Cannot read property 'createChildCompiler' of undefined

[sohailalam2]

Original Issue at: vuejs/vue-cli#3192 and webpack-contrib/thread-loader#55

Here is a minimum reproducible test repo https://github.com/sohailalam2/mrt-vue-comlinkjs-worker-loader

Vue Cli Version

3.2.1

Environment info

Environment Info:

  System:
    OS: Windows 10
    CPU: (8) x64 Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
  Binaries:
    Node: Not Found
    Yarn: Not Found
    npm: 6.5.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: 42.17134.1.0
  npmPackages:
    @vue/babel-preset-app:  3.2.0
    @vue/cli-overlay:  3.2.0
    @vue/cli-plugin-babel: ^3.2.0 => 3.2.0
    @vue/cli-plugin-e2e-cypress: ^3.2.0 => 3.2.0
    @vue/cli-plugin-eslint: ^3.2.0 => 3.2.1
    @vue/cli-plugin-pwa: ^3.2.0 => 3.2.0
    @vue/cli-plugin-unit-jest: ^3.2.0 => 3.2.0
    @vue/cli-service: ^3.2.0 => 3.2.0
    @vue/cli-shared-utils:  3.2.0
    @vue/component-compiler-utils:  2.3.1
    @vue/eslint-config-airbnb: ^4.0.0 => 4.0.0
    @vue/preload-webpack-plugin:  1.1.0
    @vue/test-utils: ^1.0.0-beta.20 => 1.0.0-beta.27
    @vue/web-component-wrapper:  1.2.0
    babel-helper-vue-jsx-merge-props:  2.0.3
    babel-plugin-transform-vue-jsx:  4.0.1
    eslint-plugin-vue: ^5.0.0-0 => 5.0.0
    jest-serializer-vue:  2.0.2
    vue: ^2.5.17 => 2.5.21
    vue-eslint-parser:  2.0.3
    vue-hot-reload-api:  2.3.1
    vue-jest:  3.0.2
    vue-loader:  15.4.2
    vue-router: ^3.0.1 => 3.0.2
    vue-style-loader:  4.1.2
    vue-template-compiler: ^2.5.17 => 2.5.21
    vue-template-es2015-compiler:  1.6.0
    vuex: ^3.0.1 => 3.0.1
  npmGlobalPackages:
    @vue/cli: Not Found

Steps to reproduce

Step 1: Create vue.config.js with the following

module.exports = {
  parallel: true,
  chainWebpack: (config) => {
    config.module.rule('worker')
      .test(/\.worker\.js$/i)
      .use('worker-loader')
      .loader('worker-loader');
  },
};

Step 2: npm run serve

What is expected?

Should successfully build the project

What is actually happening?

ERROR Failed to compile with 1 errors 4:46:14 PM

error in ./src/workers/sample.worker.js

Module build failed (from ./node_modules/thread-loader/dist/cjs.js):
Thread Loader (Worker 0)
Cannot read property 'createChildCompiler' of undefined

at Object.pitch (xxxxx\node_modules\worker-loader\dist\index.js:83:39)

@ ./node_modules/cache-loader/dist/cjs.js??ref--12-0!./node_modules/thread-loader/dist/cjs.js!./node_modules/babel-loader/lib!./node_modules/cache-loader/dist/cjs.js??ref--0-0!./node_modules/vue-loader/
lib??vue-loader-options!./src/components/HelloWorld.vue?vue&type=script&lang=js& 45:0-51 71:33-45
@ ./src/components/HelloWorld.vue?vue&type=script&lang=js&
@ ./src/components/HelloWorld.vue
@ ./node_modules/cache-loader/dist/cjs.js??ref--12-0!./node_modules/thread-loader/dist/cjs.js!./node_modules/babel-loader/lib!./node_modules/cache-loader/dist/cjs.js??ref--0-0!./node_modules/vue-loader/
lib??vue-loader-options!./src/views/Home.vue?vue&type=script&lang=js&
@ ./src/views/Home.vue?vue&type=script&lang=js&
@ ./src/views/Home.vue
@ ./src/router.js
@ ./src/main.js
@ multi ./src/main.js

ERROR Build failed with errors.
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] build: vue-cli-service build --modern
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

---

Turning off parallel flag in vue.config.js successfully builds the project

module.exports = {
  parallel: false,
  chainWebpack: (config) => {
    config.module.rule('worker')
      .test(/\.worker\.js$/i)
      .use('worker-loader')
      .loader('worker-loader');
  },
};

[alexander-akait]

Please don't spam issue in may repos, also your reproducible test repo is not look as minimum.

Simple example = fast fix.

[sohailalam2]

Apologies... don't mean to spam... I just don't know what's the root cause of this - Vue Cli or Worker Loader or Thread Loader?

About the reproducible test, it's quite straightforward because I have used Vue Cli to generate the code and made only some small changes. If you want more explanation, I can document the details but I don't know how else to reproduce this issue.

[alexander-akait]

@sohailalam2 don't worry just put link on reproducible test repo here, in my todo list

[stoplion]

Having same issue with worker loader

[illbredmiscreant]

Any status change in regards to this issue? Also experiencing this problem.

[alexander-akait]

PR welcome

[chopfitzroy]

Same issue, not sure what is the cause, if I nuke the node_modules directory and reinstall it does work, but eventually breaks again and I have to reinstall.

UPDATE

parallel: false, does not appear to fix the issue, still having to nuke node_modules and re-install on each occurrence.

UPDATE 2

Seems to be some sort of caching issues, because it happens whenever I modify the worker file.

[raczosala]

perhaps is related with webpack-contrib/thread-loader#27

[wanecek]

I'm also running into the issue described above. I created a slightly smaller case fr reproduction, maybe this can help in isolating the issue @evilebottnawi? :)

To summarize, the build-task fails with the error-message above. Removing the node_modules folder does not fix the issue for me.

[PowerfulPony]

The same error that appeared after using worker-loader appears only with npm run build. That is, for npm run serve everything works as usual, using vue-cli.

Module build failed (from ./node_modules/thread-loader/dist/cjs.js):
Thread Loader (Worker 0)
Cannot read property 'createChildCompiler' of undefined
    at PoolWorker.fromErrorObj (...\node_modules\thread-loader\dist\WorkerPool:258:12)
    at Object.pitch (...\node_modules\worker-loader\dist\index.js:83:39)

It helps off parallel parallel: false,

[Yanfei-Qiao]

Also run into this problem, parallel: false helps, but I want to know if there is an elegent solution

[sysebert]

@CrashyBang's fix worked for me (having to delete node_modules and re-running npm install).

This allowed the npm run build to finish (like others in this thread have stated, npm run serve works fine)

[zoswing]

it seems that you should add "options"
e.g.

config.module
      .rule('worker')
      .test(/\.worker\.js$/)
      .use('worker-loader')
      .loader('worker-loader')
      .options({ name: '[name].[hash].js' })
      .end()

by the way "parallel" should be 'false'

[a-froghyar]

I'm facing the same issue described above, only deleting node_modules and installing everything again solves the problem temporarily (until changes in the worker). Has anyone found out a solution?

[alexander-akait]

Problem in thread-loader side, we will fix it in the near future, sorry for delay, as workaround you can disable thread-loader for worker files using exclude: /\.worker\.js$/

[brianhelba]

@evilebottnawi Until this is actually fixed, is there an open issue tracking this bug? The thread-loader issue was closed in favor of this one.

Thanks for the update and workaround.