Add RNode.IsNilOrEmpty and test.

kyaml/yaml/types.go

@@ -383,6 +383,15 @@ func (rn *RNode) IsTaggedNull() bool {
 	return !rn.IsNil() && IsYNodeTaggedNull(rn.YNode())
 }
 
+// IsNilOrEmpty is true if the node is nil,
+// has no YNode, or has YNode that appears empty.
+func (rn *RNode) IsNilOrEmpty() bool {
+	return rn.IsNil() ||
+		IsYNodeTaggedNull(rn.YNode()) ||
+		IsYNodeEmptyMap(rn.YNode()) ||
+		IsYNodeEmptySeq(rn.YNode())
+}
+
 // GetMeta returns the ResourceMeta for an RNode
 func (rn *RNode) GetMeta() (ResourceMeta, error) {
 	if IsMissingOrNull(rn) {

kyaml/yaml/types_test.go

@@ -323,3 +323,35 @@ func TestIsTaggedNull(t *testing.T) {
 		t.Fatalf("empty list should not be tagged null")
 	}
 }
+
+func TestRNodeIsNilOrEmpty(t *testing.T) {
+	var rn *RNode
+
+	if !rn.IsNilOrEmpty() {
+		t.Fatalf("uninitialized RNode should be empty")
+	}
+
+	if !NewRNode(nil).IsNilOrEmpty() {
+		t.Fatalf("missing value YNode should be empty")
+	}
+
+	if !MakeNullNode().IsNilOrEmpty() {
+		t.Fatalf("value tagged null should be empty")
+	}
+
+	if !NewMapRNode(nil).IsNilOrEmpty() {
+		t.Fatalf("empty map should be empty")
+	}
+
+	if NewMapRNode(&map[string]string{"foo": "bar"}).IsNilOrEmpty() {
+		t.Fatalf("non-empty map should not be empty")
+	}
+
+	if !NewListRNode().IsNilOrEmpty() {
+		t.Fatalf("empty list should be empty")
+	}
+
+	if NewListRNode("foo").IsNilOrEmpty() {
+		t.Fatalf("non-empty list should not be empty")
+	}
+}