fix copy comments to include document comments

kyaml/comments/comments.go

@@ -11,6 +11,7 @@ import (
 
 // CopyComments recursively copies the comments on fields in from to fields in to
 func CopyComments(from, to *yaml.RNode) error {
+	copy(from, to)
 	// walk the fields copying comments
 	_, err := walk.Walker{
 		Sources:            []*yaml.RNode{from, to},
@@ -44,13 +45,13 @@ func copy(from, to *yaml.RNode) {
 	if from == nil || to == nil {
 		return
 	}
-	if from.YNode().LineComment != "" {
+	if from.Document().LineComment != "" {
-		to.YNode().LineComment = from.YNode().LineComment
+		to.Document().LineComment = from.Document().LineComment
 	}
-	if from.YNode().HeadComment != "" {
+	if from.Document().HeadComment != "" {
-		to.YNode().HeadComment = from.YNode().HeadComment
+		to.Document().HeadComment = from.Document().HeadComment
 	}
-	if from.YNode().FootComment != "" {
+	if from.Document().FootComment != "" {
-		to.YNode().FootComment = from.YNode().FootComment
+		to.Document().FootComment = from.Document().FootComment
 	}
 }

kyaml/comments/comments_test.go

@@ -0,0 +1,65 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package comments
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+func TestCopyComments(t *testing.T) {
+	from, err := yaml.Parse(`# A
+#
+# B
+
+# C
+apiVersion: apps/v1
+kind: Deployment
+spec: # comment 1
+  # comment 2
+  replicas: 3 # comment 3
+  # comment 4
+`)
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+
+	to, err := yaml.Parse(`apiVersion: apps/v1
+kind: Deployment
+spec:
+  replicas: 4
+`)
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+
+	err = CopyComments(from, to)
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+
+	actual, err := to.String()
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+
+	expected := `# A
+#
+# B
+
+# C
+apiVersion: apps/v1
+kind: Deployment
+spec: # comment 1
+  # comment 2
+  replicas: 4 # comment 3
+  # comment 4
+`
+
+	if !assert.Equal(t, expected, actual) {
+		t.FailNow()
+	}
+}