From e4ff4da7c8ac7f25f08c7764fba0d1daf59c56cc Mon Sep 17 00:00:00 2001
From: Vincent Voyer <vincent@codeagain.com>
Date: Fri, 25 Aug 2023 18:25:15 +0200
Subject: [PATCH] fix(DX): More precise error messages for export const config
 deprecation (#54492)
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Before:
```
Error: `export const config` in /vercel/path0/src/app/api/route.js is deprecated. Please change `runtime` property to segment export config. See https://nextjs.org/docs/app/api-reference/file-conventions/route-segment-config
```

After:
```
Error: `export const config` in /vercel/path0/src/app/api/route.js is deprecated:
  - Change `config.runtime…` to `export const runtime = "edge"`
  - Change `config.regions…` to `export const preferredRegion = ["us-east-1"]`
Visit https://nextjs.org/docs/app/api-reference/file-conventions/route-segment-config for more information.
```

The values proposed in Change.. are the actual ones from the customers, they can just copy paste.

Closes NEXT-1560
---
 .../src/build/analysis/get-page-static-info.ts  | 17 ++++++++++++++++-
 .../app/legacy-runtime-config/page.js           |  1 +
 .../index.test.ts                               | 10 ++++++++--
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/packages/next/src/build/analysis/get-page-static-info.ts b/packages/next/src/build/analysis/get-page-static-info.ts
index 9951b583b1..6d6cc421f8 100644
--- a/packages/next/src/build/analysis/get-page-static-info.ts
+++ b/packages/next/src/build/analysis/get-page-static-info.ts
@@ -527,7 +527,22 @@ export async function getPageStaticInfo(params: {
 
     if (pageType === 'app') {
       if (config) {
-        const message = `\`export const config\` in ${pageFilePath} is deprecated. Please change \`runtime\` property to segment export config. See https://nextjs.org/docs/app/api-reference/file-conventions/route-segment-config`
+        let message = `Page config in ${pageFilePath} is deprecated. Replace \`export const config=…\` with the following:`
+
+        if (config.runtime) {
+          message += `\n  - \`export const runtime = ${JSON.stringify(
+            config.runtime
+          )}\``
+        }
+
+        if (config.regions) {
+          message += `\n  - \`export const preferredRegion = ${JSON.stringify(
+            config.regions
+          )}\``
+        }
+
+        message += `\nVisit https://nextjs.org/docs/app/api-reference/file-conventions/route-segment-config for more information.`
+
         if (isDev) {
           Log.warnOnce(message)
         } else {
diff --git a/test/e2e/app-dir-legacy-edge-runtime-config/app/legacy-runtime-config/page.js b/test/e2e/app-dir-legacy-edge-runtime-config/app/legacy-runtime-config/page.js
index 5d8f880535..d1387c9d24 100644
--- a/test/e2e/app-dir-legacy-edge-runtime-config/app/legacy-runtime-config/page.js
+++ b/test/e2e/app-dir-legacy-edge-runtime-config/app/legacy-runtime-config/page.js
@@ -9,4 +9,5 @@ export default function Page() {
 
 export const config = {
   runtime: 'edge',
+  regions: ['us-east-1'],
 }
diff --git a/test/e2e/app-dir-legacy-edge-runtime-config/index.test.ts b/test/e2e/app-dir-legacy-edge-runtime-config/index.test.ts
index 23a1f111c4..628692f9f5 100644
--- a/test/e2e/app-dir-legacy-edge-runtime-config/index.test.ts
+++ b/test/e2e/app-dir-legacy-edge-runtime-config/index.test.ts
@@ -19,9 +19,15 @@ createNextDescribe(
       } else {
         expect(error).toBeDefined()
       }
-      expect(next.cliOutput).toContain('`export const config`')
+
+      expect(next.cliOutput).toContain('Page config in ')
       expect(next.cliOutput).toContain(
-        'app/legacy-runtime-config/page.js is deprecated. Please change `runtime` property to segment export config. See https://nextjs.org/docs/app/api-reference/file-conventions/route-segment-config'
+        // the full path is more complex, we only care about this part
+        'app/legacy-runtime-config/page.js is deprecated. Replace `export const config=…` with the following:'
+      )
+      expect(next.cliOutput).toContain('- `export const runtime = "edge"`')
+      expect(next.cliOutput).toContain(
+        '- `export const preferredRegion = ["us-east-1"]`'
       )
     })
   }