@@ -103,13 +103,6 @@ func updateService(flags *pflag.FlagSet, spec *swarm.ServiceSpec) error {

 		}

 	}

-	updateListOpts := func(flag string, field *[]string) {

-		if flags.Changed(flag) {

-			value := flags.Lookup(flag).Value.(*opts.ListOpts)

-			*field = value.GetAll()

-		}

-	}

-

 	updateInt64Value := func(flag string, field *int64) {

 		if flags.Changed(flag) {

 			*field = flags.Lookup(flag).Value.(int64Value).Value()

@@ -243,15 +236,10 @@ func anyChanged(flags *pflag.FlagSet, fields ...string) bool {

 func updatePlacement(flags *pflag.FlagSet, placement *swarm.Placement) {

 	field, _ := flags.GetStringSlice(flagConstraintAdd)

-	constraints := &placement.Constraints

 	placement.Constraints = append(placement.Constraints, field...)

 	toRemove := buildToRemoveSet(flags, flagConstraintRemove)

-	for i, constraint := range placement.Constraints {

-		if _, exists := toRemove[constraint]; exists {

-			*constraints = append((*constraints)[:i], (*constraints)[i+1:]...)

-		}

-	}

+	placement.Constraints = removeItems(placement.Constraints, toRemove, itemKey)

 }

 func updateLabels(flags *pflag.FlagSet, field *map[string]string) {

@@ -280,12 +268,7 @@ func updateEnvironment(flags *pflag.FlagSet, field *[]string) {

 		*field = append(*field, value.GetAll()...)

 	}

 	toRemove := buildToRemoveSet(flags, flagEnvRemove)

-	for i, env := range *field {

-		key := envKey(env)

-		if _, exists := toRemove[key]; exists {

-			*field = append((*field)[:i], (*field)[i+1:]...)

-		}

-	}

+	*field = removeItems(*field, toRemove, envKey)

 }

 func envKey(value string) string {

@@ -293,6 +276,10 @@ func envKey(value string) string {

 	return kv[0]

 }

+func itemKey(value string) string {

+	return value

+}

+

 func buildToRemoveSet(flags *pflag.FlagSet, flag string) map[string]struct{} {

 	var empty struct{}

 	toRemove := make(map[string]struct{})

@@ -308,17 +295,34 @@ func buildToRemoveSet(flags *pflag.FlagSet, flag string) map[string]struct{} {

 	return toRemove

 }

+func removeItems(

+	seq []string,

+	toRemove map[string]struct{},

+	keyFunc func(string) string,

+) []string {

+	newSeq := []string{}

+	for _, item := range seq {

+		if _, exists := toRemove[keyFunc(item)]; !exists {

+			newSeq = append(newSeq, item)

+		}

+	}

+	return newSeq

+}

+

 func updateMounts(flags *pflag.FlagSet, mounts *[]swarm.Mount) {

 	if flags.Changed(flagMountAdd) {

 		values := flags.Lookup(flagMountAdd).Value.(*MountOpt).Value()

 		*mounts = append(*mounts, values...)

 	}

 	toRemove := buildToRemoveSet(flags, flagMountRemove)

-	for i, mount := range *mounts {

-		if _, exists := toRemove[mount.Target]; exists {

-			*mounts = append((*mounts)[:i], (*mounts)[i+1:]...)

+

+	newMounts := []swarm.Mount{}

+	for _, mount := range *mounts {

+		if _, exists := toRemove[mount.Target]; !exists {

+			newMounts = append(newMounts, mount)

 		}

 	}

+	*mounts = newMounts

 }

 func updatePorts(flags *pflag.FlagSet, portConfig *[]swarm.PortConfig) {

@@ -331,19 +335,27 @@ func updatePorts(flags *pflag.FlagSet, portConfig *[]swarm.PortConfig) {

 		}

 	}

-	if flags.Changed(flagPublishRemove) {

-		toRemove := flags.Lookup(flagPublishRemove).Value.(*opts.ListOpts).GetAll()

+	if !flags.Changed(flagPublishRemove) {

+		return

+	}

+	toRemove := flags.Lookup(flagPublishRemove).Value.(*opts.ListOpts).GetAll()

+	newPorts := []swarm.PortConfig{}

+portLoop:

+	for _, port := range *portConfig {

 		for _, rawTargetPort := range toRemove {

 			targetPort := nat.Port(rawTargetPort)

-			for i, port := range *portConfig {

-				if string(port.Protocol) == targetPort.Proto() &&

-					port.TargetPort == uint32(targetPort.Int()) {

-					*portConfig = append((*portConfig)[:i], (*portConfig)[i+1:]...)

-					break

-				}

+			if equalPort(targetPort, port) {

+				continue portLoop

 			}

 		}

+		newPorts = append(newPorts, port)

 	}

+	*portConfig = newPorts

+}

+

+func equalPort(targetPort nat.Port, port swarm.PortConfig) bool {

+	return (string(port.Protocol) == targetPort.Proto() &&

+		port.TargetPort == uint32(targetPort.Int()))

 }

 func updateNetworks(flags *pflag.FlagSet, attachments *[]swarm.NetworkAttachmentConfig) {

@@ -354,11 +366,13 @@ func updateNetworks(flags *pflag.FlagSet, attachments *[]swarm.NetworkAttachment

 		}

 	}

 	toRemove := buildToRemoveSet(flags, flagNetworkRemove)

-	for i, network := range *attachments {

-		if _, exists := toRemove[network.Target]; exists {

-			*attachments = append((*attachments)[:i], (*attachments)[i+1:]...)

+	newNetworks := []swarm.NetworkAttachmentConfig{}

+	for _, network := range *attachments {

+		if _, exists := toRemove[network.Target]; !exists {

+			newNetworks = append(newNetworks, network)

 		}

 	}

+	*attachments = newNetworks

 }

 func updateReplicas(flags *pflag.FlagSet, serviceMode *swarm.ServiceMode) error {

@@ -35,6 +35,15 @@ func TestUpdateLabels(t *testing.T) {

 	assert.Equal(t, labels["toadd"], "newlabel")

 }

+func TestUpdateLabelsRemoveALabelThatDoesNotExist(t *testing.T) {

+	flags := newUpdateCommand(nil).Flags()

+	flags.Set("label-rm", "dne")

+

+	labels := map[string]string{"foo": "theoldlabel"}

+	updateLabels(flags, &labels)

+	assert.Equal(t, len(labels), 1)

+}

+

 func TestUpdatePlacement(t *testing.T) {

 	flags := newUpdateCommand(nil).Flags()

 	flags.Set("constraint-add", "node=toadd")

@@ -63,6 +72,18 @@ func TestUpdateEnvironment(t *testing.T) {

 	assert.Equal(t, envs[1], "toadd=newenv")

 }

+func TestUpdateEnvironmentWithDuplicateValues(t *testing.T) {

+	flags := newUpdateCommand(nil).Flags()

+	flags.Set("env-add", "foo=newenv")

+	flags.Set("env-add", "foo=dupe")

+	flags.Set("env-rm", "foo")

+

+	envs := []string{"foo=value"}

+

+	updateEnvironment(flags, &envs)

+	assert.Equal(t, len(envs), 0)

+}

+

 func TestUpdateMounts(t *testing.T) {

 	flags := newUpdateCommand(nil).Flags()

 	flags.Set("mount-add", "type=volume,target=/toadd")