Question

I’ll try to provide as much context as possible.

Been trying to override Mage_GoogleShopping_Model_Attribute_Link for 2 days now but I’m unable to get Magento to pickup my version of the file.

Mage_GoogleShopping_Model_Attribute_Link class is in app/code/core/Mage/GoogleShopping/Model/Attribute/Link.php

I put my class Safoo_Froogle_GoogleShopping_Model_Attribute_Link in /app/code/local/Safoo/Froogle/GoogleShopping/Model/Attribute/Link.php

Then my config.xml:

<global>
...
 <models>
        <safoofroogle>
            <class>Safoo_Froogle_Model</class>
        </safoofroogle>
        <googleshopping>
            <rewrite>
              <attribute_link>Safoo_Froogle_GoogleShopping_Model_Attribute_Link</attribute_link>
            </rewrite>
      </googleshopping>
    </models>
    <helpers>
      <googleshopping>
            <rewrite>
              <price>Safoo_Froogle_GoogleShopping_Helper_Price</price>
            </rewrite>
      </googleshopping>
    </helpers>

(Note the Helper Rewrite above works perfectly.)

I debugged the call to the Link model in Mage_GoogleShopping_Model_Type::_createAttribute

protected function _createAttribute($name)
{
    $modelName = 'googleshopping/attribute_' . $this->_prepareModelName($name);
    $useDefault = false;
###LOGGING###
    Mage::log($modelName); 
    Mage::log(get_class(Mage::getModel($modelName)  )); 
###LOGGING###
    try {
        $attributeModel = Mage::getModel($modelName);
        $useDefault = !$attributeModel;
    } catch (Exception $e) {
        $useDefault = true;
    }
    if ($useDefault) {
        $attributeModel = Mage::getModel('googleshopping/attribute_default');
    }
    $attributeModel->setName($name);

    return $attributeModel;
}

And this is the result of the 2 log statements:

2011-11-01T06:57:17+00:00 DEBUG (7): googleshopping/attribute_Link
2011-11-01T06:57:17+00:00 DEBUG (7): Mage_GoogleShopping_Model_Attribute_Link

So Mage::getModel('googleshopping/attribute_Link') is still fetching Mage_GoogleShopping_Model_Attribute_Link.

The only way I’ve been able to override the class is to copy the Link.php file into the corresponding local directory: app/code/local/Mage/GoogleShopping/Model/Attribute/Link.php but wanted to avoid that.

Just not working. My Helper Overload works. And I thought I should be able to override this class just like shown here:

http://www.magentocommerce.com/boards/viewthread/222046

http://www.magentocommerce.com/boards/viewthread/35787/

Any ideas?

Answer 1

You’ve uncovered a bug in the Mage_GoogleShopping_Model_Type class that’s preventing your rewrite from being applied. Based on your debugging, here’s the code that eventually gets called to instantiate a model

Mage::getModel('googleshopping/attribute_Link')

Although it’s not enforced everywhere in code, it’s a well established guideline that all class aliases ('googleshopping/attribute_Link' is a class alias) should be lowercase. Because of the capital letter L in attribute_Link, when Magento looks for the class name to use in a rewrite, it searches for a node named with a capital L.

<attribute_Link>Safoo_Froogle_GoogleShopping_Model_Attribute_Link</attribute_Link>

Fortunately, you can work around this. Just make your config.xml rewrite section look like this, and your rewrite should work

<googleshopping>
    <rewrite>
        <attribute_Link>Safoo_Froogle_GoogleShopping_Model_Attribute_Link</attribute_Link>
        <attribute_link>Safoo_Froogle_GoogleShopping_Model_Attribute_Link</attribute_link>
    </rewrite>
</googleshopping>

This way you’ll catch instantiations in the form Mage::getModel('googleshopping/attribute_Link') AND in the form Mage::getModel('googleshopping/attribute_link').

For future reference, when you’re debugging rewrites, the

Mage_Core_Model_Config::getGroupedClassName

method in

app/code/core/Mage/Core/Model/Config.php 

is where Magento does its lookup for class rewrites.