doc: add docstring for parent and delete a duplicate if condition

applylib/applyset/parentref.go

@@ -1,3 +1,19 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+// This package provides Parent object related methods.
 package applyset
 
 import (
@@ -6,7 +22,8 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 )
 
-// This parentref.go guarantees the main k-d-p don't need to import the kubectl.
+// Parent is aimed for adaption. We want users to us Parent rather than the third-party/forked ParentRef directly.
+// This gives us more flexibility to change the third-party/forked without introducing breaking changes to users.
 type Parent interface {
 	GroupVersionKind() schema.GroupVersionKind
 	Name() string
@@ -15,6 +32,7 @@ type Parent interface {
 	GetSubject() runtime.Object
 }
 
+// NewParentRef initialize a ParentRef object.
 func NewParentRef(object runtime.Object, name, namespace string, rest *meta.RESTMapping) *ParentRef {
 	return &ParentRef{
 		object:      object,
@@ -26,29 +44,35 @@ func NewParentRef(object runtime.Object, name, namespace string, rest *meta.REST
 
 var _ Parent = &ParentRef{}
 
+// ParentRef defines the Parent object information
 type ParentRef struct {
 	namespace   string
 	name        string
 	restMapping *meta.RESTMapping
 	object      runtime.Object
 }
 
+// GroupVersionKind returns the parent GroupVersionKind
 func (p *ParentRef) GroupVersionKind() schema.GroupVersionKind {
 	return p.object.GetObjectKind().GroupVersionKind()
 }
 
+// Name returns the parent Name
 func (p *ParentRef) Name() string {
 	return p.name
 }
 
+// Namespace returns the parent Namespace
 func (p *ParentRef) Namespace() string {
 	return p.namespace
 }
 
+// RESTMapping returns the parent RESTMapping
 func (p *ParentRef) RESTMapping() *meta.RESTMapping {
 	return p.restMapping
 }
 
+// GetSubject returns the parent runtime.Object
 func (p *ParentRef) GetSubject() runtime.Object {
 	return p.object
 }

pkg/restmapper/controllerrestmapper.go

@@ -93,9 +93,6 @@ func (m *ControllerRESTMapper) RESTMappings(gk schema.GroupKind, versions ...str
 			return nil, err
 		}
 		group, found := allGroups[gk.Group]
-		if err != nil {
-			return nil, err
-		}
 		if !found {
 			return nil, &meta.NoResourceMatchError{PartialResource: schema.GroupVersionResource{Group: gk.Group, Resource: gk.Kind}}
 		}