@@ -189,7 +189,7 @@ func from(b *Builder, args []string, attributes map[string]bool, original string

 		return err

 	}

 	b.resetImageCache()

-	if _, err := b.imageContexts.new(ctxName, true); err != nil {

+	if _, err := b.imageContexts.add(ctxName); err != nil {

 		return err

 	}

@@ -846,11 +846,7 @@ func mountByRef(b *Builder, name string) (*imageMount, error) {

 	if err != nil {

 		return nil, err

 	}

-	im, err := b.imageContexts.new("", false)

-	if err != nil {

-		return nil, err

-	}

-	im.id = image.ImageID()

+	im := b.imageContexts.newImageMount(image.ImageID())

 	return im, nil

 }

@@ -22,7 +22,11 @@ type imageContexts struct {

 	currentName string

 }

-func (ic *imageContexts) new(name string, increment bool) (*imageMount, error) {

+func (ic *imageContexts) newImageMount(id string) *imageMount {

+	return &imageMount{ic: ic, id: id}

+}

+

+func (ic *imageContexts) add(name string) (*imageMount, error) {

 	im := &imageMount{ic: ic}

 	if len(name) > 0 {

 		if ic.byName == nil {

@@ -33,10 +37,8 @@ func (ic *imageContexts) new(name string, increment bool) (*imageMount, error) {

 		}

 		ic.byName[name] = im

 	}

-	if increment {

-		ic.list = append(ic.list, im)

-	}

 	ic.currentName = name

+	ic.list = append(ic.list, im)

 	return im, nil

 }