Merge Merge Requests via Gitaly

4 files changed, 80 insertions, 3 deletions

diff --git a/lib/gitlab/git/operation_service.rb b/lib/gitlab/git/operation_service.rb
index d835dcca8ba..ab94ba8a73a 100644
--- a/lib/gitlab/git/operation_service.rb
+++ b/lib/gitlab/git/operation_service.rb
@@ -3,9 +3,17 @@ module Gitlab
     class OperationService
       include Gitlab::Git::Popen
 
-      WithBranchResult = Struct.new(:newrev, :repo_created, :branch_created) do
+      BranchUpdate = Struct.new(:newrev, :repo_created, :branch_created) do
         alias_method :repo_created?, :repo_created
         alias_method :branch_created?, :branch_created
+
+        def self.from_gitaly(branch_update)
+          new(
+            branch_update.commit_id,
+            branch_update.repo_created,
+            branch_update.branch_created
+          )
+        end
       end
 
       attr_reader :user, :repository
@@ -112,7 +120,7 @@ module Gitlab
         ref = Gitlab::Git::BRANCH_REF_PREFIX + branch_name
         update_ref_in_hooks(ref, newrev, oldrev)
 
-        WithBranchResult.new(newrev, was_empty, was_empty || Gitlab::Git.blank_ref?(oldrev))
+        BranchUpdate.new(newrev, was_empty, was_empty || Gitlab::Git.blank_ref?(oldrev))
       end
 
       def find_oldrev_from_branch(newrev, branch)
diff --git a/lib/gitlab/git/repository.rb b/lib/gitlab/git/repository.rb
index a6b2d189f18..f99be3cef7b 100644
--- a/lib/gitlab/git/repository.rb
+++ b/lib/gitlab/git/repository.rb
@@ -704,7 +704,17 @@ module Gitlab
         tags.find { |tag| tag.name == name }
       end
 
-      def merge(user, source_sha, target_branch, message)
+      def merge(user, source_sha, target_branch, message, &block)
+        gitaly_migrate(:operation_user_merge_branch) do |is_enabled|
+          if is_enabled
+            gitaly_operation_client.user_merge_branch(user, source_sha, target_branch, message, &block)
+          else
+            rugged_merge(user, source_sha, target_branch, message, &block)
+          end
+        end
+      end
+
+      def rugged_merge(user, source_sha, target_branch, message)
         committer = Gitlab::Git.committer_hash(email: user.email, name: user.name)
 
         OperationService.new(user, self).with_branch(target_branch) do |start_commit|
diff --git a/lib/gitlab/gitaly_client/operation_service.rb b/lib/gitlab/gitaly_client/operation_service.rb
index 81ddaf13e10..91f34011f6e 100644
--- a/lib/gitlab/gitaly_client/operation_service.rb
+++ b/lib/gitlab/gitaly_client/operation_service.rb
@@ -74,6 +74,37 @@ module Gitlab
           raise Gitlab::Git::HooksService::PreReceiveError, pre_receive_error
         end
       end
+
+      def user_merge_branch(user, source_sha, target_branch, message)
+        request_enum = QueueEnumerator.new
+        response_enum = GitalyClient.call(
+          @repository.storage,
+          :operation_service,
+          :user_merge_branch,
+          request_enum.each
+        )
+
+        request_enum.push(
+          Gitaly::UserMergeBranchRequest.new(
+            repository: @gitaly_repo,
+            user: Util.gitaly_user(user),
+            commit_id: source_sha,
+            branch: GitalyClient.encode(target_branch),
+            message: GitalyClient.encode(message)
+          )
+        )
+
+        yield response_enum.next.commit_id
+
+        request_enum.push(Gitaly::UserMergeBranchRequest.new(apply: true))
+
+        branch_update = response_enum.next.branch_update
+        raise Gitlab::Git::CommitError.new('failed to apply merge to branch') unless branch_update.commit_id.present?
+
+        Gitlab::Git::OperationService::BranchUpdate.from_gitaly(branch_update)
+      ensure
+        request_enum.close
+      end
     end
   end
 end
diff --git a/lib/gitlab/gitaly_client/queue_enumerator.rb b/lib/gitlab/gitaly_client/queue_enumerator.rb
new file mode 100644
index 00000000000..b8018029552
--- /dev/null
+++ b/lib/gitlab/gitaly_client/queue_enumerator.rb
@@ -0,0 +1,28 @@
+module Gitlab
+  module GitalyClient
+    class QueueEnumerator
+      def initialize
+        @queue = Queue.new
+      end
+
+      def push(elem)
+        @queue << elem
+      end
+
+      def close
+        push(:close)
+      end
+
+      def each
+        return enum_for(:each) unless block_given?
+
+        loop do
+          elem = @queue.pop
+          break if elem == :close
+
+          yield elem
+        end
+      end
+    end
+  end
+end