Yarn does not install dependencies correctly for package

[evancarter-iex]

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

Bug Report

What is the current behavior?

Yarn does not handle the dependencies for the Jade package properly. It does not install "uglify-js" despite it clearly being listed in the dependencies section of the package.json.

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

https://github.com/pugjs/pug/tree/v1.x.x is the jade package.

1. Add jade to your dependencies (yarn add jade)
2. Run yarn, yarn install --production
3. Notice that uglify-js is not included

What is the expected behavior?
Based on the dependencies listed here, https://github.com/pugjs/pug/blob/v1.x.x/package.json it uglify-js should be included in production

[ghost]

Under 0.27.0 ran yarn add jade --production and had no issues installing package.

[bestander]

Yep, can't repro either.