ui-react: hygiene-review layout test reads the item before it renders #1685

Context

On PR #1628, CI run 38175368489, job layout (1) (114576698355) failed once:

FAIL ui-react-layout (chromium) ../ui-react/tests/browser/hygiene-review.layout.tsx > Later confirms the stored hygiene option and prints the server's waitUntil receipt
TypeError: Cannot read properties of null (reading 'dataset')
 ❯ ../ui-react/tests/browser/hygiene-review.layout.tsx:374:23

The test reads current().dataset.hygieneId immediately after await scene() (test("Later confirms the stored hygiene option, packages/ui-react/tests/browser/hygiene-review.layout.tsx:372-374). current() (packages/ui-react/tests/browser/hygiene-review.layout.tsx:111-113) is a synchronous querySelector with a non-null assertion. If the hygiene item has not rendered when scene() resolves, it returns null. PR #1628 changed only failed-turn report code. On the next head (e968372a, run 38176899684), the same layout shard passed with no code change near hygiene review. The failure looks like a rendering race in the test setup.

Scope

• Make the test wait until the hygiene item is rendered before it reads it. For example, scene() or this test could poll for [data-hygiene-id], and the other tests that call current() straight after scene() should get the same fix.

Out of scope

• Hygiene review product behavior.
• Other layout tests and ui-react: focus-ring visibility test flakes in the browser shard #1584.

Acceptance criteria

• No test in hygiene-review.layout.tsx reads current() before the item is known to be rendered.
• Repeated local runs of the file in the pinned browser image (node scripts/visual.mjs --project=ui-react-layout) pass. A mutation that delays the item's render makes the old code fail on the null read and the new code pass.

Verification

• Repeated ui-react-layout runs, with the delayed-render mutation receipt recorded in the PR.

Contract impact

None.

Current-source diagnostic handoff — 2026-10-12

Inspected main acec591c83a730e5d68f36bae2b807f95bb5d9c9: scene (packages/ui-react/tests/browser/hygiene-review.layout.tsx:57-110) mounts through flushSync then waits a fixed 160ms settle (:53-55). current (:111-113) synchronously queries the item, while the Later test immediately reads its dataset (:372-374). flushSync does not establish completion of the review request and item rendering. The original CI null read is observed, but request/render phase timing is not captured; The controlled delayed-response reproduction below resolves that readiness gap; it does not identify the original CI runner scheduling event. Scope is harness readiness, so type: test is appropriate; preserve explicitly deferred p3. Native #736 fits the deterministic keyless-verification outcome.

Controlled pinned-browser reproduction — 2026-10-12

Source acec591c83a730e5d68f36bae2b807f95bb5d9c9, frozen install and built exports; Bun 1.4.2, Vitest 4.1.11, pinned mcr.microsoft.com/playwright:v1.63.0-noble image ID sha256:eff16c30e6f3f4af0a03fa4b706120d5e9b0891c344a27d64559aff5900a4a27, checksum-verified fonts, network disabled, fileParallelism=false. From ui-kit, run node /repo/node_modules/vitest/vitest.mjs run --project=ui-react-layout --browser.fileParallelism=false ../ui-react/tests/browser/hygiene-review.layout.tsx -t 'Later confirms the stored hygiene option' in the pinned offline container with the fixture’s Bun binary available.

• Unmodified focused control: exit 0; one selected test passes, 57 filtered.
• Add only await new Promise(resolve => setTimeout(resolve, 600)) after reviewReads++ in the existing review-request interception, before delegating to real fetch. The actual Later test fails with TypeError: Cannot read properties of null (reading 'dataset') at the unchanged current().dataset.hygieneId read (instrumented line 375; original line 374). Exit 1, one named test fails; request/fixture startup succeeds and no test deadline is relaxed.
• Restore the source byte-for-byte and rerun the same focused selection; exit 0, one selected test passes and 57 are filtered, with the same named command.

This establishes that fixed scene settling does not wait for actual review data/render completion. Implement condition-based readiness in the existing scene/appropriate callers, preserve Later receipt and neighboring hygiene assertions, and prove the correction under this delayed-response condition. No product fix was implemented by triage. With the complete existing brief and a controlled failing boundary, remove needs: repro and add agent-ready; preserve explicit p3 and native #736 membership.