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lib: disable default memory leak warning for AbortSignal · nodejs/node@81c94a3 · GitHub

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Commit 81c94a3

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phryneas
authored and
ruyadorno
committed
lib: disable default memory leak warning for AbortSignal
This change sets the default `kMaxEventTargetListeners` property for `AbortSignal` instances to 0, disabling the check per default, to enable users to write isomorphic library code. If desirable, the max event target listeners check can still be enabled for individual `AbortSignal` instances by calling `setMaxListeners` on them. Refs: #54758 PR-URL: #55816 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
1 parent 381e705 commit 81c94a3

3 files changed

Lines changed: 29 additions & 11 deletions

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‎doc/api/events.md‎

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@@ -1171,6 +1171,10 @@ that a "possible EventEmitter memory leak" has been detected. For any single
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`EventEmitter`, the `emitter.getMaxListeners()` and `emitter.setMaxListeners()`
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methods can be used to temporarily avoid this warning:
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`defaultMaxListeners` has no effect on `AbortSignal` instances. While it is
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still possible to use [`emitter.setMaxListeners(n)`][] to set a warning limit
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for individual `AbortSignal` instances, per default `AbortSignal` instances will not warn.
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```mjs
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import { EventEmitter } from 'node:events';
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const emitter = new EventEmitter();

‎lib/internal/abort_controller.js‎

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@@ -28,6 +28,7 @@ const {
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kResistStopPropagation,
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kWeakHandler,
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} = require('internal/event_target');
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const { kMaxEventTargetListeners } = require('events');
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const {
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customInspectSymbol,
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kEmptyObject,
@@ -165,6 +166,7 @@ class AbortSignal extends EventTarget {
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}
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super();
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this[kMaxEventTargetListeners] = 0;
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const {
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aborted = false,
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reason = undefined,

‎test/parallel/test-eventtarget-memoryleakwarning.js‎

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@@ -12,22 +12,22 @@ const { setTimeout } = require('timers/promises');
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common.expectWarning({
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MaxListenersExceededWarning: [
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['Possible EventTarget memory leak detected. 3 foo listeners added to ' +
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'EventTarget. MaxListeners is 2. Use events.setMaxListeners() ' +
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'EventTarget. MaxListeners is 2. Use events.setMaxListeners() ' +
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'to increase limit'],
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['Possible EventTarget memory leak detected. 3 foo listeners added to ' +
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'[MessagePort [EventTarget]]. ' +
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'MaxListeners is 2. ' +
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'Use events.setMaxListeners() to increase ' +
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'[MessagePort [EventTarget]]. ' +
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'MaxListeners is 2. ' +
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'Use events.setMaxListeners() to increase ' +
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'limit'],
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['Possible EventTarget memory leak detected. 3 foo listeners added to ' +
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'[MessagePort [EventTarget]]. ' +
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'MaxListeners is 2. ' +
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'Use events.setMaxListeners() to increase ' +
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'[MessagePort [EventTarget]]. ' +
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'MaxListeners is 2. ' +
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'Use events.setMaxListeners() to increase ' +
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'limit'],
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['Possible EventTarget memory leak detected. 3 foo listeners added to ' +
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'[AbortSignal]. ' +
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'MaxListeners is 2. ' +
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'Use events.setMaxListeners() to increase ' +
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['Possible EventTarget memory leak detected. 2 foo listeners added to ' +
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'[AbortSignal]. ' +
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'MaxListeners is 1. ' +
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'Use events.setMaxListeners() to increase ' +
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'limit'],
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],
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});
@@ -65,13 +65,25 @@ common.expectWarning({
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mc.port1.addEventListener('foo', () => {});
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mc.port1.addEventListener('foo', () => {});
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mc.port1.addEventListener('foo', () => {});
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}
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{
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// No warning emitted because AbortController ignores `EventEmitter.defaultMaxListeners`
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setMaxListeners(2);
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const ac = new AbortController();
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ac.signal.addEventListener('foo', () => {});
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ac.signal.addEventListener('foo', () => {});
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ac.signal.addEventListener('foo', () => {});
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}
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{
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// Will still warn as `setMaxListeners` can still manually set a limit
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const ac = new AbortController();
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setMaxListeners(1, ac.signal);
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ac.signal.addEventListener('foo', () => {});
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ac.signal.addEventListener('foo', () => {});
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}
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{
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// It works for EventEmitters also
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const ee = new EventEmitter();

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