From 23935e544f9aae729ecf0ad589d9918738556573 Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Mon, 12 Oct 2020 17:16:52 -0500
Subject: [PATCH 1/3] Add i18n items to routes manifest

---
 packages/next/build/index.ts | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/packages/next/build/index.ts b/packages/next/build/index.ts
index 1ddb4f3d3c98..e6542fe97d2a 100644
--- a/packages/next/build/index.ts
+++ b/packages/next/build/index.ts
@@ -306,6 +306,15 @@ export default async function build(
       dataRouteRegex: string
       namedDataRouteRegex?: string
     }>
+    i18n?: {
+      locales: string[]
+      defaultLocale: string[]
+      domains: Array<{
+        domain: string
+        defaultLocale: string
+        locales: string[]
+      }>
+    }
   } = {
     version: 3,
     pages404: true,
@@ -325,6 +334,7 @@ export default async function build(
         }
       }),
     dataRoutes: [],
+    i18n: config.experimental.i18n,
   }
 
   await promises.mkdir(distDir, { recursive: true })

From 7cf7661d8c2aaa96fc46b5033edfd296df8f5a84 Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Wed, 14 Oct 2020 16:08:24 -0500
Subject: [PATCH 2/3] Add error

---
 packages/next/export/index.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/packages/next/export/index.ts b/packages/next/export/index.ts
index cc5f14a7a5ff..318ff6e920fd 100644
--- a/packages/next/export/index.ts
+++ b/packages/next/export/index.ts
@@ -285,6 +285,12 @@ export default async function exportApp(
 
   const { i18n } = nextConfig.experimental
 
+  if (i18n && !options.buildExport) {
+    throw new Error(
+      `i18n support is not compatible with next export. See here for more info on deploying: https://nextjs.org/docs/deployment`
+    )
+  }
+
   // Start the rendering process
   const renderOpts = {
     dir,

From d0d75d4589696345ad7f1998040368d13a2b8f5d Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Wed, 14 Oct 2020 16:53:36 -0500
Subject: [PATCH 3/3] Add tests

---
 packages/next/build/index.ts                  |  2 +-
 .../i18n-support/test/index.test.js           | 25 +++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/packages/next/build/index.ts b/packages/next/build/index.ts
index 96ae19b413b5..dd87c15fede9 100644
--- a/packages/next/build/index.ts
+++ b/packages/next/build/index.ts
@@ -334,7 +334,7 @@ export default async function build(
         }
       }),
     dataRoutes: [],
-    i18n: config.experimental.i18n,
+    i18n: config.experimental.i18n || undefined,
   }
 
   await promises.mkdir(distDir, { recursive: true })
diff --git a/test/integration/i18n-support/test/index.test.js b/test/integration/i18n-support/test/index.test.js
index c34cdc488221..94e4eea25fa9 100644
--- a/test/integration/i18n-support/test/index.test.js
+++ b/test/integration/i18n-support/test/index.test.js
@@ -27,6 +27,31 @@ let appPort
 const locales = ['en-US', 'nl-NL', 'nl-BE', 'nl', 'fr-BE', 'fr', 'en']
 
 function runTests(isDev) {
+  if (!isDev) {
+    it('should add i18n config to routes-manifest', async () => {
+      const routesManifest = await fs.readJSON(
+        join(appDir, '.next/routes-manifest.json')
+      )
+
+      expect(routesManifest.i18n).toEqual({
+        locales: ['en-US', 'nl-NL', 'nl-BE', 'nl', 'fr-BE', 'fr', 'en'],
+        defaultLocale: 'en-US',
+        domains: [
+          {
+            http: true,
+            domain: 'example.be',
+            defaultLocale: 'nl-BE',
+          },
+          {
+            http: true,
+            domain: 'example.fr',
+            defaultLocale: 'fr',
+          },
+        ],
+      })
+    })
+  }
+
   it('should update asPath on the client correctly', async () => {
     for (const check of ['en', 'En']) {
       const browser = await webdriver(appPort, `/${check}`)