MUI X Date Pickers Pro not working with Joy UI

[viktorbasta]

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Steps to reproduce 🕹

Link to live example:
https://codesandbox.io/s/mui-joy-mui-x-date-pickers-pro-not-working-vmzlvy?file=/src/App.tsx

Steps:

1. Install latest versions of Joy UI and Date Pickers Pro X
2. Insert LocalizationProvider as a child of CssVarsProvider
3. Insert DateRangePicker as a child of LocalizationProvider

Versions:

"@emotion/react": "11.10.6",
"@emotion/styled": "11.10.6",
"@mui/joy": "5.0.0-alpha.70",
"@mui/material": "5.11.12",
"@mui/x-date-pickers-pro": "6.0.1",

Current behavior 😯

Undefined property errors:

TypeError Cannot read properties of undefined (reading 'create')
TypeError Cannot read properties of undefined (reading 'borderRadius')

Expected behavior 🤔

DatePicker should appear and no errors should be shown.

Context 🔦

Trying to use a Date Picker Pro X in a Joy UI project. This worked before with other versions, but I cannot for the life of me reproduce a working version.

Your environment 🌎

No response

[viktorbasta]

Problem was because of breaking changes in #35739. Had to merge mui theme like is done here: Joy UI feat. Material UI sandbox