Webpack hangs until "process out of memory" error

I’m submitting a bug report

Webpack version: 3.1.0

Webpack Karma version: 2.0.4

Karma version: 1.7.0

Please tell us about your environment: OSX 10.12.5

Browser: Chrome 59.0.3071.115

Current behavior: Webpack hangs while creating initial bundles, until eventually aborting with FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory.

Expected/desired behavior: Webpack would correctly bundle the files and the test suite would be run.

Gulp config:

const path = require('path');
const gulp = require('gulp');
const { Server } = require('karma');

const rootPath = path.join(__dirname, '..', '..');

gulp.task('karma:modules', (done) => {
  new Server({
    configFile: path.resolve('wf_modules/karma.conf.js'),
    browsers: ['Chrome', 'Firefox'],
    files: [
        require.resolve('wf_polyfills/polyfills.min.js'),
        path.join(rootPath, 'browser_tests/js/setup.js'),
        path.join(rootPath, 'browser_tests/src-test/**/*.js'),
        path.join(rootPath, 'common_tests/src-test/**/*.js')
    ]
  }, done).start();
});

Karma config:

require('babel-core/register');

const path = require('path');
const webpack = require('webpack');

const testPaths = [
    __dirname,
    path.join(__dirname, 'browser')
];

module.exports = function(config) {
  config.set({
    frameworks: ['mocha'],

    files: [
      '../node_modules/wf_polyfills/polyfills.min.js',
      'browser_tests/js/setup.js',
      'browser_tests/src-test/**/*.js',
      'common_tests/src-test/**/*.js'
    ],
    preprocessors: {
      'browser_tests/js/setup.js': ['webpack'],
      'browser_tests/src-test/**/*.js': ['webpack'],
      'common_tests/src-test/**/*.js': ['webpack']
    },

    webpack: {
      module: {
        rules: [
          {
            test: /\.js$/,
            exclude: /node_modules/,
            use: {
              loader: 'babel-loader?cacheDirectory=true'
            }
          }
        ]
      },
      resolve: {
        modules: [...testPaths, 'node_modules']
      },
      plugins: [
        new webpack.DefinePlugin({
          'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV)
        })
      ]
    },

    reporters: ['dots'],

    logLevel: 'debug',
    autoWatch: false,
    singleRun: true,
    browserNoActivityTimeout: 60000,

    reportSlowerThan: 1000
  });
};

Full error output:

<--- Last few GCs --->

  171011 ms: Scavenge 4355.3 (4435.5) -> 4355.3 (4435.5) MB, 0.5 / 0 ms (+ 5.5 ms in 1 steps since last GC) [allocation failure] [incremental marking delaying mark-sweep].
  171476 ms: Mark-sweep 4355.3 (4435.5) -> 4346.0 (4427.0) MB, 464.4 / 0 ms (+ 18.6 ms in 3 steps since start of marking, biggest step 10.7 ms) [last resort gc].
  171937 ms: Mark-sweep 4346.0 (4427.0) -> 4346.4 (4427.0) MB, 461.8 / 0 ms [last resort gc].


<--- JS stacktrace --->

==== JS stack trace =========================================

Security context: 0x84dfd5b4629 <JS Object>
    2: new constructor(aka Buffer) [buffer.js:~50] [pc=0x5d96174aab5] (this=0x38b37c1a4d1 <a Buffer with map 0x2432238174a9>,arg=0x139cae404101 <Very long string[2218385]>,encoding=0x84dfd5bd739 <String[4]: utf8>)
    4: writeOut [/Users/me/Repos/my_repo/node_modules/webpack/lib/Compiler.js:343] [pc=0x5d9617cd5b6] (this=0x1d37c435eb11 <a Compiler with map 0x2432238da641>,err=0x84dfd504101 <nul...

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory
Abort trap: 6

This also still occurs if I use the node --max_old_space_size=4096 flag.

[jakemmarsh]

Re-opened as we’re still seeing this issue. It looks to only occur when using devtool: 'inline-source-map'. This would be a non-issue if external source maps functioned correctly, but they do not as seen in #224

[petrkoutnycz]

Any updates on this?