class ProjectLabel < Label belongs_to :project validates :project, presence: true validate :title_must_not_exist_at_group_level delegate :group, to: :project, allow_nil: true def to_reference(target_project = nil, format: :id) super(project, target_project, format: format) end private def title_must_not_exist_at_group_level return unless group.present? && title_changed? if group.labels.with_title(self.title).exists? errors.add(:title, :label_already_exists_at_group_level, group: group.name) end end end