for a student that switched groups?

I'd say that he should pass a lab if at submission time he was member of a group that passed the lab.

That could be exploited by switching to a new group just before they submit and then leaving it for a new one.

I feel that there is a concept of "resubmission" warranted akin to "reexam". Or maybe my use of Fire was not appropriate: to facilitate a lab reexam, I just changed the deadlines (removed the first deadline and reset the final deadline).

If a new concept is not wanted, for now a workaround would be to display on the student page all groups a student ever has been in and all their lab results. For the grade table there could be a column that alerts of "manual check needed" if a student has submitted the same labs with different groups and the results are diverging.

[Evgeny Kotelnikov]

Sort submissions by date and not number (fix #165)

→ <<cset 8f85714964d2>>

[Evgeny Kotelnikov]

Thank you very much for the report!

The semantics of passing a lab is the following. A student is considered having passed a lab if their "deciding submission" has been accepted. The "deciding submission" to a lab is the latest non-withdrawn submission made on behalf of any group.

The bug that I just fixed had to do with how "the latest" was calculated. Instead of using the submission with the latest date of submission, Fire was using the submission with the largest attempt number. The attempt number is local to each combination of group and lab. If a student has only ever been a member of one group, the order of dates of submissions corresponds to the order of attempt numbers. This is obviously broken if a student submits as a member of more than one group.

I deployed the fix to plt-lp2-17, Mohamed should now see the correct status.