frames: trace tier — update-site wait for a mounted occurrence's new { $tr } record

[ryansolid]

Stacked on #3860 (wip/frames-tiers-integration @ 5c5991cbd); one commit, independent of the C2 (live wire tier) ruling.

Summary

#syncSlots' mounted branch guarded the update site against the regions tier only (needsRegions, C4); the trace tier's wait covered the fresh mount alone. A MOUNTED occurrence's new slot record whose literal args carry a { $tr } container-trace marker while the trace tier is absent — a live slot op minting the page's first trace after the shell, a refetch adding a projection arg — was pushed into the live binding raw, the marker read as the value.

Now that record stays pending in the store: the live binding keeps the args it shows, needsTrace starts the load (nothing announced it), and the install's flush re-syncs with the tier in place and applies the record as an args change into the same mount, the marker materialized. C4's regions update-site wait, mirrored — one clause:

if (needsRegions(record) || needsTrace(record.args)) continue;

Pin

test/consistency/tier-trace-hold.spec.tsx — "update site: a MOUNTED occurrence's new record carrying { $tr } while the tier is absent stays pending …" (document face). An occurrence mounts at t=0 on a trace-free record with the tier absent; post-shell, a sc:live slot op re-sends its record with a marker arg → the loader is called once, the binding still reads ["first", undefined], the <li> still shows first, no mount, no error; after gate.release() the same mount reads second / { n: 5 } and the <li> shows 5, no warnings. On the base the pin fails at its first assertion (the loader is never called — the marker went into the binding raw).

Measured

Exact A/B of the built dist through scripts/size's bundler (turbo --force; the base copy reproduces the Phase 1 base record byte-for-byte):

scenario	base (min / br)	head (min / br)	Δ
frames: eager client consumer	40,000 / 13,083	40,012 / 13,086	+12 / +3
page: base server components	119,044 / 37,772	119,056 / 37,747	+12 / −25
page: live server components	130,915 / 41,427	130,927 / 41,396	+12 / −31

Non-SC scenarios 0 / 0 (every signals / app / server scenario byte-identical to the base). The page brotli deltas are a context effect of the now-repeated needsRegions(record) || needsTrace(record.args) phrase, inside the ± 50 band. No cap changed. (The three pre-existing FAILs in pnpm size — signals: core floor, signals: + isPending/latest, app: CSR — are the base's, byte-identical here.)

Tests

• packages/web: client suite 129 files / 1187 passed; hydrate suite 86 files / 439 passed (expected-fail counts unchanged).
• Harness CONSISTENCY_FUZZ=1 CONSISTENCY_CASES=500, seeds 3289 and 91501: SC arm 0 findings; generic arm with CONSISTENCY_IGNORE=C1,C9,C19,E 0 findings.

Public API changes

None. (needsTrace is module-internal; no export, option, prop, parameter, or diagnostic changes.)

Docs

Plan §3 row C3: one clause — "Update-site wait landed (fix PR)".

Changeset: .changeset/frames-trace-update-site-wait.md (@solidjs/web patch).

[changeset-bot]

🦋 Changeset detected

Latest commit: 5af48f5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 12 packages

Name	Type
@solidjs/web	Patch
@solidjs/babel-plugin	Patch
@solidjs/diagnostics	Patch
@solidjs/element	Patch
@solidjs/h	Patch
@solidjs/html	Patch
test-integration	Patch
todos-server-example	Patch
@solidjs/compiler	Patch
@solidjs/signals	Patch
solid-js	Patch
@solidjs/universal	Patch

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[ryansolid]

Folded into #3860 (wip/frames-tiers-integration) per the maintainer — "merging is a bottleneck." This PR's one commit 5af48f58c is already on the integration branch as C6's cherry-pick 6b7213d64 — same patch-id (git cherry lists it as equivalent) — and the branch was fast-forwarded past it to #3868's head d9395e398. The branch is kept.

On the integrated head the update-site wait covers the trace tier (needsRegions(record) || needsTrace(record.args)), and its pin in tier-trace-hold — a MOUNTED occurrence's new record carrying { $tr } while the tier is absent stays pending, the install's flush applies it as an args change — is green. Recorded under #3860's Behaviour; no public surface.

— Claude via Cursor