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]
           explained = yes
             creator   root:
              source   file:plan.py
             product   step:cat bar.txt > egg.txt
             product   step:cat foo1.txt foo2.txt > bar.txt
             product   step:echo inp1 > foo1.txt
             product   step:echo inp2 > foo2.txt

step:echo inp1 > foo1.txt
               state = PENDING
                need = OPTIONAL
           explained = yes
             creator   step:./plan.py
             product   file:foo1.txt
                sink   file:foo1.txt

file:foo1.txt
               state = PLANNED
             creator   step:echo inp1 > foo1.txt
              source   step:echo inp1 > foo1.txt
                sink   step:cat foo1.txt foo2.txt > bar.txt

step:echo inp2 > foo2.txt
               state = PENDING
                need = OPTIONAL
           explained = yes
             creator   step:./plan.py
             product   file:foo2.txt
                sink   file:foo2.txt

file:foo2.txt
               state = PLANNED
             creator   step:echo inp2 > foo2.txt
              source   step:echo inp2 > foo2.txt
                sink   step:cat foo1.txt foo2.txt > bar.txt

step:cat foo1.txt foo2.txt > bar.txt
               state = PENDING
                need = OPTIONAL
           explained = yes
             creator   step:./plan.py
              source   file:foo1.txt
              source   file:foo2.txt
             product   file:bar.txt
                sink   file:bar.txt

file:bar.txt
               state = PLANNED
             creator   step:cat foo1.txt foo2.txt > bar.txt
              source   step:cat foo1.txt foo2.txt > bar.txt
                sink   step:cat bar.txt > egg.txt

step:cat bar.txt > egg.txt
               state = PENDING
                need = OPTIONAL
           explained = yes
             creator   step:./plan.py
              source   file:bar.txt
             product   file:egg.txt
                sink   file:egg.txt

file:egg.txt
               state = PLANNED
             creator   step:cat bar.txt > egg.txt
              source   step:cat bar.txt > egg.txt
