From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Mike Hommey <mh@glandium.org>
Cc: git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
"Emily Shaffer" <emilyshaffer@google.com>,
"Jeff King" <peff@peff.net>, "René Scharfe" <l.s.r@web.de>
Subject: Re: [PATCH 8/8] hook-list.h: add a generated list of hooks, like config-list.h
Date: Tue, 16 Nov 2021 13:01:00 +0100 [thread overview]
Message-ID: <211116.86y25opapy.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <20211115230032.3or3qqlsdnxjtrol@glandium.org>
On Tue, Nov 16 2021, Mike Hommey wrote:
> 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.
Ah, you're obviously right. I don't know what I was thinking yesterday.
I submitted a re-roll of the greater dependency fix-up & optimization
series I've got kicking around, which includes a fix for this
issue. Thank you for the report:
https://lore.kernel.org/git/cover-v3-00.23-00000000000-20211116T114334Z-avarab@gmail.com
next prev parent reply other threads:[~2021-11-16 12:13 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 10:29 [PATCH 0/8] Makefile: generate a hook-list.h, prep for config-based-hooks Ævar Arnfjörð Bjarmason
2021-09-23 10:29 ` [PATCH 1/8] Makefile: mark "check" target as .PHONY Ævar Arnfjörð Bjarmason
2021-09-23 10:29 ` [PATCH 2/8] Makefile: stop hardcoding {command,config}-list.h Ævar Arnfjörð Bjarmason
2021-09-23 10:29 ` [PATCH 3/8] Makefile: don't perform "mv $@+ $@" dance for $(GENERATED_H) Ævar Arnfjörð Bjarmason
2021-09-23 10:29 ` [PATCH 4/8] Makefile: remove an out-of-date comment Ævar Arnfjörð Bjarmason
2021-09-23 10:30 ` [PATCH 5/8] hook.[ch]: move find_hook() from run-command.c to hook.c Ævar Arnfjörð Bjarmason
2021-09-23 10:30 ` [PATCH 6/8] hook.c: add a hook_exists() wrapper and use it in bugreport.c Ævar Arnfjörð Bjarmason
2021-09-23 10:30 ` [PATCH 7/8] hook.c users: use "hook_exists()" instead of "find_hook()" Ævar Arnfjörð Bjarmason
2021-09-23 10:30 ` [PATCH 8/8] hook-list.h: add a generated list of hooks, like config-list.h Ævar Arnfjörð Bjarmason
2021-09-24 10:19 ` Phillip Wood
2021-09-24 15:51 ` Junio C Hamano
2021-09-24 16:39 ` René Scharfe
2021-09-24 19:30 ` Ævar Arnfjörð Bjarmason
2021-09-24 19:56 ` René Scharfe
2021-09-24 20:09 ` Ævar Arnfjörð Bjarmason
2021-09-27 9:24 ` Phillip Wood
2021-09-27 10:36 ` Ævar Arnfjörð Bjarmason
2021-11-15 22:04 ` Mike Hommey
2021-11-15 22:26 ` Ævar Arnfjörð Bjarmason
2021-11-15 22:40 ` Mike Hommey
2021-11-15 22:49 ` Ævar Arnfjörð Bjarmason
2021-11-15 23:00 ` Mike Hommey
2021-11-16 12:01 ` Ævar Arnfjörð Bjarmason [this message]
2021-11-17 8:39 ` Junio C Hamano
2021-09-26 19:03 ` [PATCH v2 0/8] Makefile: generate a hook-list.h, prep for config-based-hooks Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 1/8] Makefile: mark "check" target as .PHONY Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 2/8] Makefile: stop hardcoding {command,config}-list.h Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 3/8] Makefile: don't perform "mv $@+ $@" dance for $(GENERATED_H) Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 4/8] Makefile: remove an out-of-date comment Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 5/8] hook.[ch]: move find_hook() from run-command.c to hook.c Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 6/8] hook.c: add a hook_exists() wrapper and use it in bugreport.c Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 7/8] hook.c users: use "hook_exists()" instead of "find_hook()" Ævar Arnfjörð Bjarmason
2021-09-26 19:03 ` [PATCH v2 8/8] hook-list.h: add a generated list of hooks, like config-list.h Ævar Arnfjörð Bjarmason
2021-09-27 16:48 ` Junio C Hamano
2021-09-27 18:00 ` René Scharfe
2021-09-27 20:23 ` Junio C Hamano
2021-09-27 9:30 ` [PATCH v2 0/8] Makefile: generate a hook-list.h, prep for config-based-hooks Phillip Wood
2021-09-27 10:38 ` Ævar Arnfjörð Bjarmason
2021-09-27 18:01 ` Phillip Wood
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