fix: allow some recursion for middleware subrequests

packages/next/src/server/web/sandbox/context.ts

@@ -232,6 +232,10 @@ const NativeModuleMap = (() => {
   return new Map(Object.entries(mods))
 })()
 
+export const requestStore = new AsyncLocalStorage<{
+  headers: Headers
+}>()
+
 /**
  * Create a module cache specific for the provided parameters. It includes
  * a runtime context, require cache and paths cache.
@@ -335,6 +339,19 @@ Learn More: https://nextjs.org/docs/messages/edge-dynamic-code-evaluation`),
         }
 
         init.headers = new Headers(init.headers ?? {})
+
+        // Forward subrequest header from incoming request to outgoing request
+        const store = requestStore.getStore()
+        if (
+          store?.headers.has('x-middleware-subrequest') &&
+          !init.headers.has('x-middleware-subrequest')
+        ) {
+          init.headers.set(
+            'x-middleware-subrequest',
+            store.headers.get('x-middleware-subrequest') ?? ''
+          )
+        }
+
         const prevs =
           init.headers.get(`x-middleware-subrequest`)?.split(':') || []
         const value = prevs.concat(options.moduleName).join(':')
@@ -385,6 +402,13 @@ Learn More: https://nextjs.org/docs/messages/edge-dynamic-code-evaluation`),
               : String(input)
           validateURL(url)
           super(url, init)
+
+          const store = requestStore.getStore()
+          if (store) {
+            new Headers(init?.headers).forEach((value, key) => {
+              store.headers.set(key, value)
+            })
+          }
           this.next = init?.next
         }
       }

packages/next/src/server/web/sandbox/sandbox.ts

@@ -1,7 +1,7 @@
 import type { NodejsRequestData, FetchEventResult, RequestData } from '../types'
 import type { EdgeFunctionDefinition } from '../../../build/webpack/plugins/middleware-plugin'
 import type { EdgeRuntime } from 'next/dist/compiled/edge-runtime'
-import { getModuleContext } from './context'
+import { getModuleContext, requestStore } from './context'
 import { requestToBodyStream } from '../../body-streams'
 import { NEXT_RSC_UNION_QUERY } from '../../../client/components/app-router-headers'
 
@@ -82,7 +82,14 @@ export const run = withTaggedErrors(async function runWithTaggedErrors(params) {
   const runtime = await getRuntimeContext(params)
   const subreq = params.request.headers[`x-middleware-subrequest`]
   const subrequests = typeof subreq === 'string' ? subreq.split(':') : []
-  if (subrequests.includes(params.name)) {
+
+  const MAX_RECURSION_DEPTH = 5
+  const depth = subrequests.reduce(
+    (acc, curr) => (curr === params.name ? acc + 1 : acc),
+    0
+  )
+
+  if (depth >= MAX_RECURSION_DEPTH) {
     return {
       waitUntil: Promise.resolve(),
       response: new runtime.context.Response(null, {
@@ -108,17 +115,26 @@ export const run = withTaggedErrors(async function runWithTaggedErrors(params) {
 
   params.request.url = urlInstance.toString()
 
+  const headers = new Headers()
+  for (const [key, value] of Object.entries(params.request.headers)) {
+    headers.set(key, value?.toString() ?? '')
+  }
+
   try {
-    const result = await edgeFunction({
-      request: {
-        ...params.request,
-        body:
-          cloned && requestToBodyStream(runtime.context, KUint8Array, cloned),
-      },
+    let result: FetchEventResult | undefined = undefined
+    await requestStore.run({ headers }, async () => {
+      result = await edgeFunction({
+        request: {
+          ...params.request,
+          body:
+            cloned && requestToBodyStream(runtime.context, KUint8Array, cloned),
+        },
+      })
+      for (const headerName of FORBIDDEN_HEADERS) {
+        result.response.headers.delete(headerName)
+      }
     })
-    for (const headerName of FORBIDDEN_HEADERS) {
-      result.response.headers.delete(headerName)
-    }
+    if (!result) throw new Error('Edge function did not return a response')
     return result
   } finally {
     await params.request.body?.finalize()

test/e2e/app-dir/app-routes-subrequests/app-routes-subrequests.test.ts

@@ -0,0 +1,18 @@
+import { createNextDescribe } from 'e2e-utils'
+
+const bathPath = process.env.BASE_PATH ?? ''
+
+createNextDescribe(
+  'app-routes-subrequests',
+  {
+    files: __dirname,
+    skipDeployment: true,
+  },
+  ({ next }) => {
+    it('shortcuts after 5 subrequests', async () => {
+      expect(JSON.parse(await next.render(bathPath + '/'))).toEqual({
+        count: 5,
+      })
+    })
+  }
+)

test/e2e/app-dir/app-routes-subrequests/app/route.ts

@@ -0,0 +1,11 @@
+import { NextRequest, NextResponse } from 'next/server'
+
+export const runtime = 'edge'
+
+let count = 0
+
+export const GET = async (req: NextRequest) => {
+  await fetch(req.nextUrl)
+  count++
+  return NextResponse.json({ count })
+}

test/e2e/app-dir/app-routes-subrequests/next.config.js

@@ -0,0 +1,10 @@
+/**
+ * @type {import('next').NextConfig}
+ */
+const config = {
+  typescript: {
+    ignoreBuildErrors: true,
+  },
+}
+
+module.exports = config