storybook bundling error

Describe the bug After upgrading material-ui “4.7.1” a few days ago, I can’t run storybook anymore. this is the error given when bundling:

ERROR in ./node_modules/@material-ui/core/esm/Popper/Popper.js Module not found: Error: Cannot find file: ‘popper.js’ does not match the corresponding name on disk: ‘./node_modules/@material-ui/core/esm/Popper/Popper.js’.

in the file ./node_modules/@material-ui/core/esm/Popper/Popper.js it’s importing like this: import PopperJS from 'popper.js'; I think storybook thinks it’s a file whereas popper.js is a dependency package for material-ui

[Tucker-Eric]

I was running into the same issue and I was able to fix this locally with adding the following to .storybook/webpack.config.js

module.exports = ({ config }) => {
  config.resolve.alias = {
    'popper.js$': 'popper.js/dist/esm/popper.js',
    ...config.resolve.alias
  };
  return config;
};

I think this may just be a windows issue due to case insensitivity where it’s thinking poppper.js should resolve to Popper.js and the names don’t match. I was receiving the error on windows but not on CentOS.

I hope this helps!

[barakplasma]

thanks @Tucker-Eric for https://github.com/storybookjs/storybook/issues/9077#issuecomment-570402934 , it was the only way for me to fix our Next.js 9.1.1 SSR builds after upgrading to Storybook 6.0.26