From bb5a924dd7c336778f2d743ceb69e018358b83ad Mon Sep 17 00:00:00 2001
From: James M Snell <jasnell@gmail.com>
Date: Sat, 14 Jun 2025 14:49:17 -0700
Subject: [PATCH] process: move multipleResolves event to EOL

The `multipleResolves` event has been deprecated for several
years now. It's time.
---
 doc/api/deprecations.md                       |  9 +-
 doc/api/process.md                            | 90 -------------------
 lib/internal/process/promises.js              | 70 +--------------
 test/parallel/test-events-once.js             |  1 -
 test/parallel/test-promise-swallowed-event.js | 58 ------------
 .../test-timers-immediate-promisified.js      |  2 -
 .../test-timers-interval-promisified.js       |  2 -
 .../test-timers-timeout-promisified.js        |  2 -
 test/parallel/test-warn-multipleResolves.mjs  | 14 ---
 9 files changed, 10 insertions(+), 238 deletions(-)
 delete mode 100644 test/parallel/test-promise-swallowed-event.js
 delete mode 100644 test/parallel/test-warn-multipleResolves.mjs

diff --git a/doc/api/deprecations.md b/doc/api/deprecations.md
index 84f5224de2060c..119c2bc676f122 100644
--- a/doc/api/deprecations.md
+++ b/doc/api/deprecations.md
@@ -3332,6 +3332,9 @@ the errors used for value type validation.
 
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/58707
+    description: End-of-Life.
   - version: v18.0.0
     pr-url: https://github.com/nodejs/node/pull/41896
     description: Runtime deprecation.
@@ -3342,10 +3345,10 @@ changes:
     description: Documentation-only deprecation.
 -->
 
-Type: Runtime
+Type: End-of-Life
 
-This event was deprecated because it did not work with V8 promise combinators
-which diminished its usefulness.
+This event was deprecated and removed because it did not work with V8 promise
+combinators which diminished its usefulness.
 
 ### DEP0161: `process._getActiveRequests()` and `process._getActiveHandles()`
 
diff --git a/doc/api/process.md b/doc/api/process.md
index b3c74c99ec49b4..9182d25219c92f 100644
--- a/doc/api/process.md
+++ b/doc/api/process.md
@@ -176,95 +176,6 @@ process, the `message` argument can contain data that JSON is not able
 to represent.
 See [Advanced serialization for `child_process`][] for more details.
 
-### Event: `'multipleResolves'`
-
-<!-- YAML
-added: v10.12.0
-deprecated:
-  - v17.6.0
-  - v16.15.0
--->
-
-> Stability: 0 - Deprecated
-
-* `type` {string} The resolution type. One of `'resolve'` or `'reject'`.
-* `promise` {Promise} The promise that resolved or rejected more than once.
-* `value` {any} The value with which the promise was either resolved or
-  rejected after the original resolve.
-
-The `'multipleResolves'` event is emitted whenever a `Promise` has been either:
-
-* Resolved more than once.
-* Rejected more than once.
-* Rejected after resolve.
-* Resolved after reject.
-
-This is useful for tracking potential errors in an application while using the
-`Promise` constructor, as multiple resolutions are silently swallowed. However,
-the occurrence of this event does not necessarily indicate an error. For
-example, [`Promise.race()`][] can trigger a `'multipleResolves'` event.
-
-Because of the unreliability of the event in cases like the
-[`Promise.race()`][] example above it has been deprecated.
-
-```mjs
-import process from 'node:process';
-
-process.on('multipleResolves', (type, promise, reason) => {
-  console.error(type, promise, reason);
-  setImmediate(() => process.exit(1));
-});
-
-async function main() {
-  try {
-    return await new Promise((resolve, reject) => {
-      resolve('First call');
-      resolve('Swallowed resolve');
-      reject(new Error('Swallowed reject'));
-    });
-  } catch {
-    throw new Error('Failed');
-  }
-}
-
-main().then(console.log);
-// resolve: Promise { 'First call' } 'Swallowed resolve'
-// reject: Promise { 'First call' } Error: Swallowed reject
-//     at Promise (*)
-//     at new Promise (<anonymous>)
-//     at main (*)
-// First call
-```
-
-```cjs
-const process = require('node:process');
-
-process.on('multipleResolves', (type, promise, reason) => {
-  console.error(type, promise, reason);
-  setImmediate(() => process.exit(1));
-});
-
-async function main() {
-  try {
-    return await new Promise((resolve, reject) => {
-      resolve('First call');
-      resolve('Swallowed resolve');
-      reject(new Error('Swallowed reject'));
-    });
-  } catch {
-    throw new Error('Failed');
-  }
-}
-
-main().then(console.log);
-// resolve: Promise { 'First call' } 'Swallowed resolve'
-// reject: Promise { 'First call' } Error: Swallowed reject
-//     at Promise (*)
-//     at new Promise (<anonymous>)
-//     at main (*)
-// First call
-```
-
 ### Event: `'rejectionHandled'`
 
 <!-- YAML
@@ -4603,7 +4514,6 @@ cases:
 [`Error`]: errors.md#class-error
 [`EventEmitter`]: events.md#class-eventemitter
 [`NODE_OPTIONS`]: cli.md#node_optionsoptions
-[`Promise.race()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/race
 [`Worker`]: worker_threads.md#class-worker
 [`Worker` constructor]: worker_threads.md#new-workerfilename-options
 [`console.error()`]: console.md#consoleerrordata-args
diff --git a/lib/internal/process/promises.js b/lib/internal/process/promises.js
index 90eaef5c773718..56a9f287a0a86e 100644
--- a/lib/internal/process/promises.js
+++ b/lib/internal/process/promises.js
@@ -20,8 +20,6 @@ const {
   setPromiseRejectCallback,
 } = internalBinding('task_queue');
 
-const { deprecate } = require('internal/util');
-
 const {
   noSideEffectsToString,
   triggerUncaughtException,
@@ -43,27 +41,6 @@ const AsyncContextFrame = require('internal/async_context_frame');
 // *Must* match Environment::TickInfo::Fields in src/env.h.
 const kHasRejectionToWarn = 1;
 
-// By default true because in cases where process is not a global
-// it is not possible to determine if the user has added a listener
-// to the process object.
-let hasMultipleResolvesListener = true;
-
-if (process.on) {
-  hasMultipleResolvesListener = process.listenerCount('multipleResolves') !== 0;
-
-  process.on('newListener', (eventName) => {
-    if (eventName === 'multipleResolves') {
-      hasMultipleResolvesListener = true;
-    }
-  });
-
-  process.on('removeListener', (eventName) => {
-    if (eventName === 'multipleResolves') {
-      hasMultipleResolvesListener = process.listenerCount('multipleResolves') !== 0;
-    }
-  });
-}
-
 /**
  * Errors & Warnings
  */
@@ -192,55 +169,16 @@ function promiseRejectHandler(type, promise, reason) {
       handledRejection(promise);
       break;
     case kPromiseRejectAfterResolved: // 2
-      if (hasMultipleResolvesListener) {
-        resolveErrorReject(promise, reason);
-      }
+      // Do nothing in this case. Previous we would emit a multipleResolves
+      // event but that was deprecated then later removed.
       break;
     case kPromiseResolveAfterResolved: // 3
-      if (hasMultipleResolvesListener) {
-        resolveErrorResolve(promise, reason);
-      }
+      // Do nothing in this case. Previous we would emit a multipleResolves
+      // event but that was deprecated then later removed.
       break;
   }
 }
 
-const multipleResolvesDeprecate = deprecate(
-  () => {},
-  'The multipleResolves event has been deprecated.',
-  'DEP0160',
-);
-
-/**
- * @param {Promise} promise
- * @param {Error} reason
- */
-function resolveErrorResolve(promise, reason) {
-  // We have to wrap this in a next tick. Otherwise the error could be caught by
-  // the executed promise.
-  process.nextTick(() => {
-    // Emit the multipleResolves event.
-    // This is a deprecated event, so we have to check if it's being listened to.
-    if (process.emit('multipleResolves', 'resolve', promise, reason)) {
-      // If the event is being listened to, emit a deprecation warning.
-      multipleResolvesDeprecate();
-    }
-  });
-}
-
-/**
- * @param {Promise} promise
- * @param {Error} reason
- */
-function resolveErrorReject(promise, reason) {
-  // We have to wrap this in a next tick. Otherwise the error could be caught by
-  // the executed promise.
-  process.nextTick(() => {
-    if (process.emit('multipleResolves', 'reject', promise, reason)) {
-      multipleResolvesDeprecate();
-    }
-  });
-}
-
 /**
  * @param {Promise} promise
  * @param {PromiseInfo} promiseInfo
diff --git a/test/parallel/test-events-once.js b/test/parallel/test-events-once.js
index 950b266cc2b82a..7ed2b2a69ce950 100644
--- a/test/parallel/test-events-once.js
+++ b/test/parallel/test-events-once.js
@@ -104,7 +104,6 @@ async function stopListeningAfterCatchingError() {
   } catch (_e) {
     err = _e;
   }
-  process.removeAllListeners('multipleResolves');
   strictEqual(err, expected);
   strictEqual(ee.listenerCount('error'), 0);
   strictEqual(ee.listenerCount('myevent'), 0);
diff --git a/test/parallel/test-promise-swallowed-event.js b/test/parallel/test-promise-swallowed-event.js
deleted file mode 100644
index e9b97ab19d329d..00000000000000
--- a/test/parallel/test-promise-swallowed-event.js
+++ /dev/null
@@ -1,58 +0,0 @@
-'use strict';
-
-const common = require('../common');
-const assert = require('assert');
-
-const rejection = new Error('Swallowed reject');
-const rejection2 = new TypeError('Weird');
-const resolveMessage = 'First call';
-const rejectPromise = new Promise((r) => setTimeout(r, 10, rejection2));
-const swallowedResolve = 'Swallowed resolve';
-const swallowedResolve2 = 'Foobar';
-
-process.on('multipleResolves', common.mustCall(handler, 4));
-
-const p1 = new Promise((resolve, reject) => {
-  resolve(resolveMessage);
-  resolve(swallowedResolve);
-  reject(rejection);
-});
-
-const p2 = new Promise((resolve, reject) => {
-  reject(rejectPromise);
-  resolve(swallowedResolve2);
-  reject(rejection2);
-}).catch(common.mustCall((exception) => {
-  assert.strictEqual(exception, rejectPromise);
-}));
-
-const expected = [
-  'resolve',
-  p1,
-  swallowedResolve,
-  'reject',
-  p1,
-  rejection,
-  'resolve',
-  p2,
-  swallowedResolve2,
-  'reject',
-  p2,
-  rejection2,
-];
-
-let count = 0;
-
-function handler(type, promise, reason) {
-  assert.strictEqual(type, expected.shift());
-  // In the first two cases the promise is identical because it's not delayed.
-  // The other two cases are not identical, because the `promise` is caught in a
-  // state when it has no knowledge about the `.catch()` handler that is
-  // attached to it right afterwards.
-  if (count++ < 2) {
-    assert.strictEqual(promise, expected.shift());
-  } else {
-    assert.notStrictEqual(promise, expected.shift());
-  }
-  assert.strictEqual(reason, expected.shift());
-}
diff --git a/test/parallel/test-timers-immediate-promisified.js b/test/parallel/test-timers-immediate-promisified.js
index 586fd501273ae3..768daf3a494e9b 100644
--- a/test/parallel/test-timers-immediate-promisified.js
+++ b/test/parallel/test-timers-immediate-promisified.js
@@ -14,8 +14,6 @@ const setPromiseImmediate = promisify(timers.setImmediate);
 
 assert.strictEqual(setPromiseImmediate, timerPromises.setImmediate);
 
-process.on('multipleResolves', common.mustNotCall());
-
 {
   const promise = setPromiseImmediate();
   promise.then(common.mustCall((value) => {
diff --git a/test/parallel/test-timers-interval-promisified.js b/test/parallel/test-timers-interval-promisified.js
index e9434625e38026..87afeee67bcff7 100644
--- a/test/parallel/test-timers-interval-promisified.js
+++ b/test/parallel/test-timers-interval-promisified.js
@@ -14,8 +14,6 @@ const setPromiseTimeout = promisify(timers.setTimeout);
 
 const { setInterval } = timerPromises;
 
-process.on('multipleResolves', common.mustNotCall());
-
 {
   const iterable = setInterval(1, undefined);
   const iterator = iterable[Symbol.asyncIterator]();
diff --git a/test/parallel/test-timers-timeout-promisified.js b/test/parallel/test-timers-timeout-promisified.js
index a89ccad7305f89..a540448a9b8e83 100644
--- a/test/parallel/test-timers-timeout-promisified.js
+++ b/test/parallel/test-timers-timeout-promisified.js
@@ -14,8 +14,6 @@ const setPromiseTimeout = promisify(timers.setTimeout);
 
 assert.strictEqual(setPromiseTimeout, timerPromises.setTimeout);
 
-process.on('multipleResolves', common.mustNotCall());
-
 {
   const promise = setPromiseTimeout(1);
   promise.then(common.mustCall((value) => {
diff --git a/test/parallel/test-warn-multipleResolves.mjs b/test/parallel/test-warn-multipleResolves.mjs
deleted file mode 100644
index 9320ff2635e563..00000000000000
--- a/test/parallel/test-warn-multipleResolves.mjs
+++ /dev/null
@@ -1,14 +0,0 @@
-import { expectWarning, mustCall } from '../common/index.mjs';
-
-expectWarning(
-  'DeprecationWarning',
-  'The multipleResolves event has been deprecated.',
-  'DEP0160',
-);
-
-process.on('multipleResolves', mustCall());
-
-new Promise((resolve) => {
-  resolve();
-  resolve();
-});