add null value handle

internal/api/group/group.go

@@ -84,6 +84,9 @@ func GetGroupMembersInfo(c *gin.Context) {
 	}
 
 	memberListResp := api.GetGroupMembersInfoResp{CommResp: api.CommResp{ErrCode: RpcResp.ErrCode, ErrMsg: RpcResp.ErrMsg}, Data: RpcResp.MemberList}
+	if len(RpcResp.MemberList) == 0 {
+		memberListResp.Data = []*open_im_sdk.GroupMemberFullInfo{}
+	}
 	log.NewInfo(req.OperationID, "GetGroupMembersInfo api return ", memberListResp)
 	c.JSON(http.StatusOK, memberListResp)
 }