Of course you are right, as usual. I just felt like that was a lot of hoop-jumping. People already chide me for my affinity for baroque Makefiles...
On Sat, Jan 26, 2019 at 11:01 AM Ian Lance Taylor <i...@golang.org> wrote: > > On Fri, Jan 25, 2019 at 7:55 PM Tim Hockin <thoc...@google.com> wrote: > > > > Fair point, of course. > > > > I care because Kubernetes and it's family of projects have Makefiles to > > encapsulate trickier aspects of building, including code generation. > > Compiling kubernetes takes a LONG time. It would be nice to avoid > > re-triggering secondary actions when the primary artifacts have not changed. > > > > Could I checksum? Sure, but then I am writing a custom builder, so I might > > as well use Bazel (which has other issues). > > > > It's not a huge deal, today, but I really wanted to understand it. It just > > seemed broken. > > While understanding that the approach is second best, Makefiles are > fully able to handle files that have the same contents but updated > timestamps. You separate the file you create and the file you use. > Then you write a Makefile target like > > progtouse: stmp-progtouse; @true # Yes, the "; @true" is important. > stmp-progtouse: dependencies to build progtobuild > # commands to build progtobuild > $(SHELL) mvifdiff.sh progtobuild progtouse > echo >$@ > > The shell script mvifdiff.sh is simply > > if cmp -s "$1" "$2" ; then > rm -f -- "$1" > else > mv -f -- "$1" "$2" > fi > > Then everything else depends on, and uses, progtouse. > > Remember to remove stmp-progtouse in your clean targets. > > Ian -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
