fix(signals): publish value and error outcomes consistently

.changeset/latest-held-error.md

@@ -0,0 +1,5 @@
+---
+"@solidjs/signals": patch
+---
+
+Reveal and recover reactive error outcomes consistently, including ordinary outside reads through held rejection and recovery, `latest()` derivations, projection readers, snapshots and promise-delivery helpers. Published errors remain the answer through pending retry; a revealed failure ends the initial loadingValue window while preserving successful memo prev history. Share effect callback execution and projection failure notification. Release unobserved lazy readers after async comparator failures, and allow successful direct writes to replace writable derivations' errors. Diagnostic formatting failures no longer replace the original thrown value.

packages/signals/docs/RULES-INDEX.md

@@ -63,7 +63,7 @@ Status legend: **live** stated and standing · **ruled** carries an explicit rul
 | A16 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:219` | 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:69` | async.ts×3 constants.ts×1 lanes.ts×6 scheduler.ts×2 verdict.ts×1 map.ts×1 store.ts×3 | 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:79` | 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:147` | async.ts×1 constants.ts×1 core.ts×6 scheduler.ts×2 types.ts×1 verdict.ts×4 store.ts×1 | fuzz-findings-l2.test.ts×4 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… |
+| A19 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:147` | async.ts×1 constants.ts×1 core.ts×5 scheduler.ts×2 types.ts×1 verdict.ts×4 store.ts×1 | fuzz-findings-l2.test.ts×4 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:406` | — | 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:413` | — | 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:227` | 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) … |
@@ -72,11 +72,11 @@ Status legend: **live** stated and standing · **ruled** carries an explicit rul
 | A25 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:307` | projection.ts×1 | derived-presence-async-3726.test.ts×2 uninitialized-visibility.test.ts×3 visibility-oracle-store.states.ts×7 visibility-oracle-store.test.ts×1 | [ruled 2026-07-16] A derived store's seed is a draft, never an observable value — (**ruled 2026-07-16**, #2897) **A derived store's seed is a draft, never an observable value.** The seed exists for th… |
 | A26 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:109` | — | action-await-contract.test.ts×2 fuzz-findings-l2.test.ts×1 posture-store-parity.test.ts×2 visibility-oracle-store.states.ts×2 visibility-oracle.states.ts×1 visibility-oracle.test.ts×1 | [ruled 2026-07-17] An ambient transaction window is one flush; parking is flush-driven — (**ruled 2026-07-17**, #2913; **enforcement hardened 2026-08-31**, #3141 — parking is flush-driven, and a trans… |
 | A27 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:299` | — | loading-value.test.ts×2 visibility-oracle.states.ts×18 visibility-oracle.test.ts×1 | [ruled 2026-08-10] The commit-#0 loading window is loading-class and verdict-quiet — (**ruled 2026-08-10**) **The commit-#0 loading window is loading-class and verdict-quiet.** A node born committed v… |
-| A28 | ruled, mechanism landed | `docs/SPEC-ASYNC-SEMANTICS.md:93` | constants.ts×1 core.ts×12 lanes.ts×2 scheduler.ts×3 types.ts×1 verdict.ts×2 store.ts×4 | createOptimistic.test.ts×5 fuzz-findings-l2.test.ts×6 held-derivation-not-a-proposal-3612.test.ts×1 issue-3800-repro.test.ts×1 latest-held-till-flush.test.ts×1 posture-store-parity.test.ts×5 question-scoped-pending.test.ts×3 snapshot-derived-store-rows.test.ts×1 createOptimisticStore.test.ts×10 optimistic-draft-visibility-3665.test.ts×5 optimistic-list-mutation-matrix.harness.ts×1 optimistic-list-mutation-matrix.test.ts×2 shallow.test.ts×1 woken-transaction-adopts-staged-bump.test.ts×1 treeshake.test.ts×2 verdict-contract.test.ts×1 visibility-oracle-store.states.ts×8 visibility-oracle.states.ts×8 | [ruled, mechanism landed 2026-09-15] A write becomes visible at flush — to every channel — (**ruled 2026-09-08**; supersedes the #2922 mid-tick pull) **A write becomes visible at flush — to every chan… |
+| A28 | ruled, mechanism landed | `docs/SPEC-ASYNC-SEMANTICS.md:93` | constants.ts×1 core.ts×11 lanes.ts×2 scheduler.ts×3 types.ts×1 verdict.ts×2 store.ts×4 | createOptimistic.test.ts×5 fuzz-findings-l2.test.ts×6 held-derivation-not-a-proposal-3612.test.ts×1 issue-3800-repro.test.ts×1 latest-held-till-flush.test.ts×1 posture-store-parity.test.ts×5 question-scoped-pending.test.ts×3 snapshot-derived-store-rows.test.ts×1 createOptimisticStore.test.ts×10 optimistic-draft-visibility-3665.test.ts×5 optimistic-list-mutation-matrix.harness.ts×1 optimistic-list-mutation-matrix.test.ts×2 shallow.test.ts×1 woken-transaction-adopts-staged-bump.test.ts×1 treeshake.test.ts×2 verdict-contract.test.ts×1 visibility-oracle-store.states.ts×8 visibility-oracle.states.ts×8 writable-error-outcomes.test.ts×1 | [ruled, mechanism landed 2026-09-15] A write becomes visible at flush — to every channel — (**ruled 2026-09-08**; supersedes the #2922 mid-tick pull) **A write becomes visible at flush — to every chan… |
 | A29 | amended | `docs/SPEC-ASYNC-SEMANTICS.md:117` | boundaries.ts×1 action.ts×1 async.ts×1 constants.ts×1 core.ts×13 effect.ts×1 lanes.ts×1 scheduler.ts×4 signals.ts×1 store.ts×1 | adoption-unchanged-key-read-3706.test.ts×9 body-end-supersession-visibility.test.ts×1 born-held.test.ts×3 boundary-not-born-held-3540.test.ts×4 createProjection.draft-lifetime-3585.test.ts×1 direct-commit-readers-posture.test.ts×1 fuzz-findings-l2.test.ts×6 held-conditional-memo.test.ts×1 held-frame-dependencies.test.ts×2 held-truth-lane-only.test.ts×3 l2-contract.test.ts×1 latest-held-till-flush.test.ts×2 loading-fallback-in-flush-3540.test.ts×6 loading-on-frame-following-3540.test.ts×1 mount-over-foreign-hold-3761.test.ts×1 optimistic-mount-nested-memo-3835.test.ts×1 optimistic-read-lane-not-transaction-3698.test.ts×3 posture-born-held-and-observation.test.ts×1 posture-store-parity.test.ts×6 derived-presence-async-3726.test.ts×3 optimistic-untracked-reads-f3-f5.test.ts×1 store-unchanged-read-independent-write-3688.test.ts×1 tick-scoped-pass-transaction.test.ts×2 treeshake.test.ts×3 verdict-mount-first-pass-3851.test.ts×2 verdict-mount-loading-flush-loop.test.ts×2 visibility-oracle-store.states.ts×5 visibility-oracle-store.test.ts×1 visibility-oracle.states.ts×9 visibility-oracle.test.ts×1 write-proposals-3494.test.ts×1 | [ruled, amended in place 2026-09-13 (#3408)] A tracked read served a live transaction's staged value enters that transaction — A tracked computation served a node's staged `_pendingValue` — a value a … |
 | A30 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:255` | async.ts×3 attribution.ts×1 constants.ts×1 core.ts×1 effect.ts×1 lanes.ts×1 scheduler.ts×5 | async-landing-deps-3461.test.ts×3 fuzz-findings-l2.test.ts×3 held-conditional-effect.test.ts×1 held-conditional-memo.test.ts×1 held-frame-dependencies.test.ts×2 ispending-in-boundary-on-3528.test.ts×1 lane-frame-deferred-run-3662.test.ts×1 lane-frame-held-lane-3662.test.ts×1 posture-born-held-and-observation.test.ts×1 treeshake.test.ts×2 write-proposals-3494.test.ts×2 zombie-rerun-after-commit-3546.test.ts×2 | [ruled 2026-09-13 (#3410)] A memo's dependencies are the committed frame's until the frame is replaced — A pass that _staged_ its value has not replaced the committed frame, so the committed value sti… |
 | A31 | live | `docs/SPEC-ASYNC-SEMANTICS.md:129` | boundaries.ts×1 core.ts×1 lanes.ts×1 verdict.ts×2 | fuzz-findings-l2.test.ts×6 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:137` | 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… |
+| A32 | ruled | `docs/SPEC-ASYNC-SEMANTICS.md:137` | core.ts×3 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:271` | boundaries.ts×1 scheduler.ts×2 | async-chain-supersession.test.ts×2 boundary-not-born-held-3540.test.ts×2 fuzz-findings-l2.test.ts×4 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:281` | 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 fuzz-findings-l2.test.ts×5 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

packages/signals/src/boundaries.ts

@@ -41,6 +41,8 @@
  */
 import {
   CONFIG_REDERIVE,
+  CONFIG_IN_SNAPSHOT_SCOPE,
+  CONFIG_SNAPSHOT_ERROR,
   CONFIG_HELD,
   CONFIG_OVERRIDE,
   CONFIG_VERDICT,
@@ -55,7 +57,15 @@ import {
   STATUS_PENDING,
   STATUS_UNINITIALIZED
 } from "./core/constants.js";
-import { computed, read, recompute, runWithOwner, setSignal, signal } from "./core/core.js";
+import {
+  computed,
+  read,
+  recompute,
+  runWithOwner,
+  setSignal,
+  signal,
+  snapshotCaptureActive
+} from "./core/core.js";
 import { emitDiagnostic, reportDiagnostic } from "./core/dev.js";
 import { NotReadyError, unwrapStatusError } from "./core/error.js";
 import { reportClientError } from "./core/error-hooks.js";
@@ -124,6 +134,7 @@ interface Boundary {
 
 /** Context key: the nearest boundary of a node, inherited at creation. */
 const BOUNDARY = Symbol(__DEV__ ? "boundary" : "");
+const BOUNDARY_OPTIONS = { _noSnapshot: true };
 /** Context key: the reveal controller a Loading boundary created here is a
  * slot of (reveal.ts); a boundary clears it for its content — only direct
  * children are slots. */
@@ -215,7 +226,7 @@ function catchStatus(node: Computed<any>, flags: number, error?: unknown): boole
     if (collecting.size !== 0)
       for (let b = boundaryOf(node); b !== undefined; b = b._parent ?? undefined)
         if (
-          !(node._statusFlags & unsettled(b)) &&
+          !(readerStatus(b, node) & unsettled(b)) &&
           b._readers.delete(node) &&
           b._readers.size === 0
         ) {
@@ -292,11 +303,22 @@ function release(b: Boundary): void {
 const unsettled = (b: Boundary): number =>
   b._type === STATUS_ERROR ? STATUS_ERROR | STATUS_PENDING : STATUS_PENDING;
 
+/** A frozen reader waits on its captured outcome, not the live source. */
+function readerStatus(b: Boundary, node: Computed<any>): number {
+  if (
+    snapshotCaptureActive &&
+    b._tree?._config & CONFIG_IN_SNAPSHOT_SCOPE &&
+    node._x?._snapshotValue !== undefined
+  )
+    return node._config & CONFIG_SNAPSHOT_ERROR ? STATUS_ERROR : 0;
+  return node._statusFlags;
+}
+
 export function prune(b: Boundary, pass: boolean): number {
   const mask = unsettled(b);
   for (const r of b._readers) {
     if (r._flags & REACTIVE_DISPOSED) b._readers.delete(r);
-    else if (!(r._statusFlags & mask)) {
+    else if (!(readerStatus(b, r) & mask)) {
       if (r !== b._tree && (r._config & (CONFIG_HELD | CONFIG_OVERRIDE)) === CONFIG_HELD) {
         // Landed, held: the content is that transaction's — the output's
         // pass enters it and the reveal lands with the reader's run. The
@@ -539,10 +561,15 @@ function createBoundary<T>(
   if (revealHooks !== null) context[REVEAL] = null;
   owner._context = context;
   const tree = runWithOwner(owner, () => {
-    const c = __OBSERVE__ ? computed(fn, { name: "children" }) : computed(fn);
+    // Like the output below, these are boundary structure: a nested Loading
+    // fallback can resume during hydration. Freeze the source outcomes they
+    // read, not an intermediate fallback returned by boundary plumbing.
+    const c = __OBSERVE__
+      ? computed(fn, { name: "children", _noSnapshot: true })
+      : computed(fn, BOUNDARY_OPTIONS);
     return __OBSERVE__
-      ? computed(() => flatten(read(c)), { name: "boundary" })
-      : computed(() => flatten(read(c)));
+      ? computed(() => flatten(read(c)), { name: "boundary", _noSnapshot: true })
+      : computed(() => flatten(read(c)), BOUNDARY_OPTIONS);
   });
   b._tree = tree;
   // A slot of the reveal order in its context (reveal.ts): gated until the
@@ -615,7 +642,13 @@ function createBoundary<T>(
           return fallback(b);
         // Readers under it still unready: the fallback, the tree untouched.
         // The seam re-derives this pass when they settle.
-        if (prune(b, true) !== 0) return fallback(b);
+        if (prune(b, true) !== 0) {
+          // The fallback still waits for this tree. Retain its subscription
+          // when a pending retry produced a successful inner Loading fallback;
+          // a later rejection must update the displayed error too.
+          if (type === STATUS_ERROR) link(tree, self);
+          return fallback(b);
+        }
       }
       let value: T;
       try {
@@ -656,7 +689,7 @@ function createBoundary<T>(
     // Boundary structure, not a user source: its value is fallback-or-content
     // and legitimately swaps mid-hydration (resume), so it must never be
     // frozen by snapshot capture.
-    __OBSERVE__ ? { name: "value", _noSnapshot: true } : { _noSnapshot: true }
+    __OBSERVE__ ? { name: "value", _noSnapshot: true } : BOUNDARY_OPTIONS
   );
   output._config |= CONFIG_REDERIVE;
   b._output = output;