Re: [PATCH v2 3/5] Makefile: fix "cscope" target to refer to cscope.out

From: Jeff King <peff@peff.net>
Date: Jul 1, 2021, 22:25 UTC
Message-ID: <YN5AwdVC3QAcy2tA@coredump.intra.peff.net>
In-Reply-To: <YN5AeMiTiHFrFW/7@coredump.intra.peff.net>

On Thu, Jul 01, 2021 at 06:23:52PM -0400, Jeff King wrote:

Show 37 quoted lines

> On Tue, Jun 29, 2021 at 01:12:57PM +0200, Ævar Arnfjörð Bjarmason wrote:
> 
> > diff --git a/Makefile b/Makefile
> > index faa8900097..2e3b257164 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -2737,10 +2737,12 @@ tags: FORCE
> >  	$(FIND_SOURCE_FILES) | xargs ctags -a -o tags+ && \
> >  	mv tags+ tags
> >  
> > +cscope.out:
> > +	$(QUIET_GEN)$(RM) cscope.out && \
> > +	$(FIND_SOURCE_FILES) | xargs cscope -f$@ -b
> > +
> >  .PHONY: cscope
> > -cscope:
> > -	$(QUIET_GEN)$(RM) cscope* && \
> > -	$(FIND_SOURCE_FILES) | xargs cscope -b
> > +cscope: cscope.out
> 
> Doesn't this break subsequent runs after the first generation? With a
> phony "cscope" target, "make cscope" will always run the command, even
> if it's not necessary. But with a real "cscope.out" target but not
> dependencies, it will _never_ run it, even if one of the files changed.
> 
> E.g., with your patch:
> 
>   $ make cscope.out
>     GEN cscope.out
> 
>   $ make cscope.out
>   make: 'cscope.out' is up to date.
> 
>   $ echo 'void foo(void) { }' >>git.c
>   $ make cscope.out
>   GIT_VERSION = 2.32.0.96.g5daee1b7bb.dirty
>   make: 'cscope.out' is up to date.

Ah, I see it is un-broken in the next commit, which adds actual dependencies. I think it is OK to have a temporarily-broken state in the history for something so trivial, but it might be worth mentioning it in the commit message.

-Peff