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Message-ID: <3836b482434bd0b9a609959d3696cc6113a93f2f.camel@perches.com>
Subject: Re: [Cocci] coccinelle: Convert comma to semicolons (was Re:
 [PATCH] checkpatch: Add test for comma use that should be semicolon)
From:   Joe Perches <joe@perches.com>
To:     Valdis =?UTF-8?Q?Kl=C4=93tnieks?= <valdis.kletnieks@vt.edu>
Cc:     Julia Lawall <julia.lawall@inria.fr>,
        kernel-janitors <kernel-janitors@vger.kernel.org>,
        kernelnewbies <kernelnewbies@kernelnewbies.org>,
        linux-kernel-mentees@lists.linuxfoundation.org,
        Andrew Morton <akpm@linux-foundation.org>,
        cocci <cocci@systeme.lip6.fr>,
        Giuseppe Scrivano <gscrivan@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Andy Whitcroft <apw@shadowen.org>
Date:   Fri, 21 Aug 2020 22:30:21 -0700
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On Fri, 2020-08-21 at 23:35 -0400, Valdis Klētnieks wrote:
> On Fri, 21 Aug 2020 18:08:08 -0700, Joe Perches said:
> > (forwarding on to kernel-janitors/mentees and kernelnewbies)
> > 
> > Just fyi for anyone that cares:
> > 
> > A janitorial task for someone might be to use Julia's coccinelle
> > script below to convert the existing instances of commas that
> > separate statements into semicolons.
> 
> Note that you need to *really* check for possible changes in semantics.
> It's *usually* OK to do that, but sometimes it's not...
> 
> for (i=0; i++, last++; !last) {
> 
> changing that comma to a ; will break the compile.  In other cases, it can
> introduce subtle bugs.

True enough for a general statement, though the coccinelle
script Julia provided does not change a single instance of
for loop expressions with commas.

As far as I can tell, no logic defect is introduced by the
script at all.