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From: <>
To: "'Junio C Hamano'" <>,
	"'Taylor Blau'" <>
Cc: <>,
	"'Randall S. Becker'" <>,
	"'Elijah Newren'" <>
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$> (raw)
In-Reply-To: <xmqqh6sct7jx.fsf@gitster.g>

On Tuesday, May 16, 2023 3:12 PM, Junio C Hamano wrote:
>Taylor Blau <> 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’ [-
>>      1103 |         ALLOC_GROW(git_atexit_hdlrs.handlers, + 1,
>>           |         ^~~~~~~~~~
>>     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()`).
>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
>> 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.
>> [^1]: With `git grep -E -A1 '#if(n)?def' -- **/*.c | grep '#include' -B1`.

This all makes sense to me.

  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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