feat(core): core ErrorBoundary in SSR and CSR

.changeset/devtools-drop-use-error-boundary.md

@@ -0,0 +1,5 @@
+---
+'@qwik.dev/devtools': patch
+---
+
+fix: drop the removed `useErrorBoundary` hook from the devtools hook lists

.changeset/errorboundary-to-core.md

@@ -0,0 +1,6 @@
+---
+'@qwik.dev/core': major
+'@qwik.dev/router': major
+---
+
+feat: `<ErrorBoundary>` moves to `@qwik.dev/core` behind the experimental `errorBoundary` flag and `useErrorBoundary()` is removed. `fallback$` receives `(error, reset)`, `onError$` reports caught errors, and production redacts server-origin errors to a generic message + digest while client-origin errors render as thrown.

.changeset/errored-pages-no-store.md

@@ -0,0 +1,6 @@
+---
+'@qwik.dev/core': minor
+'@qwik.dev/router': patch
+---
+
+feat: `renderToStream` reports a pre-flush `<ErrorBoundary>` catch via `onBeforeFirstFlush`; the router sends `Cache-Control: no-store` for those pages and for error documents.

.changeset/redact-serialized-signal-errors.md

@@ -0,0 +1,5 @@
+---
+'@qwik.dev/core': patch
+---
+
+fix: redact server-origin errors when serializing errored async signals in production

.changeset/suspense-deferral-through-component.md

@@ -0,0 +1,5 @@
+---
+'@qwik.dev/core': patch
+---
+
+fix: show the `Suspense` fallback when a suspending child is wrapped in an `ErrorBoundary`.

.changeset/tidy-moles-smoke.md

@@ -0,0 +1,5 @@
+---
+'@qwik.dev/core': patch
+---
+
+fix: a failed handler chunk import is no longer reported twice for streamed containers

.ruler/skills/qwik-core-development/references/core-notes.md

@@ -127,7 +127,7 @@ When a core value gains serialized state:
 1. Update the serializer and inflater together.
 2. Keep array positions or marker encodings documented in the code that owns them.
 3. Add a round-trip test in `shared/serdes` or the closest subsystem.
-4. Check SSR and client resume behavior when the value affects hydration or streamed state.
+4. Check SSR and client resume behavior when the value affects resumed or streamed state.
 
 For AsyncSignal fields, inspect the serdes tests that deserialize async signals and verify
 concurrency, timeout, stale value, and error/loading state behavior.
@@ -174,6 +174,17 @@ streaming, navigation, or integration with fixture apps. For Qwik e2e, load
 
 Never use `pnpm test.unit` for agent verification in this repo.
 
+## ErrorBoundary (experimental `errorBoundary`)
+
+Keep error state non-enumerable and out of serialized state. Store the raw throw and project it only
+at display sites; redaction is origin-based — the server display redacts in production unless the
+app returns an `Error` from `transformError`; the client display always shows the error as thrown.
+
+Reset must re-render the component that authored projected children. Identify and retain that
+component as soon as SSR error teardown determines it; store its VNode reference only when the
+projection cut prevents the client owner walk. Re-key the highest wrapper below that author so
+normal diffing recreates emptied projected content without projection-wide scheduling.
+
 ## Keep This Reference Fresh
 
 Before finishing a core task, ask:

.ruler/skills/qwik-e2e-verification/SKILL.md

@@ -27,6 +27,10 @@ Use this skill for Playwright e2e work in `e2e/**`. Keep the repo-wide rules fro
 - CLI e2e: `e2e/qwik-cli-e2e/tests/`
 - React integration e2e: `e2e/qwik-react-e2e/tests/`
 
+Apps whose directory names contain `.prod` run in production mode under the shared Qwik dev server.
+Keep exact production-only assertions in those fixtures; regular fixtures must pass after either
+`build.core.dev` or `build.core`.
+
 ## Commands
 
 Main Qwik e2e config uses `--browser`, not Playwright projects:
@@ -58,6 +62,7 @@ pnpm playwright test e2e/qwik-react-e2e/tests/reactify.spec.ts --project=chromiu
 
 Traps:
 
+- The core budget is skipped after `build.core.dev`; run `pnpm build.core` to measure it.
 - `test.e2e.router.ssg.update` regenerates the goldens only; it never touches the budgets, so a
   budget breach survives the update.
 - The update run can exit non-zero because a sibling budget assertion failed, not the golden. "N

e2e/qwik-e2e/apps/e2e/src/components/events/events.tsx

@@ -73,9 +73,9 @@ const EventsParent = component$(() => {
           <a
             href="/"
             preventdefault:click
+            stoppropagation:click
             id="prevent-default-2"
-            onClick$={(ev) => {
-              ev.stopPropagation();
+            onClick$={() => {
               store.countAnchor++;
             }}
           >

e2e/qwik-e2e/apps/e2e/src/components/suspense/ooos.tsx

@@ -9,21 +9,8 @@ import {
   type Signal,
 } from '@qwik.dev/core';
 import { SSRRaw, SSRStream, type SSRStreamWriter } from '@qwik.dev/core/internal';
-
-type OutOfOrderReleaseStore = {
-  resolved: Set<string>;
-  resolvers: Map<string, Set<() => void>>;
-};
-
-const getOutOfOrderReleaseStore = (): OutOfOrderReleaseStore =>
-  ((globalThis as any).__qwikOOOSReleaseStore ||= {
-    resolved: new Set<string>(),
-    resolvers: new Map<string, Set<() => void>>(),
-  });
-
-const getOutOfOrderReleaseKey = (requestId: string, releaseId: string): string => {
-  return `${requestId}:${releaseId}`;
-};
+import { waitForRelease } from '../../../../../utils/release-gate';
+import { WEBKIT_STREAMING_FLUSH } from '../../../../../utils/webkit-flush';
 
 const getSearchParam = (url: string | undefined, name: string): string | null => {
   return url ? new URL(url).searchParams.get(name) : null;
@@ -33,33 +20,14 @@ const waitForOutOfOrderRelease = (
   requestId: string,
   releaseId: string,
   value: JSXOutput
-): Promise<JSXOutput> => {
-  return new Promise<JSXOutput>((resolve) => {
-    const release = () => resolve(value);
-    const store = getOutOfOrderReleaseStore();
-    const key = getOutOfOrderReleaseKey(requestId, releaseId);
-    if (store.resolved.has(key)) {
-      release();
-    } else {
-      let resolvers = store.resolvers.get(key);
-      if (!resolvers) {
-        store.resolvers.set(key, (resolvers = new Set()));
-      }
-      resolvers.add(release);
-    }
-  });
-};
+): Promise<JSXOutput> => waitForRelease(requestId, releaseId).then(() => value);
 
 const escapeHtml = (value: string): string =>
   value.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
 
 const escapeAttr = (value: string): string =>
   escapeHtml(value).replace(/"/g, '&quot;').replace(/'/g, '&#39;');
 
-// WebKit buffers streamed HTML until enough early body content is emitted.
-// https://bugs.webkit.org/show_bug.cgi?id=265386
-const WEBKIT_STREAMING_FLUSH = '\u200b'.repeat(512);
-
 export const OutOfOrderSuspenseRoot = component$(() => {
   const shellCount = useSignal(0);
   const render = useSignal(0);

e2e/qwik-e2e/apps/e2e/tsconfig.json

@@ -18,7 +18,6 @@
     "outDir": "tmp",
     "noEmit": true,
     "types": ["node", "vite/client"],
-    "rootDir": ".",
     "paths": {
       "~/*": ["./src/*"]
     }

e2e/qwik-e2e/apps/error-handling-fragment/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "error-handling-fragment",
+  "description": "Serves the embedded container fragment inlined by the error-handling multi-container route.",
+  "private": true,
+  "type": "module"
+}

e2e/qwik-e2e/apps/error-handling-fragment/src/entry.ssr.tsx

@@ -0,0 +1,11 @@
+import { renderToStream, type RenderToStreamOptions } from '@qwik.dev/core/server';
+import Root from './root';
+
+export default function (opts: RenderToStreamOptions) {
+  return renderToStream(<Root />, {
+    containerTagName: 'container',
+    qwikLoader: { include: 'never' },
+    ...opts,
+    streaming: { ...opts.streaming, outOfOrder: false },
+  });
+}

e2e/qwik-e2e/apps/error-handling-fragment/src/root.tsx

@@ -0,0 +1,37 @@
+import { $, component$, ErrorBoundary, isServer, sync$, type JSXOutput } from '@qwik.dev/core';
+
+// onClick$ here would load a second core copy and re-trip Q30.
+const bumpCount = sync$((_: Event, el: Element) => {
+  const count = el.parentElement!.querySelector('#eb-fallback-count')!;
+  count.textContent = String(Number(count.textContent) + 1);
+});
+
+const FragmentFallback = component$((props: { msg: string }) => (
+  <section id="eb-fallback">
+    <p id="eb-fallback-msg">caught: {props.msg}</p>
+    <button id="eb-fallback-button" onClick$={bumpCount}>
+      Touch fallback
+    </button>
+    <span id="eb-fallback-count">0</span>
+  </section>
+));
+
+const fragmentFallback = $((e: unknown) => (
+  <FragmentFallback msg={String((e as { message?: unknown })?.message ?? e)} />
+));
+
+const FragmentThrower = component$((): JSXOutput => {
+  if (isServer) {
+    throw new Error('fragment boom');
+  }
+  return <span id="eb-fragment-client" />;
+});
+
+export default component$(() => (
+  <ErrorBoundary fallback$={fragmentFallback}>
+    <section id="eb-content">
+      <p>fragment content</p>
+    </section>
+    <FragmentThrower />
+  </ErrorBoundary>
+));

e2e/qwik-e2e/apps/error-handling-fragment/tsconfig.json

@@ -0,0 +1,23 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "target": "ES2020",
+    "module": "ES2022",
+    "lib": ["es2022", "DOM", "WebWorker", "DOM.Iterable"],
+    "jsx": "react-jsx",
+    "jsxImportSource": "@qwik.dev/core",
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "moduleResolution": "Bundler",
+    "esModuleInterop": true,
+    "allowImportingTsExtensions": true,
+    "skipLibCheck": true,
+    "incremental": true,
+    "isolatedModules": true,
+    "outDir": "tmp",
+    "noEmit": true,
+    "types": ["node", "vite/client"],
+    "rootDir": "."
+  }
+}

e2e/qwik-e2e/apps/error-handling.prod/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "error-handling.prod",
+  "description": "Prod-mode (qDev=false) twin of the error-handling router app; re-exports its routes.",
+  "private": true,
+  "type": "module",
+  "__qwik__": {
+    "qwikRouter": true
+  }
+}

e2e/qwik-e2e/apps/error-handling.prod/src/entry.ssr.tsx

@@ -0,0 +1,15 @@
+import { renderToStream, type RenderToStreamOptions } from '@qwik.dev/core/server';
+import Root from '../../error-handling/src/root';
+
+export default function (opts: RenderToStreamOptions) {
+  const url = opts.serverData?.url ? new URL(opts.serverData.url) : undefined;
+  const outOfOrder = url?.searchParams.get('outOfOrder') !== 'false';
+  return renderToStream(<Root />, {
+    base: '/error-handling.prod/build/',
+    ...opts,
+    streaming: {
+      ...opts.streaming,
+      outOfOrder,
+    },
+  });
+}

e2e/qwik-e2e/apps/error-handling.prod/src/root.tsx

@@ -0,0 +1 @@
+export { default } from '../../error-handling/src/root';

e2e/qwik-e2e/apps/error-handling.prod/src/routes/async-error-captured/index.tsx

@@ -0,0 +1 @@
+export { default } from '../../../../error-handling/src/routes/async-error-captured/index';

e2e/qwik-e2e/apps/error-handling.prod/src/routes/basic/index.tsx

@@ -0,0 +1 @@
+export { default } from '../../../../error-handling/src/routes/basic/index';

e2e/qwik-e2e/apps/error-handling.prod/src/routes/csr-event/index.tsx

@@ -0,0 +1 @@
+export { default } from '../../../../error-handling/src/routes/csr-event/index';

e2e/qwik-e2e/apps/error-handling.prod/src/routes/digest-forgery/index.tsx

@@ -0,0 +1 @@
+export { default } from '../../../../error-handling/src/routes/digest-forgery/index';

e2e/qwik-e2e/apps/error-handling.prod/src/routes/layout.tsx

@@ -0,0 +1 @@
+export { default } from '../../../error-handling/src/routes/layout';

e2e/qwik-e2e/apps/error-handling.prod/src/routes/rederive/index.tsx

@@ -0,0 +1 @@
+export { default } from '../../../../error-handling/src/routes/rederive/index';

e2e/qwik-e2e/apps/error-handling.prod/src/routes/reset/index.tsx

@@ -0,0 +1 @@
+export { default } from '../../../../error-handling/src/routes/reset/index';

e2e/qwik-e2e/apps/error-handling.prod/tsconfig.json

@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "target": "ES2020",
+    "module": "ES2022",
+    "lib": ["es2023", "DOM", "WebWorker", "DOM.Iterable"],
+    "jsx": "react-jsx",
+    "jsxImportSource": "@qwik.dev/core",
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "moduleResolution": "Bundler",
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "incremental": true,
+    "isolatedModules": true,
+    "outDir": "tmp",
+    "noEmit": true
+  },
+  "include": ["src", "./*.d.ts", "./*.config.ts"]
+}

e2e/qwik-e2e/apps/error-handling/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "error-handling",
+  "description": "Error-handling e2e app: one route per ErrorBoundary/loader scenario.",
+  "private": true,
+  "type": "module",
+  "__qwik__": {
+    "qwikRouter": true
+  }
+}