webpack-cli: "Cannot read property 'validateSchema' of undefined" with webpack-cli@3.0.0 and webpack-dev-server@3.1.4

Describe the bug

Webpack consistently fails to compile when using webpack-cli@3.0.0 with webpack-dev-server@3.1.4 (the current latest). I am uncertain whether this is a new issue in this major or if webpack-dev-server needs to get with the times.

What is the current behavior?

When running webpack-dev-server from an npm script, compilation fails with the following error:

TypeError: Cannot read property 'validateSchema' of undefined
    at Object.<anonymous> (~/repos/node_modules/webpack-cli/bin/convert-argv.js:7:46)
    at Module._compile (internal/modules/cjs/loader.js:702:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:713:10)
    at Module.load (internal/modules/cjs/loader.js:612:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:551:12)
    at Function.Module._load (internal/modules/cjs/loader.js:543:3)
    at Module.require (internal/modules/cjs/loader.js:650:17)
    at require (internal/modules/cjs/helpers.js:20:18)
    at Object.<anonymous> (~/repos/node_modules/webpack-dev-server/bin/webpack-dev-server.js:234:15)
    at Module._compile (internal/modules/cjs/loader.js:702:30)

This happens every time. The existence of a webpack.config.js file doesn’t matter.

To Reproduce

1. Create a new project with npm init.
2. npm install webpack webpack-dev-server webpack-cli --save-dev
3. In your package.json, create "scripts": { "start": "webpack-dev-server" }.
4. npm run start
5. Error!

Expected behavior Webpack compilation completes successfully, and the result is served according to webpack-dev-server’s configuration.

Please paste the results of webpack-cli info here, and mention other relevant information Promise { <pending> }

(That’s the result I get when running webpack-cli info after installing the new @webpack-cli/info package. It’s possible I’m using this wrong.)

Additional notes If this is actually an issue with webpack-dev-server, my apologies! I’ll take my concern there once we can rule out webpack-cli.