Re: [PATCH v2 3/5] doc: remove unnecessary rm instances

> Jeff King wrote:
> > On Fri, May 14, 2021 at 06:56:29AM -0500, Felipe Contreras wrote:
> > 
> > > Commits 50cff52f1a (When generating manpages, delete outdated targets
> > > first., 2007-08-02) and f9286765b2 (Documentation/Makefile: remove
> > > cmd-list.made before redirecting to it., 2007-08-06) created these rm
> > > instances for a very rare corner-case: building as root by mistake.
> > > 
> > > It's odd to have workarounds here, but nowhere else in the Makefile--
> > > which already fails in this stuation, starting from
> > > Documentation/technical/.
> > 
> > Aren't there tons more that you end up removing in the next patch? E.g.:
> > 
> >    doc.dep : $(docdep_prereqs) $(DOC_DEP_TXT) build-docdep.perl
> >   -       $(QUIET_GEN)$(RM) $@+ $@ && \
> >   -       $(PERL_PATH) ./build-docdep.perl >$@+ $(QUIET_STDERR) && \
> >   -       mv $@+ $@
> >   +       $(QUIET_GEN)$(PERL_PATH) ./build-docdep.perl >$@ $(QUIET_STDERR)
> > 
> > That does differ in that it removes $@+, too, but the premise is the
> > same (we know that $@+ could not be a problem, as we're about to
> > clobber it anyway).
> > 
> > I'm OK with getting rid of all of them, but it seems like it ought to be
> > happening all in this patch.
> 
> Yeah, but the rationale is different.
> 
>   1. $(RM) $@: these remove the target file because of permissions
>      (i.e. root owned)
>   2. $(RM) $@+ $@ && $(CODE) && mv $@+ $@: these are for interrupted builds
> 
> To get rid of #2 we need an alternative solution, like .DELETE_ON_ERROR,
> to get rid of #1 we don't, we can just do it.