Use arrays in Pipeline#latest_builds_with_artifactsreduce-queries-for-artifacts-button

This changes Ci::Pipeline#latest_builds_with_artifacts so it returns an
Array instead of a relation. Whenever we use this data we do so in two
steps:

1. Count the number of rows
2. If this number is greater than 0, iterate over the rows

By returning an Array instead we only execute 1 query of which the total
time/work is less than running either just a COUNT(*) or both queries
(in the worst case).

On GitLab.com this change should save us a few milliseconds per request
to ProjectsController#show.

1 files changed, 4 insertions, 0 deletions

diff --git a/spec/models/ci/pipeline_spec.rb b/spec/models/ci/pipeline_spec.rb
index b89b0e555d9..3a19a0753e2 100644
--- a/spec/models/ci/pipeline_spec.rb
+++ b/spec/models/ci/pipeline_spec.rb
@@ -1502,6 +1502,10 @@ describe Ci::Pipeline, :mailer do
       create(:ci_build, :success, :artifacts, pipeline: pipeline)
     end
 
+    it 'returns an Array' do
+      expect(pipeline.latest_builds_with_artifacts).to be_an_instance_of(Array)
+    end
+
     it 'returns the latest builds' do
       expect(pipeline.latest_builds_with_artifacts).to eq([build])
     end