TypeError: compilation.getCache is not a function

Describe the bug

Followed the default steps for installation. When running npm run start I get following error:

TypeError: compilation.getCache is not a function
    at C:\Users\maarten\Documents\projects\test7\node_modules\copy-webpack-plugin\dist\index.js:459:33
    at SyncHook.eval [as call] (eval at create (C:\Users\maarten\Documents\projects\test7\node_modules\tapable\lib\HookCodeFactory.js:19:10), <anonymous>:9:1)
    at SyncHook.lazyCompileHook (C:\Users\maarten\Documents\projects\test7\node_modules\tapable\lib\Hook.js:154:20)
    at Compiler.newCompilation (C:\Users\maarten\Documents\projects\test7\node_modules\webpack\lib\Compiler.js:630:30)
    at C:\Users\maarten\Documents\projects\test7\node_modules\webpack\lib\Compiler.js:667:29
    at AsyncSeriesHook.eval [as callAsync] (eval at create (C:\Users\maarten\Documents\projects\test7\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:6:1)
    at AsyncSeriesHook.lazyCompileHook (C:\Users\maarten\Documents\projects\test7\node_modules\tapable\lib\Hook.js:154:20)
    at Compiler.compile (C:\Users\maarten\Documents\projects\test7\node_modules\webpack\lib\Compiler.js:662:28)
    at C:\Users\maarten\Documents\projects\test7\node_modules\webpack\lib\Watching.js:77:18
    at AsyncSeriesHook.eval [as callAsync] (eval at create (C:\Users\maarten\Documents\projects\test7\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:24:1)

package.json

{
  "name": "testseven",
  "private": true,
  "version": "1.0.0",
  "description": "testSeven",
  "repository": "",
  "license": "UNLICENSED",
  "scripts": {
    "start": "npm run dev",
    "dev": "cross-env NODE_ENV=development webpack-dev-server --config ./build/webpack.config.js",
    "build-dev": "cross-env NODE_ENV=development node ./build/build.js",
    "build-prod": "cross-env NODE_ENV=production node ./build/build.js",
    "build-dev-cordova": "cross-env TARGET=cordova cross-env NODE_ENV=development node ./build/build.js && cd cordova && cordova build",
    "build-prod-cordova": "cross-env TARGET=cordova cross-env NODE_ENV=production node ./build/build.js && cd cordova && cordova build",
    "build-dev-cordova-ios": "cross-env TARGET=cordova cross-env NODE_ENV=development node ./build/build.js && cd cordova && cordova build ios",
    "build-prod-cordova-ios": "cross-env TARGET=cordova cross-env NODE_ENV=production node ./build/build.js && cd cordova && cordova build ios",
    "cordova-ios": "cross-env TARGET=cordova cross-env NODE_ENV=development node ./build/build.js && cd cordova && cordova run ios",
    "build-dev-cordova-android": "cross-env TARGET=cordova cross-env NODE_ENV=development node ./build/build.js && cd cordova && cordova build android",
    "build-prod-cordova-android": "cross-env TARGET=cordova cross-env NODE_ENV=production node ./build/build.js && cd cordova && cordova build android",
    "cordova-android": "cross-env TARGET=cordova cross-env NODE_ENV=development node ./build/build.js && cd cordova && cordova run android",
    "postinstall": "cpy ./node_modules/framework7-icons/fonts/*.* ./src/fonts/"
  },
  "browserslist": [
    "Android >= 7",
    "IOS >= 11",
    "Safari >= 11",
    "Chrome >= 49",
    "Firefox >= 31",
    "Samsung >= 5"
  ],
  "dependencies": {
    "dom7": "^2.1.5",
    "framework7": "^5.7.14",
    "framework7-icons": "^3.0.1",
    "framework7-svelte": "^5.7.14",
    "svelte": "^3.31.0",
    "template7": "^1.4.2"
  },
  "devDependencies": {
    "@babel/core": "^7.12.10",
    "@babel/plugin-syntax-dynamic-import": "^7.8.3",
    "@babel/plugin-transform-runtime": "^7.12.10",
    "@babel/preset-env": "^7.12.10",
    "@babel/runtime": "^7.12.5",
    "babel-loader": "^8.2.2",
    "chalk": "^4.1.0",
    "copy-webpack-plugin": "^7.0.0",
    "cpy-cli": "^3.1.1",
    "cross-env": "^7.0.3",
    "css-loader": "^5.0.1",
    "file-loader": "^6.2.0",
    "html-webpack-plugin": "^4.5.0",
    "less": "^3.12.2",
    "less-loader": "^7.1.0",
    "mini-css-extract-plugin": "^1.3.3",
    "optimize-css-assets-webpack-plugin": "^5.0.4",
    "ora": "^5.1.0",
    "postcss-loader": "^4.1.0",
    "postcss-preset-env": "^6.7.0",
    "rimraf": "^3.0.2",
    "style-loader": "^2.0.0",
    "svelte-loader": "^2.13.6",
    "terser-webpack-plugin": "^4.2.3",
    "url-loader": "^4.1.1",
    "webpack": "^4.44.2",
    "webpack-cli": "^3.3.12",
    "webpack-dev-server": "^3.11.0"
  }
}

[beebase]

Wow that was fast. Thanks a lot for the link! This indeed fixed it for me:

In my case, So called “copy-webpack-plugin”: “^7.0.0” is causing the error. I degrade to it’s previous version “copy-webpack-plugin”: “^6.3.2” Now everything working fine.

[bjoernmartin]

For those who want to understand why this downgrade is necessary: Version 7 (and by now 8) of copy-webpack-plugin require WebPack 5 to work. So this downgrade is necessary if your project still runs with Webpack 4.