[RFC 1/4] devtools: use git trailer parser for tag extraction

[Stephen Hemminger]

Replace the grep of the commit body for trailer-like lines with
git log --format="%(trailers:unfold)".  This uses the same parsing
logic as git-interpret-trailers(1), so the definition of "what is
a trailer" matches what git itself understands.

The hand-rolled pattern (grep -i -e "by *:" -e "fix.*:") could
both miss valid trailers and match non-trailer lines in the body.

The %(trailers) format specifier has been available since Git 2.11
(November 2016).

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 devtools/check-git-log.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/devtools/check-git-log.sh b/devtools/check-git-log.sh
index 45a58fab4f..1e04bca01b 100755
--- a/devtools/check-git-log.sh
+++ b/devtools/check-git-log.sh
@@ -52,7 +52,9 @@ headlines=$(git log --format='%s' --reverse $range)
 bodylines=$(git log --format='%b' --reverse $range)
 fixes=$(git log --format='%h %s' --reverse $range | grep -i ': *fix' | cut -d' ' -f1)
 stablefixes=$($selfdir/git-log-fixes.sh $range | sed '/(N\/A)$/d'  | cut -d' ' -f2)
-tags=$(git log --format='%b' --reverse $range | grep -i -e 'by *:' -e 'fix.*:')
+# Use git's own trailer parser rather than hand-rolled regex.
+# %(trailers:unfold) gives us exactly what git-interpret-trailers --parse sees.
+tags=$(git log --format='%(trailers:unfold)' --reverse $range | grep -v '^$')
 bytag='\(Reported\|Suggested\|Signed-off\|Acked\|Reviewed\|Tested\)-by:'
 reltag='Coverity issue:\|Bugzilla ID:\|Fixes:\|Cc:'
 
-- 
2.53.0