Re: [PATCH] add definitions for global variables to shell.c

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 19, 2008, 07:53 UTC
Message-ID: <7vpro5fnke.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <20080819072650.GE11842@schiele.dyndns.org>

Robert Schiele <rschiele@gmail.com> writes:

Show 20 quoted lines

> On Mon, Aug 18, 2008 at 05:29:11PM -0700, Junio C Hamano wrote:
>> Haven't looked at the real declarations but if the decl are "extern" and
>> nobody refers to them, why should the resulting object file require them
>> to be defined anywhere?  If the decl are not and in (fortran-ish) "common"
>> section, on the other hand, you shouldn't have to define them yourself
>> like this either.
>> 
>> This sounds like a compiler bug to me.
>
> This was my first thought as well but after more inspection there are two
> things to consider:
>
> 1. I was not really precise enough in my description since I didn't spot that
>    when I looked into the issue first: Actually there are references to these
>    variables in static inline functions in cache.h.  Thus there actually is a
>    reference though one that will never be used since abspath.c (that includes
>    cache.h) is not calling any of these functions.
>
> 2. Since these symbols turn out to be referenced though in dead code only I
>    wouldn't call it a compiler bug.

Ok, as I said, I didn't look. If they are indeed referenced, that is a different story.

Even if that is the case, I do not like the prospect of having to maintain a set of duplicated variable definitions. If we really wanted to address this issue, maybe we would want a separate source file that is linked to both git-shell and to the rest of the system that has nothing but definitions of these variables? I thought environment.c was meant to be something like that -- would linking environment.o pull in too many extra references these days (again, I didn't try)?