fix String protobuf generator

cmd/libs/go2idl/go-to-protobuf/protobuf/parser.go

@@ -132,7 +132,7 @@ func rewriteOptionalMethods(decl ast.Decl, isOptional OptionalFunc) {
 		switch t.Name.Name {
 		case "Unmarshal":
 			ast.Walk(&optionalItemsVisitor{}, t.Body)
-		case "MarshalTo", "Size":
+		case "MarshalTo", "Size", "String":
 			ast.Walk(&optionalItemsVisitor{}, t.Body)
 			fallthrough
 		case "Marshal":

pkg/apis/authentication/v1beta1/generated.pb.go

@@ -376,16 +376,6 @@ func sovGenerated(x uint64) (n int) {
 func sozGenerated(x uint64) (n int) {
 	return sovGenerated(uint64((x << 1) ^ uint64((int64(x) >> 63))))
 }
-func (this *ExtraValue) String() string {
-	if this == nil {
-		return "nil"
-	}
-	s := strings.Join([]string{`&ExtraValue{`,
-		`Items:` + fmt.Sprintf("%v", this.Items) + `,`,
-		`}`,
-	}, "")
-	return s
-}
 func (this *TokenReview) String() string {
 	if this == nil {
 		return "nil"

pkg/apis/authentication/v1beta1/generated.proto

@@ -32,6 +32,7 @@ option go_package = "v1beta1";
 
 // ExtraValue masks the value so protobuf can generate
 // +protobuf.nullable=true
+// +protobuf.options.(gogoproto.goproto_stringer)=false
 message ExtraValue {
   // items, if empty, will result in an empty slice
 

pkg/apis/authentication/v1beta1/types.go

@@ -17,6 +17,8 @@ limitations under the License.
 package v1beta1
 
 import (
+	"fmt"
+
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/api/v1"
 )
@@ -72,4 +74,9 @@ type UserInfo struct {
 
 // ExtraValue masks the value so protobuf can generate
 // +protobuf.nullable=true
+// +protobuf.options.(gogoproto.goproto_stringer)=false
 type ExtraValue []string
+
+func (t ExtraValue) String() string {
+	return fmt.Sprintf("%v", []string(t))
+}