项目配置css module影响到css-loader对第三方库css文件中图片url的处理

[wonyun]

What happens?

• 通过设置cssLoaderOptions.modules为true来开启项目的css modules
• 项目中引入第三方库中的css文件，如：

    import 'kindeditor/themes/default/default.css'

• 第三方库中的css样式中背景引入图片，该图片地址形式为：

  .xxx {
    background: url(background.png);
    ...
  }

然后执行npm start编译报错：

 ERROR  Failed to compile with 1 errors

 error  in ./node_modules/kindeditor/themes/default/default.css

Module build failed (from ./node_modules/mini-css-extract-plugin/dist/loader.js):
ModuleNotFoundError: Module not found: Error: Can't resolve 'background.png' in '/Users/Desktop/study/umi-question-report/node_modules/kindeditor/themes/default'
    at factory.create (/Users/Desktop/study/umi-question-report/node_modules/webpack/lib/Compilation.js:925:10)
    at factory (/Users/Desktop/study/umi-question-report/node_modules/webpack/lib/NormalModuleFactory.js:401:22)
    at resolver (/Users/Desktop/study/umi-question-report/node_modules/webpack/lib/NormalModuleFactory.js:130:21)
    at asyncLib.parallel (/Users/Desktop/study/umi-question-report/node_modules/webpack/lib/NormalModuleFactory.js:224:22)
    at /Users/Desktop/study/umi-question-report/node_modules/neo-async/async.js:2830:7
    at /Users/Desktop/study/umi-question-report/node_modules/neo-async/async.js:6877:13
    at normalResolver.resolve (/Users/Desktop/study/umi-question-report/node_modules/webpack/lib/NormalModuleFactory.js:214:25)
    at doResolve (/Users/Desktop/study/umi-question-report/node_modules/enhanced-resolve/lib/Resolver.js:213:14)
    at hook.callAsync (/Users/Desktop/study/umi-question-report/node_modules/enhanced-resolve/lib/Resolver.js:285:5)
    at _fn0 (eval at create (/Users/Desktop/study/umi-question-report/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:15:1)

 @ ./src/pages/index.tsx 3:0-47
 @ ./src/pages/.umi/router.js
 @ ./src/pages/.umi/umi.js
 @ multi ./node_modules/af-webpack/lib/webpackHotDevClient.js ./src/pages/.umi/umi.js

最小可复现仓库

具体的复现代码仓库：https://github.com/wonyun/umi-question-report
readme.md描述的比较详细

相关环境信息

• Umi 版本：2.9.0
• Node 版本：10.16.0
• 操作系统：MacBook Pro OS X EI Caption 10.11.1