Re: checkpatch, a patch checking script.

[Matt Mackall <mpm@selenic.com>]

On Sun, Apr 29, 2007 at 05:18:00PM -0700, Randy Dunlap wrote:
> Matt Mackall wrote:
> >On Sun, Apr 29, 2007 at 04:37:01PM -0700, Randy Dunlap wrote:
> >>On Sat, 28 Apr 2007 12:21:54 -0500 Matt Mackall wrote:
> >>
> >>>On Sat, Apr 28, 2007 at 01:11:01PM -0400, Dave Jones wrote:
> >>>>On Sat, Apr 28, 2007 at 11:11:36AM -0500, Matt Mackall wrote:
> >>>> > > I'm all ears for additional regexps, bug reports or other 
> >>>> suggestions.
> >>>> > 
> >>>> > Neat.
> >>>> > 
> >>>> > Does it check for:
> >>>> > 
> >>>> > functions marked extern?
> >>	data marked extern?
> >
> >It's perfectly reasonable to have a data extern declaration in a header 
> >file.
> 
> but it's not perfectly acceptable to have
> 
> extern unsigned long volatile jiffies;
> 
> in a .c file.
> 
> The biggest problem I'm seeing ATM is that this script is a bit too
> simplistic.  It doesn't know what it's looking at.  We'll have to
> address that, I think.

If you can make it run a regexp over the whole file at once rather
than a line at a time, you can deal with this with multi-line regexps.
Roughly, match:

 a +++ patch header followed by
 any number of lines not starting with +++ followed by
 the actual target expression

So, approximately:

 /+++ [\w\/]+.c(.*)\\n((([^+])|(\+[^+]))\n)*extern.*/

Or you could just make search remember what file it's in as it walks
the list of lines. But as I mentioned, multiline regexps are useful
for things other than just remembering what file we're in.

-- 
Mathematics is the supreme nostalgia of our time.