form validation - show upload errors

I'd like some help please.

I', having a contact form in which I can also upload files. I have set up the form validation and the uploading configuration according to the documentation, however I have spotted a "logic" problem.

If I submit all the form fields with valid data and select an invalid type file to upload, the form process works as correct, and redirects to my "thank you" page, whereas I should get the error message from the invalid file upload. I 'm assuming this is because the upload errors are not part of the form_validation library or the two libraries don't "communicate" some way.

How can I fix this bug ?

This is my code

PHP Code:

protected $rules = array(
        'name' => array(
            'field' => 'name',
            'label' => 'Name',
            'rules' => 'trim|required|min_length[2]',
        ),
        'email' => array(
            'field' => 'email',
            'label' => 'Email address',
            'rules' => 'trim|required|valid_email',
        ),
        'phone' => array(
            'field' => 'phone',
            'label' => 'Phone number',
            'rules' => 'trim|required',
        ),
        'comments' => array(
            'field' => 'comments',
            'label' => 'Comments',
            'rules' => 'trim|required|min_length[10]',
        ),
    );


// in my method, where I run the validation
if ($topic == 'Employment query' && count($_FILES)) {
            
    $config['max_size'] = '5000';
    $config['upload_path'] = 'content/cvs';
    $config['allowed_types'] = 'doc|docx|pdf|odt';
    $this->load->library('upload', $config);

    if ($this->upload->do_upload('upload_cv')) {
        $cv_file = $this->upload->data();
    } 
    else {
        $this->data['upload_error'] = $this->upload->display_errors('<span class="help-block">', '</span>');
    }
}

$this->form_validation->set_rules($this->rules);
if ($this->form_validation->run()) {
          // get form data and send email
          redirect('contact/thank_you');
}