Merge branch 'fix-ci-charts-error-500' into 'master'

Fix Error 500 in CI charts by gracefully handling commits with no durations

## What does this MR do?

In the CI charts, this MR reports the duration of a commit to 0 if it is `nil`.

## Are there points in the code the reviewer needs to double check?

Should we omit this commit from the chart or set it to some other value?

## Why was this MR needed?

We were getting an Error 500 here: https://gitlab.com/gitlab-org/gitlab-ce/graphs/master/ci

## What are the relevant issue numbers?

#17730 


See merge request !4245

3 files changed, 10 insertions, 1 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 3e459f8b2ba..9fa1e1cada3 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.8.2 (unreleased)
   - Fix Error 500 when accessing application settings due to nil disabled OAuth sign-in sources
+  - Fix Error 500 in CI charts by gracefully handling commits with no durations
 
 v 8.8.1
   - Add documentation for the "Health Check" feature
diff --git a/lib/ci/charts.rb b/lib/ci/charts.rb
index d53bdcbd0f2..e1636636934 100644
--- a/lib/ci/charts.rb
+++ b/lib/ci/charts.rb
@@ -64,7 +64,8 @@ module Ci
 
         commits.each do |commit|
           @labels << commit.short_sha
-          @build_times << (commit.duration / 60)
+          duration = commit.duration || 0
+          @build_times << (duration / 60)
         end
       end
     end
diff --git a/spec/lib/ci/charts_spec.rb b/spec/lib/ci/charts_spec.rb
index 50a77308cde..9d1215a5760 100644
--- a/spec/lib/ci/charts_spec.rb
+++ b/spec/lib/ci/charts_spec.rb
@@ -12,5 +12,12 @@ describe Ci::Charts, lib: true do
       chart = Ci::Charts::BuildTime.new(@commit.project)
       expect(chart.build_times).to eq([2])
     end
+
+    it 'should handle nil build times' do
+      create(:ci_commit, duration: nil, project: @commit.project)
+
+      chart = Ci::Charts::BuildTime.new(@commit.project)
+      expect(chart.build_times).to eq([2, 0])
+    end
   end
 end