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fix(app-router): emit streamed not-found/redirect meta tags in Next.js byte-exact format (#1491) #1651

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Merged
james-elicx merged 1 commit into from
May 28, 2026
Merged

fix(app-router): emit streamed not-found/redirect meta tags in Next.js byte-exact format (#1491) #1651

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11 changes: 8 additions & 3 deletions packages/vinext/src/server/app-ssr-error-meta.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -44,9 +44,14 @@ function renderSsrErrorMetaTag(error: unknown, options: SsrErrorMetaRenderOption

const httpError = parseNextHttpErrorDigest(digest);
if (httpError) {
let html = '<meta name="robots" content="noindex" />';
// Output format matches Next.js's `make-get-server-inserted-html.tsx`,
// which serializes these meta tags via React's HTML renderer. React's
// void-element output uses no space before `/>`, and Next.js tests assert
// on that exact substring (e.g. `'<meta name="robots" content="noindex"/>'`).
// https://github.com/vercel/next.js/blob/canary/packages/next/src/server/app-render/make-get-server-inserted-html.tsx
let html = '<meta name="robots" content="noindex"/>';
if ((options.nodeEnv ?? process.env.NODE_ENV) === "development") {
html += '<meta name="next-error" content="not-found" />';
html += '<meta name="next-error" content="not-found"/>';
}
return html;
}
Expand All @@ -61,7 +66,7 @@ function renderSsrErrorMetaTag(error: unknown, options: SsrErrorMetaRenderOption
delay +
";url=" +
escapeHtmlAttr(location) +
'" />'
'"/>'
);
}

Expand Down
24 changes: 12 additions & 12 deletions tests/app-ssr-error-meta.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -11,29 +11,29 @@ function digestError(digest: string): Error & { digest: string } {
describe("App SSR error meta tags", () => {
it("renders noindex meta tags for streamed notFound and HTTP access fallback errors", () => {
expect(renderSsrErrorMetaTags([digestError("NEXT_NOT_FOUND")])).toBe(
'<meta name="robots" content="noindex" />',
'<meta name="robots" content="noindex"/>',
);

expect(renderSsrErrorMetaTags([digestError("NEXT_HTTP_ERROR_FALLBACK;403")])).toBe(
'<meta name="robots" content="noindex" />',
'<meta name="robots" content="noindex"/>',
);
});

it("renders development next-error metadata for streamed notFound errors", () => {
expect(
renderSsrErrorMetaTags([digestError("NEXT_NOT_FOUND")], { nodeEnv: "development" }),
).toBe(
'<meta name="robots" content="noindex" />' + '<meta name="next-error" content="not-found" />',
'<meta name="robots" content="noindex"/>' + '<meta name="next-error" content="not-found"/>',
);
});

it("renders refresh meta tags for streamed temporary and permanent redirects", () => {
expect(renderSsrErrorMetaTags([digestError("NEXT_REDIRECT;replace;/target;307")])).toBe(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/target" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/target"/>',
);

expect(renderSsrErrorMetaTags([digestError("NEXT_REDIRECT;replace;/target;308")])).toBe(
'<meta id="__next-page-redirect" http-equiv="refresh" content="0;url=/target" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="0;url=/target"/>',
);
});

Expand All @@ -43,30 +43,30 @@ describe("App SSR error meta tags", () => {
basePath: "/docs",
}),
).toBe(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/docs/target?ok=1#done" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/docs/target?ok=1#done"/>',
);

expect(
renderSsrErrorMetaTags([digestError("NEXT_REDIRECT;replace;https%3A%2F%2Fexample.com;307")], {
basePath: "/docs",
}),
).toBe(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=https://example.com" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=https://example.com"/>',
);

expect(
renderSsrErrorMetaTags([digestError("NEXT_REDIRECT;replace;/docs%3Ffrom%3Dcheckout;307")], {
basePath: "/docs",
}),
).toBe(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/docs?from=checkout" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/docs?from=checkout"/>',
);

expect(
renderSsrErrorMetaTags([digestError("NEXT_REDIRECT;replace;/docs%23top;307")], {
basePath: "/docs",
}),
).toBe('<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/docs#top" />');
).toBe('<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/docs#top"/>');
});

it("escapes redirect meta URLs before inserting them into HTML", () => {
Expand All @@ -75,20 +75,20 @@ describe("App SSR error meta tags", () => {
digestError("NEXT_REDIRECT;replace;/target%3Fnext%3D%26%22%3Cscript%3E;307"),
]),
).toBe(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/target?next=&amp;&quot;&lt;script&gt;" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/target?next=&amp;&quot;&lt;script&gt;"/>',
);
});

it("flushes each captured SSR error meta tag once", () => {
const renderer = createSsrErrorMetaRenderer({ nodeEnv: "production" });

renderer.capture(digestError("NEXT_NOT_FOUND"));
expect(renderer.flush()).toBe('<meta name="robots" content="noindex" />');
expect(renderer.flush()).toBe('<meta name="robots" content="noindex"/>');
expect(renderer.flush()).toBe("");

renderer.capture(digestError("NEXT_REDIRECT;replace;/target;307"));
expect(renderer.flush()).toBe(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/target" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/target"/>',
);
expect(renderer.flush()).toBe("");
});
Expand Down
29 changes: 26 additions & 3 deletions tests/nextjs-compat/navigation.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,32 @@ describe("Next.js compat: navigation", () => {
expect(html).toMatch(NOINDEX_META_TAG_RE);
});

// ── Streaming meta tags for not-found / redirect ─────────────
// Ported from Next.js: test/e2e/app-dir/navigation/navigation.test.ts
// https://github.com/vercel/next.js/blob/canary/test/e2e/app-dir/navigation/navigation.test.ts#L732-L772
//
// When notFound() or redirect() is called from inside a Suspense
// boundary, the error surfaces AFTER the shell has already started
// streaming. The response can no longer return a 4xx/3xx status, so
// Next.js communicates the not-found / redirect intent via inline
// <meta> tags injected into the HTML stream. The exact substring is
// asserted in Next.js tests, so vinext must use the same format
// (React's void-element serialization — no space before `/>`).
//
// Source: packages/next/src/server/app-render/make-get-server-inserted-html.tsx

it("notFound() in Suspense streams noindex robots meta tag (exact substring)", async () => {
const { html } = await fetchHtml(baseUrl, "/suspense-notfound-test");
expect(html).toContain('<meta name="robots" content="noindex"/>');
});

it("redirect() in Suspense streams refresh meta tag (exact substring)", async () => {
const { html } = await fetchHtml(baseUrl, "/suspense-redirect-test");
expect(html).toContain(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/about"/>',
);
});

// ── Browser-only tests (documented, not ported) ──────────────
//
// The following tests ALL require Playwright and are N/A for HTTP-level testing:
Expand Down Expand Up @@ -140,7 +166,4 @@ describe("Next.js compat: navigation", () => {
//
// N/A: Metadata await promise during navigation
// Tests async metadata loading during client nav
//
// N/A: Redirect refresh meta tag
// Tests HTML meta refresh tag — would need streaming-specific fixture
});
2 changes: 1 addition & 1 deletion tests/rsc-streaming.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -451,7 +451,7 @@ describe("Tick-buffered RSC streaming (behavioral)", () => {

const shellPos = output.indexOf("<main>shell</main>");
const redirectMetaPos = output.indexOf(
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/redirect/result" />',
'<meta id="__next-page-redirect" http-equiv="refresh" content="1;url=/redirect/result"/>',
);
const boundaryPos = output.indexOf("<template>resolved boundary</template>");

Expand Down
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