Makefile given the target change without any rules

Question

Makefile given the target change without any rules

I was answering another question - Dependency ordering error for multiuser work on SO and I posted the following makefile. The OP replied that if -j

it was not specified on the command line, it would not build the target dir1/out/file.bar

. In Perplexed, I verified that it works with -j2

but not with -j1

. I looked it over and I don't see what I missed. I thought I'd post it here in case anyone knows, as I am very curious ...

$(shell mkdir dir1 >& /dev/null; touch dir1/file.foo; \
        mkdir dir2 >& /dev/null; touch dir2/file.foo)


OUTDIRS = dir1/out dir2/out
OUTPUTS = dir1/out/file.bar dir2/out/file.bar

.DEFAULT_GOAL := all

$(OUTPUTS) : | $(OUTDIRS)

$(OUTDIRS) :
        @echo "making $@"
        sleep 1
        mkdir -p $@
        @echo "done making $@"


%.bar : ../%.foo
        @echo "copying $< to $@"
        @cp $< $@

all : outputs
        @echo "done $@"

outputs : $(OUTPUTS)
        @echo "created all output files"

clean :
        @rm -rf dir1 dir2

I am running make 3.81 and the OP was using 3.82. I tried working with make -d -j1 -r

, and got the following snippet:

     Finished prerequisites of target file `dir1/out/file.bar'.
    Must remake target `dir1/out/file.bar'.
    Successfully remade target file `dir1/out/file.bar'.
    Considering target file `dir2/out/file.bar'.
     File `dir2/out/file.bar' does not exist.
      Considering target file `dir2/out/../file.foo'.
       Finished prerequisites of target file `dir2/out/../file.foo'.
      No need to remake target `dir2/out/../file.foo'.
      Pruning file `dir1/out'.
      Pruning file `dir2/out'.
     Finished prerequisites of target file `dir2/out/file.bar'.
    Must remake target `dir2/out/file.bar'.
copying dir2/out/../file.foo to dir2/out/file.bar
    Successfully remade target file `dir2/out/file.bar'.