Sass 加载器在 webpack 中不起作用

我试图在我的 webpack 配置中支持 *.scss 文件，但当我运行 webpack build 命令时，我不断收到以下错误：

ERROR in ./~/css-loader!./~/sass-loader!./app/styles.scss
Module build failed: TypeError: Cannot read property 'sections' of null
at new SourceMapConsumer (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/node_modules/postcss/node_modules/source-map/lib/source-map/source-map-consumer.js:23:21)
at PreviousMap.consumer (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/node_modules/postcss/lib/previous-map.js:37:34)
at new Input (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/node_modules/postcss/lib/input.js:42:28)
at parse (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/node_modules/postcss/lib/parse.js:17:17)
at new LazyResult (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/node_modules/postcss/lib/lazy-result.js:54:47)
at Processor.process (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/node_modules/postcss/lib/processor.js:30:16)
at processCss (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/lib/processCss.js:168:24)
at Object.module.exports (/Users/sean/Development/playground/webpack.sass.test/node_modules/css-loader/lib/loader.js:21:15)
@ ./app/styles.scss 4:14-117

我一生都无法弄清楚为什么。这是一个非常基本的设置。

我创建了一个 Dropbox 共享，其中至少说明了这一点：https://www.dropbox.com/s/quobq29ngr38mhx/webpack.sass.test.zip?dl=0 https://www.dropbox.com/s/quobq29ngr38mhx/webpack.sass.test.zip?dl=0

解压缩然后运行：

npm install
webpack

这是我的 webpack.config.js 文件：

var path = require('path')
var webpack = require('webpack')

module.exports = {
  devtool: 'eval',
  entry: [
    './app'
  ],
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'index.js',
    publicPath: '/dist/'
  },
  plugins: [
    new webpack.NoErrorsPlugin()
  ],
  resolve: {
    extensions: ['', '.js']
  },
  module: {
    loaders: [{
      test: /\.scss$/,
      loader: 'style-loader!css-loader!sass-loader'
    }]
  }
}

还有index.js入口文件：

require('./styles.scss');

alert('foo bar baz');

和 styles.scss 文件：

body {
  background-color: #000;
}

它似乎遵循 sass-loader 文档站点的建议，但我无法让它运行。

:(

有关我的环境的信息：

node - 0.12.4
npm  - 2.10.1
os   - OS X Yosemite

我已经设法找到另一种解决方法，该方法不涉及编辑 npm_modules 目录中的 css-loader 库（根据 @chriserik 的回答）。

如果将“？sourceMap”添加到 sass 加载器，则 css 加载器似乎可以处理输出。

这是我更新的配置：

var path = require('path')
var webpack = require('webpack')

module.exports = {
  devtool: 'eval',
  entry: [
    './app'
  ],
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'index.js',
    publicPath: '/dist/'
  },
  plugins: [
    new webpack.NoErrorsPlugin()
  ],
  resolve: {
    extensions: ['', '.js']
  },
  module: {
    loaders: [{
      test: /\.scss$/,
      loader: 'style!css!sass?sourceMap'
    }]
  }
}

附：我什至扩展了这个测试以包括指南针混合包含，这也有效。