perf(frames): scan for binding-slot attributes once, after the bind tier installs

[ryansolid]

Before: on a page that announces the bind tier, every frame's slot walk visited every element looking for _s:* attributes while the tier was still loading. That work was thrown away, and after the tier installed the flush walked the page again and parsed the attributes. On the HN story page with binding slots, that came to 20,750 elements visited and 15,308 attribute reads.

After: while the tier is announced or loading but not yet resident, the walk visits comments only and marks the frame held. The install's flush does the one element scan. On the same page that is 10,375 elements and 7,658 attribute reads, and hasSlotMarker (~36 ms at 4x CPU) drops out of the profile.

Behavior note: once a page announces the bind tier, a frame with no _s:* attributes now also waits for that tier before it resolves. The tier is already loading because of the announcement, so the wait is bounded by that load. Pages that don't announce the tier, and pages where the tier is already resident, behave as before. Client slots (regions tier only) never ran the element scan, so they aren't affected.

How: before the walk, collectSlots checks for the held case (bind && !B && (tierLoads.bind || announced)). In that case it sets elements.b and turns bind off, so the walk loop itself is unchanged from next. A new test in tier-bind-announced-gate.spec.tsx counts element-visiting TreeWalkers: none while the frame is held, exactly one after release. The test fails without the fix.

Size: frames eager consumer goes 11,495 -> 11,509 B brotli (+14), and 34,411 -> 34,449 B minified. The cap is raised to that measurement and is pending the maintainer's OK. This PR also updates the #4042 note to say that cap was accepted on merge.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LZkrATgvFJjgFRdDB4Drcq

[changeset-bot]

🦋 Changeset detected

Latest commit: b111d5a

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

This PR includes changesets to release 13 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
board-example	Patch
todos-server-example	Patch
@solidjs/compiler	Patch
@solidjs/signals	Patch
solid-js	Patch
@solidjs/universal	Patch

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[github-actions]

Size (brotli, eager entry chunk)

scenario	head	vs base	minified vs base	minified vs recorded	cap		lazy chunks (not counted)
signals: core floor (createSignal/Memo/Effect/Root/flush)	7.47 KB	0 B	0 B	−8 B	7.48 KB	✅
signals: + createStore	14.94 KB	0 B	0 B	−22 B	14.94 KB	⚠️ over by 3 B, 42 B minified headroom
signals: + isPending/latest	9.75 KB	0 B	0 B	−8 B	9.77 KB	✅
app: render + one signal (the simple-app floor)	9.95 KB	0 B	0 B	−8 B	9.98 KB	✅
app: hydrating (no stores) with Show/For/Loading/Errored/lazy	17.89 KB	0 B	0 B	−65 B	17.93 KB	✅	lazy-page.js 0.04 KB
app: hydrating + every store primitive family	29.54 KB	0 B	0 B	−83 B	29.57 KB	✅	lazy-page.js 0.04 KB
app: CSR with Show/For/Loading/Errored/lazy	13.04 KB	0 B	0 B	−22 B	13.07 KB	✅	lazy-page.js 0.04 KB
app: CSR, observe tier (same app on the observe artifacts)	14.64 KB	0 B	0 B	−22 B	14.64 KB	✅	lazy-page.js 0.04 KB
app: CSR, observe tier + attribution engine enabled	29.23 KB	0 B	0 B	+14 B	29.24 KB	✅	lazy-page.js 0.04 KB
app: compiled floor (one template, one text hole, one delegated click)	10.16 KB	0 B	0 B	−8 B	10.17 KB	✅
app: compiled CSR (JSX todo app: spread/merge/omit, events, class/style, keyed For, Show, Loading + lazy, store)	25.80 KB	0 B	0 B	−99 B	25.79 KB	⚠️ over by 12 B, 119 B minified headroom	stats.js 0.18 KB
app: compiled hydrating (the same JSX todo app through hydrate(), compiled hydratable)	31.69 KB	0 B	0 B	−41 B	31.64 KB	⚠️ over by 54 B, 61 B minified headroom	stats.js 0.20 KB
frames: eager client consumer (frames client + transport, lazy codec)	11.54 KB	+18 B (+0.2%)	+34 B	0 B	11.54 KB	✅
page: base server components (hydrating + dynamic + frames + sf reference)	34.27 KB	+80 B (+0.2%)	+34 B	−1335 B	34.33 KB	✅	assets.js 0.78 KB, bind.js 1.83 KB, decode.js 6.23 KB, lazy-page.js 0.04 KB, regions.js 0.80 KB, trace.js 9.01 KB, wire.js 0.93 KB
page: live server components (base + live/GET + action + isPending/latest)	37.99 KB	+61 B (+0.2%)	+34 B	−1404 B	38.15 KB	✅	assets.js 0.78 KB, bind.js 1.83 KB, decode.js 6.23 KB, lazy-page.js 0.04 KB, regions.js 0.80 KB, trace.js 9.02 KB, wire.js 0.93 KB
page: compiled base server components (the base page as JSX: templates with class/style/attributes/events, For/Show; no spread)	35.08 KB	+45 B (+0.1%)	+34 B	−2425 B	35.66 KB	✅	assets.js 0.78 KB, bind.js 1.83 KB, decode.js 6.23 KB, regions.js 0.80 KB, sc-comments.js 0.20 KB, trace.js 8.99 KB, wire.js 0.93 KB
page: compiled live server components (the compiled base page + live/GET + action + isPending/latest)	40.73 KB	+20 B (+0.0%)	+34 B	−2409 B	41.21 KB	✅	eager (counted): web.js 21.56 KB; assets.js 0.78 KB, bind.js 1.84 KB, decode.js 6.23 KB, regions.js 0.79 KB, sc-comments.js 0.19 KB, trace.js 8.97 KB, wire.js 0.93 KB
page: base + router (base page + @solidjs/router: createRouter, two routes, preload, useNavigate)	41.55 KB	−60 B (−0.1%)	+34 B	−1335 B	41.79 KB	✅	assets.js 0.78 KB, bind.js 1.85 KB, decode.js 6.23 KB, lazy-page.js 0.04 KB, regions.js 0.80 KB, server.js 1.02 KB, serverForms.js 3.58 KB, trace.js 9.01 KB, wire.js 0.94 KB
page: live + router (live page + @solidjs/router: createRouter, two routes, preload, useNavigate)	47.35 KB	+30 B (+0.1%)	+34 B	−1325 B	47.49 KB	✅	eager (counted): client.js 27.75 KB; assets.js 0.78 KB, bind.js 1.84 KB, decode.js 6.23 KB, lazy-page.js 0.04 KB, regions.js 0.81 KB, server.js 1.02 KB, serverForms.js 3.30 KB, trace.js 8.97 KB, wire.js 0.94 KB
server: floor (getRequestEvent + isServer)	1.33 KB	0 B	0 B	0 B	1.34 KB	✅
server: renderToString (the server-render floor)	20.57 KB	0 B	0 B	0 B	20.58 KB	✅

⚠️ Over the brotli cap within the minified allowance (passes)

• signals: + createStore: over brotli cap by 3 B; minified 45,343 B vs 45,365 B recorded with the cap (−22 B) — 42 B of the 20 B minified allowance left; +0 B minified over this PR's base
• app: compiled CSR (JSX todo app: spread/merge/omit, events, class/style, keyed For, Show, Loading + lazy, store): over brotli cap by 12 B; minified 80,624 B vs 80,723 B recorded with the cap (−99 B) — 119 B of the 20 B minified allowance left; +0 B minified over this PR's base
• app: compiled hydrating (the same JSX todo app through hydrate(), compiled hydratable): over brotli cap by 54 B; minified 100,920 B vs 100,961 B recorded with the cap (−41 B) — 61 B of the 20 B minified allowance left; +0 B minified over this PR's base

_{Bundled with Rolldown (what Vite ships), brotli q11, decimal KB. A scenario fails only when it is over its brotli cap and its minified size is more than 20 B over the minified recorded with the cap; over the cap within that allowance is brotli layout noise and passes with a warning. Caps and their recorded minified in scripts/size/scenarios.js; the floor and page caps in floor-caps.json are frozen (lower only, or Size-Exception: in the PR body). npm run ratchet lowers caps per RC; it never raises one (scripts/size/README.md).}

[coveralls]

Coverage Report for CI Build 38593898440

Coverage remained the same at 77.515%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	1326
Covered Lines:	1084
Line Coverage:	81.75%
Relevant Branches:	1040
Covered Branches:	750
Branch Coverage:	72.12%
Branches in Coverage %:	Yes
Coverage Strength:	27.28 hits per line

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💛 - Coveralls

[codspeed]

Merging this PR will not alter performance

⚠️ 2 benchmarks spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• readAllowed
• propagation:diamond

✅ 195 untouched benchmarks

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_{Comparing claude/project-thread-271xwi (b111d5a) with next (45691d1)}

[ryansolid]

CodSpeed flags frames adoption walk › announced, no bind at 50.9 → ~55 ms (−7%). I don't think this PR causes it:

• That cell's page announces ["regions"] only, so bind is false and the held-case check never runs.
• Since 91264e1, the walk loop is byte-identical to next's. The PR only adds one guarded line before the walk. The flag is unchanged at −7.45%.
• A local A/B of next's frame-client.ts against this head, three runs each, gives means of 7.56 / 7.82 / 8.20 ms on base and 7.74 / 8.01 / 8.38 ms on head, so there's no difference beyond noise.
• CodSpeed itself warns "Different runtime environments detected" for this comparison. The base number comes from an earlier next run.

The benchmark job was re-run once and still flagged. This needs acknowledging on CodSpeed, or a fresh base run on next.

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Generated by Claude Code