`RovingGridController.measureColumns` read `offsetTop`, and every card
in these grids is drawn by a `lit-virtualizer`, which positions its
children with a transform — which `offsetTop` does not see. So all of
them reported 0, every rendered card counted as one row, and ArrowDown
was `min(i + everything, last)` while ArrowUp was `max(i - everything,
0)`: the vertical arrows have been End and Home in the albums, artists
and genres grids since the day this was written. At 700x700 with three
real rows of 3/3/2, ArrowDown from card 0 landed on card 7.
Two things behind it, both only visible once the grid splits:
`cover-grid`'s scrollToIndex was `querySelector('lit-virtualizer')` —
always `#grid-before` — while the roving index spans the whole album
list, so with a dropdown open End scrolled the wrong half to an index
it does not contain. It now picks the half that holds the index and
rebases it.
And the focus is retried on a deadline rather than taken once at the
host's `updateComplete`: a scroll of 5 000 rows produces the card a few
hundred ms later, so the tab stop moved and nothing took focus, which
looks exactly like the key not being handled.
Also waits for the virtualizer in album-dropdown.spec's expandCard,
which flaked on roughly one run in two on main.
Component and store cases for everything in this series, several of
which exist because the thing they pin is invisible everywhere else:
- `view-lifecycle` and `keyboard-reach` — a document listener count
that does not grow across a simulated navigate cycle, and a tab
sequence that reaches the sidebar and plays a row without a mouse.
- `notifications`, `notification-store`, `confirm-dialog`,
`empty-states` — the four levels, the (level, region, key)
coalescing window, and loading/failed/empty as three states.
- `card-grid-repaint` — fails if `artists-view`'s or `genres-view`'s
per-render arrow functions are hoisted to stable fields, which is
the audit's own recommendation and takes the cards from 1 highlighted
to 0. It exists for no other reason.
- `lazy-track-details` — reads the five sources and fails on a
returning static import, the same shape as `TestNoDirectRuntimeEmits`
and for the same reason: the invariant is about what the code does
*not* say.
- `now-playing` — a position report that changes nothing must not
touch the DOM again, and a track change must. The first fails
against the old unconditional `updated()`.
- `playlist-virtualization`, `list-render-cost`, `selection`, `icons`,
and the store cases for the library-filter race, the never-settling
waiter and the per-playlist patch.
logan