DEP_WEBPACK_WATCH_WITHOUT_CALLBACK after upgrading to webpack 5.x

• Operating System: macOS Catalina Version 10.15.7
• Node Version: v14.13.1
• NPM Version: 6.14.8
• webpack Version: 5.1.0
• webpack-dev-server Version: 3.11.0
• Browser: Not relevant

• This is a bug
• This is a modification request

Code

// webpack.config.js

   // the config is not relevant in this case
   // const webpackConfig = {};
   const webpackDevConfig = {
      ...webpackConfig,
      mode: 'development',
      watch: true,
      devtool: 'eval-cheap-module-source-map',
      performance: {
         hints: false,
      },
   };

   const compiler = webpack(webpackDevConfig);

   const devServerOptions = {
      ...webpackDevConfig.devServer,
      contentBase: process.cwd() + `/serve/`,
      watchContentBase: true,
      publicPath: '/',
      hot: true,
      open: true,
      stats: 'errors-warnings',
   };
   const server = new WebpackDevServer(compiler, devServerOptions);
   server.listen(2020, '127.0.0.1');

Expected Behavior

Quiet as before upgrade to Webpack 5.x.

Actual Behavior

(node:96740) [DEP_WEBPACK_WATCH_WITHOUT_CALLBACK] DeprecationWarning: A 'callback' argument need to be provided to the 'webpack(options, callback)' function when the 'watch' option is set. There is no way to handle the 'watch' option without a callback.
(Use `node --trace-deprecation ...` to show where the warning was created)

I got the warning above when running the code after upgrading to webpack 5.x. The code I use is basically copied from the official webpack website: https://webpack.js.org/api/node/

For Bugs; How can we reproduce the behavior?

For Features; What is the motivation and/or use-case for the feature?

[alexander-akait]

Yes, you don’t need watch: true if you run watching (webpack --watch/webpack serve), because it is unnecessary, you already watch it

[alexander-akait]

Just remove watch: true from your configuration