Optional peer dependencies are incorrectly listed in package.json

[mprast]

Currently react-dom and react-native are listed as optional peer dependencies of react-redux, but they are only listed in peerDependenciesMeta and not in peerDependencies. Looking at the RFC for optional peer dependencies in Yarn v2, I'm pretty sure the correct way is to list them in both fields:
yarnpkg/rfcs#105 (comment)

Consistent with this, I'm seeing yarn v2 (with pnp) complaining that A package is trying to access another package without the second one being listed as a dependency of the first one, even when react-dom is a dep of the react-redux's direct ancestor.

Happy to provide a PR and\or a repro if you'd like!

redux: 4.0.5
react-redux: 7.2.0
react-dom: 16.12.0

[timdorr]

This is for backwards compatibility with versions of npm/yarn that don't support peerDependenciesMeta. If we add them to peerDependencies, there will be a warning emitted for every installation (since you shouldn't have both packages). By putting them in peerDependenciesMeta, package managers that support the field will assume both are optional.

Even if we implemented the fields fully, it doesn't actually represent what we want: one of the two is required to be installed. That hasn't yet been added to the spec.

[markerikson]

Yep, I'd fully expect PnP to whine about that.

Also see these previous discussions:

• Moved react-dom to dependencies #1261
• Update package.json, react-dom added in peerDependencies section. #1282
• Fix add missing peer dependency #1371
• change react-dom from devDependency to dependency #1366
• Missing peer dependency on react-dom #1424
• Adds react-dom and react-native as optional peer dependencies #1425