Peer Dependency installed incorrectly

[kostasmanionis]

Probably a bug.

I have a project that depends on "react": "^15.3.0" & "react-relay": "^0.9.2"

React-relay states it's peer dependencies like this "react": "^15.0.0 || ^0.14.0"

Now when installing with yarn, for some reason, react-relay get's a separate version of react.

I end up with this

node_modules/react@15.3.2
node_modules/react-relay/node_modules/react react@15.1.0

Shouldn't react-relay be using react@15.3.2?

Maybe some other package could be causing this, any ideas?

Running on
Yarn 0.16.1
OSX 10.11.6
Node v6.9.1

[twhid]

FWIW, this was fixed by moving react from "dependencies" to "peerDependencies" and "devDependencies" in direct dependencies of the project in question. React was erroneously included as a dependency in some internal libraries of ours, when it should have been a peer and dev dependency.

However, it should be noted that npm@3 was able to install dependencies in a way where the direct react dependency satisfied react-relay's peer dependency on react.

[kostasmanionis]

Some additional info

yarn why react revealed this

info Reasons this module exists
   - "admin-middleware#admin-layout#vg" depends on it

Package "vg" had react both in devDependencies and peerDependencies

"react": "^15.0.2",

Package "admin-layout" had react and react-relay dependencies.

"react": "~15.1.0",
"react-relay": "~0.9.0",

Package admin-middleware had no react or relay deps.

[exogen]

I've been experiencing a strange issue off and on with graphql and graphql-relay, and it's been giving me trouble for weeks. I just tracked it down to this (or a similar) Yarn issue – the issue goes away when I install with npm instead of Yarn.

• My project depends on graphql and graphql-relay (and they both definitely need to be in dependencies, not devDependencies nor peerDependencies).
• graphql-relay has a peerDependency on graphql, and it's common for its graphql peerDep to be somewhat behind the latest graphql release.
• So sometimes, if something else in the tree also depends on graphql, Yarn will cause graphql-relay to get a nested graphql under its node_modules. THIS SHOULD NEVER HAPPEN. peerDependencies should never be "realized" in this way. Even if the graphql version living above/next to graphql-relay is an incompatible version, the most that should happen is a warning. peerDependencies should never be actually installed in the package that declares them. The important part of the "peer" in "peerDependencies" isn't just the version you get, it's the instance.
• As expected, in this case, it causes an error, because my project and graphql-relay end up with different graphql instances. It's not that they're incompatible versions of graphql (although they might be) – it's that they are different instances when imported, so their instanceof, strict equality, etc. checks are all thrown off.

[ds300]

I'm getting this same issue with yarn@0.24.5

there is a repro over here: https://github.com/ds300/styled-components-native-warning-example

in this case styled-components gets a nested version of react@15 despite the fact that react is just a peer dependency for styled-components and the project has react@16 as a direct dependency.

[BYK]

@ds300 - I tried reproducing this with your instructions and it seems to be getting fixed with #4478 or an earlier PR.

That said it still prints the following warning, which seems legit:

warning "styled-components@2.1.0" has incorrect peer dependency "react@^0.14.0 || ^15.0.0-0".

I'm going to go ahead and close this but feel free to reopen if you think something is still not right.