Merge pull request #2836 from phanimarupaka/BumpKyamlAndCliUtils

Bump kyaml and cli-utils in cmd/config

README.md

@@ -9,18 +9,15 @@ patch [kubernetes style] API objects.  It's like
 [`make`], in that what it does is declared in a file,
 and it's like [`sed`], in that it emits edited text.
 
-This tool is sponsored by [sig-cli] ([KEP]), and
-inspired by [DAM].
+This tool is sponsored by [sig-cli] ([KEP]).
+
+ - [Installation instructions](https://kubernetes-sigs.github.io/kustomize/installation)
+ - [General documentation](https://kubernetes-sigs.github.io/kustomize)
+ - [Examples](examples)
 
 [![Build Status](https://prow.k8s.io/badge.svg?jobs=kustomize-presubmit-master)](https://prow.k8s.io/job-history/kubernetes-jenkins/pr-logs/directory/kustomize-presubmit-master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/kubernetes-sigs/kustomize)](https://goreportcard.com/report/github.com/kubernetes-sigs/kustomize)
 
-Download a binary from the [release page], or see
-these [instructions](https://kubernetes-sigs.github.io/kustomize/installation/).
-
-Browse the [docs](https://kubernetes-sigs.github.io/kustomize/) or jump right into the
-tested [examples](examples).
-
 ## kubectl integration
 
 Since [v1.14][kubectl announcement] the kustomize build system has been included in kubectl.

api/filters/namespace/namespace.go

@@ -112,7 +112,7 @@ func (ns Filter) roleBindingHack(obj *yaml.RNode, meta yaml.ResourceMeta) error
 	// Lookup the namespace field on all elements.
 	// We should change the fieldspec so this isn't necessary.
 	obj, err := obj.Pipe(yaml.Lookup(subjectsField))
-	if err != nil || yaml.IsEmpty(obj) {
+	if err != nil || yaml.IsMissingOrNull(obj) {
 		return err
 	}
 
@@ -125,7 +125,7 @@ func (ns Filter) roleBindingHack(obj *yaml.RNode, meta yaml.ResourceMeta) error
 		name, err := o.Pipe(
 			yaml.Lookup("name"), yaml.Match("default"),
 		)
-		if err != nil || yaml.IsEmpty(name) {
+		if err != nil || yaml.IsMissingOrNull(name) {
 			return err
 		}
 

api/filters/refvar/refvar.go

@@ -66,8 +66,7 @@ func updateNodeValue(node *yaml.Node, newValue interface{}) {
 }
 
 func (f Filter) setScalar(node *yaml.RNode) error {
-	if node.YNode().Kind != yaml.ScalarNode || node.YNode().Tag != yaml.NodeTagString {
-		// Only process string values
+	if !yaml.IsYNodeString(node.YNode()) {
 		return nil
 	}
 	v := expansion2.Expand(node.YNode().Value, f.MappingFunc)
@@ -78,11 +77,10 @@ func (f Filter) setScalar(node *yaml.RNode) error {
 func (f Filter) setMap(node *yaml.RNode) error {
 	contents := node.YNode().Content
 	for i := 0; i < len(contents); i += 2 {
-		if contents[i].Kind != yaml.ScalarNode || contents[i].Tag != yaml.NodeTagString {
+		if !yaml.IsYNodeString(contents[i]) {
 			return fmt.Errorf("invalid map key: %s, type: %s", contents[i].Value, contents[i].Tag)
 		}
-		if contents[i+1].Kind != yaml.ScalarNode || contents[i+1].Tag != yaml.NodeTagString {
-			// value is not a string
+		if !yaml.IsYNodeString(contents[i+1]) {
 			continue
 		}
 		newValue := expansion2.Expand(contents[i+1].Value, f.MappingFunc)
@@ -93,8 +91,7 @@ func (f Filter) setMap(node *yaml.RNode) error {
 
 func (f Filter) setSeq(node *yaml.RNode) error {
 	for _, item := range node.YNode().Content {
-		if item.Kind != yaml.ScalarNode || item.Tag != yaml.NodeTagString {
-			// value is not a string
+		if !yaml.IsYNodeString(item) {
 			return fmt.Errorf("invalid value type expect a string")
 		}
 		newValue := expansion2.Expand(item.Value, f.MappingFunc)

cmd/config/go.mod

@@ -14,6 +14,6 @@ require (
 	k8s.io/cli-runtime v0.17.3
 	k8s.io/client-go v0.17.3
 	k8s.io/kubectl v0.0.0-20191219154910-1528d4eea6dd
-	sigs.k8s.io/cli-utils v0.17.0
-	sigs.k8s.io/kustomize/kyaml v0.5.0
+	sigs.k8s.io/cli-utils v0.18.0
+	sigs.k8s.io/kustomize/kyaml v0.6.0
 )

cmd/config/go.sum

@@ -619,6 +619,8 @@ modernc.org/strutil v1.0.0/go.mod h1:lstksw84oURvj9y3tn8lGvRxyRC1S2+g5uuIzNfIOBs
 modernc.org/xc v1.0.0/go.mod h1:mRNCo0bvLjGhHO9WsyuKVU4q0ceiDDDoEeWDJHrNx8I=
 sigs.k8s.io/cli-utils v0.17.0 h1:iQ0nhgU8DZiRphHTErI1IHcHYp2fZaULrrFN4NF3dCc=
 sigs.k8s.io/cli-utils v0.17.0/go.mod h1:9Jqm9K2W6ShhCxsEuaz6HSRKKOXigPUx3ZfypGgxBLY=
+sigs.k8s.io/cli-utils v0.18.0 h1:PPFUhhwKsdMiYYm1DY9lZursNWSAEj8FYgMCZKVvOkQ=
+sigs.k8s.io/cli-utils v0.18.0/go.mod h1:B7KdqkSkHNIUn3cFbaR4aKUZMKtr+Benboi1w/HW/Fg=
 sigs.k8s.io/controller-runtime v0.4.0 h1:wATM6/m+3w8lj8FXNaO6Fs/rq/vqoOjO1Q116Z9NPsg=
 sigs.k8s.io/controller-runtime v0.4.0/go.mod h1:ApC79lpY3PHW9xj/w9pj+lYkLgwAAUZwfXkME1Lajns=
 sigs.k8s.io/kustomize v2.0.3+incompatible h1:JUufWFNlI44MdtnjUqVnvh29rR37PQFzPbLXqhyOyX0=
@@ -626,6 +628,8 @@ sigs.k8s.io/kustomize v2.0.3+incompatible/go.mod h1:MkjgH3RdOWrievjo6c9T245dYlB5
 sigs.k8s.io/kustomize/kyaml v0.4.0/go.mod h1:XJL84E6sOFeNrQ7CADiemc1B0EjIxHo3OhW4o1aJYNw=
 sigs.k8s.io/kustomize/kyaml v0.5.0 h1:xufpSxgpugQxtd0aN1ZsWnr3Kj0fpAi7GN4dnEs4oPg=
 sigs.k8s.io/kustomize/kyaml v0.5.0/go.mod h1:bEzbO5pN9OvlEeCLvFHo8Pu7SA26Herc2m60UeWZBdI=
+sigs.k8s.io/kustomize/kyaml v0.6.0 h1:Z/9TxsiG21sbcd6JD4IeM6BVZ2+04001KKzbxCf+qeY=
+sigs.k8s.io/kustomize/kyaml v0.6.0/go.mod h1:bEzbO5pN9OvlEeCLvFHo8Pu7SA26Herc2m60UeWZBdI=
 sigs.k8s.io/structured-merge-diff v0.0.0-20190525122527-15d366b2352e/go.mod h1:wWxsB5ozmmv/SG7nM11ayaAW51xMvak/t1r0CSlcokI=
 sigs.k8s.io/structured-merge-diff v0.0.0-20190817042607-6149e4549fca/go.mod h1:IIgPezJWb76P0hotTxzDbWsMYB8APh18qZnxkomBpxA=
 sigs.k8s.io/structured-merge-diff v1.0.1-0.20191108220359-b1b620dd3f06 h1:zD2IemQ4LmOcAumeiyDWXKUI2SO0NYDe3H6QGvPOVgU=

cmd/config/internal/commands/cmdxargs.go

@@ -177,13 +177,13 @@ func (r *XArgsRunner) runE(c *cobra.Command, _ []string) error {
 		}
 
 		if r.WrapKind != "" {
-			if kind := rw.FunctionConfig.Field("kind"); !yaml.IsFieldEmpty(kind) {
+			if kind := rw.FunctionConfig.Field("kind"); !kind.IsNilOrEmpty() {
 				kind.Value.YNode().Value = r.WrapKind
 			}
 			rw.WrappingKind = r.WrapKind
 		}
 		if r.WrapVersion != "" {
-			if version := rw.FunctionConfig.Field("apiVersion"); !yaml.IsFieldEmpty(version) {
+			if version := rw.FunctionConfig.Field("apiVersion"); !version.IsNilOrEmpty() {
 				version.Value.YNode().Value = r.WrapVersion
 			}
 			rw.WrappingAPIVersion = r.WrapVersion

kustomize/go.mod

@@ -8,13 +8,14 @@ require (
 	github.com/spf13/pflag v1.0.5
 	k8s.io/client-go v0.17.3
 	sigs.k8s.io/kustomize/api v0.5.1
-	sigs.k8s.io/kustomize/cmd/config v0.4.2
+	sigs.k8s.io/kustomize/cmd/config v0.5.0
 	sigs.k8s.io/yaml v1.2.0
 )
 
 replace (
 	sigs.k8s.io/kustomize/api v0.5.1 => ../api
-	sigs.k8s.io/kustomize/cmd/config v0.4.2 => ../cmd/config
+	sigs.k8s.io/kustomize/cmd/config v0.5.0 => ../cmd/config
+	sigs.k8s.io/kustomize/kyaml => ../kyaml
 )
 
 exclude (

kyaml/fn/runtime/runtimeutil/functiontypes.go

@@ -138,7 +138,7 @@ func getFunctionSpecFromAnnotation(n *yaml.RNode, meta yaml.ResourceMeta) *Funct
 		}
 	}
 	n, err := n.Pipe(yaml.Lookup("metadata", "configFn"))
-	if err != nil || yaml.IsEmpty(n) {
+	if err != nil || yaml.IsMissingOrNull(n) {
 		return nil
 	}
 	s, err := n.String()

kyaml/kio/tree.go

@@ -238,10 +238,10 @@ func ownerToString(node *yaml.RNode) (string, error) {
 	owner := elements[0]
 	var kind, name string
 
-	if value := owner.Field("kind"); !yaml.IsFieldEmpty(value) {
+	if value := owner.Field("kind"); !value.IsNilOrEmpty() {
 		kind = value.Value.YNode().Value
 	}
-	if value := owner.Field("name"); !yaml.IsFieldEmpty(value) {
+	if value := owner.Field("name"); !value.IsNilOrEmpty() {
 		name = value.Value.YNode().Value
 	}
 

kyaml/openapi/openapi.go

@@ -36,7 +36,7 @@ type ResourceSchema struct {
 }
 
 // IsEmpty returns true if the ResourceSchema is empty
-func (rs *ResourceSchema) IsEmpty() bool {
+func (rs *ResourceSchema) IsMissingOrNull() bool {
 	if rs == nil || rs.Schema == nil {
 		return true
 	}
@@ -84,7 +84,7 @@ func AddSchemaFromFileUsingField(path, field string) error {
 	if field != "" {
 		// get the field containing the openAPI
 		m := y.Field(field)
-		if yaml.IsFieldEmpty(m) {
+		if m.IsNilOrEmpty() {
 			// doesn't contain openAPI definitions
 			return nil
 		}

kyaml/setters2/list.go

@@ -53,7 +53,7 @@ func (l *List) listSetters(object *yaml.RNode, resourcePath string) error {
 	if err != nil {
 		return err
 	}
-	if yaml.IsEmpty(def) {
+	if yaml.IsMissingOrNull(def) {
 		return nil
 	}
 
@@ -73,7 +73,7 @@ func (l *List) listSetters(object *yaml.RNode, resourcePath string) error {
 		if err != nil {
 			return err
 		}
-		if yaml.IsEmpty(setterNode) {
+		if yaml.IsMissingOrNull(setterNode) {
 			// has the setter prefix, but missing the setter extension
 			return errors.Errorf("missing x-k8s-cli.setter for %s", key)
 		}
@@ -126,7 +126,7 @@ func (l *List) listSubst(object *yaml.RNode) error {
 	if err != nil {
 		return err
 	}
-	if yaml.IsEmpty(def) {
+	if yaml.IsMissingOrNull(def) {
 		return nil
 	}
 
@@ -146,7 +146,7 @@ func (l *List) listSubst(object *yaml.RNode) error {
 		if err != nil {
 			return err
 		}
-		if yaml.IsEmpty(substNode) {
+		if yaml.IsMissingOrNull(substNode) {
 			// has the substitution prefix, but missing the setter extension
 			return errors.Errorf("missing x-k8s-cli.substitution for %s", key)
 		}

kyaml/setters2/walk.go

@@ -110,7 +110,7 @@ func getSchema(r *yaml.RNode, s *openapi.ResourceSchema, field string) *openapi.
 		return s
 	}
 
-	if yaml.IsEmpty(r) {
+	if yaml.IsMissingOrNull(r) {
 		return nil
 	}
 

kyaml/yaml/fns.go

@@ -70,7 +70,7 @@ func (e ElementSetter) Filter(rn *RNode) (*RNode, error) {
 		newNode := NewRNode(elem)
 
 		// empty elements are not valid -- they at least need an associative key
-		if IsEmpty(newNode) || IsEmptyMap(newNode) {
+		if IsMissingOrNull(newNode) || IsEmptyMap(newNode) {
 			continue
 		}
 
@@ -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))
 	}
 
@@ -549,7 +549,7 @@ func IsFoundOrError(rn *RNode, err error) bool {
 
 func ErrorIfAnyInvalidAndNonNull(kind yaml.Kind, rn ...*RNode) error {
 	for i := range rn {
-		if IsEmpty(rn[i]) {
+		if IsMissingOrNull(rn[i]) {
 			continue
 		}
 		if err := ErrorIfInvalid(rn[i], kind); err != nil {
@@ -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 IsMissingOrNull(rn) {
 		// node has no type, pass validation
 		return nil
 	}

kyaml/yaml/merge2/merge2.go

@@ -52,11 +52,11 @@ func (m Merger) VisitMap(nodes walk.Sources, s *openapi.ResourceSchema) (*yaml.R
 	if err := m.SetStyle(nodes); err != nil {
 		return nil, err
 	}
-	if yaml.IsEmpty(nodes.Dest()) {
+	if yaml.IsMissingOrNull(nodes.Dest()) {
 		// Add
 		return nodes.Origin(), nil
 	}
-	if yaml.IsNull(nodes.Origin()) {
+	if nodes.Origin().IsTaggedNull() {
 		// clear the value
 		return walk.ClearNode, nil
 	}
@@ -108,11 +108,11 @@ func (m Merger) VisitList(nodes walk.Sources, s *openapi.ResourceSchema, kind wa
 	}
 
 	// Add
-	if yaml.IsEmpty(nodes.Dest()) {
+	if yaml.IsMissingOrNull(nodes.Dest()) {
 		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
 	}
@@ -39,11 +39,11 @@ func (m Visitor) VisitMap(nodes walk.Sources, s *openapi.ResourceSchema) (*yaml.
 }
 
 func (m Visitor) visitAList(nodes walk.Sources, _ *openapi.ResourceSchema) (*yaml.RNode, error) {
-	if yaml.IsEmpty(nodes.Updated()) && !yaml.IsEmpty(nodes.Origin()) {
+	if yaml.IsMissingOrNull(nodes.Updated()) && !yaml.IsMissingOrNull(nodes.Origin()) {
 		// implicitly cleared from update -- element was deleted
 		return walk.ClearNode, nil
 	}
-	if yaml.IsEmpty(nodes.Dest()) {
+	if yaml.IsMissingOrNull(nodes.Dest()) {
 		// not cleared, but missing from the dest
 		// initialize a new value that can be recursively merged
 		return yaml.NewRNode(&yaml.Node{Kind: yaml.SequenceNode}), nil
@@ -54,15 +54,15 @@ 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
 	}
-	if yaml.IsEmpty(nodes.Updated()) != yaml.IsEmpty(nodes.Origin()) {
+	if yaml.IsMissingOrNull(nodes.Updated()) != yaml.IsMissingOrNull(nodes.Origin()) {
 		// value added or removed in update
 		return nodes.Updated(), nil
 	}
-	if yaml.IsEmpty(nodes.Updated()) && yaml.IsEmpty(nodes.Origin()) {
+	if yaml.IsMissingOrNull(nodes.Updated()) && yaml.IsMissingOrNull(nodes.Origin()) {
 		// value added or removed in update
 		return nodes.Dest(), nil
 	}
@@ -91,16 +91,16 @@ 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
 	}
 
-	if yaml.IsEmpty(nodes.Updated()) != yaml.IsEmpty(nodes.Origin()) {
+	if yaml.IsMissingOrNull(nodes.Updated()) != yaml.IsMissingOrNull(nodes.Origin()) {
 		// value added or removed in update
 		return nodes.Updated(), nil
 	}
-	if yaml.IsEmpty(nodes.Updated()) && yaml.IsEmpty(nodes.Origin()) {
+	if yaml.IsMissingOrNull(nodes.Updated()) && yaml.IsMissingOrNull(nodes.Origin()) {
 		// value not present in source or dest
 		return nodes.Dest(), nil
 	}

kyaml/yaml/schema/schema.go

@@ -22,7 +22,7 @@ func IsAssociative(schema *openapi.ResourceSchema, nodes []*yaml.RNode, infer bo
 	}
 	for i := range nodes {
 		node := nodes[i]
-		if yaml.IsEmpty(node) {
+		if yaml.IsMissingOrNull(node) {
 			continue
 		}
 		if node.IsAssociative() {

kyaml/yaml/types.go

@@ -33,48 +33,32 @@ func MakeNullNode() *RNode {
 	return NewRNode(&Node{Tag: NodeTagNull})
 }
 
-// IsMissingOrNull returns true if the RNode is nil or contains and explicitly null value.
+// IsMissingOrNull is true if the RNode is nil or explicitly tagged null.
+// TODO: make this a method on RNode.
 func IsMissingOrNull(node *RNode) bool {
-	return IsNil(node) || node.YNode().Tag == NodeTagNull
+	return node.IsNil() || node.YNode().Tag == NodeTagNull
 }
 
-// IsEmpty returns true if the RNode is MissingOrNull
-func IsEmpty(node *RNode) bool {
-	return IsMissingOrNull(node)
-}
-
-// IsEmptyMap returns true if the RNode is an empty node or an empty map
+// IsEmptyMap returns true if the RNode is an empty node or an empty map.
+// TODO: make this a method on RNode.
 func IsEmptyMap(node *RNode) bool {
-	if IsEmpty(node) {
-		return true
-	}
-	return IsYNodeEmptyMap(node.YNode())
+	return IsMissingOrNull(node) || IsYNodeEmptyMap(node.YNode())
 }
 
-// IsNil return true if the node is nil, or its underlying YNode is nil.
-func IsNil(node *RNode) bool {
-	return node == nil || node.YNode() == nil
-}
-
-func IsNull(node *RNode) bool {
-	return !IsNil(node) && node.YNode().Tag == NodeTagNull
-}
-
-func IsFieldEmpty(node *MapNode) bool {
-	if node == nil || node.Value == nil || node.Value.YNode() == nil ||
-		node.Value.YNode().Tag == NodeTagNull {
-		return true
-	}
-	return IsYNodeEmptyMap(node.Value.YNode()) ||
-		IsYNodeEmptySeq(node.Value.YNode())
+// IsYNodeTaggedNull returns true if the node is explicitly tagged Null.
+func IsYNodeTaggedNull(n *yaml.Node) bool {
+	return n != nil && n.Tag == NodeTagNull
 }
 
+// IsYNodeEmptyMap is true if the Node is a non-nil empty map.
 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
 }
 
+
+// IsYNodeEmptyMap is true if the Node is a non-nil empty sequence.
 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.
@@ -89,17 +73,12 @@ func IsYNodeString(n *yaml.Node) bool {
 
 // GetValue returns underlying yaml.Node Value field
 func GetValue(node *RNode) string {
-	if IsEmpty(node) {
+	if IsMissingOrNull(node) {
 		return ""
 	}
 	return node.YNode().Value
 }
 
-func IsFieldNull(node *MapNode) bool {
-	return node != nil && node.Value != nil && node.Value.YNode() != nil &&
-		node.Value.YNode().Tag == NodeTagNull
-}
-
 // Parser parses values into configuration.
 type Parser struct {
 	Kind  string `yaml:"kind,omitempty"`
@@ -275,6 +254,12 @@ type MapNode struct {
 	Value *RNode
 }
 
+// IsNilOrEmpty returns true if the MapNode is nil,
+// has no value, or has a value that appears empty.
+func (mn *MapNode) IsNilOrEmpty() bool {
+	return mn == nil || mn.Value.IsNilOrEmpty()
+}
+
 type MapNodeSlice []*MapNode
 
 func (m MapNodeSlice) Keys() []*RNode {
@@ -379,9 +364,28 @@ const (
 	LabelsField      = "labels"
 )
 
+// IsNil is true if the node is nil, or its underlying YNode is nil.
+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())
+}
+
+// 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 IsEmpty(rn) {
+	if IsMissingOrNull(rn) {
 		return ResourceMeta{}, nil
 	}
 	missingMeta := true
@@ -396,17 +400,17 @@ func (rn *RNode) GetMeta() (ResourceMeta, error) {
 	m := ResourceMeta{}
 
 	// TODO: consider optimizing this parsing
-	if f := n.Field(APIVersionField); !IsFieldEmpty(f) {
+	if f := n.Field(APIVersionField); !f.IsNilOrEmpty() {
 		m.APIVersion = GetValue(f.Value)
 		missingMeta = false
 	}
-	if f := n.Field(KindField); !IsFieldEmpty(f) {
+	if f := n.Field(KindField); !f.IsNilOrEmpty() {
 		m.Kind = GetValue(f.Value)
 		missingMeta = false
 	}
 
 	mf := n.Field(MetadataField)
-	if IsFieldEmpty(mf) {
+	if mf.IsNilOrEmpty() {
 		if missingMeta {
 			return m, ErrMissingMetadata
 		}
@@ -414,16 +418,16 @@ func (rn *RNode) GetMeta() (ResourceMeta, error) {
 	}
 	meta := mf.Value
 
-	if f := meta.Field(NameField); !IsFieldEmpty(f) {
+	if f := meta.Field(NameField); !f.IsNilOrEmpty() {
 		m.Name = f.Value.YNode().Value
 		missingMeta = false
 	}
-	if f := meta.Field(NamespaceField); !IsFieldEmpty(f) {
+	if f := meta.Field(NamespaceField); !f.IsNilOrEmpty() {
 		m.Namespace = GetValue(f.Value)
 		missingMeta = false
 	}
 
-	if f := meta.Field(LabelsField); !IsFieldEmpty(f) {
+	if f := meta.Field(LabelsField); !f.IsNilOrEmpty() {
 		m.Labels = map[string]string{}
 		_ = f.Value.VisitFields(func(node *MapNode) error {
 			m.Labels[GetValue(node.Key)] = GetValue(node.Value)
@@ -431,7 +435,7 @@ func (rn *RNode) GetMeta() (ResourceMeta, error) {
 		})
 		missingMeta = false
 	}
-	if f := meta.Field(AnnotationsField); !IsFieldEmpty(f) {
+	if f := meta.Field(AnnotationsField); !f.IsNilOrEmpty() {
 		m.Annotations = map[string]string{}
 		_ = f.Value.VisitFields(func(node *MapNode) error {
 			m.Annotations[GetValue(node.Key)] = GetValue(node.Value)
@@ -650,7 +654,7 @@ func (rn *RNode) ElementValues(key string) ([]string, error) {
 	var elements []string
 	for i := 0; i < len(rn.Content()); i++ {
 		field := NewRNode(rn.Content()[i]).Field(key)
-		if !IsFieldEmpty(field) {
+		if !field.IsNilOrEmpty() {
 			elements = append(elements, field.Value.YNode().Value)
 		}
 	}

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")
@@ -183,42 +238,26 @@ func TestIsMissingOrNull(t *testing.T) {
 	if !IsMissingOrNull(MakeNullNode()) {
 		t.Fatalf("input: with NullNodeTag")
 	}
-}
 
-func TestIsEmpty(t *testing.T) {
-	if !IsEmpty(nil) {
-		t.Fatalf("input: nil")
-	}
-
-	// missing value or null value
-	if !IsEmpty(NewRNode(nil)) {
-		t.Fatalf("input: nil value")
-	}
-	// not array or map
-	if IsEmpty(NewScalarRNode("foo")) {
-		t.Fatalf("input: not array or map")
-	}
-}
-
-func TestIsEmpty_Arrays(t *testing.T) {
-	node := NewListRNode()
 	// empty array. empty array is not expected as empty
-	if IsEmpty(node) {
+	if IsMissingOrNull(NewListRNode()) {
 		t.Fatalf("input: empty array")
 	}
+
 	// array with 1 item
-	node = NewListRNode("foo")
-	if IsEmpty(node) {
+	node := NewListRNode("foo")
+	if IsMissingOrNull(node) {
 		t.Fatalf("input: array with 1 item")
 	}
+
 	// delete the item in array
 	node.value.Content = nil
-	if IsEmpty(node) {
+	if IsMissingOrNull(node) {
 		t.Fatalf("input: empty array")
 	}
 }
 
-func TestIsEmpty_Maps(t *testing.T) {
+func TestIsEmptyMap(t *testing.T) {
 	node := NewMapRNode(nil)
 	// empty map
 	if !IsEmptyMap(node) {
@@ -237,3 +276,126 @@ func TestIsEmpty_Maps(t *testing.T) {
 		t.Fatalf("input: empty map")
 	}
 }
+
+func TestIsNil(t *testing.T) {
+	var rn *RNode
+
+	if !rn.IsNil() {
+		t.Fatalf("uninitialized RNode should be nil")
+	}
+
+	if !NewRNode(nil).IsNil() {
+		t.Fatalf("missing value YNode should be nil")
+	}
+
+	if MakeNullNode().IsNil() {
+		t.Fatalf("value tagged null is not nil")
+	}
+
+	if NewMapRNode(nil).IsNil() {
+		t.Fatalf("empty map not nil")
+	}
+
+	if NewListRNode().IsNil() {
+		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")
+	}
+}
+
+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")
+	}
+}
+
+func TestMapNodeIsNilOrEmpty(t *testing.T) {
+	var mn *MapNode
+
+	if !mn.IsNilOrEmpty() {
+		t.Fatalf("nil should be empty")
+	}
+
+	mn = &MapNode{Key: MakeNullNode()}
+	if !mn.IsNilOrEmpty() {
+		t.Fatalf("missing value should be empty")
+	}
+
+	mn.Value = NewRNode(nil)
+	if !mn.IsNilOrEmpty() {
+		t.Fatalf("missing value YNode should be empty")
+	}
+
+	mn.Value = MakeNullNode()
+	if !mn.IsNilOrEmpty() {
+		t.Fatalf("value tagged null should be empty")
+	}
+
+	mn.Value = NewMapRNode(nil)
+	if !mn.IsNilOrEmpty() {
+		t.Fatalf("empty map should be empty")
+	}
+
+	mn.Value = NewMapRNode(&map[string]string{"foo": "bar"})
+	if mn.IsNilOrEmpty() {
+		t.Fatalf("non-empty map should not be empty")
+	}
+
+	mn.Value = NewListRNode()
+	if !mn.IsNilOrEmpty() {
+		t.Fatalf("empty list should be empty")
+	}
+
+	mn.Value = NewListRNode("foo")
+	if mn.IsNilOrEmpty() {
+		t.Fatalf("non-empty list should not be empty")
+	}
+}

kyaml/yaml/walk/associative_sequence.go

@@ -51,7 +51,7 @@ func (l *Walker) walkAssociativeSequence() (*yaml.RNode, error) {
 			if err != nil {
 				return nil, err
 			}
-			if yaml.IsEmpty(val) || yaml.IsEmptyMap(val) {
+			if yaml.IsMissingOrNull(val) || yaml.IsEmptyMap(val) {
 				_, err = dest.Pipe(yaml.ElementSetter{Key: key, Value: value})
 				if err != nil {
 					return nil, err
@@ -74,7 +74,7 @@ func (l *Walker) walkAssociativeSequence() (*yaml.RNode, error) {
 			}
 		}
 		// field is empty
-		if yaml.IsEmpty(dest) {
+		if yaml.IsMissingOrNull(dest) {
 			return nil, nil
 		}
 		return dest, nil
@@ -97,7 +97,7 @@ func (l *Walker) walkAssociativeSequence() (*yaml.RNode, error) {
 		if err != nil {
 			return nil, err
 		}
-		if yaml.IsEmpty(val) {
+		if yaml.IsMissingOrNull(val) {
 			_, err = dest.Pipe(yaml.ElementSetter{Key: key, Value: value})
 			if err != nil {
 				return nil, err
@@ -121,7 +121,7 @@ func (l *Walker) walkAssociativeSequence() (*yaml.RNode, error) {
 	}
 
 	// field is empty
-	if yaml.IsEmpty(dest) {
+	if yaml.IsMissingOrNull(dest) {
 		return nil, nil
 	}
 	return dest, nil

kyaml/yaml/walk/map.go

@@ -39,7 +39,7 @@ func (l Walker) walkMap() (*yaml.RNode, error) {
 					continue
 				}
 				field := l.Sources[i].Field(key)
-				if field == nil || yaml.IsEmpty(field.Key) {
+				if field == nil || yaml.IsMissingOrNull(field.Key) {
 					keys = append(keys, nil)
 					continue
 				}
@@ -148,7 +148,7 @@ func (l Walker) fieldValue(fieldName string) ([]*yaml.RNode, *openapi.ResourceSc
 		field := l.Sources[i].Field(fieldName)
 		f, s := l.valueIfPresent(field)
 		fields = append(fields, f)
-		if sch == nil && !s.IsEmpty() {
+		if sch == nil && !s.IsMissingOrNull() {
 			sch = s
 		}
 	}

kyaml/yaml/walk/walk.go

@@ -40,7 +40,7 @@ type Walker struct {
 
 func (l Walker) Kind() yaml.Kind {
 	for _, s := range l.Sources {
-		if !yaml.IsEmpty(s) {
+		if !yaml.IsMissingOrNull(s) {
 			return s.YNode().Kind
 		}
 	}
@@ -83,7 +83,7 @@ func (l Walker) Walk() (*yaml.RNode, error) {
 func (l Walker) GetSchema() *openapi.ResourceSchema {
 	for i := range l.Sources {
 		r := l.Sources[i]
-		if yaml.IsEmpty(r) {
+		if yaml.IsMissingOrNull(r) {
 			continue
 		}
 
@@ -106,7 +106,7 @@ func (l Walker) GetSchema() *openapi.ResourceSchema {
 	}
 	for i := range l.Sources {
 		r := l.Sources[i]
-		if yaml.IsEmpty(r) {
+		if yaml.IsMissingOrNull(r) {
 			continue
 		}
 

site/content/en/api-reference/kustomization/vars/_index.md

@@ -71,7 +71,7 @@ can only be placed in particular fields of
 particular objects as specified by kustomize's
 configuration data.
 
-The default config data for vars is at [/api/konfig/builtinpluginconsts/varreference.go](/konfig/builtinpluginconsts/varreference.go)
+The default config data for vars is at [/api/konfig/builtinpluginconsts/varreference.go](https://github.com/kubernetes-sigs/kustomize/blob/master/api/konfig/builtinpluginconsts/varreference.go)
 Long story short, the default targets are all
 container command args and env value fields.