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Every change in the UI comes from comparing a snapshot with the one before it. Nothing is hand-entered, and no changelog files are stored. If the comparison logic improves, past days can be recomputed from the original snapshots.

Matching assignments

An assignment is identified by its name and due date. For each class, the two snapshots’ assignments are matched on that pair:
Because name and due date form the identity, renaming an assignment or moving its due date appears as one deletion plus one addition, not as a modification. The deleted-assignments page will list the old version. This is expected behavior and worth knowing before raising a “deleted assignment” with a teacher.
If a class lists two assignments with the same name and due date, they share one identity and only one of them is compared.

Fields compared

For matched assignments, these fields are compared:
  • category
  • score_raw
  • percent
  • grade
  • has_comments
  • each status flag on its own: collected, late, missing, exempt, absent, incomplete, excluded
A flag change is reported as a single field, so the day view shows a readable row such as:
An assignment counts once as modified no matter how many of its fields changed.

Class-level changes

Separately from assignments, each snapshot records:
  • classes that appeared or disappeared
  • classes whose final_grade changed
These are counted in class_level in the rolling index and kept out of the assignment totals.

Two layers, one definition

Change detection runs in two places for performance reasons:
1

Rolling index (Python, after each scrape)

The scraper’s /append-index endpoint diffs the new snapshot against the previous one and stores the counts. The calendar colors each day from these counts without fetching any snapshots.
2

Day view (TypeScript, on demand)

When you open a day, the browser fetches that snapshot and the previous one and diffs them field by field to produce the detail rows.
The two implementations must agree, or a day could be colored as changed with no detail rows to explain it. A test in the repository reads the field list from the TypeScript diff and fails if it differs from the Python one.

Calendar colors

Each day takes the color of its most significant change: