Yarn 1 vs Yarn 4 : peer dependency installation

[vladide]

Hi,

I have a question regarding Yarn Berry's behavior with peer dependencies installation.

I don't see this behavior clearly explained in the docs, or in the migration guide

Found some info in rulebook : https://yarnpkg.com/advanced/rulebook

Also similar issue reported by others (#6665)

Is that correct statement that Yarn 4 does not automatically install peer dependencies, and requires them to be explicitly added to the top-level package.json?

Example :
Project A

{
  "name": "project-a",
  "version": "1.0.0",
  "dependencies": {
    "b": "^1.0.0",
  }
}

Project B

{
  "name": "project-b",
  "version": "1.0.0",
  "peerDependencies": {
    "graphql": ">= 15.3.0 < 17.0.0"
  },
  }
}

This would not install graphql when building project A , where it would have worked with Yarn v1

[arcanis]

Peer dependencies have never been auto-installed, on any Yarn version.

[vladide]

I suppose this is why I & others concluded that it worked in Yarn 1 and with Yarn v2 + was broken

#6665 (comment)