Error when rewriting classes: call to member function on non-object

Question

Pre

I'm trying to do a very basic rewrite just to see if I can make it work. Unfortunately, no matter what class I rewrite I get fatal errors somewhere in magento.

This is my code for trying to rewrite the class Mage_Catalog_Model_Product. There are fatal errors for this in the admin panel under

Catalog/Manage Products:

Fatal error: Call to a member function getResource() on a non-object in /home/domain/public_html/magento/includes/src/Mage_Adminhtml_Block_Catalog_Product_Grid.php on line 179

and Catalog/Manage Categories:

Fatal error: Call to a member function getCollection() on a non-object in /home/domain/public_html/magento/includes/src/Mage_Adminhtml_Block_Catalog_Category_Tab_Product.php on line 76

My code

app/etc/modules/Test_Catalog.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Test_Catalog>
            <active>true</active>
            <codePool>community</codePool>
        </Test_Catalog>
    </modules>
</config>

--

app/code/community/Test/Catalog/etc/config.xml

<config>
    <global>
        <models>
            <catalog>
                <rewrite>
                    <product>Test_Catalog_Model_Product</product>
                </rewrite>
            </catalog>
        </models>
    </global>
</config>

--

app/code/community/Test/Catalog/Model/Product.php

<?php
class Test_Catalog_Model_Product extends Mage_Catalog_Model_Product {

}

My thoughts

These errors appear to go away when I delete or comment out the entire Test_Catalog.xml file. Deleting or commenting out the Product.php file keeps these errors. It's the combination of the initiator xml file in app/etc/modules/ and the config.xml having a rewrite in it. See the Edit heading.

I've tried placing a require statement above the class declaration in Product.php but these errors remained.

I originally had a function in Product.php but I took it out and the errors stayed the same.

I can add more files like the ones with the errors if anyone wants, but those are unaltered from installation.

Edit

Following this tutorial: http://code.tutsplus.com/tutorials/understand-overriding-in-magento-models--cms-23354

I now get this error under Catalog/Manage Categories

Fatal error: Call to a member function setStoreId() on a non-object in /home/domain/public_html/magento/app/code/core/Mage/Adminhtml/controllers/Catalog/CategoryController.php on line 52

The problem is apparently something to do with the permissions(?) on my domain. I've already set mostly every permission to 755. Does anyone have an idea what specific file permissions should be changed, if this is the problem?

Through some playing around I've narrowed the problem down to specifically being the product node in config.xml. Here's an example of what causes the error and what doesn't.

<!-- This still causes the error -->
<config>
    <global>
        <models>
            <catalog>
                <rewrite>
                    <product>This_Is_Not_A_File_Path</product>
                </rewrite>
            </catalog>
        </models>
    </global>
</config>

<!-- No error -->
<config>
    <global>
        <models>
            <catalog>
               <rewrite>
                   <notproduct>Test_Cat_Model_Product</notproduct>
               </rewrite>
            </catalog>
        </models>
    </global>
</config>

Final Note

Maybe something of interest is that my Magento files don't have a local folder under code - Just community and core. Could this be caused by an incomplete installation, or is this correct for Magento version 1.9.2.4?

Answer 1

Assuming that:

• Your cache is disabled
• You do not have compilation mode on

The answer is: your code is correct, problem does not come from your code.

The only possible reasons are:

• Some typo you did not paste here
• A permission issue (PHP process cannot read your Product.php class)

In other words Magento cannot read your Product.php class.

If you think it is a permission issue try to set everything to 777 for a test.

Remember to reset your permission once done to avoid security holes.