Cannot read property 'outputOptions' of undefined

[FuncWei]

Compile prompt me：
Module build failed: Thread Loader (Worker 0)
Cannot read property 'outputOptions' of undefined
at PoolWorker.fromErrorObj(...)

[alexander-akait]

Please use issue template

[likeavenus]

Hi, I have the same problem after I abandoned the isomorphic style loader and added a mini css extract pluginin css config:

`import autoprefixer from 'autoprefixer';
import mqpacker from 'css-mqpacker';
import calc from 'postcss-calc';
import partialImport from 'postcss-partial-import';
import postcssUrl from 'postcss-url';
import cssvariables from 'postcss-css-variables';
import mediaVariables from 'postcss-media-variables';
import path from 'path';
import { warmup } from 'thread-loader';
import resolveConfig from '../resolve';
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

warmup({}, [MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader']);
const css = isDev => ({
test: /.css$/,
exclude: /node_modules/,
use: [
'thread-loader',
{
loader: MiniCssExtractPlugin.loader,
},
{
loader: 'css-loader',
options: {
modules: true,
sourceMap: isDev,
importLoaders: 1,
localIdentName: '[name][local]_[hash:base64:5]',
minimize: isDev,
onlyLocals: true,
discardComments: { removeAll: true }
}
},
{
loader: 'postcss-loader',
options: {
ident: 'postcss',
plugins: [

      partialImport({
        resolve(id, basedir) {
          if (!/\.css$/.test(id)) id = `${id}.css`;

          // Webpack aliases
          const alias = resolveConfig.alias;
          const aliasesKeys = Object.keys(alias);
          let resolveId;
          for (let alias of aliasesKeys) {
            if (new RegExp(`^${alias}`).test(id)) {
              resolveId = `./${id}`;
              break;
            }
          }

          if (resolveId) {
            return path.resolve(resolveId);
          }

          // From folder
          if (/^\./.test(id)) return path.resolve(basedir, id);

          // Node modules
          return path.resolve('./node_modules', id);
        }
      }),
      mediaVariables(),
      cssvariables(),
      calc(),
      autoprefixer({
        browsers: ['>1%', 'last 4 versions', 'Firefox ESR', 'not ie < 9']
      }),
      postcssUrl,
      mediaVariables(),
      mqpacker
    ]
  }
},

],
});

export default css;
`

[AprilArcus]

Similar error originates here, in the case of css modules.

https://github.com/webpack-contrib/css-loader/blob/v6.2.0/src/utils.js#L530

The loaderContext passed to getModulesOptions does not have a _compilation key. It originates as the loaders this https://github.com/webpack-contrib/css-loader/blob/v6.2.0/src/index.js.

[vagusX]

How's going?

[thl3538]

How's going?

[xsfxtsxxr]

Try to use "css-loader": "1.0.1" and "thread-loader": "^3.0.4"

[alexander-akait]

Fixed