Re: [bug #19108] Pattern rules with multiple target patterns do not honor the dependencies of all targets correctly

[Philip Guenther]

To reiterate, here's the involved rules from the makefile:
------
x: x.tgt1 x.tgt2
      @echo "making x"
      touch $@
x.tgt2: dep
dep:
      @echo "making dep"
      sleep 5
      touch $@
%.tgt1 %.tgt2: %.src
      cp $< $(patsubst %.src,%.tgt1,$<)
      cp $< $(patsubst %.src,%.tgt2,$<)
-------

So your argument is that once make has decided to use the
multiple-target pattern rule to generate x.tgt1, it should set the
dependencies of each target of that rule to the union of their
existing dependencies because generating x.tgt1 will also generate the
others.

Hmm.  While that would seem to makes sense, it also applies to the
user written dependencies.  That is, why isn't this a failure of the
makefile writer to declare the x.tgt1->dep dependency?  In what way
does the generation of x.tgt2 depend on 'dep' that the generation of
x.tgt1 does not share?


Philip Guenther