Bump libcompose

Replace empty slices with nils in unmarshaled libcompose datatypes.

glide.yaml

@@ -27,7 +27,7 @@ import:
   version: 58b270c338e831ac6668a29788c72d202f9fc251
 
 - package: github.com/docker/libcompose
-  version: 5cad17e57c7c5a2faa180b75c5beb90afc7dde05
+  version: d4939c5f375cfe102e04810cf0db4127cfbb1875
 
 - package: github.com/docker/libcontainer
   version: 83a102cc68a09d890cce3b6c2e5c14c49e6373a0

vendor/github.com/docker/libcompose/Dockerfile

@@ -1,5 +1,5 @@
 # This file describes the standard way to build libcompose, using docker
-FROM golang:1.5.1
+FROM golang:1.5.2
 
 RUN apt-get update && apt-get install -y \
     iptables \

vendor/github.com/docker/libcompose/project/types_yaml.go

@@ -19,6 +19,9 @@ func (s Stringorslice) MarshalYAML() (tag string, value interface{}, err error)
 }
 
 func toStrings(s []interface{}) ([]string, error) {
+	if len(s) == 0 {
+		return nil, nil
+	}
 	r := make([]string, len(s))
 	for k, v := range s {
 		if sv, ok := v.(string); ok {
@@ -81,7 +84,6 @@ func (s Command) MarshalYAML() (tag string, value interface{}, err error) {
 
 // UnmarshalYAML implements the Unmarshaller interface.
 func (s *Command) UnmarshalYAML(tag string, value interface{}) error {
-	var err error
 	switch value := value.(type) {
 	case []interface{}:
 		parts, err := toStrings(value)
@@ -90,11 +92,15 @@ func (s *Command) UnmarshalYAML(tag string, value interface{}) error {
 		}
 		s.parts = parts
 	case string:
-		s.parts, err = shlex.Split(value)
+		parts, err := shlex.Split(value)
+		if err != nil {
+			return err
+		}
+		s.parts = parts
 	default:
 		return fmt.Errorf("Failed to unmarshal Command: %#v", value)
 	}
-	return err
+	return nil
 }
 
 // ToString returns the parts of the command as a string (joined by spaces).
@@ -188,6 +194,9 @@ func (s MaporEqualSlice) MarshalYAML() (tag string, value interface{}, err error
 }
 
 func toSepMapParts(value map[interface{}]interface{}, sep string) ([]string, error) {
+	if len(value) == 0 {
+		return nil, nil
+	}
 	parts := make([]string, 0, len(value))
 	for k, v := range value {
 		if sk, ok := k.(string); ok {

vendor/github.com/docker/libcompose/project/types_yaml_test.go

@@ -1,11 +1,12 @@
 package project
 
 import (
+	"fmt"
+	"strings"
 	"testing"
 
 	yaml "github.com/cloudfoundry-incubator/candiedyaml"
 
-	"fmt"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -22,14 +23,10 @@ func newTestConfig() TestConfig {
 		SystemContainers: map[string]*ServiceConfig{
 			"udev": {
 				Image:      "udev",
-				Entrypoint: Command{[]string{}},
-				Command:    Command{[]string{}},
 				Restart:    "always",
 				Net:        "host",
 				Privileged: true,
 				DNS:        Stringorslice{[]string{"8.8.8.8", "8.8.4.4"}},
-				DNSSearch:  Stringorslice{[]string{}},
-				EnvFile:    Stringorslice{[]string{}},
 				Environment: MaporEqualSlice{[]string{
 					"DAEMON=true",
 				}},
@@ -37,27 +34,19 @@ func newTestConfig() TestConfig {
 					"io.rancher.os.detach": "true",
 					"io.rancher.os.scope":  "system",
 				}},
-				Links: MaporColonSlice{[]string{}},
 				VolumesFrom: []string{
 					"system-volumes",
 				},
 			},
 			"system-volumes": {
 				Image:      "state",
-				Entrypoint:  Command{[]string{}},
-				Command:     Command{[]string{}},
 				Net:        "none",
 				ReadOnly:   true,
 				Privileged: true,
-				DNS:         Stringorslice{[]string{}},
-				DNSSearch:   Stringorslice{[]string{}},
-				EnvFile:     Stringorslice{[]string{}},
-				Environment: MaporEqualSlice{[]string{}},
 				Labels: SliceorMap{map[string]string{
 					"io.rancher.os.createonly": "true",
 					"io.rancher.os.scope":      "system",
 				}},
-				Links: MaporColonSlice{[]string{}},
 				Volumes: []string{
 					"/dev:/host/dev",
 					"/var/lib/rancher/conf:/var/lib/rancher/conf",
@@ -221,6 +210,26 @@ func TestUnmarshalCommand(t *testing.T) {
 	err = yaml.Unmarshal(bytes, s2)
 
 	assert.Nil(t, err)
-	assert.Equal(t, []string{"bash"}, s.Command.Slice())
-	assert.Nil(t, s.Entrypoint.Slice())
+	assert.Equal(t, []string{"bash"}, s2.Command.Slice())
+	assert.Nil(t, s2.Entrypoint.Slice())
+}
+
+var sampleEmptyCommand = `{}`
+
+func TestUnmarshalEmptyCommand(t *testing.T) {
+	s := &StructCommand{}
+	err := yaml.Unmarshal([]byte(sampleEmptyCommand), s)
+
+	assert.Nil(t, err)
+	assert.Nil(t, s.Command.Slice())
+
+	bytes, err := yaml.Marshal(s)
+	assert.Nil(t, err)
+	assert.Equal(t, "entrypoint: []\ncommand: []", strings.TrimSpace(string(bytes)))
+
+	s2 := &StructCommand{}
+	err = yaml.Unmarshal(bytes, s2)
+
+	assert.Nil(t, err)
+	assert.Nil(t, s2.Command.Slice())
 }