From e4e7b07aa3bb6b39e94dd14e5c2daa2741594469 Mon Sep 17 00:00:00 2001
From: Steven <steven@ceriously.com>
Date: Thu, 12 May 2022 16:30:48 -0400
Subject: [PATCH 1/2] Fix return type of middleware `req.cookies.get()`

---
 packages/next/server/web/spec-extension/cookies.ts             | 2 +-
 .../middleware-typescript/app/pages/rewrites/_middleware.ts    | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/next/server/web/spec-extension/cookies.ts b/packages/next/server/web/spec-extension/cookies.ts
index 791d0be5cf4b..8dc6cc15aa70 100644
--- a/packages/next/server/web/spec-extension/cookies.ts
+++ b/packages/next/server/web/spec-extension/cookies.ts
@@ -35,7 +35,7 @@ const deserializeCookie = (input: Request | Response): string[] => {
 
 const serializeCookie = (input: string[]) => input.join(', ')
 
-export class Cookies extends Map<string, any> {
+export class Cookies extends Map<string, string> {
   constructor(input?: string | null) {
     const parsedInput = typeof input === 'string' ? cookie.parse(input) : {}
     super(Object.entries(parsedInput))
diff --git a/test/production/middleware-typescript/app/pages/rewrites/_middleware.ts b/test/production/middleware-typescript/app/pages/rewrites/_middleware.ts
index 402ce456671d..441e171245ab 100644
--- a/test/production/middleware-typescript/app/pages/rewrites/_middleware.ts
+++ b/test/production/middleware-typescript/app/pages/rewrites/_middleware.ts
@@ -10,6 +10,9 @@ export const middleware: NextMiddleware = async function (request) {
       const response = NextResponse.rewrite(`/rewrites/${bucket}`)
       response.cookies.set('bucket', bucket, { maxAge: 10 })
       return response
+    } else {
+      // check that `bucket` is type "string", not "any"
+      bucket.toUpperCase()
     }
 
     return NextResponse.rewrite(`/rewrites/${bucket}`)

From 53925159f439ec0dc1e21848d281d5cc16b8a9d7 Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Thu, 12 May 2022 16:07:03 -0500
Subject: [PATCH 2/2] fix build

---
 packages/next/server/web/spec-extension/cookies.ts | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/packages/next/server/web/spec-extension/cookies.ts b/packages/next/server/web/spec-extension/cookies.ts
index 8dc6cc15aa70..e1b06f646ddb 100644
--- a/packages/next/server/web/spec-extension/cookies.ts
+++ b/packages/next/server/web/spec-extension/cookies.ts
@@ -62,6 +62,13 @@ export class NextCookies extends Cookies {
   set = (...args: Parameters<Cookies['set']>) => {
     const isAlreadyAdded = super.has(args[0])
     const store = super.set(...args)
+    const currentCookie = store.get(args[0])
+
+    if (typeof currentCookie !== 'string') {
+      throw new Error(
+        `Invariant: failed to generate cookie for ${JSON.stringify(args)}`
+      )
+    }
 
     if (isAlreadyAdded) {
       const setCookie = serializeCookie(
@@ -73,13 +80,13 @@ export class NextCookies extends Cookies {
       if (setCookie) {
         this.response.headers.set(
           'set-cookie',
-          [store.get(args[0]), setCookie].join(', ')
+          [currentCookie, setCookie].join(', ')
         )
       } else {
-        this.response.headers.set('set-cookie', store.get(args[0]))
+        this.response.headers.set('set-cookie', currentCookie)
       }
     } else {
-      this.response.headers.append('set-cookie', store.get(args[0]))
+      this.response.headers.append('set-cookie', currentCookie)
     }
 
     return store