Regression: socket option for serve is ignored

[Roang-zero1]

Describe the bug

If using the socket option while using the webpack serve command, it is ignored and default parameters (localhost:8000) are used.

This is a regression of 4668ea7 caused by 2cdf5ce

What is the current behavior?

webpack serve will listen to the default TCP host and port instead of the socket.

To Reproduce

Minimal reproduction repository: https://github.com/Roang-zero1/webpack-dev-server-unix-socket-bug

Steps to reproduce the behavior:

1. Clone the https://github.com/Roang-zero1/webpack-dev-server-unix-socket-bug repository
2. Run yarn install
3. Use yarn run serve to start the server
4. Server is now available under localhost:8000

Expected behavior

webpack should serve on the configured socket

Screenshots

Please paste the results of webpack-cli info here, and mention other relevant information

System:
OS: Linux 5.4 Ubuntu 20.04.1 LTS (Focal Fossa)
CPU: (1) x64 Intel(R) Core(TM) i5-9400H CPU @ 2.50GHz
Memory: 1.56 GB / 3.77 GB
Binaries:
Node: 10.19.0 - /tmp/yarn--1603453945580-0.7487274551062431/node
Yarn: 1.22.10 - /tmp/yarn--1603453945580-0.7487274551062431/yarn
Packages:
webpack: ^5.2.0 => 5.2.0
webpack-cli: ^4.1.0 => 4.1.0
webpack-dev-server: ^3.11.0 => 3.11.0

Additional context

This is related to webpack-dev-server ignoring the socket option (webpack/webpack-dev-server#2787)

[alexander-akait]

webpack/webpack-dev-server#2787 (comment)

[alexander-akait]

webpack/webpack.js.org#4091