Document CSS prop incompatibility with babel-plugin-transform-react-inline-elements

[apostolos]

What:
transform-react-inline-elements breaks CSS prop.

The plugin order is complicated because babel plugins don’t run one after the other, they run at the same time, so you have a JSXElement (babel-plugin-transform-react-inline-elements does it’s stuff here) and a JSXOpeningElement (where the css prop stuff runs), the JSXElement will be visited and the plugins that visit that node will run in the order they’re specified in the babel config and if the JSXElement is replaced there the JSXOpeningElement never gets visited.

Why:
This behavior should be documented. babel-plugin-transform-react-inline-elements is usually only included in production, therefore it's highly likely that someone might use CSS prop in development thinking it is working fine. But as soon as they compile the project for production styles will silently fail.

Checklist:

• Documentation
• Tests N/A
• Code complete N/A

[codecov]

Codecov Report

Merging #348 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #348   +/-   ##
=======================================
  Coverage   97.36%   97.36%           
=======================================
  Files          17       17           
  Lines         569      569           
  Branches      134      134           
=======================================
  Hits          554      554           
  Misses         11       11           
  Partials        4        4

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 60b4486...b5537cd. Read the comment docs.

[tkh44]

Thank you @apostolos

[GuillaumeCisco]

Is there a way to get both working?
We got the issue in our production environment as babel-plugin-transform-react-inline-elements was included only in production.
Furthermore, the migrating documentation from 9 to 10 should heavily warn about this.