optimize field.Set{} -> nil

pkg/registry/certificates/strategy.go

@@ -184,5 +184,5 @@ func Matcher(label labels.Selector, field fields.Selector) *generic.SelectionPre
 
 // SelectableFields returns a field set that can be used for filter selection
 func SelectableFields(obj *certificates.CertificateSigningRequest) fields.Set {
-	return fields.Set{}
+	return nil
 }

pkg/registry/clusterrole/strategy.go

@@ -118,5 +118,5 @@ func Matcher(label labels.Selector, field fields.Selector) *generic.SelectionPre
 
 // SelectableFields returns a field set that can be used for filter selection
 func SelectableFields(obj *rbac.ClusterRole) fields.Set {
-	return fields.Set{}
+	return nil
 }

pkg/registry/clusterrolebinding/strategy.go

@@ -118,5 +118,5 @@ func Matcher(label labels.Selector, field fields.Selector) *generic.SelectionPre
 
 // SelectableFields returns a field set that can be used for filter selection
 func SelectableFields(obj *rbac.ClusterRoleBinding) fields.Set {
-	return fields.Set{}
+	return nil
 }

pkg/registry/generic/matcher.go

@@ -68,7 +68,11 @@ func (s *SelectionPredicate) Matches(obj runtime.Object) (bool, error) {
 	if err != nil {
 		return false, err
 	}
-	return s.Label.Matches(labels) && s.Field.Matches(fields), nil
+	matched := s.Label.Matches(labels)
+	if s.Field != nil {
+		matched = (matched && s.Field.Matches(fields))
+	}
+	return matched, nil
 }
 
 // MatchesSingle will return (name, true) if and only if s.Field matches on the object's

pkg/registry/horizontalpodautoscaler/strategy.go

@@ -85,7 +85,7 @@ func (autoscalerStrategy) AllowUnconditionalUpdate() bool {
 }
 
 func AutoscalerToSelectableFields(hpa *autoscaling.HorizontalPodAutoscaler) fields.Set {
-	return fields.Set{}
+	return nil
 }
 
 func MatchAutoscaler(label labels.Selector, field fields.Selector) *generic.SelectionPredicate {

pkg/registry/limitrange/strategy.go

@@ -75,7 +75,7 @@ func (limitrangeStrategy) AllowUnconditionalUpdate() bool {
 }
 
 func LimitRangeToSelectableFields(limitRange *api.LimitRange) fields.Set {
-	return fields.Set{}
+	return nil
 }
 
 func (limitrangeStrategy) Export(api.Context, runtime.Object, bool) error {

pkg/registry/podtemplate/strategy.go

@@ -83,7 +83,7 @@ func (podTemplateStrategy) Export(ctx api.Context, obj runtime.Object, exact boo
 }
 
 func PodTemplateToSelectableFields(podTemplate *api.PodTemplate) fields.Set {
-	return fields.Set{}
+	return nil
 }
 
 func MatchPodTemplate(label labels.Selector, field fields.Selector) *generic.SelectionPredicate {

pkg/registry/role/strategy.go

@@ -118,5 +118,5 @@ func Matcher(label labels.Selector, field fields.Selector) *generic.SelectionPre
 
 // SelectableFields returns a field set that can be used for filter selection
 func SelectableFields(obj *rbac.Role) fields.Set {
-	return fields.Set{}
+	return nil
 }

pkg/registry/rolebinding/strategy.go

@@ -118,5 +118,5 @@ func Matcher(label labels.Selector, field fields.Selector) *generic.SelectionPre
 
 // SelectableFields returns a field set that can be used for filter selection
 func SelectableFields(obj *rbac.RoleBinding) fields.Set {
-	return fields.Set{}
+	return nil
 }

pkg/registry/thirdpartyresource/strategy.go

@@ -94,5 +94,5 @@ func Matcher(label labels.Selector, field fields.Selector) *generic.SelectionPre
 
 // SelectableFields returns a field set that can be used for filter selection
 func SelectableFields(obj *extensions.ThirdPartyResource) fields.Set {
-	return fields.Set{}
+	return nil
 }

pkg/registry/thirdpartyresourcedata/strategy.go

@@ -91,5 +91,5 @@ func Matcher(label labels.Selector, field fields.Selector) *generic.SelectionPre
 
 // SelectableFields returns a field set that can be used for filter selection
 func SelectableFields(obj *extensions.ThirdPartyResourceData) fields.Set {
-	return fields.Set{}
+	return nil
 }