Yarn: Bug or expected behavior with the transitive dependency "reusing"?

Created on 25 Sep 2017 · 7Comments · Source: yarnpkg/yarn

Hello. I found some strange behavior. Is this a bug or is it an expected behavior?

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
Please see below.

If the current behavior is a bug, please provide the steps to reproduce.
I have the following package.json:

{
  "name": "pm-playground",
  "private": true,
  "dependencies": {
    "babel-cli": "6.26.0",
    "core-js": "2.4.1"
  }
}

I run yarn install and now I have the following directories hierarchy in node_modules:

    …
    [email protected]
        node_modules
            [email protected]
    [email protected]
    …

babel-cli has babel-runtime^6.26.0 in the dependencies. babel-runtime has core-js@^2.4.0 in the dependencies, so top-level [email protected] should satisfy babel-runtime requirement, but Yarn installed [email protected] instead of "reusing" the top-level [email protected].

What is the expected behavior?
I expect the following node_modules directory structure:

    …
    [email protected]
    [email protected]
    …

[email protected] is "reusing" the top-level [email protected] and does not install [email protected].

Please mention your node.js, yarn and operating system version.
Node.js - 8.5.0
Yarn - 1.1.0
OS - Win 10

Source

vkrol

Most helpful comment

@vkrol yup. I'd create an issue in the website repo and ping @arcanis about it. We may also try adding a check about possible duplicates in the tree and show people an info message about this.

BYK on 29 Sep 2017

👍2

All 7 comments

Seeing the same issue for multiple packages across different repos after updating to v1.1.0. Removing the lock-file and re-creating it seems to resolve it.

simonkberg on 25 Sep 2017

@simonkberg in my case this issue is not resolved after re-creating yarn.lock.

vkrol on 25 Sep 2017

Unless they are listed as peerDependencies there is no expectation that they would be resolved to the same dependency. That's the "ideal" case but not a given, so this behavior is not a bug.

BYK on 26 Sep 2017

@BYK thank you for the information! I think that I can close this issue now. But maybe we need to document this somewhere? What do you think about it? I am not sure, but it can confuse someone else.

vkrol on 26 Sep 2017

@vkrol maybe we can create an FAQ page for this since it has been brought up so many times recently.

BYK on 29 Sep 2017

👍1

@BYK I agree. This will be very helpful. Do we need to create the separate issue for it?

vkrol on 29 Sep 2017