Storybook: Upgrading from Storybook 4.1.13 to 5.0.0 - Cannot find module '@emotion/core/package.json'

[sargant]

Describe the bug

When upgrading from Storybook 4.1.13 to 5.0.0, an attempt to run start-storybook results in the error message Error: Cannot find module '@emotion/core/package.json.

There is no node_modules/@emotion/core folder. The only copy that gets installed is due to the dependencies within @storybook/[email protected], so it's not at the top-level node_modules folder, but instead at node_modules/@storybook/theming/node_modules/@emotion/core.

To Reproduce
Steps to reproduce the behavior:

1. Start with the following dependencies:

@storybook/[email protected]
@storybook/[email protected]
@storybook/[email protected]
@storybook/[email protected]
@storybook/[email protected]

1. Upgrade to Storybook 5:

> yarn remove @storybook/addon-options
> yarn upgrade --latest @storybook/react @storybook/addon-actions 
      @storybook/addon-knobs @storybook/@addon-storyshots
> yarn add --dev --exact @babel/core babel-loader

1. Attempt to start Storybook

> yarn run start-storybook -- -p 9001

Environment

Windows 10
node 10.15.0
yarn 1.13.0

Additional context
Removing yarn.lock and node_modules and reinstalling purely from the package.json file also fails.

[sargant]

Note that installing @storybook/theming fixes the error - is this package now mandatory?

[shilman]

Should not be mandatory. We're still trying to get to the bottom of this -- feels like a yarn bug, but it's all pretty opaque. @emotion/core and @storybook/theming are def in your dependency tree, but they are just not getting hoisted properly AFAIK.

[viktormill]

Im getting the exactly same error with npm and package-lock. Error: Cannot find module '@emotion/core/package.json'

[shilman]

Resolving this as a duplicate to https://github.com/storybooks/storybook/issues/5817

We still don't know what's going on tho