func (p4 patch4T) mangle(task *state.Task) error { snapsup, snapst, err := p4.snapSetupAndState(task) if err != nil { return err } var hadCandidate bool if err := p4.getMaybe(task, "had-candidate", &hadCandidate); err != nil && err != state.ErrNoState { return err } if hadCandidate { change := task.Change() if change.Kind() != "revert-snap" { return fmt.Errorf("had-candidate true for task %s (%s) of non-revert change %s (%s)", task.ID(), task.Kind(), change.ID(), change.Kind()) } } task.Clear("had-candidate") task.Set("old-candidate-index", snapst.LastIndex(snapsup.SideInfo.Revision)) return nil }