fix(signals): a fold repeats no unchanged presence to a held node (#3743, supersedes #3744)

.changeset/reconcile-unchanged-presence-no-hold.md

@@ -0,0 +1,9 @@
+---
+"@solidjs/signals": patch
+---
+
+A store fold's presence notification (`in` subscribers) now diffs the old and new presence of each observed key before writing the node, as the value notification already does (#3743). `setSignal` joins a held node's transaction before its equality gate (A34 (1): a write to a held node is a proposal, the same value or another), so a `reconcile()` outside an action that had deleted an observed key — the incoming snapshot leaving it absent too — made the whole tick the action's: an unrelated `a.value` stayed stale until the action settled. A real presence change still notifies and still proposes on a held node.
+
+The adoption's diff base now materializes a nested prototype-overlay draft (a wide owned record) before it is taken: through the overlay's prototype a key the draft had deleted still read as present, so the presence skip fired on a real deletion and a reconcile restoring the key never re-proposed on the held leaf (it committed the draft's `undefined` beside a backing that had the key).
+
+Two optimistic-store fixes the diff uncovered: a container carrying an arrangement guess is now told of an arrangement change whether or not anything subscribes to the container (for a guessed container the write is the landing that judges the guess — before, only the unconditional presence write reached the lane, so a newer question's rows landing beneath an optimistic push published beside it when the reader subscribed to leaves only); and an older truth re-based under an arrangement guess no longer re-stages a slot whose row the committed backing already shows by key, nor an unchanged `length` (a spurious frame for leaf-only readers).

packages/signals/docs/RULES-INDEX.md

@@ -62,7 +62,7 @@ Status legend: **live** stated and standing · **ruled** carries an explicit rul
 | A15 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:221` | async.ts×2 constants.ts×1 core.ts×3 lanes.ts×4 scheduler.ts×13 verdict.ts×2 | async-chain-supersession.test.ts×1 first-observer-stale-reader.test.ts×1 held-restore.test.ts×1 l2-contract.test.ts×7 lane-contract.test.ts×1 lane-hold-on-observation.test.ts×1 lane-outside-view.test.ts×1 lane-pass-stamped-effect-3662.test.ts×1 mount-over-foreign-hold-3761.test.ts×2 overlapping-flights.test.ts×3 posture-born-held-and-observation.test.ts×4 posture-store-parity.test.ts×2 reveal-carve-out.test.ts×2 shared-effect-no-entangle.test.ts×1 spec-async-semantics.test.ts×2 stale-read-uninitialized-cross-transition.test.ts×1 superseded-source-blocks-3462.test.ts×2 tick-scoped-pass-transaction.test.ts×1 treeshake.test.ts×4 visibility-oracle-store.states.ts×6 visibility-oracle.states.ts×7 visibility-oracle.test.ts×1 write-proposals-3494.test.ts×1 | [ruled, amended in place 2026-07-06 (promoted from B3)] Transition entanglement is graph-driven; lanes settle as one reveal — (was B3) Transition entanglement is graph-driven: writes whose async work … |
 | A16 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:193` | scheduler.ts×1 | spec-async-semantics.test.ts×1 strict-read-pending-store.test.ts×2 uninitialized-visibility.test.ts×1 visibility-oracle-store.states.ts×2 visibility-oracle.states.ts×2 visibility-oracle.test.ts×1 | [ruled, amended in place 2026-07-06 (promoted from B5)] `isPending` never throws in untracked contexts — (was B5) `isPending` never throws in untracked contexts — thunks that throw real errors or read… |
 | A17 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:51` | async.ts×3 constants.ts×1 lanes.ts×5 scheduler.ts×2 verdict.ts×1 map.ts×1 store.ts×3 | lane-uninitialized-landing-3648.test.ts×5 optimistic-read-lane-not-transaction-3698.test.ts×2 optimistic-undefined-override.test.ts×1 posture-store-parity.test.ts×1 refresh-await.test.ts×1 reveal-gating-contract.test.ts×3 spec-async-semantics.test.ts×10 createOptimisticStore.test.ts×2 kanban-a17-fixture.test.ts×3 optimistic-list-mutation-matrix.test.ts×1 optimistic-maparray-index-frame-f1.test.ts×1 optimistic-untracked-reads-f3-f5.test.ts×1 signal-store-twins-qd.test.ts×1 treeshake.test.ts×1 until.test.ts×1 visibility-oracle-store.states.ts×24 visibility-oracle-store.test.ts×1 visibility-oracle.states.ts×20 visibility-oracle.test.ts×1 | [ruled, amended in place 2026-07-06 (promoted from C4)] An active override is the displayed value until its transaction commits, and the graph's value until its own source answers — **Statement (curre… |
-| A18 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:61` | action.ts×1 async.ts×2 core.ts×3 lanes.ts×8 scheduler.ts×2 types.ts×1 verdict.ts×1 map.ts×1 optimistic.ts×1 projection.ts×1 | body-end-supersession-visibility.test.ts×4 createOptimistic.test.ts×3 lane-contract.test.ts×1 lane-frame-deferred-run-3662.test.ts×1 lane-outside-view.test.ts×1 lane-uninitialized-landing-3648.test.ts×5 optimistic-move-duplicate-3548.test.ts×2 optimistic-read-lane-not-transaction-3698.test.ts×4 posture-store-parity.test.ts×5 spec-async-semantics.test.ts×3 flight-owned-transaction.test.ts×1 optimistic-list-mutation-matrix.test.ts×1 optimistic-untracked-reads-f3-f5.test.ts×1 signal-store-twins-qd.test.ts×1 superseded-before-first-commit.test.ts×4 visibility-oracle-store.states.ts×8 visibility-oracle-store.test.ts×1 visibility-oracle.states.ts×19 visibility-oracle.test.ts×1 | [ruled, amended in place 2026-07-07 (promoted from B4)] An override lives exactly as long as its own transaction; a newer truth from the source supersedes it in the graph immediately, on screen at com… |
+| A18 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:61` | action.ts×1 async.ts×2 core.ts×3 lanes.ts×8 scheduler.ts×2 types.ts×1 verdict.ts×1 map.ts×1 optimistic.ts×1 projection.ts×1 | body-end-supersession-visibility.test.ts×4 createOptimistic.test.ts×3 lane-contract.test.ts×1 lane-frame-deferred-run-3662.test.ts×1 lane-outside-view.test.ts×1 lane-uninitialized-landing-3648.test.ts×5 optimistic-move-duplicate-3548.test.ts×2 optimistic-read-lane-not-transaction-3698.test.ts×4 posture-store-parity.test.ts×5 spec-async-semantics.test.ts×3 flight-owned-transaction.test.ts×1 optimistic-list-mutation-matrix.test.ts×1 optimistic-untracked-reads-f3-f5.test.ts×1 signal-store-twins-qd.test.ts×1 unchanged-presence-no-hold-3743.test.ts×2 superseded-before-first-commit.test.ts×4 visibility-oracle-store.states.ts×8 visibility-oracle-store.test.ts×1 visibility-oracle.states.ts×19 visibility-oracle.test.ts×1 | [ruled, amended in place 2026-07-07 (promoted from B4)] An override lives exactly as long as its own transaction; a newer truth from the source supersedes it in the graph immediately, on screen at com… |
 | A19 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:121` | constants.ts×1 core.ts×6 scheduler.ts×2 types.ts×1 verdict.ts×4 store.ts×1 | lane-uninitialized-landing-3648.test.ts×2 mount-over-foreign-hold-3761.test.ts×2 spec-async-semantics.test.ts×3 derived-presence-async-3726.test.ts×2 superseded-before-first-commit.test.ts×3 uninitialized-visibility.test.ts×1 visibility-oracle-store.states.ts×8 visibility-oracle-store.test.ts×1 visibility-oracle.states.ts×14 visibility-oracle.test.ts×1 write-proposals-3494.test.ts×1 | [ruled, amended in place 2026-07-07 (promoted from C1)] `isPending(x)` ≡ the observable value is not final (three causes) — (was C1 — **partially reverses an earlier decision**) **Definition: `isPendi… |
 | A20 | superseded | `docs/SPEC-ASYNC-SEMANTICS.md:380` | — | question-scoped-pending.test.ts×2 spec-async-semantics.test.ts×3 createOptimisticStore.test.ts×1 | [superseded 2026-07-13 by A24] (superseded) Optimistic writes announce a store-wide pending — (**SUPERSEDED 2026-07-13 by A24** — the mask is deleted; optimistic writes are verdict-inert. Kept for the… |
 | A21 | superseded | `docs/SPEC-ASYNC-SEMANTICS.md:387` | — | question-scoped-pending.test.ts×3 spec-async-semantics.test.ts×3 | [superseded 2026-07-13 by A24] (superseded) The store-wide mask — (**SUPERSEDED 2026-07-13 by A24** — the store-wide mask is deleted with the mask model; nothing silences a new question. The effective… |
@@ -78,7 +78,7 @@ Status legend: **live** stated and standing · **ruled** carries an explicit rul
 | A31 | live | `docs/SPEC-ASYNC-SEMANTICS.md:103` | boundaries.ts×1 core.ts×1 verdict.ts×1 | ispending-combined-atomic-3442.test.ts×1 | [live 2026-09-14 (#3442)] A memo computes under its own lane posture, never its puller's — A memo's value is one shared slot every reader sees, so its pass runs under the lane posture the memo itself … |
 | A32 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:111` | core.ts×4 lanes.ts×1 store.ts×1 | visibility-oracle-store.states.ts×8 visibility-oracle-store.test.ts×1 visibility-oracle.states.ts×9 visibility-oracle.test.ts×1 | [ruled 2026-09-14] Children-forbidden readers see the frame, not the graph — `createTrackedEffect` and `onSettled` callbacks are effect-phase code that runs after the frame is decided. They read the f… |
 | A33 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:245` | boundaries.ts×1 scheduler.ts×1 | async-chain-supersession.test.ts×2 boundary-not-born-held-3540.test.ts×2 ispending-in-boundary-on-3528.test.ts×2 loading-reset-collects-forwarded-3459.test.ts×3 | [ruled 2026-09-12 (#3375)] A fallback-caught flight holds no transaction; a Loading reset moves the hold onto the boundary — A `<Loading>` boundary showing its fallback is the display of everything un… |
-| A34 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:255` | constants.ts×1 core.ts×6 lanes.ts×2 scheduler.ts×2 store.ts×3 | a34-writes-then-derivations.test.ts×2 createMemo.test.ts×1 derived-write-then-derivation-3733.test.ts×1 finalize-reentry.test.ts×2 held-derivation-not-a-proposal-3612.test.ts×6 optimistic-list-mutation-matrix.test.ts×1 woken-transaction-adopts-staged-bump.test.ts×1 transition-corpse-revival.test.ts×1 treeshake.test.ts×2 visibility-oracle.states.ts×2 write-proposals-3494.test.ts×5 | [ruled 2026-09-16 (#3494)] A write is a proposal: one on a held node entangles its tick; one that nets to the committed value is none — A write proposes a value for a node. **Held, both are suggestion… |
+| A34 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:255` | constants.ts×1 core.ts×6 lanes.ts×2 scheduler.ts×2 store.ts×4 | a34-writes-then-derivations.test.ts×2 createMemo.test.ts×1 derived-write-then-derivation-3733.test.ts×1 finalize-reentry.test.ts×2 held-derivation-not-a-proposal-3612.test.ts×6 optimistic-list-mutation-matrix.test.ts×1 unchanged-presence-no-hold-3743.test.ts×3 woken-transaction-adopts-staged-bump.test.ts×1 transition-corpse-revival.test.ts×1 treeshake.test.ts×2 visibility-oracle.states.ts×2 write-proposals-3494.test.ts×5 | [ruled 2026-09-16 (#3494)] A write is a proposal: one on a held node entangles its tick; one that nets to the committed value is none — A write proposes a value for a node. **Held, both are suggestion… |
 ## V — fixed violations
 
 | id | status | defined | cited in src | cited in tests | statement (at definition) |
@@ -390,7 +390,7 @@ Status legend: **live** stated and standing · **ruled** carries an explicit rul
 | §6c | live | `docs/INTERNALS-STORE-STATE.md:334` | — | createProjection.async.test.ts×1 flight-owned-transaction.test.ts×1 | Store-wide status gating (RUL-7) |
 | §6d | live | `docs/INTERNALS-STORE-STATE.md:347` | reconcile.ts×2 target.ts×2 | — | Diff reachability (RUL-11) |
 | §7 | live | `docs/INTERNALS-STORE-STATE.md:359` | optimistic.ts×1 projection.ts×1 | — | Projections & optimism layering |
-| §7b | live | `docs/INTERNALS-STORE-STATE.md:369` | scheduler.ts×1 affects.ts×1 optimistic.ts×2 projection.ts×1 reconcile.ts×1 store.ts×6 target.ts×4 | optimistic-chained-revert-3672-memo.test.ts×1 | Chained backing (cross-store) — spec |
+| §7b | live | `docs/INTERNALS-STORE-STATE.md:369` | scheduler.ts×1 affects.ts×1 optimistic.ts×2 projection.ts×1 reconcile.ts×1 store.ts×7 target.ts×4 | optimistic-chained-revert-3672-memo.test.ts×1 | Chained backing (cross-store) — spec |
 | §8 | live | `docs/INTERNALS-STORE-STATE.md:440` | — | l2-contract.test.ts×1 reconcile-resend-identity.test.ts×1 | Assumptions / open questions |
 | §8b | live | `docs/INTERNALS-STORE-STATE.md:496` | — | — | Suite-mined rules (2026-08-16) — index & rulings needed |
 | §9 | live | `docs/INTERNALS-STORE-STATE.md:732` | — | — | Decision log |