CommonsChunkPlugin doesn't work with electron

Question

I have an electron app that I'm building with Webpack 2. I have a custom module (mymodule) that I want to be a separate bundle referenced by the other bundles. The problem is that when I use the CommonsChunkPlugin with my main process, electron locks up as the app is starting. I can see the electron logo appear in the doc but the window never shows up.

Note that it doesn't have to be a module I wrote, I can use lodash with CommonsChunkPlugin and get the same result.

Interestingly, if I use the CommonsChunksPlugin with the renderer process in the same way, everything works fine.

I put together a simple electron app that shows this issue.

The github repo gives more details on the situation, but here are the important parts:

electron main process:

const mymod = require('./mymodule')

app.on('ready', function() {
    console.log(mymod.abc);

    mainWindow = new BrowserWindow({width: 800, height: 600});

    mainWindow.loadURL(url.format({
        pathname: require('./index.html')
    }));
});

webpack config for main:

entry: {
    main: path.join(__dirname, './main.js'),
    mymod: ['./mymodule']
},

output: {
    path: __dirname + '/build/',
    publicPath: __dirname + '/build/',
    filename: '[name].bundle.js'
},


plugins: [
    new webpack.optimize.CommonsChunkPlugin('mymod')
]

In this state, the app will not work. If you then go into the webpack.main.js file and comment out the use of the CommonsChunkPlugin in these lines it will start working:

entry: {
    main: path.join(__dirname, './main.js'),
    // mymod: ['./mymodule']
},

output: {
    path: __dirname + '/build/',
    publicPath: __dirname + '/build/',
    filename: '[name].bundle.js'
},


plugins: [
    // new webpack.optimize.CommonsChunkPlugin('mymod')
]

Here is my environment info:

MacOS:    10.12.6
node:     v6.11.0
npm:      3.10.10
electron: v1.6.12
wepback2: 3.5.5

So what's going on here? Is this a bug with electron, webpack, or my code?

Epact