root:
             product   file:plan.py
             product   step:./plan.py

file:plan.py
               state = CONFIRMED
             creator   root:
                sink   step:./plan.py

step:./plan.py
               state = SUCCEEDED
                need = PLAN
           using_env = STEPUP_PATH_FILTER [dynamic]
             creator   root:
              source   file:plan.py
             product   step:cat msg.txt
             product   step:stepup shutdown; sleep 3; echo hello > msg.txt

step:stepup shutdown; sleep 3; echo hello > msg.txt
               state = RUNNING
                need = DEFAULT
             creator   step:./plan.py
             product   file:msg.txt
                sink   file:msg.txt

file:msg.txt
               state = PLANNED
             creator   step:stepup shutdown; sleep 3; echo hello > msg.txt
              source   step:stepup shutdown; sleep 3; echo hello > msg.txt
                sink   step:cat msg.txt

step:cat msg.txt
               state = PENDING
                need = DEFAULT
             creator   step:./plan.py
              source   file:msg.txt
