Two related ways an occurrence that only arrived through Timeline's expand
prop could disagree with the board it was drawn onto:
- `right` was computed but never clamped to chartWidth, while `left` was
clamped to 0. boardWindow's max is derived from `plotted` alone, so a base
row can never exceed it — but occurrencesOf admits any occurrence starting
at or before the window's edge, and one with no stated end then runs a full
interval past it. Inside overflow-auto that grows the pane's scrollWidth,
so the reader scrolls into empty space with no gridlines or axis. The spec
says a rule may fill the board but must never enlarge it; `right` is now
clamped the same way `left` already was.
- startMarkers read from `plotted` rather than `drawn`, so a "3 events start
<day>" label under-counted whatever expand had added to that day. Pointed
at `drawn`.
The existing "boardWindow is not widened by expansion" test only pinned
boardWindow's own purity and never rendered Timeline, despite its comment
claiming the ordering was "asserted structurally in the component below" —
no such assertion existed, and moving the expand call above boardWindow left
the suite green. Added a render-level regression test that compares the
rendered chart width with and without an expand returning far-future
occurrences; confirmed it fails if expand is called before boardWindow.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
