[webpack 5] support publicPath: "auto"

[sokra]

Expected behaviour

When using the default of publicPath: "auto", html-webpack-plugin should generate a script tag with an URL pointing to the script file.

Current behaviour

<script src="auto/main.js"></script>

Environment

webpack 5.0.0-rc.0
html-webpack-plugin: 4.4.1

Config

Copy the minimal webpack.config.js to produce this issue:

module.exports = {
  plugins: [
    new HtmlWebpackPlugin()
  ]
}

Additional context

webpack has added output.publicPath: "auto". This figures out the correct publicPath at runtime by reading it from the script tag.

html-webpack-plugin should understand this magic value and behave like publicPath: ""

[jantimon]

Is there an API to get the public path?

Right now we use:

html-webpack-plugin/index.js

Lines 533 to 540 in f3ccdd5

	/**
	* @type {string} the configured public path to the asset root
	* if a path publicPath is set in the current webpack config use it otherwise
	* fallback to a relative path
	*/
	const webpackPublicPath = webpackMajorVersion === 4
	? compilation.mainTemplate.getPublicPath({ hash: compilationHash })
	: compilation.getAssetPath(compilation.outputOptions.publicPath, { hash: compilationHash });

[sokra]

fixed by #1516

[FishOrBear]

@sokra
When using the DllReferencePlugin plugin, there is still a problem of auto.

"auto/xxx.dll.js"