Allow usage of 6.x version without md4

[olof-nord]

Feature Proposal

Feature Use Case

With Node.js v17+ removing the md4 hashing algorithm, the usage of the CompressionPlugin unfortunately breaks the build.

If Webpack 4 is detected, the Node.js createHash function is unfortunately called assuming that "md4" is available.

if (CompressionPlugin.isWebpack4()) {
    cacheData.cacheKeys = {
      nodeVersion: process.version,
      // eslint-disable-next-line global-require
      "compression-webpack-plugin": require("../package.json").version,
      algorithm: this.algorithm,
      originalAlgorithm: this.options.algorithm,
      compressionOptions: this.options.compressionOptions,
      name,
      contentHash: crypto.createHash("md4").update(input).digest("hex"),
    };
} 

https://github.com/webpack-contrib/compression-webpack-plugin/blob/v6.1.1/src/index.js#L232

If a project is not able to upgrade from Webpack 4, and thus cannot move to compression-webpack-plugin v7+, then it is stuck with Node.js 16 or forced to configure the --openssl-legacy-provider Node.js flag.

I suggest to release a 6.2.0 version of the library, and allow the hashing algorithm to optionally be provided.

new CompressionPlugin({
        test: /\.js(\?.*)?$/i,
        hashType: 'sha256',
}),

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

➜  webpack4-node18-demo git:(main) ✗ npx webpack-cli info        
The command moved into a separate package: @webpack-cli/info
Would you like to install info? (That will run npm install -D @webpack-cli/info) (yes/NO) : yes
npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR! 
npm ERR! While resolving: webpack4-node18-demo@1.0.0
npm ERR! Found: webpack@4.46.0
npm ERR! node_modules/webpack
npm ERR!   webpack@"^4.46.0" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer webpack@"5.x.x" from @webpack-cli/info@2.0.0
npm ERR! node_modules/@webpack-cli/info
npm ERR!   dev @webpack-cli/info@"*" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR! 
npm ERR! See /home/olof/.npm/eresolve-report.txt for a full report.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/olof/.npm/_logs/2022-11-17T20_41_50_732Z-debug-0.log
undefined
➜  webpack4-node18-demo git:(main) ✗ 

Node.js 18.12.1 webpack 4.46.0 compression-webpack-plugin 6.1.1

This issue is related to this PR which is trying to update mastodon to use Node.js v18. https://github.com/mastodon/mastodon/pull/20586

[alexander-akait]

Why don't update to webpack5? Is is deprecated

[olof-nord]

Very valid point, I should have clarified.

The project is configuring webpack with a ruby gem, webpacker, which unfortunately only supports webpack 4.

Webpacker has been retired - we were investigating possibilities of a solution which does not involve replacing it.

[alexander-akait]

If it is deprecated you can get all webpack configuration and runner from this package and move to own, so you will have access to update deps and start to migrate

[olof-nord]

appreciating your input!