How to remove a config xml value?

Question

I have a module which is modifying how bundled products are displayed for our store. As a part of this, we are removing the ability to display checkboxes. So, I want to change the backend so that it does not allow checkboxes as a valid input type for bundles.

I observe that Mage/Bundle/etc/config.xml defines the options in this section:

<product>
    <options>
        <bundle>
            <types>
                <select translate="label" module="bundle">
                    <label>Drop-down</label>
                </select>
                <radio translate="label" module="bundle">
                    <label>Radio Buttons</label>
                </radio>
                <checkbox translate="label" module="bundle">
                    <label>Checkbox</label>
                </checkbox>
                <multi translate="label" module="bundle">
                    <label>Multiple Select</label>
                </multi>
            </types>

However, I do not want to modify a core config file. Is there any way to have the config.xml for my module, remove the checkbox entry?

I know that blocks can be removed from the layout with a <remove "blockname"/> entry, so is there any equivalent for removing generic config values?

Answer 1

Unfortunately you cannot do it in this case because of how this method is built. Mage_Bundle_Model_Source_Option_Type::toOptionArray.
What you can do, is to rewrite that model an modify the method toOptionArray to something like this:

public function toOptionArray()
{
    $types = array();

    foreach (Mage::getConfig()->getNode(self::BUNDLE_OPTIONS_TYPES_PATH)->children() as $type) { 
        if ($type->getName() == 'checkbox'){
            continue;
        }
        $labelPath = self::BUNDLE_OPTIONS_TYPES_PATH . '/' . $type->getName() . '/label';
        $types[] = array(
            'label' => (string) Mage::getConfig()->getNode($labelPath),
            'value' => $type->getName()
        );
    }

    return $types;
}