feat(define-router): support unstable_redirect in server functions

e2e/fixtures/ssr-redirect/src/pages/action.tsx

@@ -0,0 +1,17 @@
+import { unstable_redirect as redirect } from 'waku/router/server';
+
+export default async function ActionPage() {
+  return (
+    <div>
+      <h1>Action Page</h1>
+      <form
+        action={async () => {
+          'use server';
+          redirect('/destination', 303);
+        }}
+      >
+        <button type="submit">Redirect Action</button>
+      </form>
+    </div>
+  );
+}

e2e/ssr-redirect.spec.ts

@@ -39,4 +39,22 @@ test.describe(`ssr-redirect`, () => {
     await page.click("a[href='/async']");
     await expect(page.getByRole('heading')).toHaveText('Destination Page');
   });
+
+  test('navigation in server action', async ({ page }) => {
+    await page.goto(`http://localhost:${port}/action`);
+    await expect(page.getByRole('heading')).toHaveText('Action Page');
+    await page.click('text=Redirect Action');
+    await expect(page.getByRole('heading')).toHaveText('Destination Page');
+  });
+
+  test('navigation in server action (no js)', async ({ browser }) => {
+    const context = await browser.newContext({
+      javaScriptEnabled: false,
+    });
+    const page = await context.newPage();
+    await page.goto(`http://localhost:${port}/action`);
+    await expect(page.getByRole('heading')).toHaveText('Action Page');
+    await page.click('text=Redirect Action');
+    await expect(page.getByRole('heading')).toHaveText('Destination Page');
+  });
 });

packages/waku/src/router/client.ts

@@ -462,24 +462,25 @@ const Redirect = ({
   error,
   to,
   reset,
+  handledErrorSet,
 }: {
   error: unknown;
   to: string;
   reset: () => void;
+  handledErrorSet: WeakSet<object>;
 }) => {
   const router = useContext(RouterContext);
   if (!router) {
     throw new Error('Missing Router');
   }
   const { changeRoute } = router;
-  const handledErrorSet = useRef(new WeakSet());
   useEffect(() => {
     // ensure single re-fetch per server redirection error on StrictMode
     // https://github.com/wakujs/waku/pull/1512
-    if (handledErrorSet.current.has(error as object)) {
+    if (handledErrorSet.has(error as object)) {
       return;
     }
-    handledErrorSet.current.add(error as object);
+    handledErrorSet.add(error as object);
 
     const url = new URL(to, window.location.href);
     // FIXME this condition seems too naive
@@ -511,14 +512,15 @@ const Redirect = ({
           );
         }
       });
-  }, [error, to, reset, changeRoute]);
+  }, [error, to, reset, changeRoute, handledErrorSet]);
   return null;
 };
 
 class CustomErrorHandler extends Component<
   { has404: boolean; children?: ReactNode },
   { error: unknown | null }
 > {
+  private handledErrorSet = new WeakSet();
   constructor(props: { has404: boolean; children?: ReactNode }) {
     super(props);
     this.state = { error: null };
@@ -545,6 +547,7 @@ class CustomErrorHandler extends Component<
           error,
           to: info.location,
           reset: this.reset,
+          handledErrorSet: this.handledErrorSet,
         });
       }
       throw error;

packages/waku/src/router/define-router.ts

@@ -128,7 +128,7 @@ export function unstable_notFound(): never {
 
 export function unstable_redirect(
   location: string,
-  status: 307 | 308 = 307,
+  status: 303 | 307 | 308 = 307,
 ): never {
   throw createCustomError('Redirect', { status, location });
 }
@@ -433,9 +433,27 @@ export function unstable_defineRouter(fns: {
         });
       };
       setRerender(rerender);
-      const value = await input.fn(...input.args);
-      rendered = true;
-      return renderRsc({ ...(await elementsPromise), _value: value });
+      try {
+        const value = await input.fn(...input.args);
+        return renderRsc({ ...(await elementsPromise), _value: value });
+      } catch (e) {
+        const info = getErrorInfo(e);
+        if (info?.location) {
+          const rscPath = encodeRoutePath(info.location);
+          const entries = await getEntries(
+            rscPath,
+            undefined,
+            input.req.headers,
+          );
+          if (!entries) {
+            unstable_notFound();
+          }
+          return renderRsc(entries);
+        }
+        throw e;
+      } finally {
+        rendered = true;
+      }
     }
     const pathConfigItem = await getPathConfigItem(input.pathname);
     if (pathConfigItem?.specs?.isApi && fns.handleApi) {