From bf69d061967667f71582286782f38fe548e30227 Mon Sep 17 00:00:00 2001
From: dvoytenko <dima.voytenko@vercel.com>
Date: Wed, 13 Mar 2024 18:26:34 -0700
Subject: [PATCH] Disable cache in testmode

---
 .../next/src/server/lib/incremental-cache/index.ts | 11 +++++++----
 test/e2e/testmode/testmode.test.ts                 | 14 ++++++++++++--
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/packages/next/src/server/lib/incremental-cache/index.ts b/packages/next/src/server/lib/incremental-cache/index.ts
index f829ae21920b8..58d47c8324197 100644
--- a/packages/next/src/server/lib/incremental-cache/index.ts
+++ b/packages/next/src/server/lib/incremental-cache/index.ts
@@ -66,6 +66,7 @@ export class CacheHandler {
 
 export class IncrementalCache implements IncrementalCacheType {
   dev?: boolean
+  disableForTestmode?: boolean
   cacheHandler?: CacheHandler
   hasCustomCacheHandler: boolean
   prerenderManifest: PrerenderManifest
@@ -142,6 +143,7 @@ export class IncrementalCache implements IncrementalCacheType {
       maxMemoryCacheSize = parseInt(process.env.__NEXT_TEST_MAX_ISR_CACHE, 10)
     }
     this.dev = dev
+    this.disableForTestmode = process.env.NEXT_PRIVATE_TEST_PROXY === 'true'
     // this is a hack to avoid Webpack knowing this is equal to this.minimalMode
     // because we replace this.minimalMode to true in production bundles.
     const minimalModeKey = 'minimalMode'
@@ -441,9 +443,10 @@ export class IncrementalCache implements IncrementalCacheType {
     // we don't leverage the prerender cache in dev mode
     // so that getStaticProps is always called for easier debugging
     if (
-      this.dev &&
-      (ctx.kindHint !== 'fetch' ||
-        this.requestHeaders['cache-control'] === 'no-cache')
+      this.disableForTestmode ||
+      (this.dev &&
+        (ctx.kindHint !== 'fetch' ||
+          this.requestHeaders['cache-control'] === 'no-cache'))
     ) {
       return null
     }
@@ -560,7 +563,7 @@ export class IncrementalCache implements IncrementalCacheType {
       })
     }
 
-    if (this.dev && !ctx.fetchCache) return
+    if (this.disableForTestmode || (this.dev && !ctx.fetchCache)) return
     // FetchCache has upper limit of 2MB per-entry currently
     const itemSize = JSON.stringify(data).length
     if (
diff --git a/test/e2e/testmode/testmode.test.ts b/test/e2e/testmode/testmode.test.ts
index b48129e7c240c..caf0a948823a0 100644
--- a/test/e2e/testmode/testmode.test.ts
+++ b/test/e2e/testmode/testmode.test.ts
@@ -38,11 +38,11 @@ createNextDescribe(
       proxyServer.close()
     })
 
-    const fetchForTest = async (url: string) => {
+    const fetchForTest = async (url: string, testData?: string) => {
       return next.fetch(url, {
         headers: {
           'Next-Test-Proxy-Port': String(proxyServer.port),
-          'Next-Test-Data': 'test1',
+          'Next-Test-Data': testData ?? 'test1',
         },
       })
     }
@@ -53,6 +53,16 @@ createNextDescribe(
         expect(html).toContain('<pre>test1</pre>')
       })
 
+      it('should avoid fetch cache', async () => {
+        const html1 = await (await fetchForTest('/app/rsc-fetch')).text()
+        expect(html1).toContain('<pre>test1</pre>')
+
+        const html2 = await (
+          await fetchForTest('/app/rsc-fetch', 'test2')
+        ).text()
+        expect(html2).toContain('<pre>test2</pre>')
+      })
+
       it('should handle RSC with http.get in serverless function', async () => {
         const html = await (await fetchForTest('/app/rsc-httpget')).text()
         expect(html).toContain('<pre>test1</pre>')