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Date:   Thu, 5 Aug 2021 20:17:56 +0200 (CEST)
From:   Julia Lawall <julia.lawall@inria.fr>
To:     Joe Perches <joe@perches.com>
cc:     Dan Carpenter <dan.carpenter@oracle.com>,
        Andy Whitcroft <apw@canonical.com>,
        cocci <cocci@systeme.lip6.fr>,
        Dwaipayan Ray <dwaipayanray1@gmail.com>,
        Lukas Bulwahn <lukas.bulwahn@gmail.com>,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] checkpatch: prefer = {} initializations to = {0}
In-Reply-To: <e07845c0348f389756b76e34b4728a95aa48038a.camel@perches.com>
Message-ID: <alpine.DEB.2.22.394.2108052016220.16100@hadrien>
References: <20210805104353.GD26417@kili>         <117021b44dc9ba570a0f48736d14a267a8701d0a.camel@perches.com> <e07845c0348f389756b76e34b4728a95aa48038a.camel@perches.com>
User-Agent: Alpine 2.22 (DEB 394 2020-01-19)
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Precedence: bulk


On Thu, 5 Aug 2021, Joe Perches wrote:

> On Thu, 2021-08-05 at 05:27 -0700, Joe Perches wrote:
> > On Thu, 2021-08-05 at 13:43 +0300, Dan Carpenter wrote:
> > > The "= {};" style empty struct initializer is preferred over = {0}.
> > > It avoids the situation where the first struct member is a pointer and
> > > that generates a Sparse warning about assigning using zero instead of
> > > NULL.  Also it's just nicer to look at.
>
> Perhaps a cocci script like the below could help too:
>
> $ cat zero_init_struct.cocci
> @@
> identifier name;
> identifier t;
> @@
>
> 	struct name t = {
> -	       0
> 	};
>
> @@
> identifier name;
> identifier t;
> identifier member;
> @@
>
> 	struct name t = {
> 	       ...,
> 		.member = {
> -		0
> 		},
> 		...,
> 	};

My test turns up over 1900 occurrences.  There is the question of whether
{} or { } is preferred.  The above semantic patch replaces {0} by {} and
( 0 } by { }.

julia