On Mon, Nov 15, 2021 at 11:49:31PM +0100, Ævar Arnfjörð Bjarmason wrote:
>
> On Tue, Nov 16 2021, Mike Hommey wrote:
>
> > On Mon, Nov 15, 2021 at 11:26:36PM +0100, Ævar Arnfjörð Bjarmason wrote:
> >>
> >> On Tue, Nov 16 2021, Mike Hommey wrote:
> >>
> >> > On Thu, Sep 23, 2021 at 12:30:03PM +0200, Ævar Arnfjörð Bjarmason wrote:
> >> >> -builtin/help.sp builtin/help.s builtin/help.o: config-list.h GIT-PREFIX
> >> >> +hook.sp hook.s hook.o: hook-list.h
> >> >> +
> >> >> +builtin/help.sp builtin/help.s builtin/help.o: config-list.h hook-list.h GIT-PREFIX
> >> >
> >> > hook-list.h is only included from buitin/bugreport.c, so
> >> > builtin/bugreport.o should be the one with the hook-list.h dependency,
> >> > shouldn't it?
> >>
> >> Well spotted, yes. This is a mistake. I think from some earlier WIP
> >> version of the series.
> >>
> >> In practice we don't really miss dependencies due to these sorts of
> >> mistakes since we use the .depends files, i.e. GCC & Clang figure this
> >> out for us:
> >>
> >> $ grep hook-list .depend/* */.depend/*
> >> builtin/.depend/bugreport.o.d: compat/compiler.h git-compat-util.h hook.h hook-list.h
> >> builtin/.depend/bugreport.o.d:hook-list.h:
> >
> > But aren't those .depends files are only created when compiling object
> > files, such that builtin/.depend/bugreport.o.d wouldn't exist until
> > bugreport.c is compiled, which would fail if hook-list.h wasn't created
> > before that?
>
> Fail how?
>
> I don't think it could fail, because the purpose of these dependency
> relationships is to avoid needless *re*builds. So if you're building for
> the first time it doesn't matter, your compiler will find the relevant
> things to include for you. It doesn't need what's in the Makefile to do
> that.
>
> See [1], what I said about LIB_H there applies more generally for the
> .depends files.
>
> It will only fail in the sense that it over-depends, i.e. if you do:
>
> git clean -dxf; make builtin/help.o
Try
git clean -dxf; make builtin/bugreport.o
It fails with:
CC builtin/bugreport.o
builtin/bugreport.c:7:10: fatal error: hook-list.h: そのようなファイルやディレクトリはありません
7 | #include "hook-list.h"
| ^~~~~~~~~~~~~
compilation terminated.
make: *** [Makefile:2500: builtin/bugreport.o] エラー 1
The only reason I can see why it builds at all normally is that hook.o
is built soon enough that by the time builtin/bugreport.o is built
hook-list.h has already been generated.
Mike
