From d31615b858aa8abe605924b735c32d80c244aaa9 Mon Sep 17 00:00:00 2001
From: Steven <steven@ceriously.com>
Date: Mon, 25 Oct 2021 22:37:47 -0400
Subject: [PATCH] Special case `Set-Cookie`

---
 packages/next/server/next-server.ts                         | 6 +++++-
 packages/next/server/web/utils.ts                           | 4 ++++
 .../middleware-core/pages/responses/_middleware.js          | 5 +++++
 .../middleware-core/pages/responses/deep/_middleware.js     | 3 +++
 test/integration/middleware-core/test/index.test.js         | 3 ++-
 5 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/packages/next/server/next-server.ts b/packages/next/server/next-server.ts
index cfe3191d4f50601..d9b6b7fb48b049e 100644
--- a/packages/next/server/next-server.ts
+++ b/packages/next/server/next-server.ts
@@ -1164,7 +1164,11 @@ export default class Server {
 
           for (const [key, value] of result.response.headers.entries()) {
             if (key !== 'content-encoding') {
-              res.setHeader(key, value)
+              if (key.toLowerCase() === 'set-cookie') {
+                res.setHeader(key, value.split(', '))
+              } else {
+                res.setHeader(key, value)
+              }
             }
           }
 
diff --git a/packages/next/server/web/utils.ts b/packages/next/server/web/utils.ts
index 57521b9236a97d4..130ad3bc7e21a86 100644
--- a/packages/next/server/web/utils.ts
+++ b/packages/next/server/web/utils.ts
@@ -38,6 +38,10 @@ export function toNodeHeaders(headers?: Headers): NodeHeaders {
   if (headers) {
     for (const [key, value] of headers.entries()) {
       result[key] = value
+      if (key.toLowerCase() === 'set-cookie') {
+        console.log('the value of the cookie header is' + value)
+        result[key] = value.split(', ')
+      }
     }
   }
   return result
diff --git a/test/integration/middleware-core/pages/responses/_middleware.js b/test/integration/middleware-core/pages/responses/_middleware.js
index 03f31e1c251cc81..6329017ec0d6e59 100644
--- a/test/integration/middleware-core/pages/responses/_middleware.js
+++ b/test/integration/middleware-core/pages/responses/_middleware.js
@@ -20,6 +20,11 @@ export async function middleware(request, ev) {
     next.headers.append('x-append-me', 'top')
   }
 
+  // Ensure deep can append to this value
+  if (url.searchParams.get('cookie-me') === 'true') {
+    next.headers.append('set-cookie', 'chocochip')
+  }
+
   // Sends a header
   if (url.pathname === '/responses/header') {
     next.headers.set('x-first-header', 'valid')
diff --git a/test/integration/middleware-core/pages/responses/deep/_middleware.js b/test/integration/middleware-core/pages/responses/deep/_middleware.js
index 296476e9035a392..4d7262838413b75 100644
--- a/test/integration/middleware-core/pages/responses/deep/_middleware.js
+++ b/test/integration/middleware-core/pages/responses/deep/_middleware.js
@@ -6,5 +6,8 @@ export async function middleware(request, _event) {
   if (request.nextUrl.searchParams.get('append-me') === 'true') {
     next.headers.append('x-append-me', 'deep')
   }
+  if (request.nextUrl.searchParams.get('cookie-me') === 'true') {
+    next.headers.append('set-cookie', 'oatmeal')
+  }
   return next
 }
diff --git a/test/integration/middleware-core/test/index.test.js b/test/integration/middleware-core/test/index.test.js
index 480f3f94854e4dd..75ce6db001e67da 100644
--- a/test/integration/middleware-core/test/index.test.js
+++ b/test/integration/middleware-core/test/index.test.js
@@ -329,11 +329,12 @@ function responseTests(locale = '') {
   it(`${locale} should respond with top level headers and override with deep headers`, async () => {
     const res = await fetchViaHTTP(
       context.appPort,
-      `${locale}/responses/deep?nested-header=true&append-me=true`
+      `${locale}/responses/deep?nested-header=true&append-me=true&cookie-me=true`
     )
     expect(res.headers.get('x-nested-header')).toBe('valid')
     expect(res.headers.get('x-deep-header')).toBe('valid')
     expect(res.headers.get('x-append-me')).toBe('top, deep')
+    expect(res.headers.raw()['set-cookie']).toEqual(['chocochip', 'oatmeal'])
   })
 }