fix(app-router): redirect() returns 307 on document load

packages/vinext/src/build/prerender.ts

@@ -897,12 +897,21 @@ export async function prerenderApp({
 
     rscHandler = (req: Request) => {
       // Forward the request to the local prod server.
+      // `redirect: "manual"` ensures pages that call `redirect()` surface as
+      // their original 3xx response — otherwise fetch follows the Location
+      // header server-side, the prerender harness sees a 200 for the
+      // destination page, and that destination HTML gets written under the
+      // redirecting route's filename. At runtime the prod server then serves
+      // the cached HTML with status 200 instead of emitting a 307 for the
+      // document load. Mirrors the pages-prerender `renderPage` helper above.
+      // See: https://github.com/cloudflare/vinext/issues/1530
       const parsed = new URL(req.url);
       const url = `${baseUrl}${parsed.pathname}${parsed.search}`;
       return fetch(url, {
         method: req.method,
         headers: { ...secretHeaders, ...Object.fromEntries(req.headers.entries()) },
         body: req.method !== "GET" && req.method !== "HEAD" ? req.body : undefined,
+        redirect: "manual",
       });
     };
 

tests/app-router.test.ts

@@ -2440,6 +2440,23 @@ describe("App Router Production server (startProdServer)", () => {
     expect(res.status).toBe(404);
   });
 
+  // Ported from Next.js: test/e2e/app-dir/rsc-redirect/rsc-redirect.test.ts
+  // https://github.com/vercel/next.js/blob/canary/test/e2e/app-dir/rsc-redirect/rsc-redirect.test.ts
+  //
+  // Document request (no `Rsc` header) to a page that calls `redirect()` must
+  // respond with HTTP 307 + Location. The RSC variant (`.rsc` URL or Rsc:1
+  // header) returns 200 with a flight payload — that path is covered by the
+  // sibling `.rsc` redirect tests above and by issue #1347.
+  //
+  // See: https://github.com/cloudflare/vinext/issues/1530
+  it("redirect() from Server Component returns 307 on document load (production)", async () => {
+    const res = await fetch(`${baseUrl}/redirect-test`, { redirect: "manual" });
+    expect(res.status).toBe(307);
+    const location = res.headers.get("location");
+    expect(location).toBeTruthy();
+    expect(location).toContain("/about");
+  });
+
   it("serves static assets with cache headers", async () => {
     // Find an actual hashed asset from the build (on disk under
     // `_next/static/`, matching `resolveAssetsDir("")`).

tests/prerender.test.ts

@@ -927,6 +927,27 @@ describe("prerenderApp — default mode (app-basic)", () => {
     expect(r?.status).toBe("skipped");
   });
 
+  // Ported from Next.js: test/e2e/app-dir/rsc-redirect/rsc-redirect.test.ts
+  // ('should get 307 status code for document request')
+  //
+  // A speculative prerender of a route that calls `redirect()` must not
+  // follow the redirect server-side and cache the destination's HTML under
+  // the redirecting URL. Doing so makes the prod server reply with 200 and
+  // the destination's body on every document request to the redirecting
+  // route, instead of emitting an HTTP 307 with a Location header.
+  //
+  // See: https://github.com/cloudflare/vinext/issues/1530
+  it("skips /redirect-test instead of capturing the destination HTML", () => {
+    const r = findRoute(results, "/redirect-test");
+    expect(r).toBeDefined();
+    expect(r?.status).toBe("skipped");
+    // No HTML/RSC must be written for the redirecting route — otherwise the
+    // prod server serves the cached destination body with status 200 for
+    // every document request to /redirect-test.
+    expect(fs.existsSync(path.join(outDir, "redirect-test.html"))).toBe(false);
+    expect(fs.existsSync(path.join(outDir, "redirect-test.rsc"))).toBe(false);
+  });
+
   // ── API routes — always skipped ────────────────────────────────────────────
 
   it("skips all API route handlers", () => {