From 2aaa1673372f9af9c1bafcd7b0e2f79dff3dd38c Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Thu, 10 Oct 2024 15:00:46 +0200
Subject: [PATCH] add unstable prefix to persistent caching option and force to
 provide an expected level of stability

---
 packages/next/src/build/index.ts                     |  3 ++-
 packages/next/src/server/config-schema.ts            |  4 +++-
 packages/next/src/server/config-shared.ts            |  4 +++-
 .../next/src/server/dev/hot-reloader-turbopack.ts    |  3 ++-
 packages/next/src/server/dev/turbopack-utils.ts      | 12 ++++++++++++
 5 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/packages/next/src/build/index.ts b/packages/next/src/build/index.ts
index eb651d013b0ed..f550398420c37 100644
--- a/packages/next/src/build/index.ts
+++ b/packages/next/src/build/index.ts
@@ -188,6 +188,7 @@ import {
   handlePagesErrorRoute,
   formatIssue,
   isRelevantWarning,
+  isPersistentCachingEnabled,
 } from '../server/dev/turbopack-utils'
 import { TurbopackManifestLoader } from '../server/dev/turbopack/manifest-loader'
 import type { Entrypoints } from '../server/dev/turbopack/types'
@@ -1409,7 +1410,7 @@ export default async function build(
             browserslistQuery: supportedBrowsers.join(', '),
           },
           {
-            persistentCaching: config.experimental.turbo?.persistentCaching,
+            persistentCaching: isPersistentCachingEnabled(config),
             memoryLimit: config.experimental.turbo?.memoryLimit,
           }
         )
diff --git a/packages/next/src/server/config-schema.ts b/packages/next/src/server/config-schema.ts
index f335d83233ef1..19c0d40c10c67 100644
--- a/packages/next/src/server/config-schema.ts
+++ b/packages/next/src/server/config-schema.ts
@@ -391,7 +391,9 @@ export const configSchema: zod.ZodType<NextConfig> = z.lazy(() =>
             resolveExtensions: z.array(z.string()).optional(),
             useSwcCss: z.boolean().optional(),
             treeShaking: z.boolean().optional(),
-            persistentCaching: z.boolean().optional(),
+            persistentCaching: z
+              .union([z.number(), z.literal(false)])
+              .optional(),
             memoryLimit: z.number().optional(),
             moduleIdStrategy: z.enum(['named', 'deterministic']).optional(),
           })
diff --git a/packages/next/src/server/config-shared.ts b/packages/next/src/server/config-shared.ts
index 1bb98ec08579e..cfd0e38c2971d 100644
--- a/packages/next/src/server/config-shared.ts
+++ b/packages/next/src/server/config-shared.ts
@@ -156,8 +156,10 @@ export interface ExperimentalTurboOptions {
 
   /**
    * Enable persistent caching for the turbopack dev server and build.
+   * Need to provide the expected level of stability, otherwise it will fail.
+   * Currently stability level: 1
    */
-  persistentCaching?: boolean
+  unstablePersistentCaching?: number | false
 
   /**
    * Enable tree shaking for the turbopack dev server and build.
diff --git a/packages/next/src/server/dev/hot-reloader-turbopack.ts b/packages/next/src/server/dev/hot-reloader-turbopack.ts
index 4df06edc81bd8..fdda62bcb0915 100644
--- a/packages/next/src/server/dev/hot-reloader-turbopack.ts
+++ b/packages/next/src/server/dev/hot-reloader-turbopack.ts
@@ -60,6 +60,7 @@ import {
   isWellKnownError,
   printNonFatalIssue,
   normalizedPageToTurbopackStructureRoute,
+  isPersistentCachingEnabled,
 } from './turbopack-utils'
 import {
   propagateServerField,
@@ -176,7 +177,7 @@ export async function createHotReloaderTurbopack(
       browserslistQuery: supportedBrowsers.join(', '),
     },
     {
-      persistentCaching: opts.nextConfig.experimental.turbo?.persistentCaching,
+      persistentCaching: isPersistentCachingEnabled(opts.nextConfig),
       memoryLimit: opts.nextConfig.experimental.turbo?.memoryLimit,
     }
   )
diff --git a/packages/next/src/server/dev/turbopack-utils.ts b/packages/next/src/server/dev/turbopack-utils.ts
index 211f5204c3a44..be1c11155e207 100644
--- a/packages/next/src/server/dev/turbopack-utils.ts
+++ b/packages/next/src/server/dev/turbopack-utils.ts
@@ -1159,3 +1159,15 @@ export function normalizedPageToTurbopackStructureRoute(
   }
   return entrypointKey
 }
+
+export function isPersistentCachingEnabled(
+  config: NextConfigComplete
+): boolean {
+  const unstableValue = config.experimental.turbo?.unstablePersistentCaching
+  if (typeof unstableValue === 'number' && unstableValue > 1) {
+    throw new Error(
+      'Persistent caching in this version of Turbopack is not as stable as expected. Upgrade to a newer version of Turbopack to use this feature with the expected stability.'
+    )
+  }
+  return !!unstableValue
+}