Yarn redownloads/rebuilds binaries when adding/removing unrelated packages.

[karacaenes]

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

What is the current behavior?
Yarn redownloads or rebuilds binaries on each yarn add or yarn remove which can take substantial time depending on the packages.

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

• Simplified steps to reproduce: start with empty directory.
• Open cmd/git bash/powershell
• yarn add uws

  • yarn add v1.5.1
    info No lockfile found.
    [1/4] Resolving packages...
    [2/4] Fetching packages...
    [3/4] Linking dependencies...
    [4/4] Building fresh packages...
    success Saved lockfile.
    success Saved 1 new dependency.
    info Direct dependencies
    └─ uws@9.14.0
    info All dependencies
    └─ uws@9.14.0
    Done in 9.44s.
    

• Add an arbitrary unrelated package without no shared dependencies: yarn add split.js
  • yarn adds the package, rebuilds uws

  • yarn add v1.5.1
    warning package.json: No license field
    warning No license field
    [1/4] Resolving packages...
    [2/4] Fetching packages...
    [3/4] Linking dependencies...
    [4/4] Building fresh packages...
    [1/1] ⠂ uws
    [-/1] ⠂ waiting...
    .....
    ..... 
    ..... After yarn finishes:
    success Saved 1 new dependency.
    info Direct dependencies
    └─ split.js@1.3.5
    info All dependencies
    └─ split.js@1.3.5
    warning No license field
    Done in 10.05s.
    
    

• yarn remove split.js builds uws again.

What is the expected behavior?

• Not rebuild unrelated packages

Please mention your node.js, yarn and operating system version.
Node v8.9.3
Yarn 1.5.1
Windows 10 Build 16299

[rally25rs]

duplicate #932

I have a comment toward the end of that thread specific to uws. I've been working on PR #5470 the last couple days but it's been more difficult than expected...