diff --git a/lib/internal/child_process.js b/lib/internal/child_process.js index d46a5ce03f09c6..5b212d345d51ac 100644 --- a/lib/internal/child_process.js +++ b/lib/internal/child_process.js @@ -81,6 +81,7 @@ let HTTPParser; const MAX_HANDLE_RETRANSMISSIONS = 3; const kChannelHandle = Symbol('kChannelHandle'); const kIsUsedAsStdio = Symbol('kIsUsedAsStdio'); +const kPendingMessages = Symbol('kPendingMessages'); // This object contain function to convert TCP objects to native handle objects // and back again. @@ -528,6 +529,7 @@ class Control extends EventEmitter { constructor(channel) { super(); this.#channel = channel; + this[kPendingMessages] = []; } // The methods keeping track of the counter are being used to track the @@ -701,6 +703,24 @@ function setupChannel(target, channel, serializationMode) { }); }); + target.on('newListener', function() { + + process.nextTick(() => { + if (!target.channel || !target.listenerCount('message')) + return; + + const messages = target.channel[kPendingMessages]; + const { length } = messages; + if (!length) return; + + for (let i = 0; i < length; i++) { + ReflectApply(target.emit, target, messages[i]); + } + + target.channel[kPendingMessages] = []; + }); + }); + target.send = function(message, handle, options, callback) { if (typeof handle === 'function') { callback = handle; @@ -914,7 +934,15 @@ function setupChannel(target, channel, serializationMode) { }; function emit(event, message, handle) { - target.emit(event, message, handle); + if ('internalMessage' === event || target.listenerCount('message')) { + target.emit(event, message, handle); + return; + } + + ArrayPrototypePush( + target.channel[kPendingMessages], + [event, message, handle] + ); } function handleMessage(message, handle, internal) { diff --git a/test/es-module/test-esm-child-process-fork-main.mjs b/test/es-module/test-esm-child-process-fork-main.mjs new file mode 100644 index 00000000000000..4dd47a2da97b09 --- /dev/null +++ b/test/es-module/test-esm-child-process-fork-main.mjs @@ -0,0 +1,20 @@ +import '../common/index.mjs'; +import assert from 'assert'; +import { fork } from 'child_process'; +import { once } from 'events'; +import { fileURLToPath } from 'url'; + +if (process.argv[2] !== 'child') { + const filename = fileURLToPath(import.meta.url); + const cp = fork(filename, ['child']); + const message = 'Hello World'; + cp.send(message); + + const [received] = await once(cp, 'message'); + assert.deepStrictEqual(received, message); + + cp.disconnect(); + await once(cp, 'exit'); +} else { + process.on('message', (msg) => process.send(msg)); +}