Fetching environment specific dependencies does not work in an umbrella application

[Gazler]

I have created a repository that replicates the issue. https://github.com/Gazler/deps_umbrella

The issue is that in an umbrella application, when a dependency is specified in an application for a particular environment (only: :test) the dependencies are not fetched when running mix deps.get or mix deps.get --only test from the root.

Running mix deps.get from the apps/my_app directory does succeed in fetching the dependency.

This fails with both hex dependencies ({:ecto, "~> 1.0.0", only: :test}) and git dependencies({:websocket_client, git: "https://github.com/jeremyong/websocket_client.git", only: :test})

This happens on 1.1.1 and 1.2.