Ninja phony behaviour

build1.ninja

# ninja bar.txt # builds foo.txt and bar.txt
# touch foo.txt
# ninja bar.txt # builds nothing

rule create
  command = cmd /c "echo $out > $out"

rule copy
  command = cmd /c "copy $from $out"

build foo: phony foo.txt

build bar.txt: copy foo
  from = foo.txt

build foo.txt: create

build2.ninja

# ninja bar.txt # builds foo.txt and bar.txt
# touch foo.txt
# ninja bar.txt # builds bar.txt

rule create
  command = cmd /c "echo $out > $out"

rule copy
  command = cmd /c "copy $from $out"

rule phony2
  command = cmd /c "echo nothing to do"

build foo: phony2 foo.txt

build bar.txt: copy foo
  from = foo.txt

build foo.txt: create