React 18: Upgrade to client rendering apis warning message.

[kozer]

Quick summary

We updated to React 18, and from this version, the rendering method has changed.

More info can be found here.

Visiting almost every page shows the following warning

Warning: ReactDOM.render is no longer supported in React 18. Use createRoot instead. Until you switch to the new API, your app will behave as if it's running React 17. Learn more: https://reactjs.org/link/switch

Steps to reproduce

1. Visit /sites as an example. But this has effect to other pages as well (eg /home)
2. Open the developer console.
3. Make sure that you see the warning mentioned above

What you expected to happen

This warning no longer appearing

What actually happened

The warning appears

Impact

All

Available workarounds?

Yes, not easy to implement

Platform (Simple and/or Atomic)

No response

Logs or notes

No response

[danielbachhuber]

cc @noahtallen @tyxla

[tyxla]

This warning is expected. If you take a look at @noahtallen's description in the PR that upgraded dependencies to React 18, we're intentionally not enabling concurrent mode:

Note: this does not yet enable the new rendering mode -- that will likely be a follow-up due to the size of this PR!

We're still aiming to try it out, and it is one of the next steps, but it will be a separate effort with its own extended testing round. For the time being, we're going with the old rendering mode, and the notice is expected in dev mode. I've announced that with some additional context in p4TIVU-aFJ-p2 for posterity.

Going to close that one in the meantime - let me know if you have any other concerns!

[kozer]

@tyxla , just FYI, I have already created a pr that has the appropriate changes for that to work. It's here.

In case we want to enable this, this pr will be a good start (I guess only tests needs to be updated, as from a quick navigation and testing several features, everything seems to work just fine )

cc: @danielbachhuber , @noahtallen

[tyxla]

Thanks for that work @kozer, we appreciate it!

@noahtallen let's use that PR when exploring if there are any other changes we need to do other than tests.