diff --git a/diff.c b/diff.c
index e50def4538..38773317a1 100644
--- a/diff.c
+++ b/diff.c
@@ -4547,6 +4547,7 @@ static void run_diff_cmd(const char *pgm,
 			     o, complete_rewrite);
 	} else {
 		fprintf(o->file, "* Unmerged path %s\n", name);
+		o->found_changes = 1;
 	}
 }
 
diff --git a/t/t4046-diff-unmerged.sh b/t/t4046-diff-unmerged.sh
index ffaf69335f..c606ee4c40 100755
--- a/t/t4046-diff-unmerged.sh
+++ b/t/t4046-diff-unmerged.sh
@@ -96,4 +96,12 @@ test_expect_success 'diff --stat' '
 	test_cmp diff-stat.expect diff-stat.actual
 '
 
+test_expect_success 'diff --quiet' '
+	test_expect_code 1 git diff --cached --quiet
+'
+
+test_expect_success 'diff --quiet --ignore-all-space' '
+	test_expect_code 1 git diff --cached --quiet --ignore-all-space
+'
+
 test_done