Now we could use normal relation, feedback:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5347#note_13173842

Now we could use normal relation, feedback:
09114211 · Lin Jen-Shin · 04658761 · 09114211
Commit 09114211 authored 8 years ago by Lin Jen-Shin
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -431,8 +431,7 @@ class Project < ActiveRecord::Base
  # ref can't be HEAD, can only be branch/tag name or SHA
  def latest_successful_builds_for(ref = default_branch)
-    Ci::Build.joins(:pipeline).
+    builds.where(pipeline: pipelines.latest_successful_for(ref)).
-      merge(pipelines.latest_successful_for(ref)).
      latest_successful_with_artifacts
  end