Bug: User can’t add two different sections of the same course to the timetable even when this would not be a registration error.

[joxn]

Describe the bug
For most courses it is an error to attempt to register for two different sections; for example, it’s an error to register for PSYC 201 A01 and PSYC 201 A02 simultaneously. However, some departments have upper-level seminar courses which are distinguished only by their section number; for example, PSYC 491 A01, A02, and A03 are all different courses and it is not an error to attempt to register for all of them simultaneously. Such courses seem to be distinguished in the Undergraduate Calendar by the text “Repeatable for credit” in their description. There does not seem to be any data in the Course Details view that indicates a course can be repeated for credit.

The timetable builder does not recognize that these courses have non-standard registration rules, so it forces the user to choose exactly one to be displayed on the timetable.

To Reproduce
Steps to reproduce the behavior:

1. Navigate to https://courseup.vikelabs.ca/scheduler/202109
2. In the “Search for courses…” box type psyc 491.
3. In the “Search results” pane on the left hand side, click the green + icon to add PSYC 491 to the timetable.
4. In the “Saved courses” pane on the left hand side, the three sections of PSYC 491 appear. One section at a time may be selected via a radio button. The user cannot select two or three sections simultaneously.

Expected behavior
The user should be able to select more than one section of courses that are “Repeatable for credit” simultaneously (i.e., checkbox semantics, not radio-button semantics).

Screenshots

Desktop (please complete the following information):

• OS: Windows 10
• Browser: Firefox 89.0.2

This bug is in the data representation layer, not the browser presentation layer, so it should reproduce on any browser. (It does reproduce on iPadOS 14.6 / Safari.)

Additional Context
Note that the registration system let me register for PSYC 491 A02 and A03 just fine.

[aomi]

Thanks for submitting this report. We had zero idea this was a thing (at least I've never seen it before in the engineering faculty).
I don't think this will be a trivial fix unfortunately...
Like you mentioned in the issue, the only indication that taking multiple sections of a "lecture" is possible is in the calendar data. We don't take into consideration anything from the calendar when allowing users to select their sections. The logic is simply:

If there is a lecture, lab, or tutorial offered then the user must register in one and only one for each section type offered for the class.

Internally it's simply stored as key-values like:

{
  "lecture": "A01",
  "lab": "B01",
  "tutorial": "T01"
}