Wrong version resolution with ^ of sub-dependency and failed to dedupe

[alexilyaev]

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

Bug

What is the current behavior?

A package being installed twice with different versions where it should be installed once.
Failing to dedupe.

If the current behavior is a bug, please provide the steps to reproduce.

In package.json:

  "devDependencies": {
    "stylelint": "7.12.0",
    "stylelint-webpack-plugin": "0.8.0",
  },

stylelint-webpack-plugin has in it's package.json:

  "peerDependencies": {
    "stylelint": "^7.7.0",
  },
  "dependencies": {
    "stylelint": "^7.7.0"
  },

Installing using Yarn v0.27.5

$ yarn list stylelint
yarn list v0.27.5
├─ stylelint-webpack-plugin@0.8.0
│  └─ stylelint@7.11.0
└─ stylelint@7.12.0
Done in 0.90s.

$ yarn why stylelint
yarn why v0.27.5
[1/4] Why do we have the module "stylelint"...?
[2/4] Initialising dependency graph...
[3/4] Finding dependency...
[4/4] Calculating file sizes...
info Has been hoisted to "stylelint"
info This module exists because it's specified in "devDependencies".
info Disk size without dependencies: "3.59MB"
info Disk size with unique dependencies: "13.51MB"
info Disk size with transitive dependencies: "35.55MB"
info Number of shared dependencies: 127

Installing using npm v5.0.3

Works as expected.

Running npm ls stylelint:

├── stylelint@7.12.0 
└─┬ stylelint-webpack-plugin@0.8.0
  └── stylelint@7.12.0  deduped

What is the expected behavior?

1. Should dedupe in this case
2. ^7.7.0 should have installed the latest release 7.12.0 (stylelint on npm)
3. yarn why should show version info and also why the 7.11.0 version was installed

Please mention your node.js, yarn and operating system version.

Node v6.9.1
npm v5.0.3
Yarn v0.27.5
macOS 10.12.5

Related:

• Wrong Stylelint version, not respecting peer dependency (using Yarn) webpack-contrib/stylelint-webpack-plugin#106
• [feature] improve resolution deduping #3778

[alexilyaev]

For now updated in yarn.lock the 7.11.0 version to 7.12.0 and ran yarn --force and it worked:

$ yarn list stylelint
yarn list v0.27.5
└─ stylelint@7.12.0

[bestander]

#3778 duplicate