From f8d1ee3a94c81b36938ddd6cee07cdae9a3c0743 Mon Sep 17 00:00:00 2001
From: Janka Uryga <lolzatu2@gmail.com>
Date: Thu, 6 Feb 2025 05:08:19 +0100
Subject: [PATCH 1/2] fix: work around setTimeout memory leak, improve wrappers

---
 .../server/web/sandbox/resource-managers.ts   | 51 +++++++++++++++++--
 1 file changed, 46 insertions(+), 5 deletions(-)

diff --git a/packages/next/src/server/web/sandbox/resource-managers.ts b/packages/next/src/server/web/sandbox/resource-managers.ts
index 29433fb81c097..95113069a1f02 100644
--- a/packages/next/src/server/web/sandbox/resource-managers.ts
+++ b/packages/next/src/server/web/sandbox/resource-managers.ts
@@ -1,10 +1,10 @@
-abstract class ResourceManager<T, K> {
+abstract class ResourceManager<T, Args> {
   private resources: T[] = []
 
-  abstract create(resourceArgs: K): T
+  abstract create(resourceArgs: Args): T
   abstract destroy(resource: T): void
 
-  add(resourceArgs: K) {
+  add(resourceArgs: Args) {
     const resource = this.create(resourceArgs)
     this.resources.push(resource)
     return resource
@@ -27,7 +27,7 @@ class IntervalsManager extends ResourceManager<
 > {
   create(args: Parameters<typeof setInterval>) {
     // TODO: use the edge runtime provided `setInterval` instead
-    return setInterval(...args)[Symbol.toPrimitive]()
+    return webSetIntervalPolyfill(...args)
   }
 
   destroy(interval: number) {
@@ -41,7 +41,7 @@ class TimeoutsManager extends ResourceManager<
 > {
   create(args: Parameters<typeof setTimeout>) {
     // TODO: use the edge runtime provided `setTimeout` instead
-    return setTimeout(...args)[Symbol.toPrimitive]()
+    return webSetTimeoutPolyfill(...args)
   }
 
   destroy(timeout: number) {
@@ -49,5 +49,46 @@ class TimeoutsManager extends ResourceManager<
   }
 }
 
+function webSetIntervalPolyfill<TArgs extends any[]>(
+  callback: (...args: TArgs) => void,
+  ms?: number,
+  ...args: TArgs
+): number {
+  return setInterval(() => {
+    // node's `setInterval` sets `this` to the `Timeout` instance it returned,
+    // but web `setInterval` always sets `this` to `window`
+    // see: https://developer.mozilla.org/en-US/docs/Web/API/Window/setInterval#the_this_problem
+    return callback.apply(globalThis, args)
+  }, ms)[Symbol.toPrimitive]()
+}
+
+function webSetTimeoutPolyfill<TArgs extends any[]>(
+  callback: (...args: TArgs) => void,
+  ms?: number,
+  ...args: TArgs
+): number {
+  const wrappedCallback = () => {
+    try {
+      // node's `setTimeout` sets `this` to the `Timeout` instance it returned,
+      // but web `setTimeout` always sets `this` to `window`
+      // see: https://developer.mozilla.org/en-US/docs/Web/API/Window/setTimeout#the_this_problem
+      return callback.apply(globalThis, args)
+    } finally {
+      // On certain older node versions (<20.16.0, <22.4.0),
+      // a `setTimeout` whose Timeout was converted to a primitive will leak.
+      // See: https://github.com/nodejs/node/issues/53335
+      // We can work around this by explicitly calling `clearTimeout` after the callback runs.
+      clearTimeout(timeout)
+
+      // help the GC a bit by releasing any references we're holding here.
+      timeout = undefined!
+      callback = undefined!
+      args = undefined!
+    }
+  }
+  let timeout = setTimeout(wrappedCallback, ms)
+  return timeout[Symbol.toPrimitive]()
+}
+
 export const intervalsManager = new IntervalsManager()
 export const timeoutsManager = new TimeoutsManager()

From c12aa66f3038f1886080f6e8b0fb1fd05b64d14a Mon Sep 17 00:00:00 2001
From: Janka Uryga <lolzatu2@gmail.com>
Date: Thu, 6 Feb 2025 15:26:06 +0100
Subject: [PATCH 2/2] remove useless undefined stuff

---
 packages/next/src/server/web/sandbox/resource-managers.ts | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/packages/next/src/server/web/sandbox/resource-managers.ts b/packages/next/src/server/web/sandbox/resource-managers.ts
index 95113069a1f02..7a51095d75cf6 100644
--- a/packages/next/src/server/web/sandbox/resource-managers.ts
+++ b/packages/next/src/server/web/sandbox/resource-managers.ts
@@ -79,14 +79,9 @@ function webSetTimeoutPolyfill<TArgs extends any[]>(
       // See: https://github.com/nodejs/node/issues/53335
       // We can work around this by explicitly calling `clearTimeout` after the callback runs.
       clearTimeout(timeout)
-
-      // help the GC a bit by releasing any references we're holding here.
-      timeout = undefined!
-      callback = undefined!
-      args = undefined!
     }
   }
-  let timeout = setTimeout(wrappedCallback, ms)
+  const timeout = setTimeout(wrappedCallback, ms)
   return timeout[Symbol.toPrimitive]()
 }