compression-webpack-plugin: TypeError: Cannot read property 'tapPromise' of undefined for webpack 5.6.0

• Operating System: Windows
• Node Version: v14.5.0
• PNPM Version: 5.13.1
• webpack Version: 5.6.0
• compression-webpack-plugin Version: 6.1.1

Expected Behavior

The specified files are compressed.

Actual Behavior

Crash with the following error:

ERROR  TypeError: Cannot read property 'tapPromise' of undefined
TypeError: Cannot read property 'tapPromise' of undefined
    at C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\compression-webpack-plugin\6.1.1_webpack@5.6.0\node_modules\compression-webpack-plugin\dist\index.js:349:41
    at SyncHook.eval [as call] (eval at create (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\tapable\1.1.3\node_modules\tapable\lib\HookCodeFactory.js:19:10), <anonymous>:9:1)
    at SyncHook.lazyCompileHook (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\tapable\1.1.3\node_modules\tapable\lib\Hook.js:154:20)
    at Compiler.newCompilation (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\webpack\4.44.2_93ca2875a658e9d1552850624e6b91c7\node_modules\webpack\lib\Compiler.js:630:30)
    at C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\webpack\4.44.2_93ca2875a658e9d1552850624e6b91c7\node_modules\webpack\lib\Compiler.js:667:29
    at AsyncSeriesHook.eval [as callAsync] (eval at create (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\tapable\1.1.3\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:6:1)
    at AsyncSeriesHook.lazyCompileHook (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\tapable\1.1.3\node_modules\tapable\lib\Hook.js:154:20)
    at Compiler.compile (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\webpack\4.44.2_93ca2875a658e9d1552850624e6b91c7\node_modules\webpack\lib\Compiler.js:662:28)
    at C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\webpack\4.44.2_93ca2875a658e9d1552850624e6b91c7\node_modules\webpack\lib\Compiler.js:321:11
    at Compiler.readRecords (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\webpack\4.44.2_93ca2875a658e9d1552850624e6b91c7\node_modules\webpack\lib\Compiler.js:529:11)
    at C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\webpack\4.44.2_93ca2875a658e9d1552850624e6b91c7\node_modules\webpack\lib\Compiler.js:318:10
    at eval (eval at create (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\tapable\1.1.3\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:12:1)
    at C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\webpack\4.44.2_93ca2875a658e9d1552850624e6b91c7\node_modules\webpack\lib\CachePlugin.js:50:13
    at _next0 (eval at create (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\tapable\1.1.3\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:8:1)
    at eval (eval at create (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\tapable\1.1.3\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:21:1)
    at run (C:\Users\_\Desktop\prmaster\vue\web\common\temp\node_modules\.pnpm\registry.npmjs.org\fork-ts-checker-webpack-plugin\3.1.1\node_modules\fork-ts-checker-webpack-plugin\lib\index.js:248:13)

It appears that the processAssets hook doesn’t exist?

Code

// vue.config.js
/* eslint-disable @typescript-eslint/no-var-requires, no-undef, import/no-extraneous-dependencies */
const zopfli = require('@gfx/zopfli')
const CompressionPlugin = require('compression-webpack-plugin')

module.exports = {
  filenameHashing: false,
  productionSourceMap: false,
  // publicPath: './', // Remove this if html5 history.pushState is used
  configureWebpack: config => {
    config.output.filename = '[name].js'
    config.output.webassemblyModuleFilename = 'webassembly.wasm'
    if (typeof process.env.PRODUCTION !== 'undefined')
      config.plugins.push(new CompressionPlugin({
        test: /\.(js|css|html|svg|wasm)$/,
        threshold: 2000,
        minRatio: 0.8,
        compressionOptions: {
          numiterations: 15
        },
        algorithm(input, compressionOptions, callback) {
          return zopfli.gzip(input, compressionOptions, callback)
        }
      }))
  },
  chainWebpack: config => {
    config.optimization.splitChunks(false)
  },
  css: {
    extract: {
      filename: '[name].css'
    }
  }
}

How Do We Reproduce?

pnpm run serve

---

Possibly related to #222.