Re: [PATCH v2] checkpatch: add new exception to repeated word check

[Joe Perches]

On Wed, 2020-10-14 at 11:35 -0700, Joe Perches wrote:
> On Wed, 2020-10-14 at 23:42 +0530, Dwaipayan Ray wrote:
> > On Wed, Oct 14, 2020 at 11:33 PM Joe Perches <joe@xxxxxxxxxxx> wrote:
> > > On Wed, 2020-10-14 at 22:07 +0530, Dwaipayan Ray wrote:
> > > > Recently, commit 4f6ad8aa1eac ("checkpatch: move repeated word test")
> > > > moved the repeated word test to check for more file types. But after
> > > > this, if checkpatch.pl is run on MAINTAINERS, it generates several
> > > > new warnings of the type:
> > > 
> > > Perhaps instead of adding more content checks so that
> > > word boundaries are not something like \S but also
> > > not punctuation so that content like
> > > 
> > >         git git://
> > >         @size size
> > > 
> > > does not match?
> > > 
> > > 
> > Hi,
> > So currently the words are trimmed of non alphabets before the check:
> > 
> > while ($rawline =~ /\b($word_pattern) (?=($word_pattern))/g) {
> > my $first = $1;
> > my $second = $2;
> > 
> > where, the word_pattern is:
> > my $word_pattern = '\b[A-Z]?[a-z]{2,}\b';
> 
> I'm familiar.
> 
> > So do you perhaps recommend modifying this word pattern to
> > include the punctuation as well rather than trimming them off?
> 
> Not really, perhaps use the capture group position
> markers @- @+ or $-[1] $+[1] and $-[2] $+[2] with the
> substr could be used to see what characters are
> before and after the word matches.

Perhaps something like:
---
 scripts/checkpatch.pl | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index fab38b493cef..a65eb40a5539 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3054,15 +3054,25 @@ sub process {
 
 				my $first = $1;
 				my $second = $2;
+				my $start_pos = $-[1];
+				my $end_pos = $+[2];
 
 				if ($first =~ /(?:struct|union|enum)/) {
 					pos($rawline) += length($first) + length($second) + 1;
 					next;
 				}
 
-				next if ($first ne $second);
+				next if (lc($first) ne lc($second));
 				next if ($first eq 'long');
 
+				my $start_char = "";
+				my $end_char = "";
+				$start_char = substr($rawline, $start_pos - 1, 1) if ($start_pos > 0);
+				$end_char = substr($rawline, $end_pos, 1) if (length($rawline) > $end_pos);
+
+				next if ($start_char =~ /^\S$/);
+				next if ($end_char !~ /^[\.\,\s]?$/);
+
 				if (WARN("REPEATED_WORD",
 					 "Possible repeated word: '$first'\n" . $herecurr) &&
 				    $fix) {