kuberc: introduce fuzzing for kuberc types

Signed-off-by: Maciej Szulik <soltysh@gmail.com>

Kubernetes-commit: c29accaf5819bd4b05409cecb9bbb3ba065d840b

pkg/config/fuzzer/fuzzer.go

@@ -0,0 +1,33 @@
+/*
+Copyright 2025 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.
+*/
+
+package fuzzer
+
+import (
+	"sigs.k8s.io/randfill"
+
+	runtimeserializer "k8s.io/apimachinery/pkg/runtime/serializer"
+	"k8s.io/kubectl/pkg/config"
+)
+
+// Funcs returns the fuzzer functions for the kubectl apis.
+func Funcs(codecs runtimeserializer.CodecFactory) []interface{} {
+	return []interface{}{
+		func(obj *config.Preference, c randfill.Continue) {
+			c.FillNoCustom(obj)
+		},
+	}
+}

pkg/config/scheme/scheme.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2024 The Kubernetes Authors.
+Copyright 2025 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.
@@ -14,20 +14,34 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-// Package install installs the experimental API group, making it available as
-// an option to all of the API encoding/decoding machinery.
-package install
+package scheme
 
 import (
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/kubectl/pkg/config"
 	"k8s.io/kubectl/pkg/config/v1alpha1"
 	"k8s.io/kubectl/pkg/config/v1beta1"
 )
 
-// Install registers the API group and adds types to a scheme
-func Install(scheme *runtime.Scheme) {
+var (
+	// Scheme defines methods for serializing and deserializing API objects.
+	Scheme = runtime.NewScheme()
+	// StrictCodecs provides methods for retrieving codecs and serializers
+	// for specific versions and content types.
+	StrictCodecs = serializer.NewCodecFactory(Scheme, serializer.EnableStrict)
+	// LenientCodecs provides methods for retrieving codecs and serializers
+	// for specific versions and content types.
+	LenientCodecs = serializer.NewCodecFactory(Scheme, serializer.DisableStrict)
+)
+
+func init() {
+	AddToScheme(Scheme)
+}
+
+// AddToScheme registers the API group and adds types to a scheme
+func AddToScheme(scheme *runtime.Scheme) {
 	utilruntime.Must(config.AddToScheme(scheme))
 	utilruntime.Must(v1beta1.AddToScheme(scheme))
 	utilruntime.Must(v1alpha1.AddToScheme(scheme))

pkg/config/scheme/scheme_test.go

@@ -0,0 +1,28 @@
+/*
+Copyright 2025 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.
+*/
+
+package scheme
+
+import (
+	"testing"
+
+	"k8s.io/apimachinery/pkg/api/apitesting/roundtrip"
+	"k8s.io/kubectl/pkg/config/fuzzer"
+)
+
+func TestRoundTripTypes(t *testing.T) {
+	roundtrip.RoundTripTestForScheme(t, Scheme, fuzzer.Funcs)
+}

pkg/kuberc/kuberc.go

@@ -24,16 +24,13 @@ import (
 	"regexp"
 	"strings"
 
-	"k8s.io/kubectl/pkg/config"
-	kuberc "k8s.io/kubectl/pkg/config/install"
-
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/runtime/serializer"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/util/homedir"
+	"k8s.io/kubectl/pkg/config"
 )
 
 const RecommendedKubeRCFileName = "kuberc"
@@ -44,16 +41,8 @@ var (
 
 	aliasNameRegex = regexp.MustCompile("^[a-zA-Z]+$")
 	shortHandRegex = regexp.MustCompile("^-[a-zA-Z]+$")
-
-	scheme        = runtime.NewScheme()
-	strictCodecs  = serializer.NewCodecFactory(scheme, serializer.EnableStrict)
-	lenientCodecs = serializer.NewCodecFactory(scheme, serializer.DisableStrict)
 )
 
-func init() {
-	kuberc.Install(scheme)
-}
-
 // PreferencesHandler is responsible for setting default flags
 // arguments based on user's kuberc configuration.
 type PreferencesHandler interface {

pkg/kuberc/marshal.go

@@ -24,12 +24,11 @@ import (
 	"io"
 	"os"
 
-	"k8s.io/klog/v2"
-
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	utilyaml "k8s.io/apimachinery/pkg/util/yaml"
-
+	"k8s.io/klog/v2"
 	"k8s.io/kubectl/pkg/config"
+	"k8s.io/kubectl/pkg/config/scheme"
 )
 
 // decodePreference iterates over the yamls in kuberc file to find the supported kuberc version.
@@ -58,10 +57,10 @@ func decodePreference(kubercFile string) (*config.Preference, error) {
 		}
 		// remember we attempted
 		attemptedItems++
-		pref, gvk, strictDecodeErr := strictCodecs.UniversalDecoder().Decode(doc, nil, nil)
+		pref, gvk, strictDecodeErr := scheme.StrictCodecs.UniversalDecoder().Decode(doc, nil, nil)
 		if strictDecodeErr != nil {
 			var lenientDecodeErr error
-			pref, gvk, lenientDecodeErr = lenientCodecs.UniversalDecoder().Decode(doc, nil, nil)
+			pref, gvk, lenientDecodeErr = scheme.LenientCodecs.UniversalDecoder().Decode(doc, nil, nil)
 			if lenientDecodeErr != nil {
 				// both strict and lenient failed
 				// verbose log the error with the most information about this item and continue