contrib/subtree: use %B for split subject/body

Use %B to format the commit message and body to avoid an extra newline
if a commit only has a subject line.

Signed-off-by: Techlive Zheng <techlivezheng@gmail.com>
Signed-off-by: David A. Greene <greened@obbligato.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/subtree/git-subtree.sh

@@ -296,7 +296,7 @@ copy_commit()
 	# We're going to set some environment vars here, so
 	# do it in a subshell to get rid of them safely later
 	debug copy_commit "{$1}" "{$2}" "{$3}"
-	git log -1 --pretty=format:'%an%n%ae%n%ad%n%cn%n%ce%n%cd%n%s%n%n%b' "$1" |
+	git log -1 --pretty=format:'%an%n%ae%n%ad%n%cn%n%ce%n%cd%n%B' "$1" |
 	(
 		read GIT_AUTHOR_NAME
 		read GIT_AUTHOR_EMAIL

contrib/subtree/t/t7900-subtree.sh

@@ -74,6 +74,10 @@ test_expect_success 'add sub1' '
         git branch -m master subproj
 '
 
+# Save this hash for testing later.
+
+subdir_hash=`git rev-parse HEAD`
+
 test_expect_success 'add sub2' '
         create sub2 &&
         git commit -m "sub2" &&
@@ -211,6 +215,17 @@ test_expect_success 'check split with --branch' '
 	check_equal ''"$(git rev-parse splitbr1)"'' "$spl1"
 '
 
+test_expect_success 'check hash of split' '
+	spl1=$(git subtree split --prefix subdir) &&
+	undo &&
+	git subtree split --prefix subdir --branch splitbr1test &&
+	check_equal ''"$(git rev-parse splitbr1test)"'' "$spl1"
+	git checkout splitbr1test &&
+	new_hash=$(git rev-parse HEAD~2) &&
+	git checkout mainline &&
+	check_equal ''"$new_hash"'' "$subdir_hash"
+'
+
 test_expect_success 'check split with --branch for an existing branch' '
         spl1=''"$(git subtree split --annotate='"'*'"' --prefix subdir --onto FETCH_HEAD --message "Split & rejoin" --rejoin)"'' &&
         undo &&