Gravity Forms custom validation: Ensure that the total on a product form is > 0

gistfile1.txt

/**
* Ensure that the total on a product form is > 0
*/
add_filter('gform_validation', 'actonregister_validate_total');
function actonregister_validate_total($validation_result){
    $form = $validation_result["form"];
    $current_page = rgpost('gform_source_page_number_' . $form['id']) ? rgpost('gform_source_page_number_' . $form['id']) : 1;

        foreach($form["fields"] as &$field){
            $field_page = $field['pageNumber'];
            if($field_page == $current_page && $field["type"] == "total" && rgpost("input_" . $field['id']) == "0"){
                $validation_result["is_valid"] = false;
                $field["failed_validation"] = true;
                $field["validation_message"] = "You must select at least one price.";
                break;
            }
        }

    $validation_result["form"] = $form;
    return $validation_result;
}