process: runtime deprecate multipleResolves

Author: benjamingr

lib/internal/process/promises.js

@@ -20,6 +20,8 @@ const {
   setPromiseRejectCallback
 } = internalBinding('task_queue');
 
+const { deprecate } = require('internal/util');
+
 const {
   noSideEffectsToString,
   triggerUncaughtException
@@ -124,11 +126,18 @@ function promiseRejectHandler(type, promise, reason) {
   }
 }
 
+const multipleResolvesDeprecate = deprecate(
+  () => {},
+  'The multipleResolves event has been derpecated.',
+  'DEPXXXX'
+);
 function resolveError(type, promise, reason) {
   // We have to wrap this in a next tick. Otherwise the error could be caught by
   // the executed promise.
   process.nextTick(() => {
-    process.emit('multipleResolves', type, promise, reason);
+    if (process.emit('multipleResolves', type, promise, reason)) {
+      multipleResolvesDeprecate();
+    }
   });
 }
 

test/parallel/test-warn-multipleResolves.mjs

@@ -0,0 +1,14 @@
+import { expectWarning, mustCall } from '../common/index.mjs';
+
+expectWarning(
+  'DeprecationWarning',
+  'The multipleResolves event has been derpecated.',
+  'DEPXXXX',
+);
+
+process.on('multipleResolves', mustCall());
+
+new Promise((resolve) => {
+  resolve();
+  resolve();
+});