    public function squash($force = false) {
        if ($this->cache !== null && !$force) return $this->cache;
        if ($this->parent) {
            return $this->cache = array_merge($this->parent->squash($force), $this->data);
        } else {
            return $this->cache = $this->data;
        }
    }
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.