class Xcodeproj::Project::Object::GroupableHelper

def source_tree_real_path(object)
  case object.source_tree
  when '<group>'
    object_parent = parent(object)
    if object_parent.isa == 'PBXProject'.freeze
      object.project.project_dir
    else
      real_path(object_parent)
    end
  when 'SOURCE_ROOT'
    object.project.project_dir
  when '<absolute>'
    nil
  else
    Pathname.new("${#{object.source_tree}}")
  end
end