in lib/gitlab_git/repository.rb [183:202]
def discover_default_branch
names = branch_names
return if names.empty?
return names[0] if names.length == 1
if rugged_head
extracted_name = Ref.extract_branch_name(rugged_head.name)
return extracted_name if names.include?(extracted_name)
end
if names.include?('master')
'master'
else
names[0]
end
end