rails/rails — pull request #10580 by julianvargasalvarez (2013-05-12 20:11:40+00:00)
Title: Code cleanup for ActionDispatch::Flash#call

The nested `if` was replaced by using `presence` which takes account for
the given hash when it is `nil` or when it is empty. The `else` was
removed because what it was doing was to assign to `env[KEY]` the
value it already had.