Merge branch '209786-stream-diff-stats-gitaly-call' into 'master'

Use the stream_call method when using the Gitaly Client for querying Diff Stats

See merge request gitlab-org/gitlab!33606

lib/gitlab/gitaly_client/commit_service.rb

@@ -212,8 +212,9 @@ module Gitlab
           right_commit_id: right_commit_sha
         )
 
-        response = GitalyClient.call(@repository.storage, :diff_service, :diff_stats, request, timeout: GitalyClient.medium_timeout)
-        response.flat_map(&:stats)
+        GitalyClient.streaming_call(@repository.storage, :diff_service, :diff_stats, request, timeout: GitalyClient.medium_timeout) do |response|
+          response.flat_map(&:stats)
+        end
       end
 
       def find_all_commits(opts = {})

spec/lib/gitlab/gitaly_client/commit_service_spec.rb

@@ -124,15 +124,20 @@ describe Gitlab::GitalyClient::CommitService do
     let(:left_commit_id) { 'master' }
     let(:right_commit_id) { 'cfe32cf61b73a0d5e9f13e774abde7ff789b1660' }
 
-    it 'sends an RPC request' do
+    it 'sends an RPC request and returns the stats' do
       request = Gitaly::DiffStatsRequest.new(repository: repository_message,
                                              left_commit_id: left_commit_id,
                                              right_commit_id: right_commit_id)
 
+      diff_stat_response = Gitaly::DiffStatsResponse.new(
+        stats: [{ additions: 1, deletions: 2, path: 'test' }])
+
       expect_any_instance_of(Gitaly::DiffService::Stub).to receive(:diff_stats)
-        .with(request, kind_of(Hash)).and_return([])
+        .with(request, kind_of(Hash)).and_return([diff_stat_response])
+
+      returned_value = described_class.new(repository).diff_stats(left_commit_id, right_commit_id)
 
-      described_class.new(repository).diff_stats(left_commit_id, right_commit_id)
+      expect(returned_value).to eq(diff_stat_response.stats)
     end
   end