uping:function(e){
        var that=this;
        wx.chooseMessageFile({   //从聊天获取文件，选择后存为临时文件 temp
          count: 1,
            success(res){
                console.log(res);
                var name="http://store/"+res.tempFiles[0].name;
                wx.saveFile({    //   临时文件转缓存文件    store
                    tempFilePath:res.tempFiles[0].path,
                    success(e){
                        console.log(e);
                        var f_manager =wx.getFileSystemManager();
                        f_manager.rename({   //重命名
                            oidPath:e.savedFilePath, 
                            newPath:name,
                            success(){
                                console.log("改名成功，名为:",name)
                            },
                            fail(m){
                                console.log(m);
                                console.log(e.savedFilePath,name);
                            }
                        });
                    that.update_filelist(that);   
                    }
                })
            }
        })
    }

运行结果如图：

我将savefile的返回值赋给 rename函数的oldpath，运行后报 oldpath 未定义，但在log里能正确显示值 ：http：//store......... ,请问是为什么？