记一次升级Flutter SDK失败的光辉历史

提示：本文内容颇为复杂，涉及到的疑难杂症也颇多。

一切源于一个简单的指令：flutter upgrade，然后开启了崩溃的黑色3小时。

刚打开项目，看到控制台的编译log提示​​Flutter SDK​​​可以更新，行吧，那就更新吧，想着应该也是一个很简单的事情，因为我​​Android Studio​​也是经常更新的。

ok，编译结束，​​Terminal​​​中直接执行​​flutter upgrade​​，因为之前也在官方文档中看到过升级 Flutter的介绍，内容不多，以为不复杂呢，结果这一执行直接掉进了无底的深渊。。

对插件下手

执行之后显示如下：

D:\FlutterProjects\wanandroid_flutter>flutter upgrade
Checking Dart SDK version...
Downloading Dart SDK from Flutter engine 52c7a1e849a170be4b2b2fe34142ca2c0a6fea1f...
Downloading the Dart SDK using the BITS service failed, retrying with WebRequest...
Invoke-WebRequest : 请求被中止: 未能创建 SSL/TLS 安全通道。
所在位置 D:\flutter\flutter_windows_v1.2.1-stable\flutter\bin\internal\update_dart_sdk.ps1:62 字符: 5
+     Invoke-WebRequest -Uri $dartSdkUrl -OutFile $dartSdkZip
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest]，WebException
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand
 
Error: Unable to update Dart SDK. Retrying...

网上搜了一会，根本没结果，但是我此刻也依然没当回事，并开启了一些骚操作。。

上面看到要升级​​Dart​​​的sdk，因为dart的sdk是包含在flutter中的，在as在装flutter插件的时候还提示要装dart插件，
所以我直接从插件plugin下手了。

• 卸载dart插件然后重启，卸载flutter插件然后重启。
• 安装dart插件然后重启，安装flutter插件然后重启。

但是编译还是跑不起来，报什么错忘了，继续骚操作。。

对SDK下手

既然插件不行，行吧，那就直接手动升级sdk吧，此刻心态依然乐观，说来也是心大。

然后跑去github看了一下版本

纳尼，一天一个版本？？？ 这也太假了吧，我只要正式版就行啊。

然后又跑去​​官网​​​看看：

嗯，这还差不多，我上个版本就是 ​​​1.2.1​​​的，最新​​1.5.4​​的，那行吧，下载下来

• 解压
• 删掉1.2.1的版本
• 改环境变量
• 重启AS

emmmm 还是不行，且文件全部报错，开始有一点慌了。。

然后想起来项目中的路径可能还没改呢，然后在设置中把flutter sdk路径改成1.5.4的，感觉应该可以了

改好之后，满怀着期待重新编译，依然不行，此刻心态已经有点崩了，现在是退不能退 进不能进了。

尝试一下​​invalidate and restart​​，emmm 也不行

报错如下：

Warning! This package referenced a Flutter repository via the .packages file that is no longer available. The repository from which the 'flutter' tool is currently executing will be used instead.
  running Flutter tool: D:\flutter\flutter_windows_v1.5.4-hotfix.2-stable\flutter
  previous reference  : D:\flutter\flutter_windows_v1.2.1-stable\flutter
This can happen if you deleted or moved your copy of the Flutter repository, or if it was on a volume that is no longer mounted or has been mounted at a different location. Please check your system path to verify that you are running the expected version (run 'flutter --version' to see which flutter is on your path).

嗯，我也知道两次版本不对，可是在哪改、怎么改呢。

对项目配置下手

我开始在项目中找有没有编译时类似build产生的文件，最后在根目录的​​.package​​文件中发现还是1.2.1的版本的

# Generated by pub on 2019-05-28 10:50:34.749388.
async:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/async-2.0.8/lib/
boolean_selector:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/boolean_selector-1.0.4/lib/
charcode:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/charcode-1.1.2/lib/
collection:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/collection-1.14.11/lib/
cookie_jar:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/cookie_jar-1.0.0/lib/
cupertino_icons:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/cupertino_icons-0.1.2/lib/
dio:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/dio-2.1.3/lib/
flutter:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/packages/flutter/lib/
flutter_page_indicator:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/flutter_page_indicator-0.0.3/lib/
flutter_swiper:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/flutter_swiper-1.1.6/lib/
flutter_test:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/packages/flutter_test/lib/
flutter_webview_plugin:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/flutter_webview_plugin-0.3.5/lib/
fluttertoast:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/fluttertoast-3.0.4/lib/
matcher:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/matcher-0.12.3+1/lib/
meta:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/meta-1.1.6/lib/
path:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/path-1.6.2/lib/
pedantic:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/pedantic-1.4.0/lib/
quiver:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/quiver-2.0.1/lib/
sky_engine:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/bin/cache/pkg/sky_engine/lib/
source_span:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/source_span-1.5.4/lib/
stack_trace:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/stack_trace-1.9.3/lib/
stream_channel:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/stream_channel-1.6.8/lib/
string_scanner:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/string_scanner-1.0.4/lib/
term_glyph:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/term_glyph-1.1.0/lib/
test_api:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/test_api-0.2.2/lib/
transformer_page_view:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/transformer_page_view-0.1.6/lib/
typed_data:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/typed_data-1.1.6/lib/
vector_math:file:///D:/flutter/flutter_windows_v1.2.1-stable/flutter/.pub-cache/hosted/dart-pub.mirrors.sjtug.sjtu.edu.cn%2547/vector_math-2.0.8/lib/
wanandroid_flutter:lib/

文件备份一下然后直接删掉，看看会不会编译生成，结果没有

那行吧，直接把路径替换了

天呐，依然不行，搞这个的时间早都超出预算了，心态已经崩了，只能硬着头皮上了。

只能在项目设置中尝试了。

打开​​Project Structure​​​，果然他丫的还是有问题，但是看到了黎明的曙光。

• 1，还是上面的问题。
• 2，果然还是有一个路径没有改
• 3，kotlin的直接忽略

先改掉2的路径问题

把1.2.1的版本路径换成1.5.4的路径即可。

但是1要fix的话提示我全部移除，那行吧，试试。

编译一下还是不行，此刻已然是生无可恋了。

因为之前打开了​​pubspec.yaml​​​文件查看是不是有配置什么的没改，然后随手点了下​​packages get​​​，结果OK了！！！

复盘

因为是手动升级的flutter SDK，所以项目中除了自带的库以外还有第三方的库，都还是原来的路径，在把全部路径修改完之后，需要​​packages get​​ 重新下载到新版本的路径中去才能引用。

之前也尝试过​​packages upgrade​​，但是等了半天没反应，也没在任务管理中看到下载，所以就没当回事。。

翻墙这种小事就不提了。。

期间也遇到

Waiting for another flutter command to release the startup lock...

解决办法：

• 打开任务管理器，结束掉​​Android Studio​​​ 和​​Dart.exe​​
• 删除​​flutter\bin\cache​​​目录下的​​lockfile​​文件，然后重启AS即可

本文旨为flutter upgrade 升级flutter失败之后手动升级的记录，没准你一下就成功了。。

心累。。

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官方文档：​​https://flutter.dev/​​