Overriding core model not working

Question

I want to override Mage_Catalog_Model_Config.

app/code/local/Myname/Catalog/etc/config.xml

<?xml version="1.0"?>

<config>    
    <modules>
        <Myname_Catalog>
            <version>0.1.0</version>
        </Myname_Catalog>
    </modules>

    <global>
        <models>
            <catalog>
                <rewrite>
                    <config>Myname_Catalog_Model_Config</config>
                </rewrite>
            </catalog>
        </models>
    </global>
</config>

app/etc/modules/Myname_Catalog.xml

<?xml version="1.0"?>

<config>
    <modules>
        <Myname_Catalog>
            <active>true</active>
            <codePool>local</codePool>
        </Myname_Catalog>
    </modules>
</config> 

Why on Earth is this not working??

Answer 1

You did not define your own model:

Your app/code/local/Myname/Catalog/etc/config.xml should look like this (note the <myname_catalog> section):

<?xml version="1.0"?>

<config>    
    <modules>
        <Myname_Catalog>
            <version>0.1.0</version>
        </Myname_Catalog>
    </modules>

    <global>
        <models>
            <myname_catalog>
                <class>Myname_Catalog_Model</class>
            </myname_catalog>

            <catalog>
                <rewrite>
                    <config>Myname_Catalog_Model_Config</config>
                </rewrite>
            </catalog>
        </models>
    </global>
</config>

Answer 2

Update your app/etc/modules/Myname_Catalog.xml file like below

 <?xml version="1.0"?>
<config>
<modules>
    <Myname_Catalog>
        <active>true</active>
        <codePool>local</codePool>
    <depends>
            <Mage_Catalog />
        </depends>
    </Myname_Catalog>
</modules>
</config> 

Answer 3

Change your below code

<global>
        <models>
            <catalog>
                <rewrite>
                    <config>Myname_Catalog_Model_Config</config>
                </rewrite>
            </catalog>
        </models>
    </global>

to

<global>
    <models>
        <catalog>
        <class>Myname_Catalog_Model</class>
    </catalog>
        <catalog>
        <rewrite>
            <config>Myname_Catalog_Model_Config</config>
        </rewrite>
        </catalog>
    </models>
</global>

If it don't work after changing above code, trying changing your modulename i.e. "catalog" to something else.

Answer 4

Update Module tag of your Myname_Catalog.xml inside app/etc/modules:

            <active>true</active>
                <codePool>local</codePool>
            <depends>
                <Mage_Core/>
                <Mage_Eav/>
            </depends>

If it is an Eav Model you creating, else you will need to make it <depend/> on <(AnotherNameSpace_ModuleName) />

<depends>

directives only establish a load order (or error) for module config.xml files