chore(deps): bump github.com/eclipse/paho.mqtt.golang

Bumps [github.com/eclipse/paho.mqtt.golang](https://github.com/eclipse/paho.mqtt.golang) from 1.5.0 to 1.5.1.
- [Release notes](https://github.com/eclipse/paho.mqtt.golang/releases)
- [Commits](https://github.com/eclipse/paho.mqtt.golang/compare/v1.5.0...v1.5.1)

---
updated-dependencies:
- dependency-name: github.com/eclipse/paho.mqtt.golang
  dependency-version: 1.5.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/eclipse/paho.mqtt.golang/client.go

@@ -258,12 +258,15 @@ func (c *client) Connect() Token {
 			return
 		}
 
+		var attemptCount int
+
 	RETRYCONN:
 		var conn net.Conn
 		var rc byte
 		var err error
-		conn, rc, t.sessionPresent, err = c.attemptConnection()
+		conn, rc, t.sessionPresent, err = c.attemptConnection(false, attemptCount)
 		if err != nil {
+			attemptCount++
 			if c.options.ConnectRetry {
 				DEBUG.Println(CLI, "Connect failed, sleeping for", int(c.options.ConnectRetryInterval.Seconds()), "seconds and will then retry, error:", err.Error())
 				time.Sleep(c.options.ConnectRetryInterval)
@@ -315,15 +318,17 @@ func (c *client) reconnect(connectionUp connCompletedFn) {
 		DEBUG.Println(CLI, "Detect continual connection lost after reconnect, slept for", int(slp.Seconds()), "seconds")
 	}
 
+	var attemptCount int
 	for {
 		if nil != c.options.OnReconnecting {
 			c.options.OnReconnecting(c, &c.options)
 		}
 		var err error
-		conn, _, _, err = c.attemptConnection()
+		conn, _, _, err = c.attemptConnection(true, attemptCount)
 		if err == nil {
 			break
 		}
+		attemptCount++
 		sleep, _ := c.backoff.sleepWithBackoff("attemptReconnection", initSleep, c.options.MaxReconnectInterval, c.options.ConnectTimeout, false)
 		DEBUG.Println(CLI, "Reconnect failed, slept for", int(sleep.Seconds()), "seconds:", err)
 
@@ -351,7 +356,7 @@ func (c *client) reconnect(connectionUp connCompletedFn) {
 // byte - Return code (packets.Accepted indicates a successful connection).
 // bool - SessionPresent flag from the connect ack (only valid if packets.Accepted)
 // err - Error (err != nil guarantees that conn has been set to active connection).
-func (c *client) attemptConnection() (net.Conn, byte, bool, error) {
+func (c *client) attemptConnection(isReconnect bool, attempt int) (net.Conn, byte, bool, error) {
 	protocolVersion := c.options.ProtocolVersion
 	var (
 		sessionPresent bool
@@ -360,6 +365,10 @@ func (c *client) attemptConnection() (net.Conn, byte, bool, error) {
 		rc             byte
 	)
 
+	if c.options.OnConnectionNotification != nil {
+		c.options.OnConnectionNotification(c, ConnectionNotificationConnecting{isReconnect, attempt})
+	}
+
 	c.optionsMu.Lock() // Protect c.options.Servers so that servers can be added in test cases
 	brokers := c.options.Servers
 	c.optionsMu.Unlock()
@@ -372,6 +381,9 @@ func (c *client) attemptConnection() (net.Conn, byte, bool, error) {
 			DEBUG.Println(CLI, "using custom onConnectAttempt handler...")
 			tlsCfg = c.options.OnConnectAttempt(broker, c.options.TLSConfig)
 		}
+		if c.options.OnConnectionNotification != nil {
+			c.options.OnConnectionNotification(c, ConnectionNotificationBroker{broker})
+		}
 		connDeadline := time.Now().Add(c.options.ConnectTimeout) // Time by which connection must be established
 		dialer := c.options.Dialer
 		if dialer == nil { //
@@ -388,6 +400,9 @@ func (c *client) attemptConnection() (net.Conn, byte, bool, error) {
 			ERROR.Println(CLI, err.Error())
 			WARN.Println(CLI, "failed to connect to broker, trying next")
 			rc = packets.ErrNetworkError
+			if c.options.OnConnectionNotification != nil {
+				c.options.OnConnectionNotification(c, ConnectionNotificationBrokerFailed{broker, err})
+			}
 			continue
 		}
 		DEBUG.Println(CLI, "socket connected to broker")
@@ -430,6 +445,9 @@ func (c *client) attemptConnection() (net.Conn, byte, bool, error) {
 			err = fmt.Errorf("%w : %w", packets.ConnErrors[rc], err)
 		}
 	}
+	if err != nil && c.options.OnConnectionNotification != nil {
+		c.options.OnConnectionNotification(c, ConnectionNotificationFailed{err})
+	}
 	return conn, rc, sessionPresent, err
 }
 
@@ -564,6 +582,9 @@ func (c *client) internalConnLost(whyConnLost error) {
 		if c.options.OnConnectionLost != nil {
 			go c.options.OnConnectionLost(c, whyConnLost)
 		}
+		if c.options.OnConnectionNotification != nil {
+			go c.options.OnConnectionNotification(c, ConnectionNotificationLost{whyConnLost})
+		}
 		DEBUG.Println(CLI, "internalConnLost complete")
 	}()
 }
@@ -613,6 +634,9 @@ func (c *client) startCommsWorkers(conn net.Conn, connectionUp connCompletedFn,
 	if c.options.OnConnect != nil {
 		go c.options.OnConnect(c)
 	}
+	if c.options.OnConnectionNotification != nil {
+		go c.options.OnConnectionNotification(c, ConnectionNotificationConnected{})
+	}
 
 	// c.oboundP and c.obound need to stay active for the life of the client because, depending upon the options,
 	// messages may be published while the client is disconnected (they will block unless in a goroutine). However

vendor/github.com/eclipse/paho.mqtt.golang/connnotf.go

@@ -0,0 +1,79 @@
+package mqtt
+
+import "net/url"
+
+type ConnectionNotificationType int64
+
+const (
+	ConnectionNotificationTypeConnected ConnectionNotificationType = iota
+	ConnectionNotificationTypeConnecting
+	ConnectionNotificationTypeFailed
+	ConnectionNotificationTypeLost
+	ConnectionNotificationTypeBroker
+	ConnectionNotificationTypeBrokerFailed
+)
+
+type ConnectionNotification interface {
+	Type() ConnectionNotificationType
+}
+
+// Connected
+
+type ConnectionNotificationConnected struct {
+}
+
+func (n ConnectionNotificationConnected) Type() ConnectionNotificationType {
+	return ConnectionNotificationTypeConnected
+}
+
+// Connecting
+
+type ConnectionNotificationConnecting struct {
+	IsReconnect bool
+	Attempt     int
+}
+
+func (n ConnectionNotificationConnecting) Type() ConnectionNotificationType {
+	return ConnectionNotificationTypeConnecting
+}
+
+// Connection Failed
+
+type ConnectionNotificationFailed struct {
+	Reason error
+}
+
+func (n ConnectionNotificationFailed) Type() ConnectionNotificationType {
+	return ConnectionNotificationTypeFailed
+}
+
+// Connection Lost
+
+type ConnectionNotificationLost struct {
+	Reason error // may be nil
+}
+
+func (n ConnectionNotificationLost) Type() ConnectionNotificationType {
+	return ConnectionNotificationTypeLost
+}
+
+// Broker Connection
+
+type ConnectionNotificationBroker struct {
+	Broker *url.URL
+}
+
+func (n ConnectionNotificationBroker) Type() ConnectionNotificationType {
+	return ConnectionNotificationTypeBroker
+}
+
+// Broker Connection Failed
+
+type ConnectionNotificationBrokerFailed struct {
+	Broker *url.URL
+	Reason error
+}
+
+func (n ConnectionNotificationBrokerFailed) Type() ConnectionNotificationType {
+	return ConnectionNotificationTypeBrokerFailed
+}

vendor/github.com/eclipse/paho.mqtt.golang/net.go

@@ -444,24 +444,23 @@ func startComms(conn net.Conn, // Network connection (must be active)
 }
 
 // ackFunc acknowledges a packet
-// WARNING the function returned must not be called if the comms routine is shutting down or not running
-// (it needs outgoing comms in order to send the acknowledgement). Currently this is only called from
-// matchAndDispatch which will be shutdown before the comms are
-func ackFunc(oboundP chan *PacketAndToken, persist Store, packet *packets.PublishPacket) func() {
+// WARNING sendAck may be called at any time (even after the connection is dead). At the time of writing ACK sent after
+// connection loss will be dropped (this is not ideal)
+func ackFunc(sendAck func(*PacketAndToken), persist Store, packet *packets.PublishPacket) func() {
 	return func() {
 		switch packet.Qos {
 		case 2:
 			pr := packets.NewControlPacket(packets.Pubrec).(*packets.PubrecPacket)
 			pr.MessageID = packet.MessageID
 			DEBUG.Println(NET, "putting pubrec msg on obound")
-			oboundP <- &PacketAndToken{p: pr, t: nil}
+			sendAck(&PacketAndToken{p: pr, t: nil})
 			DEBUG.Println(NET, "done putting pubrec msg on obound")
 		case 1:
 			pa := packets.NewControlPacket(packets.Puback).(*packets.PubackPacket)
 			pa.MessageID = packet.MessageID
 			DEBUG.Println(NET, "putting puback msg on obound")
-			persistOutbound(persist, pa)
-			oboundP <- &PacketAndToken{p: pa, t: nil}
+			persistOutbound(persist, pa) // May fail if store has been closed
+			sendAck(&PacketAndToken{p: pa, t: nil})
 			DEBUG.Println(NET, "done putting puback msg on obound")
 		case 0:
 			// do nothing, since there is no need to send an ack packet back

vendor/github.com/eclipse/paho.mqtt.golang/netconn.go

@@ -50,16 +50,7 @@ func openConnection(uri *url.URL, tlsc *tls.Config, timeout time.Duration, heade
 		conn, err := NewWebsocket(dialURI.String(), tlsc, timeout, headers, websocketOptions)
 		return conn, err
 	case "mqtt", "tcp":
-		allProxy := os.Getenv("all_proxy")
-		if len(allProxy) == 0 {
-			conn, err := dialer.Dial("tcp", uri.Host)
-			if err != nil {
-				return nil, err
-			}
-			return conn, nil
-		}
-		proxyDialer := proxy.FromEnvironment()
-
+		proxyDialer := proxy.FromEnvironmentUsing(dialer)
 		conn, err := proxyDialer.Dial("tcp", uri.Host)
 		if err != nil {
 			return nil, err

vendor/github.com/eclipse/paho.mqtt.golang/options.go

@@ -62,93 +62,99 @@ type ConnectionAttemptHandler func(broker *url.URL, tlsCfg *tls.Config) *tls.Con
 // Does not carry out any MQTT specific handshakes.
 type OpenConnectionFunc func(uri *url.URL, options ClientOptions) (net.Conn, error)
 
+// ConnectionNotificationHandler is invoked for any type of connection event.
+type ConnectionNotificationHandler func(Client, ConnectionNotification)
+
 // ClientOptions contains configurable options for an Client. Note that these should be set using the
 // relevant methods (e.g. AddBroker) rather than directly. See those functions for information on usage.
 // WARNING: Create the below using NewClientOptions unless you have a compelling reason not to. It is easy
 // to create a configuration with difficult to trace issues (e.g. Mosquitto 2.0.12+ will reject connections
 // with KeepAlive=0 by default).
 type ClientOptions struct {
-	Servers                 []*url.URL
-	ClientID                string
-	Username                string
-	Password                string
-	CredentialsProvider     CredentialsProvider
-	CleanSession            bool
-	Order                   bool
-	WillEnabled             bool
-	WillTopic               string
-	WillPayload             []byte
-	WillQos                 byte
-	WillRetained            bool
-	ProtocolVersion         uint
-	protocolVersionExplicit bool
-	TLSConfig               *tls.Config
-	KeepAlive               int64 // Warning: Some brokers may reject connections with Keepalive = 0.
-	PingTimeout             time.Duration
-	ConnectTimeout          time.Duration
-	MaxReconnectInterval    time.Duration
-	AutoReconnect           bool
-	ConnectRetryInterval    time.Duration
-	ConnectRetry            bool
-	Store                   Store
-	DefaultPublishHandler   MessageHandler
-	OnConnect               OnConnectHandler
-	OnConnectionLost        ConnectionLostHandler
-	OnReconnecting          ReconnectHandler
-	OnConnectAttempt        ConnectionAttemptHandler
-	WriteTimeout            time.Duration
-	MessageChannelDepth     uint
-	ResumeSubs              bool
-	HTTPHeaders             http.Header
-	WebsocketOptions        *WebsocketOptions
-	MaxResumePubInFlight    int // // 0 = no limit; otherwise this is the maximum simultaneous messages sent while resuming
-	Dialer                  *net.Dialer
-	CustomOpenConnectionFn  OpenConnectionFunc
-	AutoAckDisabled         bool
+	Servers                  []*url.URL
+	ClientID                 string
+	Username                 string
+	Password                 string
+	CredentialsProvider      CredentialsProvider
+	CleanSession             bool
+	Order                    bool
+	WillEnabled              bool
+	WillTopic                string
+	WillPayload              []byte
+	WillQos                  byte
+	WillRetained             bool
+	ProtocolVersion          uint
+	protocolVersionExplicit  bool
+	TLSConfig                *tls.Config
+	KeepAlive                int64 // Warning: Some brokers may reject connections with Keepalive = 0.
+	PingTimeout              time.Duration
+	ConnectTimeout           time.Duration
+	MaxReconnectInterval     time.Duration
+	AutoReconnect            bool
+	ConnectRetryInterval     time.Duration
+	ConnectRetry             bool
+	Store                    Store
+	DefaultPublishHandler    MessageHandler
+	OnConnect                OnConnectHandler
+	OnConnectionLost         ConnectionLostHandler
+	OnReconnecting           ReconnectHandler
+	OnConnectAttempt         ConnectionAttemptHandler
+	OnConnectionNotification ConnectionNotificationHandler
+	WriteTimeout             time.Duration
+	MessageChannelDepth      uint
+	ResumeSubs               bool
+	HTTPHeaders              http.Header
+	WebsocketOptions         *WebsocketOptions
+	MaxResumePubInFlight     int // // 0 = no limit; otherwise this is the maximum simultaneous messages sent while resuming
+	Dialer                   *net.Dialer
+	CustomOpenConnectionFn   OpenConnectionFunc
+	AutoAckDisabled          bool
 }
 
 // NewClientOptions will create a new ClientClientOptions type with some
 // default values.
-//   Port: 1883
-//   CleanSession: True
-//   Order: True (note: it is recommended that this be set to FALSE unless order is important)
-//   KeepAlive: 30 (seconds)
-//   ConnectTimeout: 30 (seconds)
-//   MaxReconnectInterval 10 (minutes)
-//   AutoReconnect: True
+//
+//	Port: 1883
+//	CleanSession: True
+//	Order: True (note: it is recommended that this be set to FALSE unless order is important)
+//	KeepAlive: 30 (seconds)
+//	ConnectTimeout: 30 (seconds)
+//	MaxReconnectInterval 10 (minutes)
+//	AutoReconnect: True
 func NewClientOptions() *ClientOptions {
 	o := &ClientOptions{
-		Servers:                 nil,
-		ClientID:                "",
-		Username:                "",
-		Password:                "",
-		CleanSession:            true,
-		Order:                   true,
-		WillEnabled:             false,
-		WillTopic:               "",
-		WillPayload:             nil,
-		WillQos:                 0,
-		WillRetained:            false,
-		ProtocolVersion:         0,
-		protocolVersionExplicit: false,
-		KeepAlive:               30,
-		PingTimeout:             10 * time.Second,
-		ConnectTimeout:          30 * time.Second,
-		MaxReconnectInterval:    10 * time.Minute,
-		AutoReconnect:           true,
-		ConnectRetryInterval:    30 * time.Second,
-		ConnectRetry:            false,
-		Store:                   nil,
-		OnConnect:               nil,
-		OnConnectionLost:        DefaultConnectionLostHandler,
-		OnConnectAttempt:        nil,
-		WriteTimeout:            0, // 0 represents timeout disabled
-		ResumeSubs:              false,
-		HTTPHeaders:             make(map[string][]string),
-		WebsocketOptions:        &WebsocketOptions{},
-		Dialer:                  &net.Dialer{Timeout: 30 * time.Second},
-		CustomOpenConnectionFn:  nil,
-		AutoAckDisabled:         false,
+		Servers:                  nil,
+		ClientID:                 "",
+		Username:                 "",
+		Password:                 "",
+		CleanSession:             true,
+		Order:                    true,
+		WillEnabled:              false,
+		WillTopic:                "",
+		WillPayload:              nil,
+		WillQos:                  0,
+		WillRetained:             false,
+		ProtocolVersion:          0,
+		protocolVersionExplicit:  false,
+		KeepAlive:                30,
+		PingTimeout:              10 * time.Second,
+		ConnectTimeout:           30 * time.Second,
+		MaxReconnectInterval:     10 * time.Minute,
+		AutoReconnect:            true,
+		ConnectRetryInterval:     30 * time.Second,
+		ConnectRetry:             false,
+		Store:                    nil,
+		OnConnect:                nil,
+		OnConnectionLost:         DefaultConnectionLostHandler,
+		OnConnectAttempt:         nil,
+		OnConnectionNotification: nil,
+		WriteTimeout:             0, // 0 represents timeout disabled
+		ResumeSubs:               false,
+		HTTPHeaders:              make(map[string][]string),
+		WebsocketOptions:         &WebsocketOptions{},
+		Dialer:                   &net.Dialer{Timeout: 30 * time.Second},
+		CustomOpenConnectionFn:   nil,
+		AutoAckDisabled:          false,
 	}
 	return o
 }
@@ -355,6 +361,13 @@ func (o *ClientOptions) SetConnectionAttemptHandler(onConnectAttempt ConnectionA
 	return o
 }
 
+// SetConnectionNotificationHandler sets the ConnectionNotificationHandler callback to receive all types of connection
+// events.
+func (o *ClientOptions) SetConnectionNotificationHandler(onConnectionNotification ConnectionNotificationHandler) *ClientOptions {
+	o.OnConnectionNotification = onConnectionNotification
+	return o
+}
+
 // SetWriteTimeout puts a limit on how long a mqtt publish should block until it unblocks with a
 // timeout error. A duration of 0 never times out. Default never times out
 func (o *ClientOptions) SetWriteTimeout(t time.Duration) *ClientOptions {
@@ -450,6 +463,7 @@ func (o *ClientOptions) SetCustomOpenConnectionFn(customOpenConnectionFn OpenCon
 }
 
 // SetAutoAckDisabled enables or disables the Automated Acking of Messages received by the handler.
+//
 //	By default it is set to false. Setting it to true will disable the auto-ack globally.
 func (o *ClientOptions) SetAutoAckDisabled(autoAckDisabled bool) *ClientOptions {
 	o.AutoAckDisabled = autoAckDisabled

vendor/github.com/eclipse/paho.mqtt.golang/packets/packets.go

@@ -330,6 +330,11 @@ func decodeBytes(b io.Reader) ([]byte, error) {
 }
 
 func encodeBytes(field []byte) []byte {
+	// Attempting to encode more than 65,535 bytes would lead to an unexpected 16-bit length and extra data written
+	// (which would be parsed as later parts of the message). The safest option is to truncate.
+	if len(field) > 65535 {
+		field = field[0:65535]
+	}
 	fieldLength := make([]byte, 2)
 	binary.BigEndian.PutUint16(fieldLength, uint16(len(field)))
 	return append(fieldLength, field...)

vendor/github.com/eclipse/paho.mqtt.golang/router.go

@@ -136,60 +136,41 @@ func (r *router) setDefaultHandler(handler MessageHandler) {
 // associated callback (or the defaultHandler, if one exists and no other route matched). If
 // anything is sent down the stop channel the function will end.
 func (r *router) matchAndDispatch(messages <-chan *packets.PublishPacket, order bool, client *client) <-chan *PacketAndToken {
-	var wg sync.WaitGroup
-	ackOutChan := make(chan *PacketAndToken) // Channel returned to caller; closed when messages channel closed
-	var ackInChan chan *PacketAndToken       // ACKs generated by ackFunc get put onto this channel
+	ackChan := make(chan *PacketAndToken) // Channel returned to caller; closed when goroutine terminates
 
-	stopAckCopy := make(chan struct{})    // Closure requests stop of go routine copying ackInChan to ackOutChan
-	ackCopyStopped := make(chan struct{}) // Closure indicates that it is safe to close ackOutChan
-	goRoutinesDone := make(chan struct{}) // closed on wg.Done()
-	if order {
-		ackInChan = ackOutChan // When order = true no go routines are used so safe to use one channel and close when done
-	} else {
-		// When order = false ACK messages are sent in go routines so ackInChan cannot be closed until all goroutines done
-		ackInChan = make(chan *PacketAndToken)
-		go func() { // go routine to copy from ackInChan to ackOutChan until stopped
-			for {
-				select {
-				case a := <-ackInChan:
-					ackOutChan <- a
-				case <-stopAckCopy:
-					close(ackCopyStopped) // Signal main go routine that it is safe to close ackOutChan
-					for {
-						select {
-						case <-ackInChan: // drain ackInChan to ensure all goRoutines can complete cleanly (ACK dropped)
-							DEBUG.Println(ROU, "matchAndDispatch received acknowledgment after processing stopped (ACK dropped).")
-						case <-goRoutinesDone:
-							close(ackInChan) // Nothing further should be sent (a panic is probably better than silent failure)
-							DEBUG.Println(ROU, "matchAndDispatch order=false copy goroutine exiting.")
-							return
-						}
-					}
-				}
-			}
-		}()
+	// In some cases message acknowledgments may come through after shutdown (connection is down etc). Where this is the
+	// case we need to accept any such requests and then ignore them. Note that this is not a perfect solution, if we
+	// have reconnected, and the session is still live, then the Ack really should be sent (see Issus #726)
+	var ackMutex sync.RWMutex
+	sendAckChan := ackChan // This will be set to nil before ackChan is closed
+	sendAck := func(ack *PacketAndToken) {
+		ackMutex.RLock()
+		defer ackMutex.RUnlock()
+		if sendAckChan != nil {
+			sendAckChan <- ack
+		} else {
+			DEBUG.Println(ROU, "matchAndDispatch received acknowledgment after processing stopped (ACK dropped).")
+		}
 	}
 
 	go func() { // Main go routine handling inbound messages
+		var handlers []MessageHandler
 		for message := range messages {
 			// DEBUG.Println(ROU, "matchAndDispatch received message")
 			sent := false
 			r.RLock()
-			m := messageFromPublish(message, ackFunc(ackInChan, client.persist, message))
-			var handlers []MessageHandler
+			m := messageFromPublish(message, ackFunc(sendAck, client.persist, message))
 			for e := r.routes.Front(); e != nil; e = e.Next() {
 				if e.Value.(*route).match(message.TopicName) {
 					if order {
 						handlers = append(handlers, e.Value.(*route).callback)
 					} else {
 						hd := e.Value.(*route).callback
-						wg.Add(1)
 						go func() {
 							hd(client, m)
 							if !client.options.AutoAckDisabled {
 								m.Ack()
 							}
-							wg.Done()
 						}()
 					}
 					sent = true
@@ -200,13 +181,11 @@ func (r *router) matchAndDispatch(messages <-chan *packets.PublishPacket, order
 					if order {
 						handlers = append(handlers, r.defaultHandler)
 					} else {
-						wg.Add(1)
 						go func() {
 							r.defaultHandler(client, m)
 							if !client.options.AutoAckDisabled {
 								m.Ack()
 							}
-							wg.Done()
 						}()
 					}
 				} else {
@@ -214,26 +193,22 @@ func (r *router) matchAndDispatch(messages <-chan *packets.PublishPacket, order
 				}
 			}
 			r.RUnlock()
-			for _, handler := range handlers {
-				handler(client, m)
-				if !client.options.AutoAckDisabled {
-					m.Ack()
+			if order {
+				for _, handler := range handlers {
+					handler(client, m)
+					if !client.options.AutoAckDisabled {
+						m.Ack()
+					}
 				}
+				handlers = handlers[:0]
 			}
 			// DEBUG.Println(ROU, "matchAndDispatch handled message")
 		}
-		if order {
-			close(ackOutChan)
-		} else { // Ensure that nothing further will be written to ackOutChan before closing it
-			close(stopAckCopy)
-			<-ackCopyStopped
-			close(ackOutChan)
-			go func() {
-				wg.Wait() // Note: If this remains running then the user has handlers that are not returning
-				close(goRoutinesDone)
-			}()
-		}
+		ackMutex.Lock()
+		sendAckChan = nil
+		ackMutex.Unlock()
+		close(ackChan) // as sendAckChan is now nil nothing further will be sent on this
 		DEBUG.Println(ROU, "matchAndDispatch exiting")
 	}()
-	return ackOutChan
+	return ackChan
 }

vendor/modules.txt

@@ -144,8 +144,8 @@ github.com/dromara/carbon/v2/calendar/hebrew
 github.com/dromara/carbon/v2/calendar/julian
 github.com/dromara/carbon/v2/calendar/lunar
 github.com/dromara/carbon/v2/calendar/persian
-# github.com/eclipse/paho.mqtt.golang v1.5.0
-## explicit; go 1.20
+# github.com/eclipse/paho.mqtt.golang v1.5.1
+## explicit; go 1.24.0
 github.com/eclipse/paho.mqtt.golang
 github.com/eclipse/paho.mqtt.golang/packets
 # github.com/emicklei/go-restful/v3 v3.11.0