From 7ce3c98d537457d4455415ff35ce32a13bd2b27d Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 27 Oct 2026 05:26:59 +0000
Subject: [PATCH 1/3] fix(solid): an Errored fallback's own failure goes to the
 next boundary up; its wait is budgeted (#4316, #4317)

#4316: when a <Loading> fails after the shell and its <Errored> renders the
fallback as the outcome (renderOutcome), a fallback hole that rejected
while the server waited for it was swallowed. The retry ran with no owner,
so the hole's error never met a handler and the outcome came back empty.
Parked in a pending outer <Loading>, the inner fragment then settled as a
blank child, and the client hydrated the blank and halted. A fallback that
threw synchronously reached the parent handler instead, but in its
no-consumer mode: an outer <Errored> serialized its error record and
rendered a fallback nobody sent.

Now a failure of the fallback, sync or async, goes to the next boundary
up. The fallback owner's handler holds it while the outcome renders, and
the retry runs under that owner. The parent is first asked for the outcome
at the same position, so an outer <Errored> whose whole content is that
position draws its fallback there and serializes its error with it.
Otherwise the failure is routed as a content failure, so a pending outer
<Loading> fails its fragment. An outer <Errored> reached that way while
it is not being pulled lets it pass and does not render.

#4317: the wait now shares the <Loading> resume loop's convergence budget
(MAX_RESUME_PASSES, internal; hydration.ts uses it in place of the 10000
literal). Past the budget it answers what is available, which is no
finished fallback. It also races each wait against the fallback owner's
teardown, so an aborted render stops waiting at once.

Tests: sync-throw twins for the parked and unparked shapes, with and
without an outer <Errored>. The server harness holds the async variant's
markup to the twin's. The hydrate spec holds its client outcome, loaded
and streamed, to the twin's, and a caught variant must claim the outer
fallback. Server specs cover the budget (a fresh pending source every
pass) and the abort.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015hPxMkC3jg3Uivh65gvaf2
---
 .../errored-fallback-hole-failure-4316.md     |   7 +
 packages/solid/src/server/hydration.ts        |  11 +-
 packages/solid/src/server/signals.ts          | 102 ++++++++++++--
 ...ored-fallback-hole-async-failure-4316.json |   5 +
 ...llback-hole-async-failure-caught-4316.json |   5 +
 ...llback-hole-async-failure-parked-4316.json |   5 +
 ...hole-async-failure-parked-caught-4316.json |   5 +
 ...rored-fallback-hole-sync-failure-4316.json |   5 +
 ...allback-hole-sync-failure-caught-4316.json |   5 +
 ...allback-hole-sync-failure-parked-4316.json |   5 +
 ...-hole-sync-failure-parked-caught-4316.json |   5 +
 packages/web/test/harness/scenarios.tsx       |  75 ++++++++++
 ...errored-parked-async-outcome-4306.spec.tsx | 131 +++++++++++++++++-
 .../errored-fallback-wait-4317.spec.tsx       | 113 +++++++++++++++
 .../test/server/hydration-harness.spec.tsx    |  44 +++++-
 15 files changed, 507 insertions(+), 16 deletions(-)
 create mode 100644 .changeset/errored-fallback-hole-failure-4316.md
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-caught-4316.json
 create mode 100644 packages/web/test/server/errored-fallback-wait-4317.spec.tsx

diff --git a/.changeset/errored-fallback-hole-failure-4316.md b/.changeset/errored-fallback-hole-failure-4316.md
new file mode 100644
index 0000000000..66a3978a9e
--- /dev/null
+++ b/.changeset/errored-fallback-hole-failure-4316.md
@@ -0,0 +1,7 @@
+---
+"solid-js": patch
+---
+
+Server: when an `<Errored>` renders its fallback for a `<Loading>` that failed after the shell, and a hole in that fallback rejects while the server waits for it, the rejection now goes to the next boundary up, as it does when a fallback throws synchronously. Inside a pending outer `<Loading>`, that outer fragment fails; under an outer `<Errored>` whose whole content is that position, the outer fallback is drawn there and the client adopts it. Before, the region streamed blank and the hydrating client halted (#4316). A synchronous throw in that fallback no longer writes an error record for an outer `<Errored>` without sending its fallback.
+
+The server's wait for that fallback now stops after the same pass budget as the `<Loading>` resume loop and then streams what it has. It also stops as soon as the render is torn down, for example when the request is aborted (#4317).
diff --git a/packages/solid/src/server/hydration.ts b/packages/solid/src/server/hydration.ts
index b62c6f2590..25fa95c24a 100644
--- a/packages/solid/src/server/hydration.ts
+++ b/packages/solid/src/server/hydration.ts
@@ -15,7 +15,8 @@ import {
   ownerId,
   onCleanup,
   inServerComponentScope,
-  edgeHooks
+  edgeHooks,
+  MAX_RESUME_PASSES
 } from "./signals.js";
 import { OBSERVE } from "@solidjs/signals";
 import { sharedConfig, NoHydrateContext, callerRenderContext } from "./shared.js";
@@ -717,15 +718,15 @@ function ssrLoadingBoundary(
     };
     (async () => {
       try {
-        // Convergence budget: each pass should retire at least one async
-        // slot, so passes are bounded by the boundary's async-slot count in
-        // any converging render — real trees sit far below this. A shape
+        // Convergence budget (`MAX_RESUME_PASSES`): each pass should retire
+        // at least one async slot, so passes are bounded by the boundary's
+        // async-slot count in any converging render. A shape
         // that plants a fresh pending source every pass (an async read whose
         // answer is never adoptable at the re-created slot) would otherwise
         // loop at microtask speed, serializing a new deferred per pass until
         // the process OOMs (#3003). Fail the boundary loudly instead.
         const checkBudget = () => {
-          if (passes <= 10000) return;
+          if (passes <= MAX_RESUME_PASSES) return;
           throw new Error(
             `<Loading> boundary discovery did not converge after ${passes} passes — ` +
               `an async source produces a new pending answer on every retry. Ensure repeated ` +
diff --git a/packages/solid/src/server/signals.ts b/packages/solid/src/server/signals.ts
index 5d493c6b8b..7fc2e1226f 100644
--- a/packages/solid/src/server/signals.ts
+++ b/packages/solid/src/server/signals.ts
@@ -3712,6 +3712,22 @@ export type BoundaryErrorHandler = (err: any, outcome?: true | string) => Bounda
 /** A rendered outcome; a function where it is still resolving (see renderOutcome). */
 export type BoundaryOutcome = string | (() => Promise<string | undefined>) | undefined | void;
 
+/**
+ * Convergence budget of a boundary's resume loop: each pass should retire at
+ * least one async slot, so passes are bounded by the slot count in any
+ * converging render — real trees sit far below this. Shared by the
+ * `<Loading>` resume loop (hydration.ts) and an `<Errored>` outcome's wait
+ * for its fallback (renderOutcome).
+ * @internal
+ */
+export const MAX_RESUME_PASSES = 10000;
+
+// Set while an `<Errored>` hands a failure of its own fallback up the
+// handler chain as a content failure (see renderOutcome's `escalate`): an
+// enclosing `<Errored>` reached that way while it is not being pulled has
+// no consumer for a fallback, so it lets the failure pass.
+let escalating = 0;
+
 const ErrorContext: Context<BoundaryErrorHandler | null> = {
   id: Symbol("ErrorContext"),
   defaultValue: null
@@ -4281,8 +4297,26 @@ export function createErrorBoundary<T, U>(
   // resolving answers with a function instead: called, it waits out the
   // fallback's holes and answers with the finished markup (or `undefined`,
   // a client hole or a failure in it), serializing the error only then
-  // (#4306).
-  const renderOutcome = (err: any, outcome: true | string): BoundaryOutcome => {
+  // (#4306). The wait shares the resume loop's convergence budget: past it
+  // the outcome is what is available, the unfinished fallback none. It stops
+  // as soon as the render is torn down (#4317).
+  // A failure of the fallback itself — a hole that throws while it renders,
+  // or rejects while it is waited out — is the next boundary up's, as a
+  // fallback's failure is when it renders in the boundary's own pull
+  // (#4316): an enclosing `<Errored>` that can draw at the asking position
+  // answers for it; otherwise it is a failure of the enclosing content (a
+  // pending `<Loading>` around this one fails its fragment), and this
+  // boundary answers nothing.
+  let answering = false;
+  let interceptor = false;
+  let pulling = false;
+  let torn = false;
+  let disposed: Promise<void> | undefined;
+  const renderOutcome = (
+    err: any,
+    outcome: true | string,
+    parentHandler: BoundaryErrorHandler | null
+  ): BoundaryOutcome => {
     let t = shown && shown.t;
     if (Array.isArray(t)) t = t[0];
     if (
@@ -4294,15 +4328,33 @@ export function createErrorBoundary<T, U>(
           !t.endsWith(`<!--pl-${outcome}-->`))
     )
       return undefined;
+    // A hole of the fallback that throws while it renders reaches the
+    // fallback owner's handler first: hold it for `escalate` instead of
+    // letting the parent handler route it from here.
+    if (parentHandler && !interceptor) {
+      interceptor = true;
+      setContext(
+        ErrorContext,
+        (e: any, o?: true | string) => {
+          if (o === undefined && answering) throw e;
+          return parentHandler(e, o);
+        },
+        outputOwner
+      );
+    }
+    let failed: { e: any } | undefined;
     // Rendered from a resume loop, where the render context the compiled
     // template reads has long moved past this boundary's: restore it.
     const inCtx = (run: () => any) => {
       const prevCtx = sharedConfig.context;
       sharedConfig.context = ctx;
+      answering = true;
       try {
         return run();
-      } catch {
+      } catch (e) {
+        if (!(e instanceof NotReadyError)) failed = { e };
       } finally {
+        answering = false;
         sharedConfig.context = prevCtx;
       }
     };
@@ -4312,13 +4364,41 @@ export function createErrorBoundary<T, U>(
       const t = resolved.t;
       return Array.isArray(t) ? t[0] : t;
     };
+    const escalate = (): BoundaryOutcome => {
+      const e = failed!.e;
+      deferredWire = undefined;
+      if (!parentHandler) return;
+      const answer = parentHandler(e, outcome);
+      if (answer !== undefined) return answer;
+      escalating++;
+      try {
+        parentHandler(e);
+      } catch {
+      } finally {
+        escalating--;
+      }
+    };
     let resolved: any = inCtx(() => ctx.resolve(ctx.escape(handleError(err, true))));
+    if (failed) return escalate();
     if (outcome === true || !resolved || !resolved.h || !resolved.h.length) return finish(resolved);
+    disposed ||= new Promise<void>(r =>
+      runWithOwner(outputOwner!, () => onCleanup(() => ((torn = true), r())))
+    );
     return async () => {
-      while (resolved && resolved.p && resolved.p.length) {
-        if (resolved.p.some((p: any) => p.$clientHole)) return;
-        await Promise.all(resolved.p).catch(() => {});
-        resolved = inCtx(() => ctx.ssr(resolved.t, ...resolved.h));
+      for (let passes = 0; resolved && resolved.p && resolved.p.length; passes++) {
+        if (torn || passes >= MAX_RESUME_PASSES || resolved.p.some((p: any) => p.$clientHole))
+          return;
+        await Promise.race([Promise.all(resolved.p).catch(() => {}), disposed]);
+        if (torn) return;
+        // Under the fallback's owner, as it rendered: a hole failing now
+        // meets the handler a sync throw did.
+        resolved = inCtx(() =>
+          runWithOwner(outputOwner!, () => ctx.ssr(resolved.t, ...resolved.h))
+        );
+        if (failed) {
+          const answer = escalate();
+          return typeof answer === "function" ? answer() : answer;
+        }
       }
       return finish(resolved);
     };
@@ -4337,16 +4417,22 @@ export function createErrorBoundary<T, U>(
       // stashed holes read from (marking them disposed drops their settlement).
       if (ctx && !pending) disposeOwner(owner, false);
       try {
+        pulling = true;
         result = ctx
           ? runWithBoundaryErrorContext(owner, resolve, (err, _parent, outcome) => {
               if (err instanceof NotReadyError) throw err;
-              if (outcome !== undefined) return renderOutcome(err, outcome);
+              if (outcome !== undefined) return renderOutcome(err, outcome, _parent);
+              // Escalated to while not pulled: no consumer for a fallback
+              // (see `escalating`).
+              if (escalating && !pulling) throw err;
               handled = true;
               result = handleError(err);
               throw err;
             })
           : runWithOwner(owner, fn);
+        pulling = false;
       } catch (err) {
+        pulling = false;
         if (err instanceof NotReadyError) throw err;
         pending = undefined;
         result = handled ? result : handleError(err);
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-4316.json
new file mode 100644
index 0000000000..e4c14e6f71
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-async-failure-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-400\"></template><i _hk=4000>loading</i><!--pl-400--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"400_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));</script><template id=\"400\" e> </template><script>$df(\"400\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[10]($R[8],$R[9]);</script><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-caught-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-caught-4316.json
new file mode 100644
index 0000000000..189cce2c86
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-async-failure-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-40000\"></template><i _hk=400000>loading</i><!--pl-40000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"40000_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));_$HY.r[\"4\"]=$R[11];</script><template id=\"40000\" e><h2 _hk=50>caught: <!--$-->no hint<!--/--></h2></template><script>$df(\"40000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[10]($R[8],$R[9]);</script><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-4316.json
new file mode 100644
index 0000000000..fe86b020e2
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-async-failure-parked-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-4\"></template><i _hk=40>outer loading</i><!--pl-4--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"400200_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"4_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));</script><template id=\"4\" e> </template><script>$R[12]($R[6],$R[13]=new Error(\"no hint\"));$df(\"4\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>($R[14]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);$R[12]($R[10],$R[13]);</script><script>$R[14]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-caught-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-caught-4316.json
new file mode 100644
index 0000000000..005805be3e
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-async-failure-parked-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-async-failure-parked-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-400\"></template><i _hk=4000>outer loading</i><!--pl-400--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"40000200_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"400_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));</script><template id=\"400\" e><h2 _hk=50>caught: <!--$-->no hint<!--/--></h2></template><script>$R[12]($R[6],$R[13]=new Error(\"no hint\"));_$HY.r[\"4\"]=$R[13];$df(\"400\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>($R[14]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);$R[12]($R[10],$R[13]);</script><script>$R[14]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-4316.json
new file mode 100644
index 0000000000..48076459cd
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-sync-failure-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-400\"></template><i _hk=4000>loading</i><!--pl-400--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"400_fr\"]=$R[7]=($R[8]=$R[2]()).p;($R[9]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[6],\"\");</script>",
+  "rest": "<template id=\"400\" e> </template><script>($R[11]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[10]=new Error(\"no user 7\"));$df(\"400\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[11]($R[8],$R[10]);</script><script>$R[9]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-caught-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-caught-4316.json
new file mode 100644
index 0000000000..ccf2bfdd06
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-sync-failure-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-40000\"></template><i _hk=400000>loading</i><!--pl-40000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"40000_fr\"]=$R[7]=($R[8]=$R[2]()).p;($R[9]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[6],\"\");</script>",
+  "rest": "<template id=\"40000\" e><h2 _hk=50>caught: <!--$-->no hint<!--/--></h2></template><script>($R[11]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[10]=new Error(\"no user 7\"));_$HY.r[\"4\"]=$R[12]=new Error(\"no hint\");$df(\"40000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[11]($R[8],$R[10]);</script><script>$R[9]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-4316.json
new file mode 100644
index 0000000000..733d2d1bb2
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-sync-failure-parked-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-4\"></template><i _hk=40>outer loading</i><!--pl-4--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"400200_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"4_fr\"]=$R[9]=($R[10]=$R[2]()).p;($R[11]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[6],\"\");</script>",
+  "rest": "<template id=\"4\" e> </template><script>($R[13]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[12]=new Error(\"no user 7\"));$df(\"4\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[11]($R[8],!0);$R[13]($R[10],$R[14]=new Error(\"no hint\"));</script><script>$R[11]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-caught-4316.json b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-caught-4316.json
new file mode 100644
index 0000000000..efeaa573f6
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-fallback-hole-sync-failure-parked-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-fallback-hole-sync-failure-parked-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-400\"></template><i _hk=4000>outer loading</i><!--pl-400--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"40000200_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"400_fr\"]=$R[9]=($R[10]=$R[2]()).p;($R[11]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[6],\"\");</script>",
+  "rest": "<template id=\"400\" e><h2 _hk=50>caught: <!--$-->no hint<!--/--></h2></template><script>($R[13]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[12]=new Error(\"no user 7\"));_$HY.r[\"4\"]=$R[14]=new Error(\"no hint\");$df(\"400\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[11]($R[8],!0);$R[13]($R[10],$R[14]);</script><script>$R[11]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/scenarios.tsx b/packages/web/test/harness/scenarios.tsx
index aaae82e4ae..e8d7226c50 100644
--- a/packages/web/test/harness/scenarios.tsx
+++ b/packages/web/test/harness/scenarios.tsx
@@ -1684,6 +1684,81 @@ function parkedRejectionAsyncFallback(late: boolean) {
   };
 }
 
+// ---------------------------------------------------------------------------
+// #4316: the #4287/#4306 failure with the Errored fallback's own hole
+// failing. `hole: "async"` reads an async memo that rejects at 10ms (after
+// the inner Loading failed at 5ms, before the outer one settles at 15ms);
+// `hole: "sync"` is its twin, a fallback that throws synchronously. The
+// fallback's failure belongs to the next boundary up, so the async variant
+// must end exactly as its twin does — server markup and client outcome.
+// `parked`: inside an outer <Loading> still pending when it fails;
+// `caught`: an outer <Errored> around everything catches it.
+export type FallbackHoleFailure = { hole: "async" | "sync"; parked: boolean; caught: boolean };
+export const fallbackHoleFailureName = (o: FallbackHoleFailure) =>
+  `errored-fallback-hole-${o.hole}-failure${o.parked ? "-parked" : ""}${o.caught ? "-caught" : ""}-4316`;
+export function fallbackHoleFailure(o: FallbackHoleFailure) {
+  return function ErroredFallbackHoleFailure() {
+    const outer = createMemo(async () => {
+      await sleep(15);
+      return "outer";
+    });
+    const user = createMemo(async (): Promise<string> => {
+      await sleep(5);
+      throw new Error("no user 7");
+    });
+    // The twin takes the async memo's owner slot too, so both variants'
+    // hydration keys line up.
+    const slot = createMemo(async (): Promise<string> => {
+      if (o.hole === "sync") return "";
+      await sleep(10);
+      throw new Error("no hint");
+    });
+    const hint =
+      o.hole === "async"
+        ? slot
+        : (): string => {
+            throw new Error("no hint");
+          };
+    const Inner = () => (
+      <Errored
+        fallback={(e: any) => (
+          <p>
+            failed: {e().message} {hint()}
+          </p>
+        )}
+      >
+        <Loading fallback={<i>loading</i>}>
+          <span>user:{user()}</span>
+        </Loading>
+      </Errored>
+    );
+    const Body = o.parked
+      ? () => (
+          <Loading fallback={<i>outer loading</i>}>
+            <b>{outer()}</b>
+            <Inner />
+          </Loading>
+        )
+      : Inner;
+    return o.caught ? (
+      <div>
+        <Errored fallback={(e: any) => <h2>caught: {e().message}</h2>}>
+          <Body />
+        </Errored>
+        <span>tail</span>
+      </div>
+    ) : (
+      <div>
+        <Body />
+        <span>tail</span>
+      </div>
+    );
+  };
+}
+export const fallbackHoleFailures: FallbackHoleFailure[] = (["async", "sync"] as const).flatMap(
+  hole => [false, true].flatMap(parked => [false, true].map(caught => ({ hole, parked, caught })))
+);
+
 // ---------------------------------------------------------------------------
 // #3414: a sync throw the SERVER catches, with a zero-arg fallback thunk
 // (`fallback={() => <Fallback />}`), inside an enclosing boundary. Errored
diff --git a/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx b/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
index 7c88c0887d..bc9e5b5bcd 100644
--- a/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
+++ b/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
@@ -15,15 +15,29 @@
  * The client claims that markup in both replay orders, without warnings;
  * hydrated after the stream it asks nothing again.
  *
+ * #4316: the same shapes (parked or not, an outer `<Errored>` or none) with
+ * the fallback's own hole failing — rejecting while the failure waits for
+ * it. The failure is the next boundary up's, as when the fallback throws
+ * synchronously: the async variant ends exactly as its sync-throw twin,
+ * the server's markup and the client's outcome alike; caught, the client
+ * claims the outer `<Errored>`'s fallback the server drew.
+ *
  * Replays the parity harness artifacts (test/server/hydration-harness.spec.tsx).
  */
 import { describe, expect, test, vi } from "vitest";
 import { existsSync, readFileSync } from "node:fs";
 import { resolve, dirname } from "node:path";
 import { fileURLToPath } from "node:url";
-import { flush } from "solid-js";
+import { flush, resetErrorHalt } from "solid-js";
 import { hydrate } from "@solidjs/web";
-import { scenarios, parkedHoleAskCount } from "../harness/scenarios.jsx";
+import {
+  scenarios,
+  parkedHoleAskCount,
+  fallbackHoleFailures,
+  fallbackHoleFailure,
+  fallbackHoleFailureName,
+  type FallbackHoleFailure
+} from "../harness/scenarios.jsx";
 
 const artifact = (name: string) =>
   resolve(dirname(fileURLToPath(import.meta.url)), `../harness/__artifacts__/${name}.json`);
@@ -93,3 +107,116 @@ describe("#4306: parked failure, Errored fallback with an async hole", () => {
     run(late, "loaded"));
   test("hole settles after the outer Loading, hydrated mid-stream", () => run(late, "streamed"));
 });
+
+type Outcome = {
+  /** The page the server's stream builds, before anything hydrates (loaded). */
+  server: string | undefined;
+  text: string;
+  halted: boolean;
+  done: boolean;
+  warnings: number;
+  /** What reached the page's uncaught-error channel (`reportError`). */
+  uncaught: string[];
+  /** In loaded mode: the client kept the server's outer-fallback node. */
+  claimed: boolean;
+};
+
+async function outcomeOf(o: FallbackHoleFailure, mode: "loaded" | "streamed"): Promise<Outcome> {
+  const name = fallbackHoleFailureName(o);
+  const file = artifact(name);
+  expect(existsSync(file)).toBe(true);
+  const { shell, rest } = JSON.parse(readFileSync(file, "utf-8"));
+  const App = fallbackHoleFailure(o);
+  const container = document.createElement("div");
+  document.body.appendChild(container);
+  (globalThis as any)._$HY = { events: [], completed: new WeakSet(), r: {}, fe() {} };
+  const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+  const errors: string[] = [];
+  const error = vi
+    .spyOn(console, "error")
+    .mockImplementation((...a: unknown[]) => void errors.push(a.map(String).join(" ")));
+  // An uncontained failure halts the page: own its uncaught channels (the
+  // platform's `reportError`, and the process's for the rethrow out of a
+  // scheduled flush) so what escapes is part of the outcome.
+  const uncaught: string[] = [];
+  const report = (e: unknown) => void uncaught.push(e instanceof Error ? e.message : String(e));
+  vi.stubGlobal("reportError", report);
+  const events = ["uncaughtException", "unhandledRejection"] as const;
+  const previous = events.map(e => process.listeners(e));
+  events.forEach(e => (process.removeAllListeners(e), process.on(e, report)));
+  resetErrorHalt();
+  const textOf = () => {
+    const clone = container.cloneNode(true) as HTMLElement;
+    clone.querySelectorAll("template").forEach(t => t.remove());
+    return clone.textContent!;
+  };
+  let dispose: (() => void) | undefined;
+  try {
+    applyChunk(container, shell, true);
+    if (mode === "loaded") applyChunk(container, rest, false);
+    const server = mode === "loaded" ? container.innerHTML : undefined;
+    const serverH2 = container.querySelector("h2");
+    try {
+      dispose = hydrate(() => <App />, container);
+    } catch {}
+    flush();
+    await sleep(10);
+    flush();
+    if (mode === "streamed") applyChunk(container, rest, false);
+    await sleep(50);
+    flush();
+    await sleep(10);
+    return {
+      server,
+      text: textOf(),
+      halted: errors.some(m => m.includes("[REACTIVITY_HALTED]")),
+      done: !!(globalThis as any)._$HY.done,
+      warnings: warn.mock.calls.length,
+      uncaught,
+      claimed: !!serverH2 && container.querySelector("h2") === serverH2
+    };
+  } finally {
+    try {
+      dispose?.();
+    } catch {}
+    await sleep(0);
+    container.remove();
+    events.forEach((e, i) => {
+      process.off(e, report);
+      for (const listener of previous[i]) process.on(e, listener as any);
+    });
+    vi.unstubAllGlobals();
+    warn.mockRestore();
+    error.mockRestore();
+    resetErrorHalt();
+  }
+}
+
+describe("#4316: the Errored fallback's own hole fails", () => {
+  for (const o of fallbackHoleFailures) {
+    if (o.hole !== "async") continue;
+    for (const mode of ["loaded", "streamed"] as const) {
+      test(`${fallbackHoleFailureName(o)} [${mode}] ends as its sync-throw twin`, async () => {
+        const outcome = await outcomeOf(o, mode);
+        const twin = await outcomeOf({ ...o, hole: "sync" }, mode);
+        // A halted page's later notices (how often the halt is reported,
+        // what it refuses after) are the halt's, not the outcome's: the
+        // comparison takes which errors escaped, and warnings while live.
+        const comparable = (r: Outcome) => ({
+          ...r,
+          uncaught: [...new Set(r.uncaught)],
+          warnings: r.halted ? undefined : r.warnings
+        });
+        expect(comparable(outcome)).toEqual(comparable(twin));
+        if (o.caught) {
+          // The outer Errored caught it on the server: the client claims
+          // its fallback and the page stays live.
+          expect(outcome.text).toBe("caught: no hinttail");
+          expect(outcome.halted).toBe(false);
+          expect(outcome.warnings).toBe(0);
+          if (mode === "loaded") expect(outcome.claimed).toBe(true);
+        }
+      });
+    }
+  }
+});
diff --git a/packages/web/test/server/errored-fallback-wait-4317.spec.tsx b/packages/web/test/server/errored-fallback-wait-4317.spec.tsx
new file mode 100644
index 0000000000..4ed4c92c5e
--- /dev/null
+++ b/packages/web/test/server/errored-fallback-wait-4317.spec.tsx
@@ -0,0 +1,113 @@
+/**
+ * @jsxImportSource @solidjs/web
+ *
+ * #4317: a post-flush `<Loading>` failure waits for the enclosing
+ * `<Errored>`'s fallback to finish before it streams the outcome (#4306).
+ * That wait is a resume loop, and keeps the `<Loading>` resume loop's two
+ * guards:
+ *
+ * - its convergence budget: a fallback hole that answers a fresh pending
+ *   source on every pass stops being waited for, and the failure streams
+ *   the outcome that is available — no finished fallback, so none: the
+ *   fragment rejects as for any unfinished fallback, and the response ends;
+ * - the render's teardown: an aborted request stops waiting at once, and
+ *   the fallback is not rendered again when its pending source lands.
+ */
+import { describe, expect, test } from "vitest";
+import { Errored, Loading, NotReadyError, createMemo } from "solid-js";
+import { renderToStream } from "@solidjs/web";
+
+const sleep = (ms: number) => new Promise<void>(r => setTimeout(r, ms));
+const MAX_RESUME_PASSES = 10000;
+
+function App(props: { hint: () => string; onRender?: () => void }) {
+  const user = createMemo(async (): Promise<string> => {
+    await sleep(5);
+    throw new Error("no user 7");
+  });
+  return (
+    <div>
+      <Errored
+        fallback={(e: any) => (
+          <p>
+            failed: {e().message} {props.hint()}
+          </p>
+        )}
+      >
+        <Loading fallback={<i>loading</i>}>
+          <span>user:{user()}</span>
+        </Loading>
+      </Errored>
+      <span>tail</span>
+    </div>
+  );
+}
+
+describe("#4317: the wait for an Errored fallback's async holes", () => {
+  test("stops at the resume loop's pass budget and streams what is available", async () => {
+    let asks = 0;
+    // Pathological: a fresh pending source on every pass, settling a turn
+    // later, so the wait never converges (and a deadline can still fire).
+    const hint = (): string => {
+      asks++;
+      throw new NotReadyError(new Promise(r => setImmediate(r)) as any);
+    };
+    const chunks: string[] = [];
+    const errors: unknown[] = [];
+    const ended = new Promise<void>(resolve =>
+      renderToStream(() => <App hint={hint} />, { onError: e => void errors.push(e) }).pipe({
+        write: (c: string) => void chunks.push(c),
+        end: resolve
+      })
+    );
+    const outcome = await Promise.race([
+      ended.then(() => "ended"),
+      sleep(15000).then(() => "still waiting")
+    ]);
+    expect(outcome).toBe("ended");
+    // The discovery render plus one per budgeted pass, never more.
+    expect(asks).toBe(MAX_RESUME_PASSES + 1);
+    const html = chunks.join("");
+    // No finished fallback: the fragment rejects with nothing drawn, and no
+    // error record claims a fallback that was never sent.
+    expect(html).toMatch(/<template id="[^"]+" e> <\/template>/);
+    expect(html).not.toContain("failed:");
+    expect(html).toContain('new Error("no user 7")');
+  }, 20000);
+
+  test("an aborted render stops waiting and renders the fallback no further", async () => {
+    let asks = 0;
+    let land!: () => void;
+    const pending = new Promise<void>(r => (land = r));
+    let settled = false;
+    const hint = (): string => {
+      asks++;
+      if (!settled) throw new NotReadyError(pending as any);
+      return "HINT";
+    };
+    const controller = new AbortController();
+    const chunks: string[] = [];
+    renderToStream(() => <App hint={hint} />, {
+      signal: controller.signal,
+      onError() {}
+    }).pipe({
+      write: (c: string) => void chunks.push(c),
+      end() {}
+    });
+    // The read fails at 5ms; the failure waits on the fallback's hole.
+    await sleep(30);
+    const asked = asks;
+    expect(asked).toBeGreaterThan(0);
+    const written = chunks.length;
+    controller.abort();
+    await sleep(0);
+    // The source lands after the teardown: nothing renders the fallback
+    // again, and nothing more is written.
+    settled = true;
+    land();
+    await sleep(30);
+    expect(asks).toBe(asked);
+    expect(chunks.length).toBe(written);
+    expect(chunks.join("")).not.toContain("HINT");
+  });
+});
diff --git a/packages/web/test/server/hydration-harness.spec.tsx b/packages/web/test/server/hydration-harness.spec.tsx
index 3750693d60..c841bc9283 100644
--- a/packages/web/test/server/hydration-harness.spec.tsx
+++ b/packages/web/test/server/hydration-harness.spec.tsx
@@ -17,7 +17,12 @@
 import { AsyncLocalStorage } from "node:async_hooks";
 import { describe, expect, test } from "vitest";
 import type { RequestEvent, ResponseStub } from "@solidjs/web";
-import { scenarios } from "../harness/scenarios.jsx";
+import {
+  scenarios,
+  fallbackHoleFailures,
+  fallbackHoleFailure,
+  fallbackHoleFailureName
+} from "../harness/scenarios.jsx";
 import { recordStream, writeArtifact } from "./artifact-recorder.js";
 
 // Render every scenario under a request event so the http-primitives
@@ -60,3 +65,40 @@ describe("hydration parity harness — server render", () => {
     });
   }
 });
+
+// #4316: an Errored fallback whose own hole fails, async (rejects while the
+// failure waits for it) and its sync-throw twin. Recorded for
+// test/hydration/errored-parked-async-outcome-4306.spec.tsx, which holds
+// the async variant to the twin's outcome on the client. Here: the same
+// markup reaches the page, and the fallback's failure is the next boundary
+// up's (the outer <Errored>'s fallback is drawn), never a blank region.
+describe("hydration parity harness — Errored fallback hole failure (#4316)", () => {
+  const visible = (full: string) =>
+    full
+      .replace(/<script[\s\S]*?<\/script>/g, "")
+      .replace(/<[^>]*>/g, " ")
+      .split(/\s+/)
+      .filter(Boolean)
+      .join(" ");
+  const recorded = new Map<string, string>();
+  for (const o of fallbackHoleFailures) {
+    const name = fallbackHoleFailureName(o);
+    test(name, async () => {
+      const App = fallbackHoleFailure(o);
+      const { shell, rest } = await storage.run(makeEvent(), () => recordStream(() => <App />));
+      writeArtifact(name, { name, shell, rest });
+      recorded.set(name, visible(shell + rest));
+      if (o.caught) expect(rest).toContain("caught: <!--$-->no hint<!--/--></h2>");
+      else expect(rest).not.toContain("caught:");
+      expect(rest).not.toContain("failed:");
+    });
+  }
+  test("the async variant sends what its sync-throw twin sends", () => {
+    for (const o of fallbackHoleFailures) {
+      if (o.hole !== "async") continue;
+      const name = fallbackHoleFailureName(o);
+      const twin = fallbackHoleFailureName({ ...o, hole: "sync" });
+      expect(recorded.get(name), name).toBe(recorded.get(twin));
+    }
+  });
+});

From f14ce8d9576fecd2f8a55c8c27fdf8673f33375a Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 27 Oct 2026 05:54:34 +0000
Subject: [PATCH 2/3] fix(solid): a fragment failing while parked in a pending
 fragment goes to the nearest boundary (#4316)

A <Loading> that failed after the shell while its fragment was parked in
an enclosing <Loading> still pending was settled as a blank region that
reported success. The renderer (web/src/server.ts registerFragment)
parks a settled child into its pending parent and resolves its `_fr`
whether or not it failed. Nothing upstream heard of the failure: the
error was routed only to an <Errored> that could draw at exactly that
position (errorOutcome). The client then hydrated the blank region as
success and halted or drew nothing.

Now the failure is the enclosing fragment's content's, as when the same
read fails in that fragment's own render pass. Handlers get an
escalation mode (ESCALATE, server-internal) for a failure that surfaced
after the render passed them:
- A <Loading> whose fragment is still pending fails it, the way a hole
  failure in its own pass does.
- An <Errored> whose finished markup sits raw in such a fragment renders
  its fallback in place of that markup (FragmentContainer.region): the
  fallback is waited for, its error is serialized once it is finished,
  and its own failure goes up the same way. An <Errored> still pending
  shows the fallback on its next pull, and one already showing its
  fallback absorbs the failure.
- A boundary already settled with a failure absorbs it.
- Otherwise the failure goes to the next boundary up.

The enclosing <Loading> applies the regions to its markup before it
settles, outermost first. If a region is not found, or its fallback never
finishes, that fragment fails with the region's error. This replaces the
`escalating` counter from 7ce3c98d5: an <Errored> fallback that fails
while the server waits for it uses the same mode, so it is drawn one
level up too.

Not covered:
- The late case. If the enclosing fragment settled before the inner read
  failed, its markup is already out. The inner fragment rejects on its own
  and the client renders it, and the client's <Errored> meets the failure,
  unchanged.
- An <Errored> inside a nested fragment that settled into the pending one
  first. Its markup is out of the enclosing fragment's own markup, so the
  enclosing fragment fails instead of drawing.

Tests: parked shapes with an <Errored> between, around the inner
<Loading> with a failing fallback, and around everything, each against a
twin with no inner <Loading> (the failure met in the enclosing pass). The
server harness holds the stream text to the twin's. The hydrate spec,
loaded and streamed, holds the client outcome to the twin's and checks
that the drawn fallback is claimed. Server specs cover the late case and
a nested fragment that settled first.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015hPxMkC3jg3Uivh65gvaf2
---
 .changeset/parked-fragment-failure-4316.md    |   5 +
 packages/solid/src/server/hydration.ts        | 104 +++++++++++-
 packages/solid/src/server/signals.ts          | 150 +++++++++++++++---
 .../parked-fragment-failure-inner-4316.json   |   5 +
 .../parked-fragment-failure-inner-A-4316.json |   5 +
 ...arked-fragment-failure-inner-A-B-4316.json |   5 +
 ...ragment-failure-inner-A-B-caught-4316.json |   5 +
 ...-fragment-failure-inner-A-caught-4316.json |   5 +
 ...ed-fragment-failure-inner-A-late-4316.json |   5 +
 .../parked-fragment-failure-inner-B-4316.json |   5 +
 ...-fragment-failure-inner-B-caught-4316.json |   5 +
 ...ed-fragment-failure-inner-caught-4316.json |   5 +
 ...rked-fragment-failure-inner-late-4316.json |   5 +
 .../parked-fragment-failure-twin-4316.json    |   5 +
 .../parked-fragment-failure-twin-A-4316.json  |   5 +
 ...parked-fragment-failure-twin-A-B-4316.json |   5 +
 ...fragment-failure-twin-A-B-caught-4316.json |   5 +
 ...d-fragment-failure-twin-A-caught-4316.json |   5 +
 .../parked-fragment-failure-twin-B-4316.json  |   5 +
 ...d-fragment-failure-twin-B-caught-4316.json |   5 +
 ...ked-fragment-failure-twin-caught-4316.json |   5 +
 packages/web/test/harness/scenarios.tsx       |  93 +++++++++++
 ...errored-parked-async-outcome-4306.spec.tsx |  86 +++++++++-
 .../test/server/hydration-harness.spec.tsx    |  51 +++++-
 .../parked-fragment-failure-4316.spec.tsx     |  81 ++++++++++
 25 files changed, 625 insertions(+), 35 deletions(-)
 create mode 100644 .changeset/parked-fragment-failure-4316.md
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-late-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-late-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-caught-4316.json
 create mode 100644 packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-caught-4316.json
 create mode 100644 packages/web/test/server/parked-fragment-failure-4316.spec.tsx

diff --git a/.changeset/parked-fragment-failure-4316.md b/.changeset/parked-fragment-failure-4316.md
new file mode 100644
index 0000000000..c6f049192d
--- /dev/null
+++ b/.changeset/parked-fragment-failure-4316.md
@@ -0,0 +1,5 @@
+---
+"solid-js": patch
+---
+
+Server: a `<Loading>` that fails after the shell while its fragment waits inside an outer `<Loading>` that is still pending no longer arrives as a blank region reported as a success. The failure now goes to the nearest enclosing boundary, as it does when the same read fails inside the outer `<Loading>`'s own render. An `<Errored>` between them draws its fallback in the outer fragment, the client adopts it, and its error is serialized with it. With no `<Errored>` between them, the outer fragment fails, and an `<Errored>` whose whole content is that outer `<Loading>` draws its fallback there. This also covers an `<Errored>` fallback that fails in that position. Before, the client hydrated the blank region and either halted or rendered nothing there (#4316).
diff --git a/packages/solid/src/server/hydration.ts b/packages/solid/src/server/hydration.ts
index 25fa95c24a..e2904a30da 100644
--- a/packages/solid/src/server/hydration.ts
+++ b/packages/solid/src/server/hydration.ts
@@ -16,7 +16,11 @@ import {
   onCleanup,
   inServerComponentScope,
   edgeHooks,
-  MAX_RESUME_PASSES
+  MAX_RESUME_PASSES,
+  ESCALATE,
+  fragmentContainer,
+  setFragmentContainer,
+  type FragmentContainer
 } from "./signals.js";
 import { OBSERVE } from "@solidjs/signals";
 import { sharedConfig, NoHydrateContext, callerRenderContext } from "./shared.js";
@@ -155,6 +159,21 @@ function ssrLoadingBoundary(
   (o as any).id = contentId;
 
   let done: ReturnType<HydrationContext["registerFragment"]> | undefined;
+  // This boundary's fragment as the boundaries rendered into it see it
+  // (`FragmentContainer`): open from registration until it settles, and
+  // the descendant `<Errored>` fallbacks to draw in place of their markup
+  // when it does (#4316). `discarded` once it settled with a failure: a
+  // later failure from inside it has nothing left to fail.
+  const container: FragmentContainer = {
+    open: false,
+    region: (from, to, err) => void regions.push({ from, to, err })
+  };
+  let regions: {
+    from: string;
+    to: string | undefined | (() => Promise<string | undefined>);
+    err: any;
+  }[] = [];
+  let discarded = false;
   let handledRenderError: any;
   let retryPromise: Promise<any> | undefined;
 
@@ -406,7 +425,21 @@ function ssrLoadingBoundary(
   // errorOutcome): the fragment settles when it lands.
   function failFragment(err: any, report: boolean, wait?: boolean): boolean | Promise<boolean> {
     const settle = (outcome: Outcome) => {
+      discarded = true;
       outcomeRendered = !!outcome && outcome.value !== undefined && !outcome.escaped;
+      // Parked in an enclosing fragment still pending, with nothing drawn at
+      // this position: the failure is that fragment's content's, as a
+      // failure in its own pass would be (#4316) — the nearest boundary up
+      // meets it there (an `<Errored>` draws its fallback in place of its
+      // markup; else the enclosing fragment fails). Settled first, so this
+      // fragment parks before the enclosing one settles; the boundary that
+      // meets it reports it.
+      if (!outcome && parentHandler && fragmentContainer(parent, true)) {
+        done!(undefined, err);
+        parentHandler(err, ESCALATE);
+        outcomeRendered = true;
+        return true;
+      }
       if (report && !outcomeRendered) {
         reportServerError(
           err,
@@ -428,6 +461,15 @@ function ssrLoadingBoundary(
       o,
       render,
       (err: any, handler, outcome) => {
+        // A failure from inside this boundary's content that surfaced after
+        // its pass (see `ESCALATE`): still pending, the fragment fails with
+        // it; already failed, there is nothing left to fail; otherwise its
+        // content is out or rendered into the enclosing output — up.
+        if (outcome === ESCALATE) {
+          if (container.open) return failOpen(err);
+          if (discarded) return true;
+          return handler ? handler(err, ESCALATE) : undefined;
+        }
         // The outcome question (see errorOutcome) is a `<Loading>`'s to pass
         // up: it owns no fallback for an error.
         if (outcome !== undefined) return handler ? handler(err, outcome) : undefined;
@@ -464,6 +506,44 @@ function ssrLoadingBoundary(
     );
   }
 
+  // An escalated failure fails the fragment while it is still pending, as a
+  // failure in its own pass does (the hole path above); the resume loop
+  // stops at its next wake.
+  function failOpen(err: any): true {
+    container.open = false;
+    discarded = true;
+    const settling = failFragment(err, true, true);
+    const settled = (streamed: boolean) => {
+      if (!outcomeRendered) reportRouted(err, "client");
+      record("error", streamed, err);
+    };
+    settling instanceof Promise ? settling.then(settled) : settled(settling);
+    return true;
+  }
+
+  // The settled markup with each descendant `<Errored>` fallback drawn in
+  // place of its markup (`container.region`), waited for until finished.
+  // Outermost first: a region inside one already replaced has gone with it.
+  // A region not found, or a fallback that never finished, fails the
+  // fragment with the region's error instead (thrown to the caller).
+  async function drawRegions(value: string): Promise<string> {
+    for (let i = 0; i < regions.length; i++) {
+      const r = regions[i];
+      if (typeof r.to === "function") r.to = await r.to();
+      if (!container.open) return value;
+    }
+    const drawn: string[] = [];
+    for (let i = regions.length - 1; i >= 0; i--) {
+      const { from, to, err } = regions[i];
+      const at = value.indexOf(from);
+      if (at < 0 && drawn.some(d => d.includes(from))) continue;
+      if (at < 0 || to === undefined) throw err;
+      value = value.slice(0, at) + to + value.slice(at + from.length);
+      drawn.push(from);
+    }
+    return value;
+  }
+
   // Only ever called from the async resume loop below — there is nothing on
   // the stack to catch a throw from here. The initial (synchronous) discovery
   // pass propagates unhandled errors directly out of runLoadingPhase to the
@@ -561,6 +641,7 @@ function ssrLoadingBoundary(
   function runDiscovery(): SSRTemplateObject | undefined {
     disposeOwner(o, false);
     serializeBuffer = [];
+    regions = [];
     retryPromise = undefined;
     resolveCount = 0;
     passes++;
@@ -672,7 +753,10 @@ function ssrLoadingBoundary(
 
   if (ctx.async) {
     const regOpts = revealGroup ? { revealGroup: revealGroup.id } : undefined;
-    done = ctx.registerFragment(id, regOpts);
+    const settle = ctx.registerFragment(id, regOpts);
+    done = (value, error, escaped) => ((container.open = false), settle(value, error, escaped));
+    container.open = true;
+    setFragmentContainer(o, container);
     let owners = fragmentOwners.get(ctx.registerFragment);
     if (!owners) fragmentOwners.set(ctx.registerFragment, (owners = {}));
     owners[id] = done;
@@ -683,7 +767,11 @@ function ssrLoadingBoundary(
     // registered in the same re-run owns the entry and its reveal slot.
     let disposed = false;
     let superseded = false;
-    onCleanup(() => (disposed = true));
+    onCleanup(() => {
+      disposed = true;
+      container.open = false;
+      setFragmentContainer(o, null);
+    });
     const abandon = () => {
       if (owners![id] !== done) return (superseded = true);
       delete owners![id];
@@ -739,6 +827,7 @@ function ssrLoadingBoundary(
           if (IS_DEV) waits!.start([retryPromise]);
           await retryPromise.catch(() => {});
           if (disposed) return abandon();
+          if (discarded) return;
           if (IS_DEV) waits!.landed();
           ret = runDiscovery();
         }
@@ -750,12 +839,19 @@ function ssrLoadingBoundary(
           if (IS_DEV) waits!.start(pending.p);
           await Promise.all(pending.p).catch(() => {});
           if (disposed) return abandon();
+          if (discarded) return;
           if (IS_DEV) waits!.landed();
           passes++;
           ret = runLoadingPhase(() => resolveIn(() => ctx.ssr(pending.t, ...pending.h))) as any;
         }
         flushSerializeBuffer();
-        const streamed = done!(ret && Array.isArray(ret.t) ? ret.t[0] : ((ret && ret.t) as any));
+        let value = ret && Array.isArray(ret.t) ? ret.t[0] : ((ret && ret.t) as any);
+        if (regions.length) {
+          value = await drawRegions(value);
+          if (disposed) return abandon();
+          if (discarded) return;
+        }
+        const streamed = done!(value);
         record("settled", streamed);
       } catch (err) {
         // A failure whose outcome is still resolving settles when it lands.
diff --git a/packages/solid/src/server/signals.ts b/packages/solid/src/server/signals.ts
index 7fc2e1226f..fdf7dbe86f 100644
--- a/packages/solid/src/server/signals.ts
+++ b/packages/solid/src/server/signals.ts
@@ -3707,10 +3707,70 @@ export function repeat<T>(
  * escapes the component. Outside a server component `outcome` is the
  * asking `<Loading>`'s id, and an `<Errored>` answers only when that
  * Loading is all of its content (#4287).
+ * Called with `ESCALATE` it is handed a failure that surfaced after the
+ * render passed this boundary (no pull of it on the stack), to meet if it
+ * still can: it answers `true` once the failure is met (see `ESCALATE`).
  */
-export type BoundaryErrorHandler = (err: any, outcome?: true | string) => BoundaryOutcome;
-/** A rendered outcome; a function where it is still resolving (see renderOutcome). */
-export type BoundaryOutcome = string | (() => Promise<string | undefined>) | undefined | void;
+export type BoundaryErrorHandler = (
+  err: any,
+  outcome?: true | string | typeof ESCALATE
+) => BoundaryOutcome;
+/**
+ * A rendered outcome; a function where it is still resolving (see
+ * renderOutcome); `true` where an escalated failure was met.
+ */
+export type BoundaryOutcome =
+  | string
+  | (() => Promise<string | undefined>)
+  | true
+  | undefined
+  | void;
+
+/**
+ * The escalation mode of a boundary error handler (#4316): a failure that
+ * surfaced after the render passed the boundaries above it — a `<Loading>`
+ * fragment failing while parked in an enclosing pending fragment, or an
+ * `<Errored>` fallback failing while the server waits for it. Each handler
+ * meets it if its region can still change, else passes it up: a `<Loading>`
+ * whose fragment is still pending fails it (as a failure in its own pass
+ * does); an `<Errored>` whose markup sits raw in such a fragment draws its
+ * fallback there (`FragmentContainer.region`), or, still pending itself,
+ * on its next pull. A boundary whose subtree is already discarded absorbs
+ * it. Answered `undefined` from the root: nothing could meet it. Not part
+ * of the public API (the server entry does not export it).
+ */
+export const ESCALATE: unique symbol = Symbol("escalate") as any;
+
+/**
+ * A pending `<Loading>` fragment, as the `<Errored>` boundaries rendered
+ * raw into it see it: still `open` until it settles, and taking a
+ * descendant `<Errored>`'s fallback (`to`, possibly still resolving) in
+ * place of its markup (`from`) when it does. Failing that — the markup is
+ * not found, or the fallback never finishes — the fragment fails with `err`.
+ * @internal
+ */
+export type FragmentContainer = {
+  open: boolean;
+  region(from: string, to: string | (() => Promise<string | undefined>), err: any): void;
+};
+const containers = /* @__PURE__ */ new WeakMap<object, FragmentContainer>();
+/** @internal A registered `<Loading>`'s content owner and its fragment. */
+export function setFragmentContainer(owner: Owner, container: FragmentContainer | null): void {
+  container ? containers.set(owner, container) : containers.delete(owner);
+}
+/**
+ * @internal The fragment `owner`'s markup is rendered into: the nearest
+ * registered `<Loading>` above it, while still open (`null` once settled —
+ * the markup is out). With `any`, any open one above it: a fragment
+ * settling there is parked in it.
+ */
+export function fragmentContainer(owner: Owner | null, any?: boolean): FragmentContainer | null {
+  for (let n = owner as unknown as SSROwner | null; n; n = n._parent) {
+    const c = containers.get(n);
+    if (c && (c.open || !any)) return c.open ? c : null;
+  }
+  return null;
+}
 
 /**
  * Convergence budget of a boundary's resume loop: each pass should retire at
@@ -3722,12 +3782,6 @@ export type BoundaryOutcome = string | (() => Promise<string | undefined>) | und
  */
 export const MAX_RESUME_PASSES = 10000;
 
-// Set while an `<Errored>` hands a failure of its own fallback up the
-// handler chain as a content failure (see renderOutcome's `escalate`): an
-// enclosing `<Errored>` reached that way while it is not being pulled has
-// no consumer for a fallback, so it lets the failure pass.
-let escalating = 0;
-
 const ErrorContext: Context<BoundaryErrorHandler | null> = {
   id: Symbol("ErrorContext"),
   defaultValue: null
@@ -3778,7 +3832,7 @@ export function runWithBoundaryErrorContext<T>(
   onError: (
     err: any,
     parentHandler: BoundaryErrorHandler | null,
-    outcome?: true | string
+    outcome?: true | string | typeof ESCALATE
   ) => BoundaryOutcome,
   context?: NonNullable<typeof sharedConfig.context>,
   boundaryId?: string
@@ -4311,7 +4365,15 @@ export function createErrorBoundary<T, U>(
   let interceptor = false;
   let pulling = false;
   let torn = false;
+  let fallbackFailed = false;
   let disposed: Promise<void> | undefined;
+  // This boundary's markup as it went into the enclosing output, where it
+  // is finished markup (no hole of it still resolving).
+  const markup = (): string | undefined => {
+    if (!shown || (shown.h && shown.h.length)) return;
+    const t = Array.isArray(shown.t) ? (shown.t.length === 1 ? shown.t[0] : undefined) : shown.t;
+    return typeof t === "string" ? t : undefined;
+  };
   const renderOutcome = (
     err: any,
     outcome: true | string,
@@ -4321,6 +4383,7 @@ export function createErrorBoundary<T, U>(
     if (Array.isArray(t)) t = t[0];
     if (
       !ctx ||
+      fallbackFailed ||
       (outcome === true
         ? !inServerComponentScope(owner as unknown as SSROwner)
         : typeof t !== "string" ||
@@ -4328,6 +4391,39 @@ export function createErrorBoundary<T, U>(
           !t.endsWith(`<!--pl-${outcome}-->`))
     )
       return undefined;
+    return drawFallback(err, outcome, parentHandler);
+  };
+  // A failure handed up after the render passed this boundary (`ESCALATE`,
+  // #4316), met as the boundary's own pull would meet it: the fallback in
+  // place of this boundary's markup. Still pending itself, the boundary is
+  // pulled again and shows it then; finished, rendered raw into a fragment
+  // still pending, the fallback takes its markup's place in that fragment
+  // (drawn as an outcome is: waited for, its error serialized once it is
+  // finished, its own failure the next boundary's). Already showing the
+  // fallback, it absorbs the failure. Otherwise — the markup is out, or its
+  // fallback failed — the next boundary up meets it.
+  const escalated = (err: any, up: BoundaryErrorHandler | null): BoundaryOutcome => {
+    if (ctx && !fallbackFailed) {
+      if (fallbackSettled) return true;
+      if (pending || pulling) return (handleError(err), true);
+      const from = markup();
+      const container = from !== undefined && fragmentContainer(parent);
+      if (container) {
+        const to = drawFallback(err, undefined, up);
+        if (fallbackFailed) return to;
+        container.region(from!, to as string | (() => Promise<string | undefined>), err);
+        return true;
+      }
+    }
+    return up ? up(err, ESCALATE) : undefined;
+  };
+  // Renders the fallback for `err` as an outcome (`outcome`: the asking
+  // position) or in place of this boundary's markup (`undefined`).
+  const drawFallback = (
+    err: any,
+    outcome: true | string | undefined,
+    parentHandler: BoundaryErrorHandler | null
+  ): BoundaryOutcome => {
     // A hole of the fallback that throws while it renders reaches the
     // fallback owner's handler first: hold it for `escalate` instead of
     // letting the parent handler route it from here.
@@ -4335,7 +4431,7 @@ export function createErrorBoundary<T, U>(
       interceptor = true;
       setContext(
         ErrorContext,
-        (e: any, o?: true | string) => {
+        (e: any, o?: true | string | typeof ESCALATE) => {
           if (o === undefined && answering) throw e;
           return parentHandler(e, o);
         },
@@ -4364,21 +4460,23 @@ export function createErrorBoundary<T, U>(
       const t = resolved.t;
       return Array.isArray(t) ? t[0] : t;
     };
+    // The fallback's failure, the next boundary's: asked to draw at the same
+    // position first (an outcome), then handed it as a failure of its
+    // content (`ESCALATE`, whose answer is this one's in place of a
+    // position's: met or not).
     const escalate = (): BoundaryOutcome => {
       const e = failed!.e;
+      fallbackFailed = true;
       deferredWire = undefined;
       if (!parentHandler) return;
-      const answer = parentHandler(e, outcome);
-      if (answer !== undefined) return answer;
-      escalating++;
-      try {
-        parentHandler(e);
-      } catch {
-      } finally {
-        escalating--;
+      if (outcome !== undefined) {
+        const answer = parentHandler(e, outcome);
+        if (answer !== undefined) return answer;
       }
+      const met = parentHandler(e, ESCALATE);
+      if (outcome === undefined) return met;
     };
-    let resolved: any = inCtx(() => ctx.resolve(ctx.escape(handleError(err, true))));
+    let resolved: any = inCtx(() => ctx!.resolve(ctx!.escape(handleError(err, true))));
     if (failed) return escalate();
     if (outcome === true || !resolved || !resolved.h || !resolved.h.length) return finish(resolved);
     disposed ||= new Promise<void>(r =>
@@ -4393,11 +4491,15 @@ export function createErrorBoundary<T, U>(
         // Under the fallback's owner, as it rendered: a hole failing now
         // meets the handler a sync throw did.
         resolved = inCtx(() =>
-          runWithOwner(outputOwner!, () => ctx.ssr(resolved.t, ...resolved.h))
+          runWithOwner(outputOwner!, () => ctx!.ssr(resolved.t, ...resolved.h))
         );
         if (failed) {
           const answer = escalate();
-          return typeof answer === "function" ? answer() : answer;
+          return typeof answer === "function"
+            ? answer()
+            : typeof answer === "string"
+              ? answer
+              : undefined;
         }
       }
       return finish(resolved);
@@ -4421,10 +4523,8 @@ export function createErrorBoundary<T, U>(
         result = ctx
           ? runWithBoundaryErrorContext(owner, resolve, (err, _parent, outcome) => {
               if (err instanceof NotReadyError) throw err;
+              if (outcome === ESCALATE) return escalated(err, _parent);
               if (outcome !== undefined) return renderOutcome(err, outcome, _parent);
-              // Escalated to while not pulled: no consumer for a fallback
-              // (see `escalating`).
-              if (escalating && !pulling) throw err;
               handled = true;
               result = handleError(err);
               throw err;
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-4316.json
new file mode 100644
index 0000000000..dec569994e
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"5000210_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<template id=\"50\" e> </template><script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>($R[13]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);$R[12]($R[10],$R[11]);</script><script>$R[12]($R[6],$R[14]=new Error(\"no hint\"));</script><script>$R[13]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-4316.json
new file mode 100644
index 0000000000..954154ccdf
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-A-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"500020010_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));_$HY.r[\"500020\"]=$R[11];</script><script>($R[13]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);</script><script>$R[12]($R[6],$R[14]=new Error(\"no hint\"));</script><template id=\"50\"><b _hk=50000>outer</b><h2 _hk=5000210>caught: <!--$-->no user 7<!--/--></h2></template><script>$R[13]($R[1],\"outer\");$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[13]($R[10],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-4316.json
new file mode 100644
index 0000000000..b2da8e35bb
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-A-B-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"50002001000_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));</script><script>$R[12]($R[6],$R[13]=new Error(\"no hint\"));_$HY.r[\"500020\"]=$R[13];</script><script>($R[14]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);</script><template id=\"50\"><b _hk=50000>outer</b><h2 _hk=5000210>caught: <!--$-->no hint<!--/--></h2></template><script>$R[14]($R[1],\"outer\");$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[14]($R[10],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-caught-4316.json
new file mode 100644
index 0000000000..ed4e878f14
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-B-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-A-B-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"5000002001000_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));</script><script>$R[12]($R[6],$R[13]=new Error(\"no hint\"));_$HY.r[\"50000020\"]=$R[13];</script><script>($R[14]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);</script><template id=\"5000\"><b _hk=5000000>outer</b><h2 _hk=500000210>caught: <!--$-->no hint<!--/--></h2></template><script>$R[14]($R[1],\"outer\");$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[14]($R[10],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-caught-4316.json
new file mode 100644
index 0000000000..71f0b0b0e8
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-A-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"50000020010_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));_$HY.r[\"50000020\"]=$R[11];</script><script>($R[13]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);</script><script>$R[12]($R[6],$R[14]=new Error(\"no hint\"));</script><template id=\"5000\"><b _hk=5000000>outer</b><h2 _hk=500000210>caught: <!--$-->no user 7<!--/--></h2></template><script>$R[13]($R[1],\"outer\");$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[13]($R[10],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-late-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-late-4316.json
new file mode 100644
index 0000000000..3a7f5989fb
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-A-late-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-A-late-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"500020010_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<template id=\"50\"><b _hk=50000>outer</b><section _hk=50002000><template id=\"pl-500020010\"></template><i _hk=5000200100>loading</i><!--pl-500020010--></section></template><script>($R[11]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[11]($R[10],!0);</script><template id=\"500020010\" e> </template><script>($R[13]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[12]=new Error(\"no user 7\"));$df(\"500020010\");</script><script>$R[13]($R[8],$R[12]);</script><script>$R[13]($R[6],$R[14]=new Error(\"no hint\"));</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-4316.json
new file mode 100644
index 0000000000..870920e8f1
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-B-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"500021000_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));</script><template id=\"50\" e> </template><script>$R[12]($R[6],$R[13]=new Error(\"no hint\"));$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>($R[14]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);$R[12]($R[10],$R[13]);</script><script>$R[14]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-caught-4316.json
new file mode 100644
index 0000000000..018c4c3b63
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-B-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-B-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"50000021000_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));</script><template id=\"5000\" e><h3 _hk=510>outermost: <!--$-->no hint<!--/--></h3></template><script>$R[12]($R[6],$R[13]=new Error(\"no hint\"));_$HY.r[\"50\"]=$R[13];$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>($R[14]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);$R[12]($R[10],$R[13]);</script><script>$R[14]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-caught-4316.json
new file mode 100644
index 0000000000..4980381f73
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"500000210_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<template id=\"5000\" e><h3 _hk=510>outermost: <!--$-->no user 7<!--/--></h3></template><script>($R[12]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[11]=new Error(\"no user 7\"));_$HY.r[\"50\"]=$R[11];$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>($R[13]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[8],!0);$R[12]($R[10],$R[11]);</script><script>$R[12]($R[6],$R[14]=new Error(\"no hint\"));</script><script>$R[13]($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-late-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-late-4316.json
new file mode 100644
index 0000000000..d5423a1fc0
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-inner-late-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-inner-late-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"5000210_fr\"]=$R[7]=($R[8]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[9]=($R[10]=$R[2]()).p;</script>",
+  "rest": "<template id=\"50\"><b _hk=50000>outer</b><section _hk=500020><template id=\"pl-5000210\"></template><i _hk=50002100>loading</i><!--pl-5000210--></section></template><script>($R[11]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[11]($R[10],!0);</script><template id=\"5000210\" e> </template><script>($R[13]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[12]=new Error(\"no user 7\"));$df(\"5000210\");</script><script>$R[13]($R[8],$R[12]);</script><script>$R[13]($R[6],$R[14]=new Error(\"no hint\"));</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-4316.json
new file mode 100644
index 0000000000..11427ae141
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<template id=\"50\" e> </template><script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[10]($R[8],$R[9]);</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));</script><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-4316.json
new file mode 100644
index 0000000000..51db2171dc
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-A-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));_$HY.r[\"500020\"]=$R[9];</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));</script><template id=\"50\"><b _hk=50000>outer</b><h2 _hk=5000210>caught: <!--$-->no user 7<!--/--></h2></template><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[12]($R[8],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-4316.json
new file mode 100644
index 0000000000..aca6f0ff43
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-A-B-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));</script><script>_$HY.r[\"500020010\"]=$R[9];</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));_$HY.r[\"500020\"]=$R[11];</script><template id=\"50\"><b _hk=50000>outer</b><h2 _hk=5000210>caught: <!--$-->no hint<!--/--></h2></template><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[12]($R[8],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-caught-4316.json
new file mode 100644
index 0000000000..7770604d16
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-B-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-A-B-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));</script><script>_$HY.r[\"50000020010\"]=$R[9];</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));_$HY.r[\"50000020\"]=$R[11];</script><template id=\"5000\"><b _hk=5000000>outer</b><h2 _hk=500000210>caught: <!--$-->no hint<!--/--></h2></template><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[12]($R[8],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-caught-4316.json
new file mode 100644
index 0000000000..f9ed93ba9a
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-A-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-A-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));_$HY.r[\"50000020\"]=$R[9];</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));</script><template id=\"5000\"><b _hk=5000000>outer</b><h2 _hk=500000210>caught: <!--$-->no user 7<!--/--></h2></template><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[12]($R[8],!0);</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-4316.json
new file mode 100644
index 0000000000..66c0f4aeac
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-B-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-50\"></template><i _hk=500>outer loading</i><!--pl-50--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"50_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));_$HY.r[\"5000210\"]=$R[9];</script><template id=\"50\" e> </template><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));$df(\"50\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[10]($R[8],$R[11]);</script><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-caught-4316.json
new file mode 100644
index 0000000000..47be9347f1
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-B-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-B-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));_$HY.r[\"500000210\"]=$R[9];</script><template id=\"5000\" e><h3 _hk=510>outermost: <!--$-->no hint<!--/--></h3></template><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));_$HY.r[\"50\"]=$R[11];$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[10]($R[8],$R[11]);</script><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-caught-4316.json b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-caught-4316.json
new file mode 100644
index 0000000000..cd8fdd32bb
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/parked-fragment-failure-twin-caught-4316.json
@@ -0,0 +1,5 @@
+{
+  "name": "parked-fragment-failure-twin-caught-4316",
+  "shell": "<div _hk=3><!--$--><template id=\"pl-5000\"></template><i _hk=50000>outer loading</i><!--pl-5000--><!--/--><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;_$HY.r[\"5000_fr\"]=$R[7]=($R[8]=$R[2]()).p;</script>",
+  "rest": "<template id=\"5000\" e><h3 _hk=510>outermost: <!--$-->no user 7<!--/--></h3></template><script>($R[10]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[9]=new Error(\"no user 7\"));_$HY.r[\"50\"]=$R[9];$df(\"5000\");function $df(e){return _$HY.f?_$HY.f(e):$dfr(e)}function $dfr(e,n,o,t){if(!(n=document.getElementById(e)))return 0;if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dq=_$HY.dq||{})[e]=1,0;for(;o&&(8!==o.nodeType||o.nodeValue!==\"pl-\"+e);)t=o.nextSibling,o.remove(),o=t;t=o.parentNode,(_$HY.v=_$HY.v||{})[e]=n.hasAttribute(\"e\")?[...n.content.childNodes]:1,o.replaceWith(n.content),n.remove(),_$HY.fe(e,t),_$HY.hp&&_$HY.hp[e]&&($dh(_$HY.hp[e]),delete _$HY.hp[e]),$dfd();return 1}function $dfl(e,o,n){if(!(o=document.getElementById(\"pl-\"+e)))return(_$HY.dlq=_$HY.dlq||{})[e]=1,0;if(o._$fl)return 1;for(n=o.nextSibling;n;){if(8===n.nodeType&&n.nodeValue===\"pl-\"+e){o.parentNode&&o.parentNode.insertBefore(o.content.cloneNode(!0),n),o._$fl=1,$dfd();return 1}n=n.nextSibling}return 0}function $dflj(e,i){for(i=0;i<e.length;i++)$dfl(e[i])}function $dfd(e,i){if(e=_$HY.dq){_$HY.dq=0;for(i in e)$df(i)}if(e=_$HY.dlq){_$HY.dlq=0;for(i in e)$dfl(i)}}function $dfs(e,c,d){(_$HY.sc=_$HY.sc||{})[e]=c,d&&((_$HY.sd=_$HY.sd||{})[e]=1)}function $dfg(e,g,i,k){if(!(g=_$HY.sg&&_$HY.sg[e]))return;for(i=0;i<g.length;i++)if(_$HY.sc&&_$HY.sc[g[i]]>0)return;for(i=0;i<g.length;i++)k=g[i],delete _$HY.sg[k],$df(k)}function $dfc(e){if(--_$HY.sc[e]<=0){delete _$HY.sc[e],_$HY.sg&&_$HY.sg[e]?$dfg(e):!(_$HY.sd&&_$HY.sd[e])&&$df(e);_$HY.sd&&delete _$HY.sd[e]}}function $dfj(e,i,n){for(i=0;i<e.length;i++)if(_$HY.sc&&_$HY.sc[e[i]]>0){for(n=0;n<e.length;n++)(_$HY.sg=_$HY.sg||{})[e[n]]=e;return}for(i=0;i<e.length;i++)$df(e[i])}function $dfe(e,t,k){(t=e.target)&&t.getAttribute&&!t._$dc&&(k=t.getAttribute(\"data-dfc\"))&&(t._$dc=1,$dfc(k))}document.addEventListener(\"load\",$dfe,!0);document.addEventListener(\"error\",$dfe,!0);</script><script>$R[10]($R[8],$R[9]);</script><script>$R[10]($R[6],$R[11]=new Error(\"no hint\"));</script><script>($R[12]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");</script>"
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/scenarios.tsx b/packages/web/test/harness/scenarios.tsx
index e8d7226c50..bb2bdb1179 100644
--- a/packages/web/test/harness/scenarios.tsx
+++ b/packages/web/test/harness/scenarios.tsx
@@ -1759,6 +1759,99 @@ export const fallbackHoleFailures: FallbackHoleFailure[] = (["async", "sync"] as
   hole => [false, true].flatMap(parked => [false, true].map(caught => ({ hole, parked, caught })))
 );
 
+// ---------------------------------------------------------------------------
+// #4316 follow-up: a `<Loading>` fragment that fails while parked in an
+// enclosing `<Loading>` still pending (`<b>{outer()}</b>`, 15ms; the inner
+// read rejects at 5ms). Its failure is the enclosing fragment's content's:
+// with an `<Errored>` between (`A`, markup around the position) that
+// Errored's fallback is drawn in the enclosing fragment; with none the
+// enclosing fragment fails (met, with `caught`, by the outermost Errored
+// that is all of its content). `B`: an Errored right around the inner
+// Loading whose fallback itself fails (`hint`, 10ms) — its failure is
+// A's. The `twin` variant has no inner Loading: the read is a hole of the
+// enclosing fragment's own pass, the failure met in that pass — what the
+// parked failure must end as. `late`: the enclosing fragment settles first
+// (2ms), so the inner one streams on its own (no twin).
+export type ParkedFailure = {
+  variant: "inner" | "twin";
+  A: boolean;
+  B: boolean;
+  caught: boolean;
+  late?: boolean;
+};
+export const parkedFailureName = (o: ParkedFailure) =>
+  `parked-fragment-failure-${o.variant}${o.A ? "-A" : ""}${o.B ? "-B" : ""}` +
+  `${o.caught ? "-caught" : ""}${o.late ? "-late" : ""}-4316`;
+export function parkedFailure(o: ParkedFailure) {
+  return function ParkedFragmentFailure() {
+    const outer = createMemo(async () => {
+      await sleep(o.late ? 2 : 15);
+      return "outer";
+    });
+    const user = createMemo(async (): Promise<string> => {
+      await sleep(5);
+      throw new Error("no user 7");
+    });
+    const hint = createMemo(async (): Promise<string> => {
+      await sleep(10);
+      throw new Error("no hint");
+    });
+    const read = () => <span>user:{user()}</span>;
+    const failing = () =>
+      o.variant === "inner" ? <Loading fallback={<i>loading</i>}>{read()}</Loading> : read();
+    const mid = () =>
+      o.B ? (
+        <Errored
+          fallback={(e: any) => (
+            <p>
+              failed: {e().message} {hint()}
+            </p>
+          )}
+        >
+          {failing()}
+        </Errored>
+      ) : (
+        failing()
+      );
+    const region = () =>
+      o.A ? (
+        <Errored fallback={(e: any) => <h2>caught: {e().message}</h2>}>
+          <section>{mid()}</section>
+        </Errored>
+      ) : (
+        <section>{mid()}</section>
+      );
+    const body = () => (
+      <Loading fallback={<i>outer loading</i>}>
+        <b>{outer()}</b>
+        {region()}
+      </Loading>
+    );
+    return (
+      <div>
+        {o.caught ? (
+          <Errored fallback={(e: any) => <h3>outermost: {e().message}</h3>}>{body()}</Errored>
+        ) : (
+          body()
+        )}
+        <span>tail</span>
+      </div>
+    );
+  };
+}
+export const parkedFailures: ParkedFailure[] = (["inner", "twin"] as const).flatMap(variant =>
+  [false, true].flatMap(A =>
+    [false, true].flatMap(B => [false, true].map(caught => ({ variant, A, B, caught })))
+  )
+);
+export const lateParkedFailures: ParkedFailure[] = [false, true].map(A => ({
+  variant: "inner" as const,
+  A,
+  B: false,
+  caught: false,
+  late: true
+}));
+
 // ---------------------------------------------------------------------------
 // #3414: a sync throw the SERVER catches, with a zero-arg fallback thunk
 // (`fallback={() => <Fallback />}`), inside an enclosing boundary. Errored
diff --git a/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx b/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
index bc9e5b5bcd..19ac5409b2 100644
--- a/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
+++ b/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
@@ -36,6 +36,10 @@ import {
   fallbackHoleFailures,
   fallbackHoleFailure,
   fallbackHoleFailureName,
+  parkedFailures,
+  lateParkedFailures,
+  parkedFailure,
+  parkedFailureName,
   type FallbackHoleFailure
 } from "../harness/scenarios.jsx";
 
@@ -121,12 +125,18 @@ type Outcome = {
   claimed: boolean;
 };
 
-async function outcomeOf(o: FallbackHoleFailure, mode: "loaded" | "streamed"): Promise<Outcome> {
-  const name = fallbackHoleFailureName(o);
+const outcomeOf = (o: FallbackHoleFailure, mode: "loaded" | "streamed") =>
+  replay(fallbackHoleFailureName(o), fallbackHoleFailure(o), mode, "h2");
+
+async function replay(
+  name: string,
+  App: () => any,
+  mode: "loaded" | "streamed",
+  claim: string
+): Promise<Outcome> {
   const file = artifact(name);
   expect(existsSync(file)).toBe(true);
   const { shell, rest } = JSON.parse(readFileSync(file, "utf-8"));
-  const App = fallbackHoleFailure(o);
   const container = document.createElement("div");
   document.body.appendChild(container);
   (globalThis as any)._$HY = { events: [], completed: new WeakSet(), r: {}, fe() {} };
@@ -155,7 +165,7 @@ async function outcomeOf(o: FallbackHoleFailure, mode: "loaded" | "streamed"): P
     applyChunk(container, shell, true);
     if (mode === "loaded") applyChunk(container, rest, false);
     const server = mode === "loaded" ? container.innerHTML : undefined;
-    const serverH2 = container.querySelector("h2");
+    const serverH2 = container.querySelector(claim);
     try {
       dispose = hydrate(() => <App />, container);
     } catch {}
@@ -173,7 +183,7 @@ async function outcomeOf(o: FallbackHoleFailure, mode: "loaded" | "streamed"): P
       done: !!(globalThis as any)._$HY.done,
       warnings: warn.mock.calls.length,
       uncaught,
-      claimed: !!serverH2 && container.querySelector("h2") === serverH2
+      claimed: !!serverH2 && container.querySelector(claim) === serverH2
     };
   } finally {
     try {
@@ -220,3 +230,69 @@ describe("#4316: the Errored fallback's own hole fails", () => {
     }
   }
 });
+
+// The #4316 follow-up: a fragment failing while parked in a pending
+// enclosing fragment ends as its twin, the same failure met in the
+// enclosing fragment's own pass: the client claims the fallback the
+// server drew there (an `<Errored>` between, else the outermost one the
+// failed enclosing fragment is all of), or, with none, renders the failed
+// fragment fresh. Hydration ids differ (the twin has no inner Loading), so
+// the server's page is compared as text. Uncontained, the page halts on
+// the client's own rejection: the text it froze at is the client tree's
+// (the inner `<Loading>` shows its fallback, the twin's the outer's), so
+// what is compared is that it halted and on what. Warnings are this
+// variant's alone: the streamed twin with an `<Errored>` around a pending
+// read misses its fallback key while it hydrates the pending fragment (a
+// client id misalignment of that shape, not of the parked failure).
+describe("#4316: a fragment failing while parked in a pending fragment", () => {
+  const comparable = (r: Outcome) => ({
+    ...r,
+    server: r.server === undefined ? undefined : textOfHtml(r.server),
+    text: r.halted ? undefined : r.text,
+    uncaught: [...new Set(r.uncaught)],
+    warnings: undefined
+  });
+  for (const o of parkedFailures) {
+    if (o.variant !== "inner") continue;
+    const claim = o.A ? "h2" : "h3";
+    for (const mode of ["loaded", "streamed"] as const) {
+      test(`${parkedFailureName(o)} [${mode}] ends as its twin`, async () => {
+        const twinOf = { ...o, variant: "twin" as const };
+        const outcome = await replay(parkedFailureName(o), parkedFailure(o), mode, claim);
+        const twin = await replay(parkedFailureName(twinOf), parkedFailure(twinOf), mode, claim);
+        expect(comparable(outcome)).toEqual(comparable(twin));
+        if (o.A || o.caught) {
+          const message = o.B ? "no hint" : "no user 7";
+          expect(outcome.text).toBe(`${o.A ? "outercaught" : "outermost"}: ${message}tail`);
+          expect(outcome.halted).toBe(false);
+          expect(outcome.warnings).toBe(0);
+          expect(outcome.uncaught).toEqual([]);
+          if (mode === "loaded") expect(outcome.claimed).toBe(true);
+        }
+      });
+    }
+  }
+  // Settled first, the enclosing fragment's markup was out before the inner
+  // read failed: its fragment rejects on its own and the client renders it,
+  // where its own `<Errored>` meets the failure.
+  for (const o of lateParkedFailures) {
+    for (const mode of ["loaded", "streamed"] as const) {
+      test(`${parkedFailureName(o)} [${mode}] is the client's to render`, async () => {
+        const outcome = await replay(parkedFailureName(o), parkedFailure(o), mode, "h2");
+        if (o.A) {
+          expect(outcome.text).toBe("outercaught: no user 7tail");
+          expect(outcome.halted).toBe(false);
+          expect(outcome.uncaught).toEqual([]);
+        } else expect(outcome.uncaught).toContain("no user 7");
+        expect(outcome.done).toBe(true);
+      });
+    }
+  }
+});
+
+function textOfHtml(html: string) {
+  const el = document.createElement("div");
+  el.innerHTML = html;
+  el.querySelectorAll("template").forEach(t => t.remove());
+  return el.textContent;
+}
diff --git a/packages/web/test/server/hydration-harness.spec.tsx b/packages/web/test/server/hydration-harness.spec.tsx
index c841bc9283..a5a3ba725b 100644
--- a/packages/web/test/server/hydration-harness.spec.tsx
+++ b/packages/web/test/server/hydration-harness.spec.tsx
@@ -21,7 +21,11 @@ import {
   scenarios,
   fallbackHoleFailures,
   fallbackHoleFailure,
-  fallbackHoleFailureName
+  fallbackHoleFailureName,
+  parkedFailures,
+  lateParkedFailures,
+  parkedFailure,
+  parkedFailureName
 } from "../harness/scenarios.jsx";
 import { recordStream, writeArtifact } from "./artifact-recorder.js";
 
@@ -102,3 +106,48 @@ describe("hydration parity harness — Errored fallback hole failure (#4316)", (
     }
   });
 });
+
+// #4316 follow-up: a fragment failing while parked in a pending enclosing
+// fragment. Recorded for test/hydration/errored-parked-async-outcome-4306
+// .spec.tsx. Here: the stream carries what the twin's does (the failure
+// met in the enclosing fragment's own pass), never the region blank.
+describe("hydration parity harness — fragment failure parked in a pending fragment (#4316)", () => {
+  const visible = (full: string) =>
+    full
+      .replace(/<script[\s\S]*?<\/script>/g, "")
+      .replace(/<[^>]*>/g, " ")
+      .split(/\s+/)
+      .filter(Boolean)
+      .join(" ");
+  const recorded = new Map<string, string>();
+  for (const o of [...parkedFailures, ...lateParkedFailures]) {
+    const name = parkedFailureName(o);
+    test(name, async () => {
+      const App = parkedFailure(o);
+      const { shell, rest } = await storage.run(makeEvent(), () => recordStream(() => <App />));
+      writeArtifact(name, { name, shell, rest });
+      recorded.set(name, visible(shell + rest));
+      if (o.late) {
+        // Settled first, the enclosing fragment's markup is out: the inner
+        // fragment rejects on its own, for the client to render.
+        expect(rest).toMatch(/<template id="[^"]+" e> <\/template>/);
+        return;
+      }
+      // Never the blank region a parked failure used to settle as.
+      expect(rest).not.toMatch(/<section[^>]*><\/section>/);
+      if (o.A)
+        expect(rest).toContain(`caught: <!--$-->${o.B ? "no hint" : "no user 7"}<!--/--></h2>`);
+      else if (o.caught)
+        expect(rest).toContain(`outermost: <!--$-->${o.B ? "no hint" : "no user 7"}<!--/--></h3>`);
+      else expect(rest).toMatch(/<template id="[^"]+" e> <\/template>/);
+    });
+  }
+  test("a parked failure sends what its twin sends", () => {
+    for (const o of parkedFailures) {
+      if (o.variant !== "inner") continue;
+      const name = parkedFailureName(o);
+      const twin = parkedFailureName({ ...o, variant: "twin" });
+      expect(recorded.get(name), name).toBe(recorded.get(twin));
+    }
+  });
+});
diff --git a/packages/web/test/server/parked-fragment-failure-4316.spec.tsx b/packages/web/test/server/parked-fragment-failure-4316.spec.tsx
new file mode 100644
index 0000000000..2e121e6792
--- /dev/null
+++ b/packages/web/test/server/parked-fragment-failure-4316.spec.tsx
@@ -0,0 +1,81 @@
+/**
+ * @jsxImportSource @solidjs/web
+ *
+ * #4316 follow-up: a `<Loading>` fragment failing while parked in an
+ * enclosing fragment still pending, with a nested `<Loading>` that settled
+ * into the enclosing fragment first (the parity shapes are in
+ * test/server/hydration-harness.spec.tsx). The enclosing fragment holds
+ * the failure either way, never a blank region settled as a success:
+ * - the `<Errored>` around the settled nested fragment draws its fallback
+ *   in the enclosing fragment, the settled fragment's markup gone with it;
+ * - an `<Errored>` inside the settled nested fragment has its markup out of
+ *   the enclosing fragment's own (it went in with that fragment's settled
+ *   markup), so the enclosing fragment fails: the client renders it, where
+ *   that `<Errored>` meets the failure.
+ */
+import { describe, expect, test } from "vitest";
+import { Errored, Loading, createMemo } from "solid-js";
+import { recordStream } from "./artifact-recorder.js";
+
+const sleep = (ms: number) => new Promise<void>(r => setTimeout(r, ms));
+
+function App(props: { inside: boolean }) {
+  const outer = createMemo(async () => (await sleep(15), "outer"));
+  const mid = createMemo(async () => (await sleep(2), "mid"));
+  const user = createMemo(async (): Promise<string> => {
+    await sleep(5);
+    throw new Error("no user 7");
+  });
+  // Thunks, so each boundary is created at its position.
+  const errored = (children: () => any) => (
+    <Errored fallback={(e: any) => <h2>caught: {e().message}</h2>}>
+      <section>{children()}</section>
+    </Errored>
+  );
+  const inner = () => (
+    <Loading fallback={<i>loading</i>}>
+      <span>user:{user()}</span>
+    </Loading>
+  );
+  const nested = (children: () => any) => (
+    <Loading fallback={<i>mid loading</i>}>
+      <em>{mid()}</em>
+      {children()}
+    </Loading>
+  );
+  return (
+    <div>
+      <Loading fallback={<i>outer loading</i>}>
+        <b>{outer()}</b>
+        {props.inside ? nested(() => errored(inner)) : errored(() => nested(inner))}
+      </Loading>
+      <span>tail</span>
+    </div>
+  );
+}
+
+const fragments = (rest: string) =>
+  [...rest.matchAll(/<template id="([^"]+)"( e)?>([\s\S]*?)<\/template>/g)].map(m => ({
+    id: m[1],
+    failed: !!m[2],
+    html: m[3]
+  }));
+
+describe("#4316: a parked failure beside a nested fragment that settled first", () => {
+  test("the Errored around the settled fragment draws its fallback in the enclosing one", async () => {
+    const { shell, rest } = await recordStream(() => <App inside={false} />, { onError() {} });
+    const outer = fragments(rest).find(f => shell.includes(`<template id="pl-${f.id}">`))!;
+    expect(outer.failed).toBe(false);
+    expect(outer.html).toContain("caught: <!--$-->no user 7<!--/--></h2>");
+    expect(outer.html).not.toContain("<section");
+    expect(rest).not.toContain("mid</em>");
+  });
+
+  test("an Errored inside the settled fragment: the enclosing fragment fails", async () => {
+    const { shell, rest } = await recordStream(() => <App inside={true} />, { onError() {} });
+    const outer = fragments(rest).find(f => shell.includes(`<template id="pl-${f.id}">`))!;
+    expect(outer.failed).toBe(true);
+    expect(rest).not.toMatch(/<section[^>]*><\/section>/);
+    expect(rest).toContain('new Error("no user 7")');
+  });
+});

From 8692ad90ba548d1562957c34a12fca1a727ed640 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 27 Oct 2026 06:17:45 +0000
Subject: [PATCH 3/3] fix(solid): an Errored fallback failing in the shell goes
 to the enclosing boundary

An `<Errored>` whose fallback failed while rendering (a hole that rejects,
or a synchronous throw) for its content's error was left blank on the
server: the boundary's error handler had already marked the error handled
before rendering the fallback, so the fallback's own failure was dropped
and the pull returned `undefined`. At shell level, with no `<Loading>`,
the shell got a blank region with the errors recorded and no markup for
them; an enclosing `<Errored>` serialized its record but never drew.

The fallback's failure now passes up from the pull: an enclosing
`<Errored>` draws its fallback in place of the region, and with none the
request fails, the same for the async hole and its sync-throw twin.
Server only; client bundles are byte-identical.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015hPxMkC3jg3Uivh65gvaf2
---
 .changeset/errored-fallback-shell-failure.md  |  5 ++
 packages/solid/src/server/signals.ts          | 16 ++++-
 ...ll-fallback-hole-async-failure-A-bare.json |  5 ++
 ...d-shell-fallback-hole-async-failure-A.json |  5 ++
 ...ell-fallback-hole-sync-failure-A-bare.json |  5 ++
 ...ed-shell-fallback-hole-sync-failure-A.json |  5 ++
 packages/web/test/harness/scenarios.tsx       | 67 +++++++++++++++++++
 ...errored-parked-async-outcome-4306.spec.tsx | 41 +++++++++++-
 .../test/server/hydration-harness.spec.tsx    | 56 +++++++++++++++-
 9 files changed, 201 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/errored-fallback-shell-failure.md
 create mode 100644 packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A-bare.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A-bare.json
 create mode 100644 packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A.json

diff --git a/.changeset/errored-fallback-shell-failure.md b/.changeset/errored-fallback-shell-failure.md
new file mode 100644
index 0000000000..10241ac557
--- /dev/null
+++ b/.changeset/errored-fallback-shell-failure.md
@@ -0,0 +1,5 @@
+---
+"solid-js": patch
+---
+
+An `<Errored>` whose fallback fails while rendering (a hole that rejects, or a synchronous throw) now passes that failure to the enclosing boundary on the server, in the shell as well as in a streamed fragment. An outer `<Errored>` draws its fallback in place of the region, and with none the request fails. Before, the region was sent blank, with the errors recorded and no markup for them.
diff --git a/packages/solid/src/server/signals.ts b/packages/solid/src/server/signals.ts
index fdf7dbe86f..b815957f6b 100644
--- a/packages/solid/src/server/signals.ts
+++ b/packages/solid/src/server/signals.ts
@@ -4512,6 +4512,7 @@ export function createErrorBoundary<T, U>(
     () => {
       let result: any;
       let handled = false;
+      let fallbackThrew: { e: any } | undefined;
       // Already showing the fallback for this request. Re-running would
       // allocate new fallback ids and serialize the error again (#3920).
       if (fallbackSettled) return fallbackResult;
@@ -4526,7 +4527,14 @@ export function createErrorBoundary<T, U>(
               if (outcome === ESCALATE) return escalated(err, _parent);
               if (outcome !== undefined) return renderOutcome(err, outcome, _parent);
               handled = true;
-              result = handleError(err);
+              // Kept apart: a failure rendering the fallback is not this
+              // boundary's to handle (see the catch).
+              try {
+                result = handleError(err);
+              } catch (e) {
+                fallbackThrew = { e };
+                throw e;
+              }
               throw err;
             })
           : runWithOwner(owner, fn);
@@ -4535,6 +4543,12 @@ export function createErrorBoundary<T, U>(
         pulling = false;
         if (err instanceof NotReadyError) throw err;
         pending = undefined;
+        // The fallback failed rendering for the content's error: that
+        // failure is the enclosing boundary's, met in its own pull (an outer
+        // `<Errored>` draws its fallback; none, and the request fails), as
+        // when the fallback below throws. Never a blank in this boundary's
+        // place with the failure dropped.
+        if (fallbackThrew) throw fallbackThrew.e;
         result = handled ? result : handleError(err);
       }
       return result;
diff --git a/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A-bare.json b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A-bare.json
new file mode 100644
index 0000000000..92cd73e79a
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A-bare.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-shell-fallback-hole-async-failure-A-bare",
+  "shell": "<div _hk=3><!--$--><h2 _hk=410>caught: <!--$-->no hint<!--/--></h2><!--/--><b>outer</b><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;($R[7]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");($R[9]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[8]=new Error(\"no user 7\"));$R[9]($R[6],$R[10]=new Error(\"no hint\"));_$HY.r[\"4000\"]=$R[8];_$HY.r[\"40\"]=$R[10];</script>",
+  "rest": ""
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A.json b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A.json
new file mode 100644
index 0000000000..1156f2efe9
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-async-failure-A.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-shell-fallback-hole-async-failure-A",
+  "shell": "<div _hk=3><!--$--><h2 _hk=410>caught: <!--$-->no hint<!--/--></h2><!--/--><b>outer</b><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;($R[7]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");($R[9]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[8]=new Error(\"no user 7\"));$R[9]($R[6],$R[10]=new Error(\"no hint\"));_$HY.r[\"40010\"]=$R[8];_$HY.r[\"40\"]=$R[10];</script>",
+  "rest": ""
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A-bare.json b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A-bare.json
new file mode 100644
index 0000000000..21cc3dbc25
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A-bare.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-shell-fallback-hole-sync-failure-A-bare",
+  "shell": "<div _hk=3><!--$--><h2 _hk=410>caught: <!--$-->no hint<!--/--></h2><!--/--><b>outer</b><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;($R[7]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");($R[9]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[8]=new Error(\"no user 7\"));$R[7]($R[6],\"\");_$HY.r[\"4000\"]=$R[8];_$HY.r[\"40\"]=$R[10]=new Error(\"no hint\");</script>",
+  "rest": ""
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A.json b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A.json
new file mode 100644
index 0000000000..d698e79423
--- /dev/null
+++ b/packages/web/test/harness/__artifacts__/errored-shell-fallback-hole-sync-failure-A.json
@@ -0,0 +1,5 @@
+{
+  "name": "errored-shell-fallback-hole-sync-failure-A",
+  "shell": "<div _hk=3><!--$--><h2 _hk=410>caught: <!--$-->no hint<!--/--></h2><!--/--><b>outer</b><span>tail</span></div><script>(self.$R=self.$R||{})[\"\"]=[];_$HY.r[\"0\"]=$R[0]=($R[1]=($R[2]=() => {\n\tconst resolver = {\n\t\tp: 0,\n\t\ts: 0,\n\t\tf: 0\n\t};\n\tresolver.p = new Promise((resolve, reject) => {\n\t\tresolver.s = resolve;\n\t\tresolver.f = reject;\n\t});\n\treturn resolver;\n})()).p;_$HY.r[\"1\"]=$R[3]=($R[4]=$R[2]()).p;_$HY.r[\"2\"]=$R[5]=($R[6]=$R[2]()).p;($R[7]=(resolver, data) => {\n\tresolver.s(data);\n\tresolver.p.s = 1;\n\tresolver.p.v = data;\n})($R[1],\"outer\");($R[9]=(resolver, data) => {\n\tresolver.f(data);\n\tresolver.p.s = 2;\n\tresolver.p.v = data;\n})($R[4],$R[8]=new Error(\"no user 7\"));$R[7]($R[6],\"\");_$HY.r[\"40010\"]=$R[8];_$HY.r[\"40\"]=$R[10]=new Error(\"no hint\");</script>",
+  "rest": ""
+}
\ No newline at end of file
diff --git a/packages/web/test/harness/scenarios.tsx b/packages/web/test/harness/scenarios.tsx
index bb2bdb1179..28b39d7b83 100644
--- a/packages/web/test/harness/scenarios.tsx
+++ b/packages/web/test/harness/scenarios.tsx
@@ -1852,6 +1852,73 @@ export const lateParkedFailures: ParkedFailure[] = [false, true].map(A => ({
   late: true
 }));
 
+// ---------------------------------------------------------------------------
+// The #4316 failure at shell level, no `<Loading>` anywhere: `B`, an
+// `<Errored>` around a read that rejects (5ms), whose fallback's own hole
+// fails too — `hole: "async"` rejects at 10ms, `hole: "sync"` is its twin,
+// a fallback that throws synchronously. The shell waits for both (and for
+// `<b>{outer()}</b>`, 15ms). B's fallback's failure is the next boundary's:
+// with `A`, an `<Errored>` around B (`section`: markup between), A's
+// fallback is drawn in the shell; with none, the request fails — both as
+// the twin does, never a blank region with B's and A's errors recorded and
+// no markup for either.
+export type ShellFallbackFailure = { hole: "async" | "sync"; A: boolean; section: boolean };
+export const shellFallbackFailureName = (o: ShellFallbackFailure) =>
+  `errored-shell-fallback-hole-${o.hole}-failure${o.A ? "-A" : ""}${o.section ? "" : "-bare"}`;
+export function shellFallbackFailure(o: ShellFallbackFailure) {
+  return function ShellFallbackFailure() {
+    const outer = createMemo(async () => {
+      await sleep(15);
+      return "outer";
+    });
+    const user = createMemo(async (): Promise<string> => {
+      await sleep(5);
+      throw new Error("no user 7");
+    });
+    // The twin takes the async memo's owner slot too, so both variants'
+    // hydration keys line up.
+    const slot = createMemo(async (): Promise<string> => {
+      if (o.hole === "sync") return "";
+      await sleep(10);
+      throw new Error("no hint");
+    });
+    const hint =
+      o.hole === "async"
+        ? slot
+        : (): string => {
+            throw new Error("no hint");
+          };
+    const B = () => (
+      <Errored
+        fallback={(e: any) => (
+          <p>
+            failed: {e().message} {hint()}
+          </p>
+        )}
+      >
+        <span>user:{user()}</span>
+      </Errored>
+    );
+    const mid = () => (o.section ? <section>{B()}</section> : B());
+    const region = () =>
+      o.A ? (
+        <Errored fallback={(e: any) => <h2>caught: {e().message}</h2>}>{mid()}</Errored>
+      ) : (
+        mid()
+      );
+    return (
+      <div>
+        {region()}
+        <b>{outer()}</b>
+        <span>tail</span>
+      </div>
+    );
+  };
+}
+export const shellFallbackFailures: ShellFallbackFailure[] = (["async", "sync"] as const).flatMap(
+  hole => [false, true].flatMap(A => [false, true].map(section => ({ hole, A, section })))
+);
+
 // ---------------------------------------------------------------------------
 // #3414: a sync throw the SERVER catches, with a zero-arg fallback thunk
 // (`fallback={() => <Fallback />}`), inside an enclosing boundary. Errored
diff --git a/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx b/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
index 19ac5409b2..32ed1bea23 100644
--- a/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
+++ b/packages/web/test/hydration/errored-parked-async-outcome-4306.spec.tsx
@@ -40,6 +40,9 @@ import {
   lateParkedFailures,
   parkedFailure,
   parkedFailureName,
+  shellFallbackFailures,
+  shellFallbackFailure,
+  shellFallbackFailureName,
   type FallbackHoleFailure
 } from "../harness/scenarios.jsx";
 
@@ -242,8 +245,10 @@ describe("#4316: the Errored fallback's own hole fails", () => {
 // (the inner `<Loading>` shows its fallback, the twin's the outer's), so
 // what is compared is that it halted and on what. Warnings are this
 // variant's alone: the streamed twin with an `<Errored>` around a pending
-// read misses its fallback key while it hydrates the pending fragment (a
-// client id misalignment of that shape, not of the parked failure).
+// read misses its fallback key while it hydrates the pending fragment —
+// the core's retry of the errored read, once the fragment releases, is
+// taken for a client write by readSerializedOrCompute's latched branch,
+// which refetches; #4319's served pass is what keeps that read latched.
 describe("#4316: a fragment failing while parked in a pending fragment", () => {
   const comparable = (r: Outcome) => ({
     ...r,
@@ -290,6 +295,38 @@ describe("#4316: a fragment failing while parked in a pending fragment", () => {
   }
 });
 
+// The same failure at shell level, no `<Loading>`: the outer `<Errored>`
+// caught B's fallback's failure on the server; the client claims its
+// fallback, ending as the sync-throw twin.
+describe("#4316: the Errored fallback's own hole fails in the shell", () => {
+  for (const o of shellFallbackFailures) {
+    if (o.hole !== "async" || !o.A) continue;
+    for (const mode of ["loaded", "streamed"] as const) {
+      test(`${shellFallbackFailureName(o)} [${mode}] ends as its sync-throw twin`, async () => {
+        const twinOf = { ...o, hole: "sync" as const };
+        const outcome = await replay(
+          shellFallbackFailureName(o),
+          shellFallbackFailure(o),
+          mode,
+          "h2"
+        );
+        const twin = await replay(
+          shellFallbackFailureName(twinOf),
+          shellFallbackFailure(twinOf),
+          mode,
+          "h2"
+        );
+        expect(outcome).toEqual(twin);
+        expect(outcome.text).toBe("caught: no hintoutertail");
+        expect(outcome.halted).toBe(false);
+        expect(outcome.warnings).toBe(0);
+        expect(outcome.uncaught).toEqual([]);
+        expect(outcome.claimed).toBe(true);
+      });
+    }
+  }
+});
+
 function textOfHtml(html: string) {
   const el = document.createElement("div");
   el.innerHTML = html;
diff --git a/packages/web/test/server/hydration-harness.spec.tsx b/packages/web/test/server/hydration-harness.spec.tsx
index a5a3ba725b..d6d8a2c4cf 100644
--- a/packages/web/test/server/hydration-harness.spec.tsx
+++ b/packages/web/test/server/hydration-harness.spec.tsx
@@ -25,7 +25,10 @@ import {
   parkedFailures,
   lateParkedFailures,
   parkedFailure,
-  parkedFailureName
+  parkedFailureName,
+  shellFallbackFailures,
+  shellFallbackFailure,
+  shellFallbackFailureName
 } from "../harness/scenarios.jsx";
 import { recordStream, writeArtifact } from "./artifact-recorder.js";
 
@@ -151,3 +154,54 @@ describe("hydration parity harness — fragment failure parked in a pending frag
     }
   });
 });
+
+// The #4316 failure at shell level, no <Loading>: an Errored fallback whose
+// own hole fails, async and its sync-throw twin. Recorded (caught by an
+// outer <Errored>) for test/hydration/errored-parked-async-outcome-4306
+// .spec.tsx. Here: the shell carries what the twin's does — the outer
+// Errored's fallback, never a blank region with the errors recorded and no
+// markup for them — and with no outer Errored the request fails, as the
+// twin's does.
+describe("hydration parity harness — Errored fallback hole failure in the shell", () => {
+  const visible = (full: string) =>
+    full
+      .replace(/<script[\s\S]*?<\/script>/g, "")
+      .replace(/<[^>]*>/g, " ")
+      .split(/\s+/)
+      .filter(Boolean)
+      .join(" ");
+  const recorded = new Map<string, { text: string; errors: string[] }>();
+  for (const o of shellFallbackFailures) {
+    const name = shellFallbackFailureName(o);
+    test(name, async () => {
+      const App = shellFallbackFailure(o);
+      const errors: string[] = [];
+      const { shell, rest } = await storage.run(makeEvent(), () =>
+        recordStream(() => <App />, {
+          onError: (e: unknown) => void errors.push(e instanceof Error ? e.message : String(e))
+        })
+      );
+      recorded.set(name, { text: visible(shell + rest), errors });
+      expect(rest).toBe("");
+      expect(errors).toContain("no hint");
+      if (o.A) {
+        writeArtifact(name, { name, shell, rest });
+        expect(shell).toContain("caught: <!--$-->no hint<!--/--></h2>");
+        expect(shell).toContain("<b>outer</b>");
+        expect(shell).not.toContain("<section");
+        expect(shell).not.toContain("failed:");
+      } else {
+        // B's fallback failed with nothing above it: the request fails.
+        expect(shell).toBe("");
+      }
+    });
+  }
+  test("the async variant sends what its sync-throw twin sends", () => {
+    for (const o of shellFallbackFailures) {
+      if (o.hole !== "async") continue;
+      const name = shellFallbackFailureName(o);
+      const twin = shellFallbackFailureName({ ...o, hole: "sync" });
+      expect(recorded.get(name), name).toEqual(recorded.get(twin));
+    }
+  });
+});