Question

What is the config required to rewrite a class that is already rewriting another class in magento?

For example, There is a community module doing the following:

<models>
    <modulea>
        <adminhtml>
            <rewrite>
                <session>CompanyA_ModuleA_Model_Adminhtml_Session</session>
            </rewrite>
        </adminhtml>
    </modulea>
</models>

I want to rewrite the community module and I am trying the following code which is not working:

<models>
    <moduleb>
        <class>CompanyB_ModuleB_Model</class>
    </moduleb>
    <modulea>
            <rewrite>
                <adminhtml_session>CompanyB_ModuleB_Model_Adminhtml_Session</adminhtml_session>
            </rewrite>
    </modulea>
</models>

What is wrong with this

Answer 1

Be carefull at your rewrite XML syntax, you have an error. It should like :

<modulea>
        <adminhtml>
            <rewrite>
                <adminhtml_session>CompanyA_ModuleA_Model_Adminhtml_Session</session>
            </rewrite>
        </adminhtml>
    </modulea>

and

<moduleb>
        <adminhtml>
            <rewrite>
                <adminhtml_session>CompanyB_ModuleB_Model_Adminhtml_Session</session>
            </rewrite>
        </adminhtml>
    </moduleb>

Next you’ll need to extends the Good PHP class in the good order. FOr example if you want CompanyA extending/rewriting CompanyB :

CompanyA file :

class CompanyA_ModuleA_Model_Adminhtml_Session extends Mage_Adminhtml_Model_Session {

CompanyB Model php file :

class CompanyB_ModuleB_Model_Adminhtml_Session extends CompanyA_ModuleA_Model_Adminhtml_Session {

Last thing, to be sure that the rewrite is done in the good order (when doing a Mage::getModel('adminhtml/session') you want to retrieve the CompanyB class and not the COmpanyA one), you’ll need to define which module depends on which. YOu do that in the app/etc/modules/Company_Module.xml file.

add for Company A :

<depends>
    <Mage_Adminhtml />
</depends>

add for Company B :

<depends>
    <CompanyA_ModuleA />
</depends>