fix(signals): nodes created mainline during a hold are born held (A29 creation-time form)

[ryansolid]

Was stacked on #3449; now rebased onto next (the three #3449 commits dropped). Fixes the two A29/A18(c) violation cells the oracle found, plus a swallowed-write bug the fix exposed.

The bug

A memo or effect created from mainline code while a transaction holds a value it reads — a component mounting on a click while an action is in flight:

// action holds setX(1); committed x is 0
createRoot(() => {
  const m = createMemo(() => x());
  createRenderEffect(m, render);   // published 1 — the HELD value, in the mainline frame
  createRenderEffect(x, render);   // published 0 — committed (stale-reader rule)
});
setY(1);                            // swallowed into the action: y never published

Two causes:

• recompute's creation arms: a create pass always direct-commits (create ||) and is never held. The fresh memo was correctly served the staged value (A29) and enterStagedRead entered the transaction — then the create arm committed the value as the memo's mainline truth anyway. Same for a superseded node: the fresh memo published the truth while a fresh direct effect beside it showed the override.
• enterStagedRead entered via initTransition from creation code, outside a flush. Nothing restores activeTransition there (the flush loop does inside a flush; action steps end with a flush), so the rest of the synchronous block — including the unrelated setY — became the action's work. The analogous reveal path (a creation-time read of a pending async node) does not do this.

The rule (maintainer, 2026-09-14)

1. (a) A node born of the held world has no committed value until the transaction commits. Readers hold; an untracked read throws NotReady (A19 exception 1).
2. The entry is the pass's, never the mainline block's.

The fix

Outside a flush, enterStagedRead records the transaction (stagedEntry) instead of entering. recompute stages the pass's node into it: _transition stamped, pushed to its _pendingNodes, STATUS_UNINITIALIZED kept; an effect is added to the transaction's _gatedSubs and skips its synchronous first run (effect()); commitPendingNode initializes the node and the replay runs the effect. read() holds readers of a node with a staged value and no committed one (stale readers enter instead of showing undefined). Inside a flush nothing changes — #3408's pin is untouched. Verdict pulls (GlobalQueue._verdictPull; the latest() shadow is created before it is marked optimistic, so the config bit alone cannot tell) and optimistic-posture nodes keep the entering path. supersededRead's staged truth is a staged read too.

A mainline mount therefore shows the committed frame for direct bindings and holds derived ones until the commit reveals both.

Verification

• New tests/born-held.test.ts: fresh memo + effect held / fresh direct effect committed / commit reveals all; unrelated write after the mount stays mainline; untracked read of a born-held memo throws until commit; in-flush branch flip unchanged (2.0.0-rc.8 conditional memo reveals a held signal value early #3408).
• Oracle: the two violation cells flip to rule. 90/90.
• @solidjs/signals 174 files / 1895 · solid-js 618 · @solidjs/web 783 — green.
• Spec: A29 amended in place (creation-time form); index regenerated.

Size

+316 B minified on the in-package core floor (23,365 → 23,681); brotli +105 B core floor, +126 +createStore, +146 +isPending/latest. Conscious bump, notes in treeshake.test.ts and .size-limit.js. Golfed once (flag as a GlobalQueue static instead of an exported setter; supersession entry moved into supersededRead outside the floor; dropped currentTransition/_valueTransition in the staging arm — the pass runs outside a flush, no merges happen). What remains is the rule: a new node state needs detection, staging, read semantics, commit-time init, and the effect skip.

Co-authored-by: Cursor cursoragent@cursor.com

Made with Cursor

Also: the last oracle violation (second commit)

isPending() under a displayed override now reads the arrival even before the node's first commit. The oracle state I had labeled "downstream never initialized" was really "the node itself never committed" — its first landing was held by a reveal that never landed — and computePendingState applied A19 exception (1) ("uninitialized is loading, not pending") before checking for an override. A displayed override is an observable value, so the override check comes first. Verdict module only, no core-floor cost. Pinned by tests/superseded-before-first-commit.test.ts; A18 (d) amended.

Oracle: 90 cells, zero violations. A pre-existing, shape-sensitive NotReadyError escaping flush() was observed while probing (reproduces on next) but could not be pinned stably; not this PR's.

Rebase onto next (2026-09-15)

• Over fix(signals): two flights through one memo settle as one unit; lane-dirtied zombies run (#3443, #3444) #3450 (Memoized sum disagrees with its async inputs during overlapping updates #3443/latest inside Show stays stale while removal is pending #3444 land on the same notifyStatus/recompute seams): in-package core floor 23,419 → 23,753 minified (+334); cap 23,750 → 23,800. Brotli against next: core floor 8708 → 8820 (+112), +createStore 15658 → 15743 (+85), +isPending/latest 11084 → 11213 (+129) — inside the caps the PR set. The six app scenarios had no headroom left (hydrating sat at 18899/18900) and now exceed by 46–123 B on the same core bytes; caps bumped +0.15–0.20 KB with notes.
• A latent tsc error surfaced (CI never ran here — the old base wasn't next): TS narrowed the module-level stagedEntry to null at the pass's reset and kept that across the compute call, so bornHeld typed null and the born-held arm was never. Re-widened with a cast at the read; no emitted code.
• RULES-INDEX.md regenerated; --check current.

Verified after rebase: signals 1905, solid 618, web client 786 / server 914, size-limit all scenarios pass.

[changeset-bot]

🦋 Changeset detected

Latest commit: 4869d98

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

This PR includes changesets to release 11 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

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[coveralls]

Coverage Report for CI Build 34946380801

Coverage remained the same at 71.842%

Details

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

Uncovered Changes

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Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	1007
Covered Lines:	772
Line Coverage:	76.66%
Relevant Branches:	790
Covered Branches:	519
Branch Coverage:	65.7%
Branches in Coverage %:	Yes
Coverage Strength:	15.09 hits per line

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💛 - Coveralls

[codspeed]

Merging this PR will not alter performance

✅ 172 untouched benchmarks

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_{Comparing fix/born-held (4869d98) with next (61a114c)}