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From: Patrick Palka <patrick@parcs.ath.cx>
To: git@vger.kernel.org
Cc: Patrick Palka <patrick@parcs.ath.cx>
Subject: [PATCH] Improve contrib/diff-highlight to highlight unevenly-sized hunks
Date: Mon, 15 Jun 2015 13:20:53 -0400	[thread overview]
Message-ID: <1434388853-23915-1-git-send-email-patrick@parcs.ath.cx> (raw)

Currently the diff-highlight script does not try to highlight hunks that
have different numbers of removed/added lines.  But we can be a little
smarter than that, without introducing much magic and complexity.

In the case of unevenly-sized hunks, we could still highlight the first
few (lexicographical) add/remove pairs.  It is not uncommon for hunks to
have common "prefixes", and in such a case this change is very useful
for spotting differences.

Signed-off-by: Patrick Palka <patrick@parcs.ath.cx>
---
 contrib/diff-highlight/diff-highlight | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/contrib/diff-highlight/diff-highlight b/contrib/diff-highlight/diff-highlight
index ffefc31..0dfbebd 100755
--- a/contrib/diff-highlight/diff-highlight
+++ b/contrib/diff-highlight/diff-highlight
@@ -88,22 +88,30 @@ sub show_hunk {
 		return;
 	}
 
-	# If we have mismatched numbers of lines on each side, we could try to
-	# be clever and match up similar lines. But for now we are simple and
-	# stupid, and only handle multi-line hunks that remove and add the same
-	# number of lines.
-	if (@$a != @$b) {
-		print @$a, @$b;
-		return;
-	}
+	# We match up the first MIN(a, b) lines on each side.
+	my $c = @$a < @$b ? @$a : @$b;
 
+	# Highlight each pair, and print each removed line of that pair.
 	my @queue;
-	for (my $i = 0; $i < @$a; $i++) {
+	for (my $i = 0; $i < $c; $i++) {
 		my ($rm, $add) = highlight_pair($a->[$i], $b->[$i]);
 		print $rm;
 		push @queue, $add;
 	}
+
+	# Print the remaining unmatched removed lines of the hunk.
+	for (my $i = $c; $i < @$a; $i++) {
+		print $a->[$i];
+	}
+
+	# Print the added lines of each highlighted pair.
 	print @queue;
+
+	# Print the remaining unmatched added lines of the hunk.
+	for (my $i = $c; $i < @$b; $i++) {
+		print $b->[$i];
+	}
+
 }
 
 sub highlight_pair {
-- 
2.4.3.413.ga5fe668

             reply	other threads:[~2015-06-15 17:21 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-15 17:20 Patrick Palka [this message]
2015-06-18 15:50 ` [PATCH] Improve contrib/diff-highlight to highlight unevenly-sized hunks Junio C Hamano
2015-06-18 16:28   ` Patrick Palka
2015-06-18 18:08     ` Junio C Hamano
2015-06-18 19:04       ` Jeff King
2015-06-18 20:14         ` Patrick Palka
2015-06-18 20:45           ` Jeff King
2015-06-18 21:23             ` Jeff King
2015-06-18 21:39               ` Junio C Hamano
2015-06-18 22:25               ` Patrick Palka
2015-06-19  3:54               ` Jeff King
2015-06-19  4:49                 ` Junio C Hamano
2015-06-19  5:32                   ` Jeff King
2015-06-19  7:34                     ` Jeff King
2015-06-19 11:38                       ` Jeff King
2015-06-19 17:20                     ` Junio C Hamano
2015-06-18 23:06             ` Patrick Palka
2015-06-18 20:23       ` Patrick Palka
2015-06-18 19:08     ` Jeff King
2015-06-18 20:27       ` Patrick Palka

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