"Error: invalid argument" when starting server with 2.1.0-beta.3

[EvHaus]

I'm submitting a bug report

webpack and webpack-dev-server version:
webpack: 2.1.0-beta.21
webpack-dev-server: 2.1.0-beta.3

Please tell us about your environment:
OSX 10.11.6

Current behavior:

When running the webpack-dev-server, I get this error:

webpack-dev-server --hot --progress --history-api-fallback --config webpack/webpack.dev.config.js --content-base html/

 http://localhost:8080/
webpack result is served from /build/
content is served from /Users/evgueni.naverniouk/Git/ux/html
404s will fallback to /index.html
webpack: wait until bundle finished: /build/app.js

/Users/evgueni.naverniouk/Git/ux/node_modules/webpack-dev-middleware/middleware.js:106
            if(err) throw err;
                    ^
Error: invalid argument
    at pathToArray (/Users/evgueni.naverniouk/Git/ux/node_modules/memory-fs/lib/MemoryFileSystem.js:44:10)
    at MemoryFileSystem.mkdirpSync (/Users/evgueni.naverniouk/Git/ux/node_modules/memory-fs/lib/MemoryFileSystem.js:139:13)
    at MemoryFileSystem.(anonymous function) [as mkdirp] (/Users/evgueni.naverniouk/Git/ux/node_modules/memory-fs/lib/MemoryFileSystem.js:279:34)
    at Compiler.<anonymous> (/Users/evgueni.naverniouk/Git/ux/node_modules/webpack/lib/Compiler.js:266:25)
    at Compiler.applyPluginsAsync (/Users/evgueni.naverniouk/Git/ux/node_modules/tapable/lib/Tapable.js:73:70)
    at Compiler.emitAssets (/Users/evgueni.naverniouk/Git/ux/node_modules/webpack/lib/Compiler.js:263:7)
    at Watching.onCompiled (/Users/evgueni.naverniouk/Git/ux/node_modules/webpack/lib/Compiler.js:55:18)
    at /Users/evgueni.naverniouk/Git/ux/node_modules/webpack/lib/Compiler.js:442:12
    at next (/Users/evgueni.naverniouk/Git/ux/node_modules/tapable/lib/Tapable.js:81:11)
    at Compiler.<anonymous> (/Users/evgueni.naverniouk/Git/ux/node_modules/webpack/lib/CachePlugin.js:61:4)

Expected/desired behavior:

Server should not fail to start.

This issue was not happening with 2.1.0-beta.0. Only started happening after upgrading to 2.1.0-beta.3

[SpaceK33z]

What happens when you set output.path to "/" in your webpack config?

If that doesn't work, could you try upgrading to 2.1.0-beta.2 and see if it also happens there?

[EvHaus]

Changing the output.path to / did not help resolve the issue.

Downgrading to 2.1.0-beta.2 makes the error go away. So looks like it was something introduced between beta.2 and beta.3

[SpaceK33z]

I can't reproduce your issue yet. Could you post a webpack config here? As minimal as possible please, so I can test it myself easily.

[EvHaus]

Sorry, I take back my previous statement. Changing output.path to / does indeed make the issue go away. My original output.path was set to ./html/build/.

Here is a minimal webpack.config.js that can be used to reproduce the issue:

module.exports = {
    entry: {
        app: ['./html/js/menu.js']
    },
    module: {
        loaders: [
            {test: /\.js$/, loader: 'babel'}
        ]
    },
    output: {
        path: './html/build/',
        publicPath: '/build/',
        filename: '[name].js'
    }
};

[SpaceK33z]

Aha. output.path can't have ./. It should be an absolute path. Also see #88 about that. I'm upping the prio of that ticket, because this issue will occur more now. I'll update the changelog to specifically mention that output.path should be an absolute path.

Previously, this wasn't an issue because the CLI overrode the output.path to be /. This was also covered in the CHANGELOG as a breaking change.

[EvHaus]

Confirmed. Using an absolute path resolves the issue. Thank you.