[next] fix app dir edge functions with basePath (#10465)

x-ref: https://github.com/vercel/vercel/pull/10394

.changeset/curvy-swans-tickle.md

@@ -0,0 +1,5 @@
+---
+"@vercel/next": patch
+---
+
+Fix Next.js with `basePath` + Edge runtime + App Router on a top level `page.jsx`

packages/next/src/index.ts

@@ -91,6 +91,7 @@ import {
   getOperationType,
   isApiPage,
   getFunctionsConfigManifest,
+  normalizeEdgeFunctionPath,
 } from './utils';
 
 export const version = 2;
@@ -2720,7 +2721,15 @@ async function getServerlessPages(params: {
   for (const edgeFunctionFile of Object.keys(
     middlewareManifest?.functions ?? {}
   )) {
-    const edgePath = (edgeFunctionFile.slice(1) || 'index') + '.js';
+    let edgePath =
+      middlewareManifest?.functions?.[edgeFunctionFile].name ||
+      edgeFunctionFile;
+
+    edgePath = normalizeEdgeFunctionPath(
+      edgePath,
+      params.appPathRoutesManifest || {}
+    );
+    edgePath = (edgePath || 'index') + '.js';
     delete normalizedAppPaths[edgePath];
     delete pages[edgePath];
   }

packages/next/src/server-build.ts

@@ -1245,10 +1245,9 @@ export async function serverBuild({
       if (ogRoute.endsWith('/route')) {
         continue;
       }
-      route = path.posix.join(
+      route = normalizeIndexOutput(
-        './',
+        path.posix.join('./', entryDirectory, route === '/' ? '/index' : route),
-        entryDirectory,
+        true
-        route === '/' ? '/index' : route
       );
 
       if (lambdas[route]) {

packages/next/src/utils.ts

@@ -2344,7 +2344,7 @@ export function normalizeIndexOutput(
   outputName: string,
   isServerMode: boolean
 ) {
-  if (outputName !== '/index' && isServerMode) {
+  if (outputName !== 'index' && outputName !== '/index' && isServerMode) {
     return outputName.replace(/\/index$/, '');
   }
   return outputName;
@@ -2521,6 +2521,29 @@ function normalizeRegions(regions: Regions): undefined | string | string[] {
   return newRegions;
 }
 
+export function normalizeEdgeFunctionPath(
+  shortPath: string,
+  appPathRoutesManifest: Record<string, string>
+) {
+  if (
+    shortPath.startsWith('app/') &&
+    (shortPath.endsWith('/page') ||
+      shortPath.endsWith('/route') ||
+      shortPath === 'app/_not-found')
+  ) {
+    const ogRoute = shortPath.replace(/^app\//, '/');
+    shortPath = (
+      appPathRoutesManifest[ogRoute] ||
+      shortPath.replace(/(^|\/)(page|route)$/, '')
+    ).replace(/^\//, '');
+
+    if (!shortPath || shortPath === '/') {
+      shortPath = 'index';
+    }
+  }
+  return shortPath;
+}
+
 export async function getMiddlewareBundle({
   entryPath,
   outputDirectory,
@@ -2699,27 +2722,19 @@ export async function getMiddlewareBundle({
       //    app/index/page -> index/index
       if (shortPath.startsWith('pages/')) {
         shortPath = shortPath.replace(/^pages\//, '');
-      } else if (
+      } else {
-        shortPath.startsWith('app/') &&
+        shortPath = normalizeEdgeFunctionPath(shortPath, appPathRoutesManifest);
-        (shortPath.endsWith('/page') ||
-          shortPath.endsWith('/route') ||
-          shortPath === 'app/_not-found')
-      ) {
-        const ogRoute = shortPath.replace(/^app\//, '/');
-        shortPath = (
-          appPathRoutesManifest[ogRoute] ||
-          shortPath.replace(/(^|\/)(page|route)$/, '')
-        ).replace(/^\//, '');
-
-        if (!shortPath || shortPath === '/') {
-          shortPath = 'index';
-        }
       }
 
       if (routesManifest?.basePath) {
-        shortPath = path.posix
+        shortPath = normalizeIndexOutput(
-          .join(routesManifest.basePath, shortPath)
+          path.posix.join(
-          .replace(/^\//, '');
+            './',
+            routesManifest?.basePath,
+            shortPath.replace(/^\//, '')
+          ),
+          true
+        );
       }
 
       worker.edgeFunction.name = shortPath;

packages/next/test/integration/edge-app-dir-basepath/app/another/page.js

@@ -0,0 +1,7 @@
+export const runtime = 'edge';
+
+const Home = () => {
+  return <div>another</div>;
+};
+
+export default Home;

packages/next/test/integration/edge-app-dir-basepath/app/dynamic/[slug]/page.js

@@ -0,0 +1,7 @@
+export const runtime = 'edge';
+
+const Home = () => {
+  return <div>dynamic</div>;
+};
+
+export default Home;

packages/next/test/integration/edge-app-dir-basepath/app/layout.js

@@ -0,0 +1,11 @@
+export const runtime = 'edge';
+
+const Layout = ({ children }) => {
+  return (
+    <html>
+      <body>{children}</body>
+    </html>
+  );
+};
+
+export default Layout;

packages/next/test/integration/edge-app-dir-basepath/app/page.js

@@ -0,0 +1,7 @@
+export const runtime = 'edge';
+
+const Home = () => {
+  return <div>Home</div>;
+};
+
+export default Home;

packages/next/test/integration/edge-app-dir-basepath/app/test/page.js

@@ -0,0 +1,7 @@
+export const runtime = 'edge';
+
+const Home = () => {
+  return <div>test</div>;
+};
+
+export default Home;

packages/next/test/integration/edge-app-dir-basepath/next.config.js

@@ -0,0 +1,7 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  reactStrictMode: true,
+  basePath: '/test',
+};
+
+module.exports = nextConfig;

packages/next/test/integration/edge-app-dir-basepath/package.json

@@ -0,0 +1,8 @@
+{
+  "dependencies": {
+    "next": "canary",
+    "react": "latest",
+    "react-dom": "latest"
+  },
+  "ignoreNextjsUpdates": true
+}

packages/next/test/integration/edge-app-dir-basepath/vercel.json

@@ -0,0 +1,4 @@
+{
+  "version": 2,
+  "builds": [{ "src": "package.json", "use": "@vercel/next" }]
+}

packages/next/test/integration/integration-2.test.js

@@ -553,3 +553,52 @@ it('Should de-dupe correctly when limit is close (uncompressed)', async () => {
   expect(lambdas.size).toBe(2);
   expect(lambdas.size).toBeLessThan(totalLambdas);
 });
+
+it('should handle edge functions in app with basePath', async () => {
+  const {
+    buildResult: { output },
+  } = await runBuildLambda(path.join(__dirname, 'edge-app-dir-basepath'));
+
+  console.error(output);
+
+  expect(output['test']).toBeDefined();
+  expect(output['test']).toBeDefined();
+  expect(output['test'].type).toBe('EdgeFunction');
+  expect(output['test'].type).toBe('EdgeFunction');
+
+  expect(output['test/another']).toBeDefined();
+  expect(output['test/another.rsc']).toBeDefined();
+  expect(output['test/another'].type).toBe('EdgeFunction');
+  expect(output['test/another.rsc'].type).toBe('EdgeFunction');
+
+  expect(output['test/dynamic/[slug]']).toBeDefined();
+  expect(output['test/dynamic/[slug].rsc']).toBeDefined();
+  expect(output['test/dynamic/[slug]'].type).toBe('EdgeFunction');
+  expect(output['test/dynamic/[slug].rsc'].type).toBe('EdgeFunction');
+
+  expect(output['test/dynamic/[slug]']).toBeDefined();
+  expect(output['test/dynamic/[slug].rsc']).toBeDefined();
+  expect(output['test/dynamic/[slug]'].type).toBe('EdgeFunction');
+  expect(output['test/dynamic/[slug].rsc'].type).toBe('EdgeFunction');
+
+  expect(output['test/test']).toBeDefined();
+  expect(output['test/test.rsc']).toBeDefined();
+  expect(output['test/test'].type).toBe('EdgeFunction');
+  expect(output['test/test.rsc'].type).toBe('EdgeFunction');
+
+  expect(output['test/_not-found']).toBeDefined();
+  expect(output['test/_not-found'].type).toBe('Lambda');
+
+  const lambdas = new Set();
+  const edgeFunctions = new Set();
+
+  for (const item of Object.values(output)) {
+    if (item.type === 'Lambda') {
+      lambdas.add(item);
+    } else if (item.type === 'EdgeFunction') {
+      edgeFunctions.add(item);
+    }
+  }
+  expect(lambdas.size).toBe(1);
+  expect(edgeFunctions.size).toBe(4);
+});