Gracefully handle case when repository's root ref does not existsh-fix-root-ref-repository

This was failing regularly with an Error 500 when the API branches endpoint
was used.

Closes #40615

1 files changed, 10 insertions, 0 deletions

diff --git a/spec/lib/gitlab/git/repository_spec.rb b/spec/lib/gitlab/git/repository_spec.rb
index 2f49bd1bcf2..08dd6ea80ff 100644
--- a/spec/lib/gitlab/git/repository_spec.rb
+++ b/spec/lib/gitlab/git/repository_spec.rb
@@ -1210,6 +1210,16 @@ describe Gitlab::Git::Repository, seed_helper: true do
       end
     end
 
+    context 'when no root ref is available' do
+      it 'returns empty list' do
+        project = create(:project, :empty_repo)
+
+        names = project.repository.merged_branch_names(%w[feature])
+
+        expect(names).to be_empty
+      end
+    end
+
     context 'when no branch names are specified' do
       before do
         repository.create_branch('identical', 'master')