Option --allowed-hosts all incorrectly parsed that lead to ignoring it by Server

[maksimr]

STR:

• node@v14.15.3
• Install webpack-dev-servernpm install --save-dev webpack webpack-dev-server webpack-cli @webpack-cli/serve
• Run webpack serve --mode development --allowed-hosts all

ER: allowedHosts: 'all'
AR: allowedHosts: ['all']

This lead to ignoring this option by Server

And visual error Invalid Host header

package.json

{
  "main": "src/jindex.js",
  "scripts": {
    "test": "webpack serve --mode development --allowed-hosts all"
  },
  "devDependencies": {
    "@webpack-cli/serve": "^1.5.2",
    "webpack": "^5.51.1",
    "webpack-cli": "^4.8.0",
    "webpack-dev-server": "^4.0.0"
  }
}

[anshumanv]

You don't need @webpack-cli/serve in your deps can you try removing that and try? we normalize the option https://github.com/webpack/webpack-dev-server/blob/f563d1d13eed75744cca2911878352581afa6a03/lib/Server.js#L198 so it shouldn't have been `['all']`

[maksimr]

@anshumanv result the same without serve as dep.

normalize in Server.js normalize string to array but here we have a case when allowedHosts passed as array with only one item string all and server expect that all would not be array.

This option converted to array here because it described as multiple in config object
And set to passed Server options object here in the commander lib

[anshumanv]

Thanks for the investigation, yep it's an issue

I'll fix it 🤞

[anshumanv]

I've done a potential fix here, I'll wait for feedback from @alexander-akait to validate the fix and then get it merged 👍