merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/t/t4025-hunk-header.sh

@@ -0,0 +1,44 @@
+#!/bin/sh
+
+test_description='diff hunk header truncation'
+
+. ./test-lib.sh
+
+N='日本語'
+N1='日'
+N2='日本'
+NS="$N$N$N$N$N$N$N$N$N$N$N$N$N"
+
+test_expect_success setup '
+
+	(
+		echo "A $NS" &&
+		for c in B C D E F G H I J K
+		do
+			echo "  $c"
+		done &&
+		echo "L  $NS" &&
+		for c in M N O P Q R S T U V
+		do
+			echo "  $c"
+		done
+	) >file &&
+	git add file &&
+
+	sed -e "/^  [EP]/s/$/ modified/" <file >file+ &&
+	mv file+ file
+
+'
+
+test_expect_success 'hunk header truncation with an overly long line' '
+
+	git diff | sed -n -e "s/^.*@@//p" >actual &&
+	(
+		echo " A $N$N$N$N$N$N$N$N$N2" &&
+		echo " L  $N$N$N$N$N$N$N$N$N1"
+	) >expected &&
+	test_cmp expected actual
+
+'
+
+test_done