feat：空指针保护

domain/service/group_s/group_op.go

@@ -182,8 +182,10 @@ func (s *GroupService) GroupIn(userId uint64, externalId string, groupUuid strin
 				if err != nil {
 					model.Log.Errorf("GroupIn GetGroupUserOrInit err:%v, groupId:%v, userId:%v", err, groupUuid, userId)
 				}
-				if err := groupUser.SetRoomInTime().Persistent(); err != nil {
-					model.Log.Errorf("GroupIn groupUser Persistent err:%v, groupId:%v, userId:%v", err, groupUuid, userId)
+				if groupUser != nil {
+					if err := groupUser.SetRoomInTime().Persistent(); err != nil {
+						model.Log.Errorf("GroupIn groupUser Persistent err:%v, groupId:%v, userId:%v", err, groupUuid, userId)
+					}
 				}
 
 				// 发送进群TIM信令。fixme: 应该发在event处理