Teach "diff --check" about new blank lines at end

When a patch adds new blank lines at the end, "git apply --whitespace"
warns.  This teaches "diff --check" to do the same.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index b7cc6b28e6..0922c708f1 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -335,4 +335,10 @@ test_expect_success 'line numbers in --check output are correct' '
 
 '
 
+test_expect_success 'checkdiff detects trailing blank lines' '
+	echo "foo();" >x &&
+	echo "" >>x &&
+	git diff --check | grep "ends with blank"
+'
+
 test_done