Allow React 19 in peerDependencies in Docusaurus v3

[tats-u]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Motivation

React 19 was stabilized.
#9985 will be fixed once you update React to 19.
#10079 was fixed in Docusaurus 3.3, but are there any remaining problems preventing Docusaurus from combined with React 19?

Self-service

• I'd be willing to do some initial work on this proposal myself.

[tats-u]

If we don't allow React 19 in Docusaurus 3.x, we will have to clarify "You may have to patch react-dom to prevent it from mixing NUL into output HTML." in the migration guide from 2.x.

[Jordaneisenburger]

I think it will take a while before we get react 19 support unfortunately: #10745

[tats-u]

I'm glad to know it but it's disappointing that React 19 is going to be supported only by Docusaurus v4.

[slorber]

Considering the low amount of changes required to support React 19, I think it should be possible to support both React 18 and React 19 in Docusaurus v3.

I'd see if we can allow React 19 in Docusaurus v3.7. If possible and for dogfooding, I'd like new initialized sites and our own website to also use React 19 asap.

The breaking change for Docusaurus v4 is to require React 19, so that we can start using new features that are not available in v18.

[Jordaneisenburger]

Considering the low amount of changes required to support React 19, I think it should be possible to support both React 18 and React 19 in Docusaurus v3.

I'd see if we can allow React 19 in Docusaurus v3.7. If possible and for dogfooding, I'd like new initialized sites and our own website to also use React 19 asap.

The breaking change for Docusaurus v4 is to require React 19, so that we can start using new features that are not available in v18.

That would be amazing, main reason for me is that we use Docusaurus in a NX repo and get a bunch of peerdep headaces from Docusaurus atm as we're upgrading our other apps to React 19

[tats-u]

The breaking change for Docusaurus v4 is to require React 19

Sorry for misunderstanding.

I think it should be possible to support both React 18 and React 19 in Docusaurus v3.

I'd see if we can allow React 19 in Docusaurus v3.7.

Thank you for considering the backport.