Merge branch 'gitaly-ff-merge' into 'master'

Incorporate Gitaly's OperationService.UserFFBranch RPC

Closes gitaly#693

See merge request gitlab-org/gitlab-ce!15040

3 files changed, 42 insertions, 9 deletions

diff --git a/lib/gitlab/git/commit.rb b/lib/gitlab/git/commit.rb
index 23ae37ff71e..d5518814483 100644
--- a/lib/gitlab/git/commit.rb
+++ b/lib/gitlab/git/commit.rb
@@ -73,7 +73,7 @@ module Gitlab
           decorate(repo, commit) if commit
         rescue Rugged::ReferenceError, Rugged::InvalidError, Rugged::ObjectError,
                Gitlab::Git::CommandError, Gitlab::Git::Repository::NoRepository,
-               Rugged::OdbError, Rugged::TreeError
+               Rugged::OdbError, Rugged::TreeError, ArgumentError
           nil
         end
 
diff --git a/lib/gitlab/git/repository.rb b/lib/gitlab/git/repository.rb
index a9e4e1130c3..4f9eac92d9a 100644
--- a/lib/gitlab/git/repository.rb
+++ b/lib/gitlab/git/repository.rb
@@ -758,13 +758,13 @@ module Gitlab
       end
 
       def ff_merge(user, source_sha, target_branch)
-        OperationService.new(user, self).with_branch(target_branch) do |our_commit|
-          raise ArgumentError, 'Invalid merge target' unless our_commit
-
-          source_sha
+        gitaly_migrate(:operation_user_ff_branch) do |is_enabled|
+          if is_enabled
+            gitaly_ff_merge(user, source_sha, target_branch)
+          else
+            rugged_ff_merge(user, source_sha, target_branch)
+          end
         end
-      rescue Rugged::ReferenceError
-        raise ArgumentError, 'Invalid merge source'
       end
 
       def revert(user:, commit:, branch_name:, message:, start_branch_name:, start_repository:)
@@ -1177,10 +1177,10 @@ module Gitlab
         Gitlab::GitalyClient.migrate(method, status: status, &block)
       rescue GRPC::NotFound => e
         raise NoRepository.new(e)
-      rescue GRPC::BadStatus => e
-        raise CommandError.new(e)
       rescue GRPC::InvalidArgument => e
         raise ArgumentError.new(e)
+      rescue GRPC::BadStatus => e
+        raise CommandError.new(e)
       end
 
       private
@@ -1622,6 +1622,22 @@ module Gitlab
 
         run_git(args, env: env)
       end
+
+      def gitaly_ff_merge(user, source_sha, target_branch)
+        gitaly_operations_client.user_ff_branch(user, source_sha, target_branch)
+      rescue GRPC::FailedPrecondition => e
+        raise CommitError, e
+      end
+
+      def rugged_ff_merge(user, source_sha, target_branch)
+        OperationService.new(user, self).with_branch(target_branch) do |our_commit|
+          raise ArgumentError, 'Invalid merge target' unless our_commit
+
+          source_sha
+        end
+      rescue Rugged::ReferenceError
+        raise ArgumentError, 'Invalid merge source'
+      end
     end
   end
 end
diff --git a/lib/gitlab/gitaly_client/operation_service.rb b/lib/gitlab/gitaly_client/operation_service.rb
index adaf255f24b..526d44a8b77 100644
--- a/lib/gitlab/gitaly_client/operation_service.rb
+++ b/lib/gitlab/gitaly_client/operation_service.rb
@@ -105,6 +105,23 @@ module Gitlab
       ensure
         request_enum.close
       end
+
+      def user_ff_branch(user, source_sha, target_branch)
+        request = Gitaly::UserFFBranchRequest.new(
+          repository: @gitaly_repo,
+          user: Gitlab::Git::User.from_gitlab(user).to_gitaly,
+          commit_id: source_sha,
+          branch: GitalyClient.encode(target_branch)
+        )
+
+        branch_update = GitalyClient.call(
+          @repository.storage,
+          :operation_service,
+          :user_ff_branch,
+          request
+        ).branch_update
+        Gitlab::Git::OperationService::BranchUpdate.from_gitaly(branch_update)
+      end
     end
   end
 end