Rom Grk

We're not keeping this part of the state in `apiRef.current.state` for some reason. We'll need to migrate it to make things work.

The approach of emotion shouldn't be able to compete with the approach of linaria, but I probably need to have a pass on PigmentCSS. We always author code with an...

This prevents the `internal_processStyles` refactor and makes the build fail. It's annoying that it's in a separate repo and depends on internal details: https://github.com/search?q=repo%3Amui%2Fpigment-css%20internal_processStyles&type=code Also weird that the build succeed...

I could either patch this in this repo with something like: ```ts import * as sc from '@mui/styled-engine' const serialize = sc.internal_serializeStyles ?? x => x // and ignore the...

So the improvement in this PR is that in a case like this: ``` ``` Before this PR, the [Button styles object](https://github.com/mui/material-ui/blob/9063a9d507d6947e2e4a096c81f356d17b1379f2/packages/mui-material/src/Button/Button.js#L97-L300) would be passed 5 times through emotion's `serializeStyles`...

I can't reproduce your results for the table benchmark, in particular the large chunk which you say is `preprocessStyle`. It has a yellow band under it in your screenshot, which...

The issues in PigmentCSS are solved, this PR is ready for review.

Performance optimization, the prop object is being recreated at multiple times in the stack (2x by React, 1x by Emotion, previously about 4-6x by MUI). Do you have a reproducible...

The prop needs to stay for compat reasons, it's passed to style functions down the line, removing it would be a breaking change. We could pay the performance cost if...

Sounds reasonable, only requires the API to stay stable so there's no effort beyond documenting it. I don't see the implementation needing a substantial refactor anytime soon, so it should...