Compiling manager fails to: comment file "xxx.worker.js.LICENSE.txt" conflicts with an existing asset

Describe the bug

When running build-storybook -c .storybook -o storybook-static, the build fails to “Compiling manager” step. This only happened with the recent 6.0.0-rc.X versions. I tried with rc 1, 10, 11, and 14. All failed to the same step

The current workaround is to use 6.0.0-beta.20. I checked what version you use in Storybook design system: https://github.com/storybookjs/design-system/blob/master/package.json and copied the same.

To Reproduce Steps to reproduce the behavior:

Run build-storybook -c .storybook -o storybook-static with new versions of major 6. Console will output this error:

12:25:47 PM: info => Compiling manager..
12:26:25 PM: ERR! => Failed to build the manager
12:26:25 PM: ERR! The comment file "1cd777c4fb4f5c3aa725.worker.js.LICENSE.txt" conflicts with an existing asset, this may lead to code corruption, please use a different name
12:26:25 PM: (node:1637) UnhandledPromiseRejectionWarning: [object Object]
12:26:25 PM: (node:1637) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
12:26:25 PM: (node:1637) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Expected behavior

I would expect the build to succeed.

Code snippets Our .storybook/main.js:

module.exports = {
  stories: ['../src/**/*.stories.@(ts|tsx|js|jsx|mdx)'],
  addons: [
    '@storybook/addon-knobs/register',
    'storybook-addon-designs/register',
    '@storybook/addon-actions',
    '@storybook/addon-links',
    {
      name: '@storybook/addon-docs',
      options: {
        configureJSX: true,
        babelOptions: {},
        sourceLoaderOptions: null,
      },
    },
  ],
};

System:

Environment Info:

  System:
    OS: Linux 5.7 Fedora 32 (Workstation Edition) 32 (Workstation Edition)
    CPU: (8) x64 Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
  Binaries:
    Node: 12.18.0 - ~/.nvm/versions/node/v12.18.0/bin/node
    npm: 6.14.4 - ~/.nvm/versions/node/v12.18.0/bin/npm
  Browsers:
    Chrome: 84.0.4147.89
    Firefox: 78.0.2
  npmPackages:
    @storybook/addon-actions: 6.0.0-rc.14 => 6.0.0-rc.14 
    @storybook/addon-docs: 6.0.0-rc.14 => 6.0.0-rc.14 
    @storybook/addon-knobs: 6.0.0-rc.14 => 6.0.0-rc.14 
    @storybook/addon-links: 6.0.0-rc.14 => 6.0.0-rc.14 
    @storybook/addons: 6.0.0-rc.14 => 6.0.0-rc.14 
    @storybook/preset-typescript: ^3.0.0 => 3.0.0 
    @storybook/react: 6.0.0-rc.14 => 6.0.0-rc.14 

Additional context

Some similar issues I found:

• https://javascriptio.com/view/3567370/license-conflicts-in-nuxt

[shilman]

I removed storybook-addon-designs and the error went away. @pocka can you help here?

[pocka]

Probably https://github.com/webpack-contrib/worker-loader/issues/260.

The addon depends on react-pdf (I know I should have put the dependency into peerDependencies), which uses Worker script imported via worker-loader. Since I’m not sure which package depends on worker-loader, a temporary workaround until a fix comes to the loader is pinning terser-webpack-plugin to v3.0.6.

with Yarn workspace

// package.json
{
  // ...
  "resolutions": {
    "terser-webpack-plugin": "3.0.6"
  }
}

with npm

$ npm i -D terser-webpack-plugin@3.0.6

If none of the above workarounds works, please tell me.