bower_components deleted when installing node_modules

[sb8244]

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

This is a bug.

What is the current behavior?

When installing node_modules from yarn, with an existing bower_components directory (custom through .bowerrc), the bower_components directory is cleared.

When re-running yarn with already installed packages, nothing is deleted.

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

1. Have package.json and bower.json in same directory
2. .bowerrc

{
  "directory": "bower_components"
}

1. Populate bower with bower install
2. Run yarn
3. node_modules exists but bower_components is empty.

What is the expected behavior?

bower_components should not be touched, because it is installed correctly.

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

➜ yarn --version
0.15.1
➜ node --version
v4.3.2
➜ sw_vers -productVersion
10.11.6

[alextreppass]

Suspect this is a dupe of #616

[sb8244]

Thanks