[jehrr]

Problem

The daily canary went red on 2026-10-13 (run 38483372156) with dom_confirm = {tiles: 19, checked: 0, confirmed: 0}. That run itself exited 0 with 109 correct rows. The next scheduled run (2026-10-14, same commit) passed with 60 tiles and 41 checked, so the failure comes and goes.

Diagnosis, measured live on 2026-10-15 (headful Chromium under Xvfb, no proxy, no key):

• /shop/browse/bakery now paints a 19-tile horizontal carousel (seasonal products) about one second before the 37-tile product grid. Tile counts polled every 250 ms went 0 → 19 → 52 → 56.
• The readiness wait counts any wc-product-tile, so the 19 carousel tiles satisfy it.
• None of the carousel's stockcodes is on page 1 of the listing. When the page-1 API answer comes back quickly, confirm_with_dom reads only the carousel. It then checks 0 rows and logs that at INFO only.

A capture taken in that gap reproduces the canary's numbers exactly: 19 tiles, 0 checked. A later read in the same session gives 37/37.

Change

• product_parser.rows_with_a_tile(rows, tiles): how many rows have a rendered tile with their own stockcode.
• page_flow.confirm_with_dom: when tiles are on screen but none matches the page's rows, it re-reads them every 500 ms for up to GRID_SETTLE_MS (10 s) until the grid shows up. If nothing ever matches, it logs a WARNING naming the tile count. Rows are never changed by this path.
• Fixture tiles_carousel_first: a real capture from one session. It holds the carousel-only read (19 tiles), the full read (56 tiles), and page 1 of the category API that the page's own UI requested, trimmed the same way as the other listing fixtures. make_fixtures.py documents and builds it.

Evidence

• Offline suite, core-only venv: 123/123, with the three engine groups skipped.
• Control: with page_flow.py restored from main and the new fixture and tests kept, test_dom_confirmation_waits_past_a_carousel_for_the_grid fails. The cross-check reads the carousel and stops at checked 0, and the give-up test errors.
• Fixture assertions: the early read matches 0 rows and gives (0, 0). The late read gives (8, 8). Pinned skus and prices are 6041394 $4.00, 49622 $5.20 and 6037735 $2.60.
• Live run with the change, the canary's exact command (bakery, 3 pages): 19 tile(s) had painted… then 37 of 37 row(s) checked against 56 rendered tile(s). Result: 109 rows, exit 0.

Not changed

• The readiness wait's selector. It still counts any tile, because the grid's class names are build hashes. The wait now sits in the cross-check, keyed on stockcodes rather than markup.
• Canary workflow changes are in the separate audit PR.

🤖 Generated with Claude Code