diff --git a/diff.c b/diff.c
index 781fa15ac1..f91f256c56 100644
--- a/diff.c
+++ b/diff.c
@@ -1465,6 +1465,10 @@ static void builtin_diff(const char *name_a,
 	const char *set = diff_get_color_opt(o, DIFF_METAINFO);
 	const char *reset = diff_get_color_opt(o, DIFF_RESET);
 
+	/* Never use a non-valid filename anywhere if at all possible */
+	name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
+	name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
+
 	a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
 	b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
 	lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
diff --git a/t/t4012-diff-binary.sh b/t/t4012-diff-binary.sh
index 64c372a025..eac12712db 100755
--- a/t/t4012-diff-binary.sh
+++ b/t/t4012-diff-binary.sh
@@ -77,4 +77,25 @@ test_expect_success 'apply binary patch' \
 	 tree1=`git write-tree` &&
 	 test "$tree1" = "$tree0"'
 
+q_to_nul() {
+	perl -pe 'y/Q/\000/'
+}
+
+nul_to_q() {
+	perl -pe 'y/\000/Q/'
+}
+
+test_expect_success 'diff --no-index with binary creation' '
+	echo Q | q_to_nul >binary &&
+	(:# hide error code from diff, which just indicates differences
+	 git diff --binary --no-index /dev/null binary >current ||
+	 true
+	) &&
+	rm binary &&
+	git apply --binary <current &&
+	echo Q >expected &&
+	nul_to_q <binary >actual &&
+	test_cmp expected actual
+'
+
 test_done