diff --git a/diff.c b/diff.c
index bf5d5f15a3..f70e6b4912 100644
--- a/diff.c
+++ b/diff.c
@@ -1627,6 +1627,7 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
 		xdemitcb_t ecb;
 
 		memset(&xecfg, 0, sizeof(xecfg));
+		xecfg.ctxlen = 1; /* at least one context line */
 		xpp.flags = XDF_NEED_MINIMAL;
 		ecb.outf = xdiff_outf;
 		ecb.priv = &data;
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index a27fccc8dc..ec98509fd2 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -341,4 +341,15 @@ test_expect_success 'checkdiff detects trailing blank lines' '
 	git diff --check | grep "ends with blank"
 '
 
+test_expect_success 'checkdiff allows new blank lines' '
+	git checkout x &&
+	mv x y &&
+	(
+		echo "/* This is new */" &&
+		echo "" &&
+		cat y
+	) >x &&
+	git diff --check
+'
+
 test_done