Add /route subpath to metadata static routes (vercel#47030)

Set the output bundle file path to `/<metadata route>/route.js` to align with other custom app routes, in order to make it easier being handled by app routes in both nextjs and vercel

packages/next/src/build/entries.ts

@@ -47,7 +47,7 @@ import { ServerRuntime } from '../../types'
 import { normalizeAppPath } from '../shared/lib/router/utils/app-paths'
 import { encodeMatchers } from './webpack/loaders/next-middleware-loader'
 import { EdgeFunctionLoaderOptions } from './webpack/loaders/next-edge-function-loader'
-import { isAppRouteRoute } from '../lib/is-app-route-route'
+import { isAppRouteRoute, isMetadataRoute } from '../lib/is-app-route-route'
 
 type ObjectValue<T> = T extends { [key: string]: infer V } ? V : never
 
@@ -99,7 +99,7 @@ export function createPagesMapping({
         previousPages[pageKey] = pagePath
       }
 
-      result[pageKey] = normalizePathSep(
+      const normalizedPath = normalizePathSep(
         join(
           pagesType === 'pages'
             ? PAGES_DIR_ALIAS
@@ -109,6 +109,11 @@ export function createPagesMapping({
           pagePath
         )
       )
+
+      // Map metadata routes to /<metadata-route>/route, e.g. /robots.txt/route.
+      // This is to mark it as app route path that could be picked up like other custom app routes.
+      result[isMetadataRoute(pageKey) ? `${pageKey}/route` : pageKey] =
+        normalizedPath
       return result
     },
     {}

packages/next/src/build/webpack/loaders/next-app-loader.ts

@@ -64,17 +64,10 @@ async function createAppRouteCode({
   pagePath: string
   resolver: PathResolver
 }): Promise<string> {
-  // Split based on any specific path separators (both `/` and `\`)...
-  const routeName = name.split('/').pop()!
-  const splittedPath = pagePath.split(/[\\/]/)
-  // Then join all but the last part with the same separator, `/`...
-  const segmentPath = splittedPath.slice(0, -1).join('/')
-  // Then add the `/route` suffix...
-  const matchedPagePath = `${segmentPath}/${routeName}`
-
+  const routePath = pagePath.replace(/[\\/]/, '/')
   // This, when used with the resolver will give us the pathname to the built
   // route handler file.
-  let resolvedPagePath = (await resolver(matchedPagePath))!
+  let resolvedPagePath = (await resolver(routePath))!
 
   if (isMetadataRoute(name)) {
     resolvedPagePath = `next-metadata-route-loader!${resolvedPagePath}`

packages/next/src/lib/is-app-route-route.ts

@@ -1,21 +1,21 @@
-import path from '../shared/lib/isomorphic/path'
-
 export function isAppRouteRoute(route: string): boolean {
   return route.endsWith('/route')
 }
 
 // Match routes that are metadata routes, e.g. /sitemap.xml, /favicon.<ext>, /<icon>.<ext>, etc.
 // TODO-METADATA: support more metadata routes with more extensions
-const staticMetadataRoutes = ['robots.txt', 'sitemap.xml', 'favicon.ico']
+const staticMetadataRoutes = [/robots\.txt/, /sitemap\.xml/, /favicon\.ico/]
 export function isMetadataRoute(route: string): boolean {
   // Remove the 'app/' or '/' prefix, only check the route name since they're only allowed in root app directory
-  const filename = route.replace(/^app\//, '').replace(/^\//, '')
-  return staticMetadataRoutes.includes(filename)
+  const filename = route
+    .replace(/^app\//, '')
+    .replace(/^\//, '')
+    .replace(/\/route$/, '')
+  return staticMetadataRoutes.some((r) => r.test(filename))
 }
 
 // Only match the static metadata files
 // TODO-METADATA: support static metadata files under nested routes folders
 export function isStaticMetadataRoute(resourcePath: string) {
-  const filename = path.basename(resourcePath)
-  return staticMetadataRoutes.includes(filename)
+  return staticMetadataRoutes.some((r) => r.test(resourcePath))
 }

packages/next/src/server/dev/hot-reloader.ts

@@ -763,7 +763,7 @@ export default class HotReloader {
                     absolutePagePath: entryData.absolutePagePath,
                     rootDir: this.dir,
                     buildId: this.buildId,
-                    bundlePath,
+                    bundlePath: bundlePath,
                     config: this.config,
                     isDev: true,
                     page,

test/e2e/app-dir/metadata/app/api/route.ts

@@ -0,0 +1,5 @@
+import { NextResponse } from 'next/server'
+
+export function GET() {
+  return new NextResponse('hello api route')
+}

test/e2e/app-dir/metadata/metadata.test.ts

@@ -7,9 +7,9 @@ createNextDescribe(
   'app dir - metadata',
   {
     files: __dirname,
-    skipDeployment: true,
+    // skipDeployment: true,
   },
-  ({ next, isNextDev }) => {
+  ({ next, isNextDev, isNextStart }) => {
     const getTitle = (browser: BrowserInterface) =>
       browser.elementByCss('title').text()
 
@@ -658,6 +658,20 @@ createNextDescribe(
         const invalidSitemapResponse = await next.fetch('/title/sitemap.xml')
         expect(invalidSitemapResponse.status).toBe(404)
       })
+
+      if (isNextStart) {
+        it('should build favicon.ico as a custom route', async () => {
+          const appPathsManifest = JSON.parse(
+            await next.readFile('.next/server/app-paths-manifest.json')
+          )
+          expect(appPathsManifest['/robots.txt/route']).toBe(
+            'app/robots.txt/route.js'
+          )
+          expect(appPathsManifest['/sitemap.xml/route']).toBe(
+            'app/sitemap.xml/route.js'
+          )
+        })
+      }
     })
 
     describe('react cache', () => {