fix(cli): use webpack-cli@4

[ylemkimon]

• This is a bugfix
• This is a feature
• This is a code refactor
• This is a test update
• This is a docs update
• This is a metadata update

For Bugs and Features; did you add new tests?

Yes

Motivation / Use-Case

• Added setupExitSignals option. Takes a boolean and if true (default on CLI), the server will close and exit the process on SIGINT and SIGTERM
• server.listen() will find free port if this.options.port is not set and port argument is not passed
• Print a warning if options.port and port passed as an argument is different
• Added CLI calling webpack serve.

Breaking Changes

• server.listen() now returns a Promise, which will resolve to server.listeningApp, after finding the free port.
• webpack-dev-server CLI, utils/createConfig, and utils/processOptions are removed.

Additional Info

webpack-cli PR: webpack/webpack-cli#2126

[ylemkimon]

This file is copied from webpack/bin/webpack.js and these lines were added.

[codecov]

Codecov Report

Merging #2845 (3db0cea) into v4 (a16bbee) will decrease coverage by 0.38%.
The diff coverage is 81.81%.

@@            Coverage Diff             @@
##               v4    #2845      +/-   ##
==========================================
- Coverage   93.01%   92.62%   -0.39%     
==========================================
  Files          39       38       -1     
  Lines        1302     1247      -55     
  Branches      355      326      -29     
==========================================
- Hits         1211     1155      -56     
  Misses         87       87              
- Partials        4        5       +1     

Impacted Files	Coverage Δ
lib/Server.js	95.47% <77.27%> (-0.85%)	⬇️
lib/utils/setupExitSignals.js	92.85% <90.90%> (-7.15%)	⬇️

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[alexander-akait]

We need improve this, but yes, it is very good job

[alexander-akait]

I need to go home (tired 😞 ), let's finish tomorrow, do you have time? Just ping me when it will be ready for review

[ylemkimon]

@evilebottnawi No worries, whenever you want. This PR is ready for review.

[alexander-akait]

Just note - let's add test on output using snapshot, we need to make sure your console output looks good, just start server via CLI do snapshot, change something and do snapshot again, I am afraid we can have some incompatibilities with webpack-cli

[alexander-akait]

Good job, thanks, I found a lot of strange deps like - find-cache-dir/util/url/many be other, can you look at code and maybe remove some of them, because I found them are unnecessary

[ylemkimon]

@evilebottnawi find-cache-dir is used to store temporary self-signed certificates:

webpack-dev-server/lib/utils/getCertificate.js

Lines 11 to 15 in ccdce35

	// Use a self-signed certificate if no certificate was configured.
	// Cycle certs every 24 hours
	const certificateDir =
	findCacheDir({ name: 'webpack-dev-server' }) || os.tmpdir();
	const certificatePath = path.join(certificateDir, 'server.pem');

util and url are polyfills of Node modules for browsers.

[ylemkimon]

Thank you for the review!

[alexander-akait]

@ylemkimon Found other bug(s) with CLI, we have https://github.com/webpack/webpack-dev-server/blob/master/bin/cli-flags.js and https://github.com/webpack/webpack-dev-server/blob/master/bin/options.js, webpack serve use cli-flags.js, also we don't supports all types, like --open without options, we need to exports all possible types, like require('webpack').cli.getArguments do it, I think it is the last problem with CLI

[ylemkimon]

v4's cli-flags seem to be set correctly, e.g., --open aceepts both Boolean and String:

webpack-dev-server/bin/cli-flags.js

Lines 53 to 55 in ccdce35

	{
	name: 'open',
	type: [String, Boolean],

[alexander-akait]

Oh, yes , I see, anyway we have one extra file, let's remove it

[ylemkimon]

Where was bin/options.js originally used?

[alexander-akait]

in bin https://github.com/webpack/webpack-dev-server/blob/master/bin/webpack-dev-server.js#L19