Use guard clause, feedback:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6084#note_14754681

lib/gitlab/ci/pipeline_duration.rb

@@ -132,9 +132,8 @@ module Gitlab
       end
 
       def process_periods(periods)
-        if periods.empty?
-          periods
-        else
+        return periods if periods.empty?
+
         periods.drop(1).inject([periods.first]) do |result, current|
           merged = try_merge_period(result.last, current)
 
@@ -146,7 +145,6 @@ module Gitlab
           end
         end
       end
-      end
 
       def try_merge_period(previous, current)
         if current.first <= previous.last