Message-ID: <1337618463.13010.4.camel@joe2Laptop>
Subject: Re: [PATCH 1/1] checkpatch: don't fake typedefs with #define
From: Joe Perches <joe@perches.com>
To: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: linux-kernel@vger.kernel.org, apw@canonical.com
Date: Mon, 21 May 2012 09:41:03 -0700
In-Reply-To: <20120521120511.GG1197@pcarmody2.research.nokia.com>
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On Mon, 2012-05-21 at 15:05 +0300, Phil Carmody wrote:
> On 17/05/12 14:24 -0700, ext Joe Perches wrote:
> > On Fri, 2012-05-18 at 00:16 +0300, Phil Carmody wrote:
> > > On 17/05/12 13:54 -0700, ext Joe Perches wrote:
> > > > > +# check for deliberate avoidance of the above anti-typedef rule
> > > > > +		if ($line =~ /#\s*define\s+$Ident\s+$Type\b/) {
> > > > > +			WARN("NEW_TYPEDEFS",
> > > > > +			     "do not fake typedefs using #define\n" . $herecurr);
> > > > > +		}
> > > > > +
> > > > 
> > > > I think the false positive rate is pretty high.
> > > > I used this and don't see too many I'd remove.
> > > > 
> > > > $ git grep -E "#\s*define\s+\w+\s+(struct|unsigned|char|short|int|long|const)\b"
> 
> I hadn't actually run that before, but to be honest, I think
> few of them have much justification. Or at least, were that
> code to be written today by one of the regular contributors,
> it probably wouldn't be written with such a #define. A lot
> do go directly against the advice in Documentation/CodingStyle.
> 
> > > > Got an example you want this to find?
> > > 
> > > Too many. Alas I can't share them.
> > 
> > Too bad.
> > 
> > If all the defines end in _t maybe you could use
> > 	if ($line =~ /^\+\s*#\s*define\s+\w+_t\s+$Type\b/) {
> > etc...
> > 
> 
> Well, certainly structs are the majority of the immediate ones I'd
> most like to nail, so how about this:
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index faea0ec..0db7f84 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2299,6 +2299,12 @@ sub process {
>                              "do not add new typedefs\n" . $herecurr);
>                 }
>  
> +# check for deliberate avoidance of the above anti-typedef rule
> +               if ($line =~ /#\s*define\s+$Ident\s+(enum|union|struct)\s+$Ident\b/) {
> +                       WARN("NEW_TYPEDEFS",
> +                            "do not fake typedefs using #define\n" . $herecurr);
> +               }

I believe this would not catch,

#define typedeflike_define_t	\
	struct foo

If it's deliberate, you probably want to.

So maybe you want to move this and use
the $stat tests like the extern or memset
tests do (look around line 3200).


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