fix(signals): an async memo over a verdict memo asks each question once

.changeset/verdict-memo-flight-no-reask.md

@@ -0,0 +1,7 @@
+---
+"@solidjs/signals": patch
+---
+
+An async memo that reads a memo using `latest()` or `isPending()` no longer asks the same question twice. Reading such a memo makes the async memo a verdict reader too (D-25). It was re-derived each time one of its verdict sources went pending, served a committed value it had already answered, and asked that question again; with two verdict sources it could ask a stale question after both had landed. Such a memo, one that calls neither `latest()` nor `isPending()` itself, now waits on a verdict source going pending like any derivation, and a re-run its hold makes reads plainly as the hold's work. It asks each question once. An async memo that calls `latest()` or `isPending()` itself is unchanged: it stays a verdict reader and shows the lane's answer ahead (F-6).
+
+A reader that groups `isPending()` with the value over a held write, such as `[isPending(m1), m1()]`, now shows the lane's answer as a plain value reader does. A pass served a held memo's committed value no longer waits on that memo's flight, and a lane's reveal leaves the stale-reader mark the held transaction's landing needs to re-run it.

packages/signals/docs/RULES-INDEX.md

@@ -54,16 +54,16 @@ Status legend: **live** stated and standing · **ruled** carries an explicit rul
 | A7 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:167` | — | fuzz-findings-l2.test.ts×1 spec-async-semantics.test.ts×2 visibility-oracle-store.states.ts×1 visibility-oracle.states.ts×1 visibility-oracle.test.ts×1 | [ruled, amended in place] Resolved async never reads `[false, undefined]` — After an async memo resolves, `[isPending(x), latest(x)]` is `[false, resolvedValue]` — never `[false, undefined]`. **Amende… |
 | A8 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:175` | — | create-deferred-3710.test.ts×1 createMemo.test.ts×1 visibility-oracle-store.states.ts×1 visibility-oracle.states.ts×2 | [ruled, amended in place 2026-07-07] `isPending(() => latest(x))` follows `x`'s own async only — verdicts are per-channel — (**re-ruled 2026-07-07c** — was "tracks the transition the same as `isPendin… |
 | A9 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:183` | projection.ts×1 target.ts×1 | spec-async-semantics.test.ts×3 visibility-oracle-store.states.ts×4 visibility-oracle-store.test.ts×1 | [ruled, amended in place 2026-07-07] Store leaves behind a firewall report the firewall's new-question refetch — `isPending` on a store leaf behind a firewall reports the firewall's refetch like any a… |
-| A10 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:191` | core.ts×3 verdict.ts×2 | createMemo.test.ts×1 error-staged-recovery.test.ts×1 fuzz-findings-l2.test.ts×1 ispending-memo-unstamped-hold-3457.test.ts×2 latest-isPending-consistency.test.ts×3 verdict-contract.test.ts×2 | [ruled] `[isPending(x), x()]` is atomic within one scope — `[isPending(x), x()]` read in one scope is atomic: a reader that observed the fresh value must not see `pending === true` for it. |
+| A10 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:191` | async.ts×1 core.ts×3 verdict.ts×3 | createMemo.test.ts×1 error-staged-recovery.test.ts×1 fuzz-findings-l2.test.ts×1 ispending-memo-unstamped-hold-3457.test.ts×2 latest-isPending-consistency.test.ts×3 verdict-contract.test.ts×2 verdict-memo-flight-no-reask.test.ts×1 | [ruled] `[isPending(x), x()]` is atomic within one scope — `[isPending(x), x()]` read in one scope is atomic: a reader that observed the fresh value must not see `pending === true` for it. |
 | A11 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:103` | — | latest-isPending-consistency.test.ts×1 loading-fallback-in-flush-3540.test.ts×2 visibility-oracle-store.states.ts×2 visibility-oracle.states.ts×1 | [ruled] Sync derivations of held sources are visible through `latest()`/`isPending()` — Sync derivations of transition-held sources are visible through `latest()`/`isPending()` (held sync recompute is… |
 | A12 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:199` | — | createOptimistic.test.ts×2 spec-async-semantics.test.ts×1 | [ruled, amended in place] Resting optimistic nodes report pending like a plain memo — A resting optimistic node reports pending via exactly the causes a plain async memo does (A19) — a reverting optim… |
 | A13 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:207` | — | spec-async-semantics.test.ts×7 | [ruled 2026-07-06 (promoted from B1)] Resting optimistic ≡ plain async memo at every checkpoint — (was B1) A resting optimistic node (no active override) is observationally identical to a plain async … |
 | A14 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:215` | — | spec-async-semantics.test.ts×1 | [ruled, amended in place 2026-07-06 (promoted from B2)] Companion nodes get child lanes that do not merge with the owner — (was B2) `isPending`/`latest` companion nodes get child lanes that do not mer… |
-| A15 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:251` | async.ts×2 constants.ts×1 core.ts×3 lanes.ts×4 scheduler.ts×15 verdict.ts×4 | async-chain-supersession.test.ts×1 boundary-output-frame-reader.test.ts×1 create-deferred-3710.test.ts×2 first-observer-stale-reader.test.ts×1 fuzz-findings-l2.test.ts×17 held-restore.test.ts×1 l2-contract.test.ts×7 l2-fuzz-existing-rules.test.ts×2 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 latest-memo-inline-parity.test.ts×1 loading-fallback-in-flush-3540.test.ts×4 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 show-stale-child-in-action-4137.test.ts×2 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 … |
+| A15 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:251` | async.ts×2 constants.ts×1 core.ts×4 lanes.ts×5 scheduler.ts×15 verdict.ts×4 | async-chain-supersession.test.ts×1 boundary-output-frame-reader.test.ts×1 create-deferred-3710.test.ts×2 first-observer-stale-reader.test.ts×1 fuzz-findings-l2.test.ts×17 held-restore.test.ts×1 l2-contract.test.ts×7 l2-fuzz-existing-rules.test.ts×2 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 latest-memo-inline-parity.test.ts×1 loading-fallback-in-flush-3540.test.ts×4 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 show-stale-child-in-action-4137.test.ts×2 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 verdict-memo-flight-no-reask.test.ts×1 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:223` | 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:71` | async.ts×3 constants.ts×1 lanes.ts×7 scheduler.ts×2 verdict.ts×1 map.ts×1 optimistic.ts×1 store.ts×3 | create-deferred-3710.test.ts×1 fuzz-findings-l2.test.ts×6 lane-uninitialized-landing-3648.test.ts×5 optimistic-over-held-row-3796.test.ts×1 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:81` | 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 l2-fuzz-existing-rules.test.ts×2 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×5 flight-owned-transaction.test.ts×1 lane-authority-twins.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:151` | async.ts×1 constants.ts×1 core.ts×6 lanes.ts×1 scheduler.ts×2 types.ts×1 verdict.ts×5 store.ts×2 | create-deferred-3710.test.ts×2 derived-store-first-landing-verdict.test.ts×1 fuzz-findings-l2.test.ts×4 lane-uninitialized-landing-3648.test.ts×2 latest-memo-inline-parity.test.ts×1 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… |
+| A19 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:151` | async.ts×1 constants.ts×1 core.ts×6 lanes.ts×1 scheduler.ts×2 types.ts×1 verdict.ts×5 store.ts×2 | create-deferred-3710.test.ts×2 derived-store-first-landing-verdict.test.ts×1 fuzz-findings-l2.test.ts×4 lane-uninitialized-landing-3648.test.ts×2 latest-memo-inline-parity.test.ts×1 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 verdict-memo-flight-no-reask.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:410` | — | 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:417` | — | 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… |
 | A22 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:231` | store.ts×1 | createProjection.draft-lifetime-3585.test.ts×1 spec-async-semantics.test.ts×1 visibility-oracle-store.states.ts×1 | [ruled, amended in place 2026-07-08] Pending is per-node; store-wide only for the firewall's own work — **Pending is per-node: store-wide verdicts exist only as the firewall's own in-flight work (A9) … |

packages/signals/src/core/async.ts

@@ -1,4 +1,5 @@
 import {
+  CONFIG_ASYNC,
   CONFIG_AUTO_DISPOSE,
   CONFIG_REDERIVE,
   CONFIG_GUESS,
@@ -13,6 +14,7 @@ import {
   EFFECT_USER,
   NOT_PENDING,
   REACTIVE_DIRTY,
+  REACTIVE_WINDOW,
   REACTIVE_DISPOSED,
   REACTIVE_RECOMPUTING_DEPS,
   REACTIVE_REASK,
@@ -44,6 +46,7 @@ import {
   schedule,
   txOf,
   freshHook,
+  holdWorkHook,
   guessing,
   laneStageHook
 } from "./scheduler.js";
@@ -60,7 +63,7 @@ export function addPendingSource(el: Computed<any>, source: Computed<any>): bool
   return true;
 }
 
-function removePendingSource(el: Computed<any>, source: Computed<any>): boolean {
+export function removePendingSource(el: Computed<any>, source: Computed<any>): boolean {
   const sources = el._x?._pendingSources;
   if (!sources?.delete(source)) return false;
   if (!sources.size) el._x!._pendingSources = undefined;
@@ -426,7 +429,10 @@ export function handleAsync<T>(
   }
 
   if (!thenable && !iterator) {
-    if (el._x !== null) el._x._inFlight = null;
+    if (el._x !== null) {
+      el._x._inFlight = null;
+      el._config &= ~CONFIG_ASYNC;
+    }
     // A sync landing is the first real answer for a loadingValue node.
     el._loading = false;
     return result as T;
@@ -461,6 +467,9 @@ export function handleAsync<T>(
   // fired _flightTeardown. A future non-recompute registration path must
   // release it here before overwriting _inFlight.
   ext(el)._inFlight = result as PromiseLike<T> | AsyncIterable<T>;
+  // D-25 (verdict.ts `holdWork`): an async memo whose answering pass opened
+  // no verdict window of its own (`markVerdictReader` clears the bit).
+  if (!(el._flags & REACTIVE_WINDOW)) el._config |= CONFIG_ASYNC;
   // The question this flight answers (A18 provenance, lanes.ts): the action
   // whose slice asked it; mainline is always the current question.
   el._x!._q = question || MAINLINE_QUESTION;
@@ -988,8 +997,15 @@ export function propagateStatus(el: Computed<any>, status: number, error: any):
     // Inheriting the error would make a probe's reader errored. A boundary's
     // output (CONFIG_REDERIVE, boundaries.ts) the same: content or fallback
     // is its pass's call.
+    // Not one D-25 makes the hold's work (verdict.ts `holdWork`): an async
+    // memo with no verdict window of its own reads a verdict memo's value,
+    // and that source going pending changes none of its reads — re-derived,
+    // it is served the committed value it already derived from (A10) and
+    // asks that question again. It waits on the source like any derivation
+    // (F-9), and asks its next question once, at the landing (#4397).
     if (
-      sub._config & (CONFIG_REDERIVE | CONFIG_VERDICT) ||
+      sub._config & CONFIG_REDERIVE ||
+      (sub._config & CONFIG_VERDICT && !(pendingSource && holdWorkHook!(sub, el))) ||
       (status === STATUS_PENDING && link._gen !== sub._depGen)
     ) {
       enqueueSub(sub);

packages/signals/src/core/constants.ts

@@ -68,6 +68,11 @@ export const REACTIVE_SCREEN_READ = 1 << 18;
  * later read of the same pass routed it into a verdict lane — that was not
  * the probe's answer (lanes.ts). Per pass. */
 export const REACTIVE_PROBE_UNANSWERED = 1 << 19;
+/** The pass opened a verdict window of its own (`isPending`/`latest`) — not
+ * only read a verdict memo (F-6, core.ts `read`). An async memo whose pass
+ * did not is D-25's hold work while its flight is up (verdict.ts
+ * `holdWork`). Per pass (1 << 20 is lanes.ts's LEFT_SHOWN). */
+export const REACTIVE_WINDOW = 1 << 21;
 
 // Static configuration bits packed into Owner/Computed/Signal _config.
 export const CONFIG_OWNED_WRITE = 1 << 0;
@@ -216,6 +221,9 @@ export const CONFIG_KEY_BAG = 1 << 28;
  * joins nothing, so two mounts under one boundary made in separate flushes
  * keep their holds apart (D-4, S-5 rows 1′–3′, #4283). */
 export const CONFIG_FRAME = 1 << 23;
+/** The node's last answering pass registered a flight: an async memo. Kept
+ * by the verdict engine alone (verdict.ts `holdWork`), which reads it. */
+export const CONFIG_ASYNC = 1 << 29;
 
 export const STATUS_NONE = 0;
 export const STATUS_PENDING = 1 << 0;