Fix wrong type assertion for gnmi version within capabilities

internal/gnmiserver/server.go

@@ -17,11 +17,8 @@ limitations under the License.
 package gnmiserver
 
 import (
-	"bytes"
-	"compress/gzip"
 	"encoding/json"
 	"fmt"
-	"io"
 	"reflect"
 	"strconv"
 	"time"
@@ -39,7 +36,6 @@ import (
 
 	"code.fbi.h-da.de/danet/gnmi-target/handler"
 	not "code.fbi.h-da.de/danet/gnmi-target/internal/notifications"
-	dpb "github.com/golang/protobuf/protoc-gen-go/descriptor"
 	"github.com/openconfig/gnmi/proto/gnmi"
 	pb "github.com/openconfig/gnmi/proto/gnmi"
 )
@@ -415,23 +411,11 @@ func (s *Server) toGoStruct(jsonTree map[string]interface{}) (ygot.ValidatedGoSt
 // TODO: Fix the deprecated path.GetElement
 //
 //nolint:all
-func getGNMIServiceVersion() (*string, error) {
-	gzB, _ := (&pb.Update{}).Descriptor()
-	r, err := gzip.NewReader(bytes.NewReader(gzB))
-	if err != nil {
-		return nil, fmt.Errorf("error in initializing gzip reader: %w", err)
-	}
-	defer r.Close() //nolint:errcheck
-	b, err := io.ReadAll(r)
-	if err != nil {
-		return nil, fmt.Errorf("error in reading gzip data: %w", err)
-	}
-	desc := &dpb.FileDescriptorProto{}
-	if err := proto.Unmarshal(b, desc); err != nil {
-		return nil, fmt.Errorf("error in unmarshaling proto: %w", err)
-	}
-	ver := proto.GetExtension(desc.Options, pb.E_GnmiService)
-	return ver.(*string), nil
+func getGNMIServiceVersion() (string, error) {
+	gzB := (&pb.Update{}).ProtoReflect().Descriptor()
+	parentOptions := gzB.Parent().Options()
+	ver := proto.GetExtension(parentOptions, pb.E_GnmiService)
+	return ver.(string), nil
 }
 
 // deleteKeyedListEntry deletes the keyed list entry from node that matches the
@@ -572,7 +556,7 @@ func (s *Server) Capabilities(ctx context.Context, req *pb.CapabilityRequest) (*
 	return &pb.CapabilityResponse{
 		SupportedModels:    s.model.modelData,
 		SupportedEncodings: supportedEncodings,
-		GNMIVersion:        *ver,
+		GNMIVersion:        ver,
 	}, nil
 }