Re: [PATCH] git-compat-util.h: introduce CALLOC(x)

From: Jeff King <peff@peff.net>
Date: Dec 6, 2022, 01:43 UTC
Message-ID: <Y46eVnYrcOGAbUhi@coredump.intra.peff.net>
In-Reply-To: <Y45yaYV3xFB/xR2G@nand.local>

On Mon, Dec 05, 2022 at 05:36:25PM -0500, Taylor Blau wrote:

Show 21 quoted lines

> On Mon, Dec 05, 2022 at 10:01:11PM +0100, René Scharfe wrote:
> > This rule would turn this code:
> >
> > 	struct foo *bar = xcalloc(1, sizeof(*bar));
> > 	int i;
> >
> > ... into:
> >
> > 	struct foo *bar;
> > 	CALLOC(bar);
> > 	int i;
> >
> > ... which violates the coding guideline to not mix declarations and
> > statements (-Wdeclaration-after-statement).
> 
> Yeah, I was wondering about this myself when I wrote this part of the
> Coccinelle patch.
> 
> Is there an intelligent way to tell it to put the first statement after
> all declarations? I couldn't find anything after a quick scan of the
> documentation nor our own patches.

It feels like generating the code as above is not the end of the world. The most valuable thing that coccinelle is doing here is _finding_ the location, and telling you "it's supposed to be like this". It is great when the "this" post-image is perfect and doesn't need further tweaking.

But if the compiler then reminds you "hey, you need to go a bit further manually", that doesn't seem so bad. In other words, I would be happy to follow that work flow if I introduced a bare xcalloc(). My only worry is that somebody less experienced with the project (or with C) would get confused.

-Peff