Migrate Gitlab::Git::Repository#find_branch to Gitaly

GITALY_SERVER_VERSION

-0.36.0
+0.37.0

Gemfile

@@ -397,7 +397,7 @@ group :ed25519 do
 end
 # Gitaly GRPC client
-gem 'gitaly-proto', '~> 0.31.0', require: 'gitaly'
+gem 'gitaly-proto', '~> 0.32.0', require: 'gitaly'
 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-proto (0.31.0)
+    gitaly-proto (0.32.0)
       google-protobuf (~> 3.1)
       grpc (~> 1.0)
     github-linguist (4.7.6)
@@ -1020,7 +1020,7 @@ DEPENDENCIES
   gettext (~> 3.2.2)
   gettext_i18n_rails (~> 1.8.0)
   gettext_i18n_rails_js (~> 1.2.0)
-  gitaly-proto (~> 0.31.0)
+  gitaly-proto (~> 0.32.0)
   github-linguist (~> 4.7.0)
   gitlab-flowdock-git-hook (~> 1.0.1)
   gitlab-markup (~> 1.5.1)

lib/gitlab/git/repository.rb

@@ -134,15 +134,19 @@ module Gitlab
       # This is to work around a bug in libgit2 that causes in-memory refs to
       # be stale/invalid when packed-refs is changed.
       # See https://gitlab.com/gitlab-org/gitlab-ce/issues/15392#note_14538333
-      #
-      # Gitaly migration: https://gitlab.com/gitlab-org/gitaly/issues/474
       def find_branch(name, force_reload = false)
-        reload_rugged if force_reload
-        rugged_ref = rugged.branches[name]
-        if rugged_ref
-          target_commit = Gitlab::Git::Commit.find(self, rugged_ref.target)
-          Gitlab::Git::Branch.new(self, rugged_ref.name, rugged_ref.target, target_commit)
+        gitaly_migrate(:find_branch) do |is_enabled|
+          if is_enabled
+            gitaly_ref_client.find_branch(name)
+          else
+            reload_rugged if force_reload
+            rugged_ref = rugged.branches[name]
+            if rugged_ref
+              target_commit = Gitlab::Git::Commit.find(self, rugged_ref.target)
+              Gitlab::Git::Branch.new(self, rugged_ref.name, rugged_ref.target, target_commit)
+            end
+          end
         end
       end

lib/gitlab/gitaly_client/ref_service.rb

@@ -78,6 +78,20 @@ module Gitlab
         raise ArgumentError, e.message
       end
+      def find_branch(branch_name)
+        request = Gitaly::DeleteBranchRequest.new(
+          repository: @gitaly_repo,
+          name: GitalyClient.encode(branch_name)
+        )
+
+        response = GitalyClient.call(@repository.storage, :ref_service, :find_branch, request)
+        branch = response.branch
+        return unless branch
+
+        target_commit = Gitlab::Git::Commit.decorate(@repository, branch.target_commit)
+        Gitlab::Git::Branch.new(@repository, encode!(branch.name.dup), branch.target_commit.id, target_commit)
+      end
+
       private
       def consume_refs_response(response)

spec/lib/gitlab/git/repository_spec.rb

@@ -916,27 +916,37 @@ describe Gitlab::Git::Repository, seed_helper: true do
   end
   describe '#find_branch' do
-    it 'should return a Branch for master' do
-      branch = repository.find_branch('master')
-      expect(branch).to be_a_kind_of(Gitlab::Git::Branch)
-      expect(branch.name).to eq('master')
-    end
-    it 'should handle non-existent branch' do
-      branch = repository.find_branch('this-is-garbage')
-      expect(branch).to eq(nil)
+    shared_examples 'finding a branch' do
+      it 'should return a Branch for master' do
+        branch = repository.find_branch('master')
+        expect(branch).to be_a_kind_of(Gitlab::Git::Branch)
+        expect(branch.name).to eq('master')
+      end
+      it 'should handle non-existent branch' do
+        branch = repository.find_branch('this-is-garbage')
+        expect(branch).to eq(nil)
+      end
     end
-    it 'should reload Rugged::Repository and return master' do
-      expect(Rugged::Repository).to receive(:new).twice.and_call_original
-      repository.find_branch('master')
-      branch = repository.find_branch('master', force_reload: true)
-      expect(branch).to be_a_kind_of(Gitlab::Git::Branch)
-      expect(branch.name).to eq('master')
+    context 'when Gitaly find_branch feature is enabled' do
+      it_behaves_like 'finding a branch'
+    end
+    context 'when Gitaly find_branch feature is disabled', skip_gitaly_mock: true do
+      it_behaves_like 'finding a branch'
+      it 'should reload Rugged::Repository and return master' do
+        expect(Rugged::Repository).to receive(:new).twice.and_call_original
+
+        repository.find_branch('master')
+        branch = repository.find_branch('master', force_reload: true)
+
+        expect(branch).to be_a_kind_of(Gitlab::Git::Branch)
+        expect(branch.name).to eq('master')
+      end
     end
   end