Fix error when deleting an empty list of refs

changelogs/unreleased/xeodon-gitlab-ce-fix-45743-master-fix-gitaly-delete-refs.yml

+---
+title: Fix error when deleting an empty list of refs
+merge_request:
+author:
+type: fixed

lib/gitlab/git/repository.rb

@@ -2346,7 +2346,7 @@ module Gitlab
       end
 
       def gitaly_delete_refs(*ref_names)
-        gitaly_ref_client.delete_refs(refs: ref_names)
+        gitaly_ref_client.delete_refs(refs: ref_names) if ref_names.any?
       end
 
       def rugged_remove_remote(remote_name)

spec/lib/gitlab/git/repository_spec.rb

@@ -600,6 +600,10 @@ describe Gitlab::Git::Repository, seed_helper: true do
         end
       end
 
+      it 'does not fail when deleting an empty list of refs' do
+        expect { repo.delete_refs(*[]) }.not_to raise_error
+      end
+
       it 'raises an error if it failed' do
         expect { repo.delete_refs('refs\heads\fix') }.to raise_error(Gitlab::Git::Repository::GitError)
       end