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   file:work.py
             product   st:dir_inp/
             product   step:./work.py

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

step:./work.py
               state = SUCCEEDED
                need = DEFAULT
           using_env = STEPUP_PATH_FILTER [dynamic]
             creator   step:./plan.py
              source   file:dir_inp/inp.txt [dynamic]
              source   file:work.py
             product   file:dir_out/out.txt
             product   file:dir_vol/vol.txt
                sink   file:dir_out/out.txt [dynamic]
                sink   file:dir_vol/vol.txt [dynamic]

st:dir_inp/
             creator   step:./plan.py
             product   file:dir_inp/inp.txt

file:dir_inp/inp.txt
               state = CONFIRMED
             creator   st:dir_inp/
                sink   step:./work.py

file:dir_out/out.txt
               state = BUILT
             creator   step:./work.py
              source   step:./work.py

file:dir_vol/vol.txt
               state = VOLATILE
             creator   step:./work.py
              source   step:./work.py
