strictly backwards compatible alternative

reflection/serverreflection.go

@@ -54,27 +54,30 @@ import (
 	"google.golang.org/grpc/status"
 )
 
-// GRPCServer is the interface provided by a gRPC server. It is implemented by
-// *grpc.Server, but could also be implemented by other concrete types. It acts
-// as a registry, for accumulating the services exposed by the server.
-type GRPCServer interface {
+// ServiceRegistrar acts as a registry of exposed gRPC service. It is also an
+// interface provided by a gRPC server (*grpc.Server).
+type ServiceRegistrar interface {
 	grpc.ServiceRegistrar
+	// GetServiceInfo returns information on the services registered thus far.
 	GetServiceInfo() map[string]grpc.ServiceInfo
 }
 
-var _ GRPCServer = (*grpc.Server)(nil)
-
 type serverReflectionServer struct {
 	rpb.UnimplementedServerReflectionServer
-	s GRPCServer
+	s ServiceRegistrar
 
 	initSymbols  sync.Once
 	serviceNames []string
 	symbols      map[string]*dpb.FileDescriptorProto // map of fully-qualified names to files
 }
 
 // Register registers the server reflection service on the given gRPC server.
-func Register(s GRPCServer) {
+func Register(s *grpc.Server) {
+	RegisterWithRegistrar(s)
+}
+
+// RegisterWithRegistrar registers the server reflection service on the given service registrar.
+func RegisterWithRegistrar(s ServiceRegistrar) {
 	rpb.RegisterServerReflectionServer(s, &serverReflectionServer{
 		s: s,
 	})