Migrate Git::CommitStats to Gitaly

lib/gitlab/git/commit.rb

@@ -352,7 +352,7 @@ module Gitlab
       end
       def stats
-        Gitlab::Git::CommitStats.new(self)
+        Gitlab::Git::CommitStats.new(@repository, self)
       end
       def to_patch(options = {})

lib/gitlab/git/commit_stats.rb

@@ -10,12 +10,29 @@ module Gitlab
       # Instantiate a CommitStats object
       #
       # Gitaly migration: https://gitlab.com/gitlab-org/gitaly/issues/323
-      def initialize(commit)
+      def initialize(repo, commit)
         @id = commit.id
         @additions = 0
         @deletions = 0
         @total = 0
+        repo.gitaly_migrate(:commit_stats) do |is_enabled|
+          if is_enabled
+            gitaly_stats(repo, commit)
+          else
+            rugged_stats(commit)
+          end
+        end
+      end
+
+      def gitaly_stats(repo, commit)
+        stats = repo.gitaly_commit_client.commit_stats(@id)
+        @additions = stats.additions
+        @deletions = stats.deletions
+        @total = @additions + @deletions
+      end
+
+      def rugged_stats(commit)
         diff = commit.rugged_diff_from_parent
         diff.each_patch do |p|

lib/gitlab/gitaly_client/commit_service.rb

@@ -204,6 +204,14 @@ module Gitlab
         response.sum(&:data)
       end
+      def commit_stats(revision)
+        request = Gitaly::CommitStatsRequest.new(
+          repository: @gitaly_repo,
+          revision: GitalyClient.encode(revision)
+        )
+        GitalyClient.call(@repository.storage, :commit_service, :commit_stats, request)
+      end
+
       private
       def commit_diff_request_params(commit, options = {})

spec/lib/gitlab/git/commit_spec.rb

@@ -401,7 +401,7 @@ describe Gitlab::Git::Commit, seed_helper: true do
     end
   end
-  describe '#stats' do
+  shared_examples '#stats' do
     subject { commit.stats }
     describe '#additions' do
@@ -415,6 +415,14 @@ describe Gitlab::Git::Commit, seed_helper: true do
     end
   end
+  describe '#stats with gitaly on' do
+    it_should_behave_like '#stats'
+  end
+
+  describe '#stats with gitaly disabled', skip_gitaly_mock: true do
+    it_should_behave_like '#stats'
+  end
+
   describe '#to_diff' do
     subject { commit.to_diff }

spec/lib/gitlab/gitaly_client/commit_service_spec.rb

@@ -165,4 +165,29 @@ describe Gitlab::GitalyClient::CommitService do
       expect(subject).to eq("my diff")
     end
   end
+
+  describe '#commit_stats' do
+    let(:request) do
+      Gitaly::CommitStatsRequest.new(
+        repository: repository_message, revision: revision
+      )
+    end
+    let(:response) do
+      Gitaly::CommitStatsResponse.new(
+        oid: revision,
+        additions: 11,
+        deletions: 15
+      )
+    end
+
+    subject { described_class.new(repository).commit_stats(revision) }
+
+    it 'sends an RPC request' do
+      expect_any_instance_of(Gitaly::CommitService::Stub).to receive(:commit_stats)
+        .with(request, kind_of(Hash)).and_return(response)
+
+      expect(subject.additions).to eq(11)
+      expect(subject.deletions).to eq(15)
+    end
+  end
 end