Load commit in batches for pipelines#index

Uses `list_commits_by_oid` on the CommitService, to request the needed
commits for pipelines. These commits are needed to display the user that
created the commit and the commit title.

This includes fixes for tests failing that depended on the commit
being `nil`. However, now these are batch loaded, this doesn't happen
anymore and the commits are an instance of BatchLoader.

2 files changed, 87 insertions, 0 deletions

diff --git a/spec/models/commit_spec.rb b/spec/models/commit_spec.rb
index d18a5c9dfa6..cd955a5eb69 100644
--- a/spec/models/commit_spec.rb
+++ b/spec/models/commit_spec.rb
@@ -13,6 +13,45 @@ describe Commit do
     it { is_expected.to include_module(StaticModel) }
   end
 
+  describe '.lazy' do
+    set(:project) { create(:project, :repository) }
+
+    context 'when the commits are found' do
+      let(:oids) do
+        %w(
+          498214de67004b1da3d820901307bed2a68a8ef6
+          c642fe9b8b9f28f9225d7ea953fe14e74748d53b
+          6f6d7e7ed97bb5f0054f2b1df789b39ca89b6ff9
+          048721d90c449b244b7b4c53a9186b04330174ec
+          281d3a76f31c812dbf48abce82ccf6860adedd81
+        )
+      end
+
+      subject { oids.map { |oid| described_class.lazy(project, oid) } }
+
+      it 'batches requests for commits' do
+        expect(project.repository).to receive(:commits_by).once.and_call_original
+
+        subject.first.title
+        subject.last.title
+      end
+
+      it 'maintains ordering' do
+        subject.each_with_index do |commit, i|
+          expect(commit.id).to eq(oids[i])
+        end
+      end
+    end
+
+    context 'when not found' do
+      it 'returns nil as commit' do
+        commit = described_class.lazy(project, 'deadbeef').__sync
+
+        expect(commit).to be_nil
+      end
+    end
+  end
+
   describe '#author' do
     it 'looks up the author in a case-insensitive way' do
       user = create(:user, email: commit.author_email.upcase)
diff --git a/spec/models/repository_spec.rb b/spec/models/repository_spec.rb
index 799d99c0369..8a3531c1898 100644
--- a/spec/models/repository_spec.rb
+++ b/spec/models/repository_spec.rb
@@ -239,6 +239,54 @@ describe Repository do
     end
   end
 
+  describe '#commits_by' do
+    set(:project) { create(:project, :repository) }
+
+    shared_examples 'batch commits fetching' do
+      let(:oids) { TestEnv::BRANCH_SHA.values }
+
+      subject { project.repository.commits_by(oids: oids) }
+
+      it 'finds each commit' do
+        expect(subject).not_to include(nil)
+        expect(subject.size).to eq(oids.size)
+      end
+
+      it 'returns only Commit instances' do
+        expect(subject).to all( be_a(Commit) )
+      end
+
+      context 'when some commits are not found ' do
+        let(:oids) do
+          ['deadbeef'] + TestEnv::BRANCH_SHA.values.first(10)
+        end
+
+        it 'returns only found commits' do
+          expect(subject).not_to include(nil)
+          expect(subject.size).to eq(10)
+        end
+      end
+
+      context 'when no oids are passed' do
+        let(:oids) { [] }
+
+        it 'does not call #batch_by_oid' do
+          expect(Gitlab::Git::Commit).not_to receive(:batch_by_oid)
+
+          subject
+        end
+      end
+    end
+
+    context 'when Gitaly list_commits_by_oid is enabled' do
+      it_behaves_like 'batch commits fetching'
+    end
+
+    context 'when Gitaly list_commits_by_oid is enabled', :disable_gitaly do
+      it_behaves_like 'batch commits fetching'
+    end
+  end
+
   describe '#find_commits_by_message' do
     shared_examples 'finding commits by message' do
       it 'returns commits with messages containing a given string' do