Fix middleware experimental trace case (#70372)

This ensures we don't overwrite/copy stale middleware chunks with experimental tracing.
vercel · Sep 23, 2024 · b6a695b · b6a695b
1 parent 17bdfd8
commit b6a695b
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Showing 4 changed files with 44 additions and 7 deletions.
diff --git a/packages/next/src/build/index.ts b/packages/next/src/build/index.ts
@@ -1776,9 +1776,12 @@ export default async function build(
             {
               filter(item) {
                 // we copy page chunks separately to not copy stale entries
-                return !item.match(/^[/\\](pages|app)[/\\]/)
+                return (
+                  !item.startsWith('/middleware.js') &&
+                  !item.match(/^[/\\](pages|app)[/\\]/)
+                )
               },
-              overwrite: true,
+              overwrite: false,
             }
           )
         }

diff --git a/packages/next/src/lib/recursive-copy.ts b/packages/next/src/lib/recursive-copy.ts
@@ -66,11 +66,14 @@ export async function recursiveCopy(
       // we remove the base path (from) and replace \ by / (windows)
       filter(item.replace(from, '').replace(/\\/g, '/'))
     ) {
-      await promises.copyFile(
-        item,
-        target,
-        overwrite ? undefined : COPYFILE_EXCL
-      )
+      await promises
+        .copyFile(item, target, overwrite ? undefined : COPYFILE_EXCL)
+        .catch((err) => {
+          // if overwrite is false we shouldn't fail on EEXIST
+          if (err.code !== 'EEXIST') {
+            throw err
+          }
+        })
       sema.release()
     } else {
       sema.release()

diff --git a/test/e2e/app-dir/app/flying-shuttle.test.ts b/test/e2e/app-dir/app/flying-shuttle.test.ts
@@ -400,5 +400,28 @@ import { nextTestSetup, isNextStart } from 'e2e-utils'
         await next.patchFile(dataPath, originalDataContent)
       }
     })
+
+    it('should have updated middleware on change', async () => {
+      await next.stop()
+
+      const dataPath = 'middleware.js'
+      const originalDataContent = await next.readFile(dataPath)
+
+      try {
+        await next.patchFile(
+          dataPath,
+          originalDataContent.replace(
+            `'x-flying-shuttle': '1'`,
+            `'x-flying-shuttle': '2'`
+          )
+        )
+        await nextStart()
+
+        const res = await next.fetch('/flying-shuttle')
+        expect(res.headers.get('x-flying-shuttle')).toBe('2')
+      } finally {
+        await next.patchFile(dataPath, originalDataContent)
+      }
+    })
   }
 )
diff --git a/test/e2e/app-dir/app/middleware.js b/test/e2e/app-dir/app/middleware.js
@@ -6,6 +6,14 @@ import { NextResponse } from 'next/server'
  * @returns {Promise<NextResponse | undefined>}
  */
 export async function middleware(request) {
+  if (request.nextUrl.pathname === '/flying-shuttle') {
+    return NextResponse.next({
+      headers: {
+        'x-flying-shuttle': '1',
+      },
+    })
+  }
+
   if (request.nextUrl.pathname === '/searchparams-normalization-bug') {
     const headers = new Headers(request.headers)
     headers.set('test', request.nextUrl.searchParams.get('val') || '')