[PATCH v3] checkpatch: fix TYPO_SPELLING check for words with apostrophe

[Dwaipayan Ray]

checkpatch reports a false TYPO_SPELLING warning for some words
containing an apostrophe when run with --codespell option.

A false positive is "doesn't". Occurrence of the word causes
checkpatch to emit the following warning:

"WARNING: 'doesn'' may be misspelled - perhaps 'doesn't'?"

Modify the regex pattern to be more in line with the codespell
default word matching regex. This fixes the word capture and
avoids the false warning.

In addition, highlight the misspelled word location by adding a
caret below the word.

Suggested-by: Joe Perches <joe@xxxxxxxxxxx>
Reported-by: Peilin Ye <yepeilin.cs@xxxxxxxxx>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@xxxxxxxxx>
---
Changes in v3:
- Highlight misspelled word location using a caret

Changes in v2:
- Use the default codespell word regex.
- Modify commit message to specify --codespell usage

 scripts/checkpatch.pl | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 3c86ea737e9c..e8c1ed0b1fad 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3106,15 +3106,18 @@ sub process {
 # Check for various typo / spelling mistakes
 		if (defined($misspellings) &&
 		    ($in_commit_log || $line =~ /^(?:\+|Subject:)/i)) {
-			while ($rawline =~ /(?:^|[^a-z@])($misspellings)(?:\b|$|[^a-z@])/gi) {
+			while ($rawline =~ /(?:^|[^\w\-'`])($misspellings)(?:[^\w\-'`]|$)/gi) {
 				my $typo = $1;
+				my $blank = copy_spacing($rawline);
+				my $ptr = substr($blank, 0, $-[1]) . "^";
+				my $hereptr = "$hereline$ptr\n";
 				my $typo_fix = $spelling_fix{lc($typo)};
 				$typo_fix = ucfirst($typo_fix) if ($typo =~ /^[A-Z]/);
 				$typo_fix = uc($typo_fix) if ($typo =~ /^[A-Z]+$/);
 				my $msg_level = \&WARN;
 				$msg_level = \&CHK if ($file);
 				if (&{$msg_level}("TYPO_SPELLING",
-						  "'$typo' may be misspelled - perhaps '$typo_fix'?\n" . $herecurr) &&
+						  "'$typo' may be misspelled - perhaps '$typo_fix'?\n" . $hereptr) &&
 				    $fix) {
 					$fixed[$fixlinenr] =~ s/(^|[^A-Za-z@])($typo)($|[^A-Za-z@])/$1$typo_fix$3/;
 				}
-- 
2.27.0