Incorporate DiffService.CommitPatch Gitaly RPC

GITALY_SERVER_VERSION

-0.32.0
+0.33.0

Gemfile

@@ -401,7 +401,7 @@ group :ed25519 do
 end
 
 # Gitaly GRPC client
-gem 'gitaly', '~> 0.29.0'
+gem 'gitaly', '~> 0.30.0'
 
 gem 'toml-rb', '~> 0.3.15', require: false
 

Gemfile.lock

@@ -275,7 +275,7 @@ GEM
       po_to_json (>= 1.0.0)
       rails (>= 3.2.0)
     gherkin-ruby (0.3.2)
-    gitaly (0.29.0)
+    gitaly (0.30.0)
       google-protobuf (~> 3.1)
       grpc (~> 1.0)
     github-linguist (4.7.6)
@@ -1019,7 +1019,7 @@ DEPENDENCIES
   gettext (~> 3.2.2)
   gettext_i18n_rails (~> 1.8.0)
   gettext_i18n_rails_js (~> 1.2.0)
-  gitaly (~> 0.29.0)
+  gitaly (~> 0.30.0)
   github-linguist (~> 4.7.0)
   gitlab-flowdock-git-hook (~> 1.0.1)
   gitlab-markup (~> 1.5.1)

lib/gitlab/git/commit.rb

@@ -271,8 +271,14 @@ module Gitlab
       #
       # Gitaly migration: https://gitlab.com/gitlab-org/gitaly/issues/324
       def to_diff
+        Gitlab::GitalyClient.migrate(:commit_patch) do |is_enabled|
+          if is_enabled
+            @repository.gitaly_commit_client.patch(id)
+          else
             rugged_diff_from_parent.patch
           end
+        end
+      end
 
       # Returns a diff object for the changes from this commit's first parent.
       # If there is no parent, then the diff is between this commit and an

lib/gitlab/gitaly_client/commit_service.rb

@@ -194,6 +194,16 @@ module Gitlab
         response.commit
       end
 
+      def patch(revision)
+        request = Gitaly::CommitPatchRequest.new(
+          repository: @gitaly_repo,
+          revision: GitalyClient.encode(revision)
+        )
+        response = GitalyClient.call(@repository.storage, :diff_service, :commit_patch, request)
+
+        response.sum(&:data)
+      end
+
       private
 
       def commit_diff_request_params(commit, options = {})

spec/lib/gitlab/gitaly_client/commit_service_spec.rb

@@ -126,4 +126,29 @@ describe Gitlab::GitalyClient::CommitService do
       described_class.new(repository).find_commit(revision)
     end
   end
+
+  describe '#patch' do
+    let(:request) do
+      Gitaly::CommitPatchRequest.new(
+        repository: repository_message, revision: revision
+      )
+    end
+    let(:response) { [double(data: "my "), double(data: "diff")] }
+
+    subject { described_class.new(repository).patch(revision) }
+
+    it 'sends an RPC request' do
+      expect_any_instance_of(Gitaly::DiffService::Stub).to receive(:commit_patch)
+        .with(request, kind_of(Hash)).and_return([])
+
+      subject
+    end
+
+    it 'concatenates the responses data' do
+      allow_any_instance_of(Gitaly::DiffService::Stub).to receive(:commit_patch)
+        .with(request, kind_of(Hash)).and_return(response)
+
+      expect(subject).to eq("my diff")
+    end
+  end
 end