diff --git a/lib/git_adapter_patch.rb b/lib/git_adapter_patch.rb
index b3fe79a..8d6f308 100644
--- a/lib/git_adapter_patch.rb
+++ b/lib/git_adapter_patch.rb
@@ -11,6 +11,7 @@ module Redmine
 
         def branches(*args)
           all_branches = branches_original(*args)
+          return [] if !all_branches
           all_branches.find_all { |b| !b.start_with?("wip/") }
         end
       end