[RFC PATCH] checkpatch: check for 2 or more spaces around assignment of a declaration

[Joe Perches <joe@perches.com>]

On Wed, 2015-05-20 at 19:59 +0200, Jean Delvare wrote:
> On Wed, 20 May 2015 22:44:52 +0530, Sudip Mukherjee wrote:
> > On Wed, May 20, 2015 at 05:49:07PM +0200, Wolfram Sang wrote:
> > > On Wed, May 20, 2015 at 08:57:00PM +0530, Sudip Mukherjee wrote:
> > > >  static struct parport_driver i2c_parport_driver = {
> > > > -	.name	= "i2c-parport",
> > > > -	.attach	= i2c_parport_attach,
> > > > -	.detach	= i2c_parport_detach,
> > > > +	.name		= "i2c-parport",
> > > > +	.match_port	= i2c_parport_attach,
> > > > +	.detach		= i2c_parport_detach,
> > > > +	.devmodel	= true,
> > > 
> > > Minor nit: I prefer to not use tabs but a single space after the struct
> > > member names. Less hazzle in the future and still readable IMO.
> >
> > It was having space originally. I changed that into tab as it was
> > looking good with them as aligned.
> 
> As the driver maintainer, I am fine with both unaligned or tab-aligned.
> Space-aligned as I did originally was not a good idea, I admit.

Perhaps space aligned declarations should have some
checkpatch --strict warning for 2 or more spaces
around any assignment of the declaration.

	int a   = 1;		// 2+ spaces before =
	int b	=  2;		// 2+ spaces after =
	int c	=	3;	// uses tabs around =, no warning
	int d		= 4;	// uses 2 tabs before =, no warning
	
Something like:
---
 scripts/checkpatch.pl | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 89b1df4..8f9d26f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3902,6 +3902,13 @@ sub process {
 			    "multiple assignments should be avoided\n" . $herecurr);
 		}
 
+# check for space aligned declarations
+		if ($line =~ /^.\s*(?:$Declare|$DeclareMisordered)\s*$Ident {2,}=\s*(?:$Lval|$Constant|$String)/ ||
+		    $line =~ /^.\s*(?:$Declare|$DeclareMisordered)\s*$Ident\s*= {2,}(?:$Lval|$Constant|$String)/) {
+			CHK("SPACING",
+			    "Avoid multiple space assigments - prefer a single space or tabs\n" . $herecurr);
+		}
+
 ## # check for multiple declarations, allowing for a function declaration
 ## # continuation.
 ## 		if ($line =~ /^.\s*$Type\s+$Ident(?:\s*=[^,{]*)?\s*,\s*$Ident.*/ &&