[ryansolid]

Before: two async memos m1 and m2 both answer, then a write re-asks both, all in one tick. c = m1() + m2() has no value yet. latest(c) threw NotReadyError, because m2's answer was dropped. The one-source case (c = m1()) already read the answer after #4459.

After: latest(c) reads 13 (both answers) and isPending(c) is true until the re-ask lands. Every answer that resolved before the write is answered, then re-asked, whatever order the answers resolve in.

Cause: setS(2) stages the write and queues its flush. m1's answer reaction runs first, lands, and called flush() synchronously. That flush carried the write, so it re-asked m2 before m2's answer reaction ran, and m2's answer was then dropped as superseded.

How: in handleAsync's landing, before the landing stages its own value, it notes whether a write is staged with its flush queued (pendingNodes holding a staged _pendingValue). If so, the landing does not flush itself: the write's queued flush carries this landing and every answer queued ahead of it (F-10). Streams still flush per yield. An answer that resolves after the write is still dropped as superseded. The check is gated on holdWorkHook, because only latest/isPending can tell an answered-then-reasked node from one with no value. With plain reads only, the sequence is identical before and after.

Rules: D-22 (both answers are produced values; answered, then re-asked), F-10 (a write is visible at the flush that carries it), F-9 (the re-ask is a new question, so c is pending on it).

Tests: tests/two-sources-answered-reasked-4495.test.ts, 8 cases: one and two sources, reverse resolve order, c reading m2 first, only one source re-asked (both orders), the re-ask's answers landing next, and two controls (answered in its own tick; answered after the write stays dropped). 4 of the 8 fail on next. Signals 6088 passed / 17 expected fail; web 1579 passed / 7 expected fail.

Limits, not pinned: a status-only flush already queued before the answer and the write still re-asks and drops that answer; an async iterator's first yield in this ordering is excluded on purpose to keep per-yield flushes.

Timing change: with holdWorkHook loaded, code that resolves a flight, writes in the same tick, then awaits the flight's own promise (res(5); setU(1); await p; u()) now sees the write unflushed (u() is 0), the same as awaiting any plain promise. Before, the landing's own flush carried the write.

Size (client, vs next 643a7a7; no ledger edits in this PR):

Scenario	Brotli	Minified
signals: + isPending/latest	11,271 → 11,293 (+22)	+34
page: live server components	38,969 → 38,981 (+12)	+36
page: compiled live server components	42,931 → 42,959 (+28)	+34
page: live + router	48,569 → 48,605 (+36)	+36
app: CSR, observe tier	15,193 → 15,186 (−7)	0
app: CSR, observe tier + attribution engine	29,760 → 29,762 (+2)	0

Every other scenario is unchanged; hello world stays at 9,973 B.

Closes #4495

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Generated by Claude Code

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Generated by Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: 6b98aba

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

This PR includes changesets to release 15 packages

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

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[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)	7.41 KB	0 B	0 B	+15 B	7.43 KB	✅
signals: + createStore	14.96 KB	0 B	0 B	+6 B	14.97 KB	✅
signals: + isPending/latest	11.29 KB	+22 B (+0.2%)	+34 B	+34 B	11.29 KB	❌ over by 3 B
signals: + until/refresh (truth readers, no optimism)	8.05 KB	0 B	0 B	+2 B	8.06 KB	✅
app: render + one signal (the simple-app floor)	9.79 KB	0 B	0 B	+15 B	9.78 KB	⚠️ over by 8 B, 5 B minified headroom
app: hydrating (no stores) with Show/For/Loading/Errored/lazy	18.72 KB	0 B	0 B	0 B	18.74 KB	✅	lazy-page.js 0.04 KB
app: hydrating + every store primitive family	32.47 KB	0 B	0 B	0 B	32.48 KB	✅	lazy-page.js 0.04 KB
app: CSR with Show/For/Loading/Errored/lazy	13.45 KB	0 B	0 B	+9 B	13.47 KB	✅	lazy-page.js 0.04 KB
app: CSR, observe tier (same app on the observe artifacts)	15.19 KB	−7 B (−0.0%)	0 B	+9 B	15.20 KB	✅	lazy-page.js 0.04 KB
app: CSR, observe tier + attribution engine enabled	29.76 KB	+2 B (+0.0%)	0 B	+9 B	29.78 KB	✅	lazy-page.js 0.04 KB
app: compiled floor (one template, one text hole, one delegated click)	9.97 KB	0 B	0 B	+2 B	9.98 KB	✅
app: compiled CSR (JSX todo app: spread/merge/omit, events, class/style, keyed For, Show, Loading + lazy, store)	26.27 KB	0 B	0 B	+13 B	26.33 KB	✅	stats.js 0.18 KB
app: compiled hydrating (the same JSX todo app through hydrate(), compiled hydratable)	32.48 KB	0 B	0 B	+7 B	32.54 KB	✅	stats.js 0.20 KB
frames: eager client consumer (frames client + transport, lazy codec)	11.75 KB	0 B	0 B	0 B	11.77 KB	✅
page: base server components (hydrating + dynamic + frames + sf reference)	33.73 KB	0 B	0 B	0 B	33.77 KB	✅	assets.js 0.78 KB, decode.js 7.09 KB, lazy-page.js 0.04 KB, regions.js 1.06 KB, trace.js 9.10 KB, wire.js 3.47 KB
page: live server components (base + live/GET + action + isPending/latest)	38.98 KB	+12 B (+0.0%)	+36 B	+36 B	38.98 KB	❌ over by 1 B	assets.js 0.78 KB, decode.js 7.09 KB, lazy-page.js 0.04 KB, regions.js 1.06 KB, trace.js 9.11 KB, wire.js 3.47 KB
page: compiled base server components (the base page as JSX: templates with class/style/attributes/events, For/Show; no spread)	35.66 KB	0 B	0 B	0 B	35.72 KB	✅	assets.js 0.78 KB, decode.js 7.09 KB, regions.js 1.06 KB, sc-comments.js 0.20 KB, trace.js 9.06 KB, wire.js 3.47 KB
page: compiled live server components (the compiled base page + live/GET + action + isPending/latest)	42.96 KB	+28 B (+0.1%)	+34 B	+34 B	42.95 KB	❌ over by 9 B	eager (counted): web.js 22.98 KB; assets.js 0.78 KB, decode.js 7.09 KB, regions.js 1.08 KB, sc-comments.js 0.19 KB, trace.js 9.09 KB, wire.js 3.47 KB
page: base + router (base page + @solidjs/router: createRouter, two routes, preload, useNavigate)	41.13 KB	0 B	0 B	0 B	41.25 KB	✅	assets.js 0.78 KB, decode.js 7.09 KB, lazy-page.js 0.04 KB, regions.js 1.06 KB, server.js 1.03 KB, serverForms.js 3.59 KB, trace.js 9.06 KB, wire.js 3.48 KB
page: live + router (live page + @solidjs/router: createRouter, two routes, preload, useNavigate)	48.60 KB	+36 B (+0.1%)	+36 B	+36 B	48.58 KB	❌ over by 25 B	eager (counted): client.js 28.10 KB; assets.js 0.78 KB, decode.js 7.09 KB, lazy-page.js 0.04 KB, regions.js 1.07 KB, server.js 1.03 KB, serverForms.js 3.30 KB, trace.js 9.06 KB, wire.js 3.49 KB
server: floor (getRequestEvent + isServer)	1.27 KB	0 B	0 B	0 B	1.29 KB	✅
server: renderToString (the server-render floor)	22.79 KB	0 B	0 B	0 B	22.80 KB	✅

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

• app: render + one signal (the simple-app floor): over brotli cap by 8 B; minified 26,754 B vs 26,739 B recorded with the cap (+15 B) — 5 B of the 20 B minified allowance left; +0 B minified over this PR's base

❌ Fails the gate

• signals: + isPending/latest: over brotli cap by 3 B; minified 31,135 B vs 31,101 B recorded with the cap (+34 B) — 14 B past the 20 B minified allowance; +34 B minified over this PR's base. real growth: reduce it, or raise the cap and its recorded minified in this PR with a reason (frozen floors need Size-Exception:)
• page: live server components (base + live/GET + action + isPending/latest): over brotli cap by 1 B; minified 117,894 B vs 117,858 B recorded with the cap (+36 B) — 16 B past the 20 B minified allowance; +36 B minified over this PR's base. real growth: reduce it, or raise the cap and its recorded minified in this PR with a reason (frozen floors need Size-Exception:)
• page: compiled live server components (the compiled base page + live/GET + action + isPending/latest): over brotli cap by 9 B; minified 126,052 B vs 126,018 B recorded with the cap (+34 B) — 14 B past the 20 B minified allowance; +34 B minified over this PR's base. real growth: reduce it, or raise the cap and its recorded minified in this PR with a reason (frozen floors need Size-Exception:)
• page: live + router (live page + @solidjs/router: createRouter, two routes, preload, useNavigate): over brotli cap by 25 B; minified 143,305 B vs 143,269 B recorded with the cap (+36 B) — 16 B past the 20 B minified allowance; +36 B minified over this PR's base. real growth: reduce it, or raise the cap and its recorded minified in this PR with a reason (frozen floors need Size-Exception:)

_{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 41118325782

Coverage remained the same at 78.1%

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.

---

Coverage Stats

Relevant Lines:	1362
Covered Lines:	1125
Line Coverage:	82.6%
Relevant Branches:	1090
Covered Branches:	790
Branch Coverage:	72.48%
Branches in Coverage %:	Yes
Coverage Strength:	29.77 hits per line

---

💛 - Coveralls

[ryansolid]

Size gate (check), updated after #4501 re-recorded the ledger and this branch merged it (6b98aba): the rows still over are this PR's own measured growth. isPending/latest is +34 B minified, live server components +36 B, compiled live +34 B and live + router +36 B, as listed in the body. Under the current batch process, fix PRs carry no ledger edits, and these rows are re-recorded in one ledger PR after the batch merges. Tests pass.

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Generated by Claude Code

[codspeed]

Merging this PR will improve performance by 9.15%

1 warning

⚠️ 4 benchmarks are dominated by system calls

System calls cannot be simulated consistently and are left out of the measure. The reported value understates the real cost. Switch to the Walltime instrument to measure them.

Learn more about system calls

See affected benchmarks

⚡ 1 improved benchmark
✅ 199 untouched benchmarks
⏩ 5 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	memo + sync render effect only (reference)	34.9 ms	32 ms	+9.15%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing claude/project-thread-x1ore2-4495 (6b98aba) with next (14a8190)}

Footnotes

1. 5 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩