The bug here was more mundane, that the registration process went like:
1. Choose your individual classes, which reserves a spot for you
2. Click the overall "Finalize your class selection"
3. All validations run, including both things like "are you taking the right number of credits" and "do you meet the prerequisites for each class"
Classes that were restricted to juniors and seniors opened up to everyone if they didn't fill up by the start of the semester. So I chose my classes and didn't finalize until the semester started. Muahaha.
In the modern era this is typically solved via these "your cart will only reserve your items for 15 minutes" type warnings, but back in the olden days when I was an undergrad, that level of technology wasn't widespread yet.
1. Choose your individual classes, which reserves a spot for you
2. Click the overall "Finalize your class selection"
3. All validations run, including both things like "are you taking the right number of credits" and "do you meet the prerequisites for each class"
Classes that were restricted to juniors and seniors opened up to everyone if they didn't fill up by the start of the semester. So I chose my classes and didn't finalize until the semester started. Muahaha.
In the modern era this is typically solved via these "your cart will only reserve your items for 15 minutes" type warnings, but back in the olden days when I was an undergrad, that level of technology wasn't widespread yet.