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:bar/plan.py
             product   file:foo/inp.txt
             product   file:inp.txt
             product   step:./plan.py  # wd=bar

file:bar/plan.py
               state = CONFIRMED
             creator   step:./plan.py
                sink   step:./plan.py  # wd=bar

file:foo/inp.txt
               state = CONFIRMED
             creator   step:./plan.py
                sink   step:cp -p ../foo/inp.txt ../foo/out.txt  # wd=bar

file:inp.txt
               state = CONFIRMED
             creator   step:./plan.py
                sink   step:cp -p ../inp.txt ../out.txt  # wd=bar

step:./plan.py  # wd=bar
               state = SUCCEEDED
                need = PLAN
           using_env = INPS [dynamic]
                     = STEPUP_PATH_FILTER [dynamic]
             creator   step:./plan.py
              source   file:bar/plan.py
             product   step:cp -p ../foo/inp.txt ../foo/out.txt  # wd=bar
             product   step:cp -p ../inp.txt ../out.txt  # wd=bar

step:cp -p ../inp.txt ../out.txt  # wd=bar
               state = SUCCEEDED
                need = DEFAULT
             creator   step:./plan.py  # wd=bar
              source   file:inp.txt
             product   file:out.txt
                sink   file:out.txt

file:out.txt
               state = BUILT
             creator   step:cp -p ../inp.txt ../out.txt  # wd=bar
              source   step:cp -p ../inp.txt ../out.txt  # wd=bar

step:cp -p ../foo/inp.txt ../foo/out.txt  # wd=bar
               state = SUCCEEDED
                need = DEFAULT
             creator   step:./plan.py  # wd=bar
              source   file:foo/inp.txt
             product   file:foo/out.txt
                sink   file:foo/out.txt

file:foo/out.txt
               state = BUILT
             creator   step:cp -p ../foo/inp.txt ../foo/out.txt  # wd=bar
              source   step:cp -p ../foo/inp.txt ../foo/out.txt  # wd=bar
