rails/rails — pull request #16402 by bogdan (2014-08-05 14:30:52+00:00)
Title: Fixed #select form builder helper to support block without html output

Example code:

``` haml
= form.select(:campaign_id) do
- available_campaigns.each do |c|
%option{value: c.id}= c.name
```

Cause nil exception when `available_campaigns` is empty Array.