CHANGELOG.md

@@ -1,5 +1,9 @@
 # Release History
 
+## 4.3.5
+
+fix(drain-leak): fix regression introduced in #1301 (#1401)
+
 ## 4.3.4
 
 fix(dependency): migrate LruMap from collections to lru-cache (#1396)

README.md

@@ -6,6 +6,14 @@
 MQTT.js is a client library for the [MQTT](http://mqtt.org/) protocol, written
 in JavaScript for node.js and the browser.
 
+| :warning: WARNING          |
+|:---------------------------|
+| our default branch has been moved from *master* to *main*      |
+
+| :boom: MQTT.js vNext          |
+|:---------------------------|
+| Want to contribute to the next generation of **MQTT.js**? Join the discussion [here](https://github.com/mqttjs/MQTT.js/discussions/1324).       |
+
 ## Table of Contents
 * [__MQTT.js vNext__](#vnext)
 * [Upgrade notes](#notes)

lib/client.js

@@ -175,7 +175,7 @@ function sendPacket (client, packet, cb) {
   debug('sendPacket :: writing to stream')
   const result = mqttPacket.writeToStream(packet, client.stream, client.options)
   debug('sendPacket :: writeToStream result %s', result)
-  if (!result && cb) {
+  if (!result && cb && cb !== nop) {
     debug('sendPacket :: handle events on `drain` once through callback.')
     client.stream.once('drain', cb)
   } else if (cb) {
@@ -190,6 +190,8 @@ function flush (queue) {
     Object.keys(queue).forEach(function (messageId) {
       if (typeof queue[messageId].cb === 'function') {
         queue[messageId].cb(new Error('Connection closed'))
+        // This is suspicious.  Why do we only delete this if we have a callbck?
+        // If this is by-design, then adding no as callback would cause this to get deleted unintentionally.
         delete queue[messageId]
       }
     })
@@ -569,7 +571,7 @@ MqttClient.prototype._handlePacket = function (packet, done) {
 
 MqttClient.prototype._checkDisconnecting = function (callback) {
   if (this.disconnecting) {
-    if (callback) {
+    if (callback && callback !== nop) {
       callback(new Error('client disconnecting'))
     } else {
       this.emit('error', new Error('client disconnecting'))
@@ -1581,7 +1583,7 @@ MqttClient.prototype._handleAck = function (packet) {
   const that = this
   let err
 
-  if (!cb) {
+  if (!cb || cb === nop) {
     debug('_handleAck :: Server sent an ack in error. Ignoring.')
     // Server sent an ack in error, ignore it.
     return

package.json

@@ -1,7 +1,7 @@
 {
   "name": "mqtt",
   "description": "A library for the MQTT protocol",
-  "version": "4.3.4",
+  "version": "4.3.5",
   "contributors": [
     "Adam Rudd <adamvrr@gmail.com>",
     "Matteo Collina <matteo.collina@gmail.com> (https://github.com/mcollina)",