From: <rsbecker@nexbridge.com>
To: "'Junio C Hamano'" <gitster@pobox.com>,
"'Taylor Blau'" <me@ttaylorr.com>
Cc: <git@vger.kernel.org>,
"'Randall S. Becker'" <randall.becker@nexbridge.ca>,
"'Elijah Newren'" <newren@gmail.com>
Subject: RE: [PATCH] run-command.c: fix missing include under `NO_PTHREADS`
Date: Tue, 16 May 2023 15:13:57 -0400 [thread overview]
Message-ID: <00a601d9882a$93c7a940$bb56fbc0$@nexbridge.com> (raw)
In-Reply-To: <xmqqh6sct7jx.fsf@gitster.g>
On Tuesday, May 16, 2023 3:12 PM, Junio C Hamano wrote:
>Taylor Blau <me@ttaylorr.com> writes:
>
>> When building git with `NO_PTHREADS=YesPlease`, we fail to build
>> run-command.o since we don't have a definition for ALLOC_GROW:
>>
>> $ make NO_PTHREADS=1 DEVELOPER=1 run-command.o
>> GIT_VERSION = 2.41.0.rc0.1.g787eb3beae.dirty
>> CC run-command.o
>> run-command.c: In function ‘git_atexit’:
>> run-command.c:1103:9: error: implicit declaration of function ‘ALLOC_GROW’ [-
>Werror=implicit-function-declaration]
>> 1103 | ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1,
>git_atexit_hdlrs.alloc);
>> | ^~~~~~~~~~
>> cc1: all warnings being treated as errors
>> make: *** [Makefile:2715: run-command.o] Error 1
>
>I am OK to give a reproduction recipe, i.e. the "$ make" command line, to make it
>easy for people, who cannot remember how to define make variables from the
>command line, to try out themselves, but I hate the "build transcript" in the log
>message, when a few lines of prose suffices.
>
>How about this?
>
> Git 2.41-rc0 fails to compile run-command.c with NO_PTHREADS
> defined, i.e.
>
> $ make NO_PTHREADS=1 run-command.o
>
> as ALLOC_GROW() macro is used in the atexit() emulation but the
> macro definition is not available.
>
>> This bisects to 36bf195890 (alloc.h: move ALLOC_GROW() functions from
>> cache.h, 2023-02-24), which replaced includes of "cache.h" with
>> "alloc.h", which is the new home of `ALLOC_GROW()` (and
>> `ALLOC_GROW_BY()`).
>
>Good.
>Insert something like:
>
> We can see that run-command.c is the only one that try to use
> these macros without including <alloc.h>.
>
> $ git grep -l -e '[^_]ALLOC_GROW(' -e 'ALLOC_GROW_BY(' \*.c | sort >/tmp/1
> $ git grep -l 'alloc\.h' \*.c | sort >/tmp/2
> $ comm -23 /tmp/[12]
> compat/simple-ipc/ipc-unix-socket.c
> run-command.c
>
> The "compat/" file only talks about the macro in the comment,
> and is not broken.
>
>here. What I am aiming for is to tell readers what they do not have to spend their
>time on. As we encourage people to make sure to look for other errors that come
>from the same root cause when making a fix, avoiding duplicated work by telling
>what they do not have to look at is rather important.
>
>> run-command.c compiles fine when `NO_PTHREADS` is undefined, since its
>> use of `ALLOC_GROW()` is behind a `#ifndef NO_PTHREADS`. (Everything
>> else compiles fine when NO_PTHREADS is defined, so this is the only
>> spot that needs fixing).
>
>I think we can say that, but is probably coered by the three-line summary I gave
>above.
>
>> We could fix this by conditionally including "alloc.h" when
>> `NO_PTHREADS` is defined. But we have relatively few examples of
>> conditional includes throughout the tree[^1].
>>
>> Instead, include "alloc.h" unconditionally in run-command.c to allow
>> it to successfully compile even when NO_PTHREADS is defined.
>
>Good.
>
>> [^1]: With `git grep -E -A1 '#if(n)?def' -- **/*.c | grep '#include' -B1`.
>
>Good.
This all makes sense to me.
next prev parent reply other threads:[~2023-05-16 19:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-16 16:58 [BUG] Git 2.41.0-rc0 - Compile Error ALLOC_GROW rsbecker
2023-05-16 17:06 ` Taylor Blau
2023-05-16 17:19 ` Junio C Hamano
2023-05-16 17:24 ` [PATCH] run-command.c: need alloc.h for our own at-exit handler emulation Junio C Hamano
2023-05-16 17:33 ` rsbecker
2023-05-16 17:57 ` Taylor Blau
2023-05-16 18:01 ` Taylor Blau
2023-05-16 18:44 ` Junio C Hamano
2023-05-16 18:47 ` Taylor Blau
2023-05-16 18:53 ` Junio C Hamano
2023-05-16 17:56 ` [PATCH] run-command.c: fix missing include under `NO_PTHREADS` Taylor Blau
2023-05-16 19:12 ` Junio C Hamano
2023-05-16 19:13 ` rsbecker [this message]
2023-05-16 21:33 ` Taylor Blau
2023-05-18 4:16 ` Elijah Newren
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