avoid npe on tasks without variables
avoid npe on tasks without variables

icfantv/deck,sgarlick987/deck,zanthrash/deck-1,zanthrash/deck-1,duftler/deck,ajordens/deck,kenzanlabs/deck,spinnaker/deck,spinnaker/deck,zanthrash/deck-old,HaishiBai/deck,ajordens/deck,icfantv/deck,sgarlick987/deck,zanthrash/deck-1,spinnaker/deck,HaishiBai/deck,kenzanlabs/deck,duftler/deck,spinnaker/deck,duftler/deck,HaishiBai/deck,icfantv/deck,duftler/deck,sgarlick987/deck,ajordens/deck,icfantv/deck,kenzanlabs/deck,zanthrash/deck-old,ajordens/deck,sgarlick987/deck