Add tests for IsTaggedNull, IsYNodeEmptySeq and IsYNodeEmptyMap.

kyaml/yaml/fns.go

@@ -482,7 +482,7 @@ func (s FieldSetter) Filter(rn *RNode) (*RNode, error) {
 	}
 
 	// Clear the field if it is empty, or explicitly null
-	if s.Value == nil || IsNull(s.Value) {
+	if s.Value == nil || s.Value.IsTaggedNull() {
 		return rn.Pipe(Clear(s.Name))
 	}
 
@@ -568,7 +568,7 @@ var nodeTypeIndex = map[yaml.Kind]string{
 }
 
 func ErrorIfInvalid(rn *RNode, kind yaml.Kind) error {
-	if rn == nil || rn.YNode() == nil || IsNull(rn) {
+	if rn == nil || rn.YNode() == nil || rn.IsTaggedNull() {
 		// node has no type, pass validation
 		return nil
 	}

kyaml/yaml/merge2/merge2.go

@@ -56,7 +56,7 @@ func (m Merger) VisitMap(nodes walk.Sources, s *openapi.ResourceSchema) (*yaml.R
 		// Add
 		return nodes.Origin(), nil
 	}
-	if yaml.IsNull(nodes.Origin()) {
+	if nodes.Origin().IsTaggedNull() {
 		// clear the value
 		return walk.ClearNode, nil
 	}
@@ -112,7 +112,7 @@ func (m Merger) VisitList(nodes walk.Sources, s *openapi.ResourceSchema, kind wa
 		return nodes.Origin(), nil
 	}
 	// Clear
-	if yaml.IsNull(nodes.Origin()) {
+	if nodes.Origin().IsTaggedNull() {
 		return walk.ClearNode, nil
 	}
 	// Recursively Merge dest

kyaml/yaml/merge3/visitor.go

@@ -20,7 +20,7 @@ const (
 type Visitor struct{}
 
 func (m Visitor) VisitMap(nodes walk.Sources, s *openapi.ResourceSchema) (*yaml.RNode, error) {
-	if yaml.IsNull(nodes.Updated()) || yaml.IsNull(nodes.Dest()) {
+	if nodes.Updated().IsTaggedNull() || nodes.Dest().IsTaggedNull() {
 		// explicitly cleared from either dest or update
 		return walk.ClearNode, nil
 	}
@@ -54,7 +54,7 @@ func (m Visitor) visitAList(nodes walk.Sources, _ *openapi.ResourceSchema) (*yam
 }
 
 func (m Visitor) VisitScalar(nodes walk.Sources, s *openapi.ResourceSchema) (*yaml.RNode, error) {
-	if yaml.IsNull(nodes.Updated()) || yaml.IsNull(nodes.Dest()) {
+	if nodes.Updated().IsTaggedNull() || nodes.Dest().IsTaggedNull() {
 		// explicitly cleared from either dest or update
 		return nil, nil
 	}
@@ -91,7 +91,7 @@ func (m Visitor) VisitScalar(nodes walk.Sources, s *openapi.ResourceSchema) (*ya
 }
 
 func (m Visitor) visitNAList(nodes walk.Sources) (*yaml.RNode, error) {
-	if yaml.IsNull(nodes.Updated()) || yaml.IsNull(nodes.Dest()) {
+	if nodes.Updated().IsTaggedNull() || nodes.Dest().IsTaggedNull() {
 		// explicitly cleared from either dest or update
 		return walk.ClearNode, nil
 	}

kyaml/yaml/types.go

@@ -49,10 +49,6 @@ func IsEmptyMap(node *RNode) bool {
 	return IsMissingOrNull(node) || IsYNodeEmptyMap(node.YNode())
 }
 
-func IsNull(node *RNode) bool {
-	return !node.IsNil() && node.YNode().Tag == NodeTagNull
-}
-
 func IsFieldEmpty(node *MapNode) bool {
 	if node == nil || node.Value == nil || node.Value.YNode() == nil ||
 		node.Value.YNode().Tag == NodeTagNull {
@@ -63,11 +59,16 @@ func IsFieldEmpty(node *MapNode) bool {
 }
 
 func IsYNodeEmptyMap(n *yaml.Node) bool {
-	return n.Kind == yaml.MappingNode && len(n.Content) == 0
+	return n != nil && n.Kind == yaml.MappingNode && len(n.Content) == 0
+}
+
+// IsYNodeTaggedNull returns true if the node is explicitly tagged Null.
+func IsYNodeTaggedNull(n *yaml.Node) bool {
+	return n != nil && n.Tag == NodeTagNull
 }
 
 func IsYNodeEmptySeq(n *yaml.Node) bool {
-	return n.Kind == yaml.SequenceNode && len(n.Content) == 0
+	return n != nil && n.Kind == yaml.SequenceNode && len(n.Content) == 0
 }
 
 // IsYNodeEmptyDoc is true if the node is a Document with no content.
@@ -377,6 +378,11 @@ func (rn *RNode) IsNil() bool {
 	return rn == nil || rn.YNode() == nil
 }
 
+// IsTaggedNull is true if a non-nil node is explicitly tagged Null.
+func (rn *RNode) IsTaggedNull() bool {
+	return !rn.IsNil() && IsYNodeTaggedNull(rn.YNode())
+}
+
 // GetMeta returns the ResourceMeta for an RNode
 func (rn *RNode) GetMeta() (ResourceMeta, error) {
 	if IsMissingOrNull(rn) {

kyaml/yaml/types_test.go

@@ -167,6 +167,61 @@ type: string
 	assert.Equal(t, expected, actual)
 }
 
+func TestIsYNodeTaggedNull(t *testing.T) {
+	if IsYNodeTaggedNull(nil) {
+		t.Fatalf("nil cannot be tagged null")
+	}
+	if IsYNodeTaggedNull(&Node{}) {
+		t.Fatalf("untagged node is not tagged")
+	}
+	if IsYNodeTaggedNull(&Node{Tag: NodeTagFloat}) {
+		t.Fatalf("float tagged node is not tagged")
+	}
+	if !IsYNodeTaggedNull(&Node{Tag: NodeTagNull}) {
+		t.Fatalf("tagged node is tagged")
+	}
+}
+
+func TestIsYNodeEmptyMap(t *testing.T) {
+	if IsYNodeEmptyMap(nil) {
+		t.Fatalf("nil cannot be a map")
+	}
+	if IsYNodeEmptyMap(&Node{}) {
+		t.Fatalf("raw node is not a map")
+	}
+	if IsYNodeEmptyMap(&Node{Kind: SequenceNode}) {
+		t.Fatalf("seq node is not a map")
+	}
+	n := &Node{Kind: MappingNode}
+	if !IsYNodeEmptyMap(n) {
+		t.Fatalf("empty mapping node is an empty mapping node")
+	}
+	n.Content = append(n.Content, &Node{Kind: SequenceNode})
+	if IsYNodeEmptyMap(n) {
+		t.Fatalf("a node with content isn't empty")
+	}
+}
+
+func TestIsYNodeEmptySeq(t *testing.T) {
+	if IsYNodeEmptySeq(nil) {
+		t.Fatalf("nil cannot be a map")
+	}
+	if IsYNodeEmptySeq(&Node{}) {
+		t.Fatalf("raw node is not a map")
+	}
+	if IsYNodeEmptySeq(&Node{Kind: MappingNode}) {
+		t.Fatalf("map node is not a sequence")
+	}
+	n := &Node{Kind: SequenceNode}
+	if !IsYNodeEmptySeq(n) {
+		t.Fatalf("empty sequence node is an empty sequence node")
+	}
+	n.Content = append(n.Content, &Node{Kind: MappingNode})
+	if IsYNodeEmptySeq(n) {
+		t.Fatalf("a node with content isn't empty")
+	}
+}
+
 func TestIsMissingOrNull(t *testing.T) {
 	if !IsMissingOrNull(nil) {
 		t.Fatalf("input: nil")
@@ -244,3 +299,27 @@ func TestIsNil(t *testing.T) {
 		t.Fatalf("empty list not nil")
 	}
 }
+
+func TestIsTaggedNull(t *testing.T) {
+	var rn *RNode
+
+	if rn.IsTaggedNull() {
+		t.Fatalf("nil RNode cannot be tagged")
+	}
+
+	if NewRNode(nil).IsTaggedNull() {
+		t.Fatalf("bare RNode should not be tagged")
+	}
+
+	if !MakeNullNode().IsTaggedNull() {
+		t.Fatalf("a null node is tagged null by definition")
+	}
+
+	if NewMapRNode(nil).IsTaggedNull() {
+		t.Fatalf("empty map should not be tagged null")
+	}
+
+	if NewListRNode().IsTaggedNull() {
+		t.Fatalf("empty list should not be tagged null")
+	}
+}