From dccc763b9e12caab11e88296b82f39af29d6d8e3 Mon Sep 17 00:00:00 2001
From: "Kamat, Trivikram" <16024985+trivikr@users.noreply.github.com>
Date: Mon, 27 Apr 2026 18:07:44 -0700
Subject: [PATCH] fix(cache): allow streamed entries at maxEntrySize limit

Assisted-by: openai:gpt-5.5
Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
---
 lib/cache/memory-cache-store.js               |  2 +-
 lib/cache/sqlite-cache-store.js               |  2 +-
 .../cache-store-test-utils.js                 | 39 +++++++++++++++++++
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/lib/cache/memory-cache-store.js b/lib/cache/memory-cache-store.js
index dba29ae4de9..ea9c6cae7e9 100644
--- a/lib/cache/memory-cache-store.js
+++ b/lib/cache/memory-cache-store.js
@@ -138,7 +138,7 @@ class MemoryCacheStore extends EventEmitter {
 
         entry.size += chunk.byteLength
 
-        if (entry.size >= store.#maxEntrySize) {
+        if (entry.size > store.#maxEntrySize) {
           this.destroy()
         } else {
           entry.body.push(chunk)
diff --git a/lib/cache/sqlite-cache-store.js b/lib/cache/sqlite-cache-store.js
index 9ddbefcac4b..9503bf10287 100644
--- a/lib/cache/sqlite-cache-store.js
+++ b/lib/cache/sqlite-cache-store.js
@@ -325,7 +325,7 @@ module.exports = class SqliteCacheStore {
       write (chunk, encoding, callback) {
         size += chunk.byteLength
 
-        if (size < store.#maxEntrySize) {
+        if (size <= store.#maxEntrySize) {
           body.push(chunk)
         } else {
           this.destroy()
diff --git a/test/cache-interceptor/cache-store-test-utils.js b/test/cache-interceptor/cache-store-test-utils.js
index 54616b89744..4d5d44fe329 100644
--- a/test/cache-interceptor/cache-store-test-utils.js
+++ b/test/cache-interceptor/cache-store-test-utils.js
@@ -108,6 +108,45 @@ function cacheStoreTests (CacheStore, options) {
       }
     })
 
+    test('caches streamed body at maxEntrySize boundary', options, async () => {
+      /**
+       * @type {import('../../types/cache-interceptor.d.ts').default.CacheKey}
+       */
+      const key = {
+        origin: 'localhost',
+        path: '/',
+        method: 'GET',
+        headers: {}
+      }
+
+      /**
+       * @type {import('../../types/cache-interceptor.d.ts').default.CacheValue}
+       */
+      const value = {
+        statusCode: 200,
+        statusMessage: '',
+        headers: { foo: 'bar' },
+        cacheControlDirectives: {},
+        cachedAt: Date.now(),
+        staleAt: Date.now() + 10000,
+        deleteAt: Date.now() + 20000
+      }
+
+      const body = [Buffer.from('asd'), Buffer.from('123')]
+      const store = new CacheStore({ maxEntrySize: 6 })
+      const writable = store.createWriteStream(key, value)
+
+      notEqual(writable, undefined)
+
+      const finished = once(writable, 'finish')
+      writeBody(writable, body)
+      await finished
+
+      const result = await store.get(structuredClone(key))
+      notEqual(result, undefined)
+      await compareGetResults(result, value, body)
+    })
+
     test('returns stale response before deleteAt', options, async () => {
       const clock = FakeTimers.install({
         shouldClearNativeTimers: true