[Rails 5.2.0.rc1 / Webpack] fresh app, webpack-dev-server fails to start

[rafaelfranca]

From @hansondr on March 12, 2018 22:5

Steps to reproduce

Create a new 5.2.0.rc1 application with webpack enabled:
rails _5.2.0.rc1_ new webpack_test --webpack

Attempt to start the webpack-dev-server:
cd webpack_test
bin/webpack-dev-server

Expected behavior

webpack-dev-server starts up

Actual behavior

Errors out with the following:

The CLI moved into a separate package: webpack-cli.
Please install 'webpack-cli' in addition to webpack itself to use the CLI.
-> When using npm: npm install webpack-cli -D
-> When using yarn: yarn add webpack-cli -D
module.js:549
    throw err;
    ^

Error: Cannot find module 'webpack-cli/bin/config-yargs'
    at Function.Module._resolveFilename (module.js:547:15)
    at Function.Module._load (module.js:474:25)
    at Module.require (module.js:596:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/home/drh/src/webpack_test/node_modules/webpack-dev-server/bin/webpack-dev-server.js:65:1)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)

System configuration

Rails version: 5.2.0.rc1

Ruby version: 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux]

Temporary Solution

By manually editing the webpack-dev-server entry within package.json to target versions less than 3.0 e.g.

{
  "name": "webpack_test",
  "private": true,
  "dependencies": {
    "@rails/webpacker": "^3.3.0"
  },
  "devDependencies": {
    "webpack-dev-server": "<3.0.0"
  }
}

Copied from original issue: rails/rails#32232

[gauravtiwari]

Thanks @rafaelfranca. Published a new patch version that fixes the issue.