migrate to upstream libcompose in one and a half go

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

@@ -15,9 +15,6 @@ type Stringorslice struct {
 
 // MarshalYAML implements the Marshaller interface.
 func (s Stringorslice) MarshalYAML() (tag string, value interface{}, err error) {
-	if s.parts == nil {
-		return "", []string{}, nil
-	}
 	return "", s.parts, nil
 }
 
@@ -67,9 +64,6 @@ type Command struct {
 
 // MarshalYAML implements the Marshaller interface.
 func (s Command) MarshalYAML() (tag string, value interface{}, err error) {
-	if s.parts == nil {
-		return "", []string{}, nil
-	}
 	return "", s.parts, nil
 }
 
@@ -113,9 +107,6 @@ type SliceorMap struct {
 
 // MarshalYAML implements the Marshaller interface.
 func (s SliceorMap) MarshalYAML() (tag string, value interface{}, err error) {
-	if s.parts == nil {
-		return "", map[string]string{}, nil
-	}
 	return "", s.parts, nil
 }
 
@@ -169,9 +160,6 @@ type MaporEqualSlice struct {
 
 // MarshalYAML implements the Marshaller interface.
 func (s MaporEqualSlice) MarshalYAML() (tag string, value interface{}, err error) {
-	if s.parts == nil {
-		return "", []string{}, nil
-	}
 	return "", s.parts, nil
 }
 
@@ -214,9 +202,6 @@ type MaporColonSlice struct {
 
 // MarshalYAML implements the Marshaller interface.
 func (s MaporColonSlice) MarshalYAML() (tag string, value interface{}, err error) {
-	if s.parts == nil {
-		return "", []string{}, nil
-	}
 	return "", s.parts, nil
 }
 
@@ -259,9 +244,6 @@ type MaporSpaceSlice struct {
 
 // MarshalYAML implements the Marshaller interface.
 func (s MaporSpaceSlice) MarshalYAML() (tag string, value interface{}, err error) {
-	if s.parts == nil {
-		return "", []string{}, nil
-	}
 	return "", s.parts, nil
 }
 

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

@@ -120,6 +120,11 @@ type StructSliceorMap struct {
 	Bars []string   `yaml:"bars"`
 }
 
+type StructCommand struct {
+	Entrypoint Command `yaml:"entrypoint,flow,omitempty"`
+	Command    Command `yaml:"command,flow,omitempty"`
+}
+
 func TestSliceOrMapYaml(t *testing.T) {
 	str := `{foos: [bar=baz, far=faz]}`
 
@@ -192,3 +197,24 @@ func TestMaporsliceYaml(t *testing.T) {
 	assert.True(t, contains(s2.Foo.parts, "bar=baz"))
 	assert.True(t, contains(s2.Foo.parts, "far=faz"))
 }
+
+var sampleStructCommand = `command: bash`
+
+func TestUnmarshalCommand(t *testing.T) {
+	s := &StructCommand{}
+	err := yaml.Unmarshal([]byte(sampleStructCommand), s)
+
+	assert.Nil(t, err)
+	assert.Equal(t, []string{"bash"}, s.Command.Slice())
+	assert.Nil(t, s.Entrypoint.Slice())
+
+	bytes, err := yaml.Marshal(s)
+	assert.Nil(t, err)
+
+	s2 := &StructCommand{}
+	err = yaml.Unmarshal(bytes, s2)
+
+	assert.Nil(t, err)
+	assert.Equal(t, []string{"bash"}, s.Command.Slice())
+	assert.Nil(t, s.Entrypoint.Slice())
+}