Problems Overriding Magento Community Module Controller

Question

First of all, the Answer here is very helpful: Overriding a Magento Controller in community extention

However, despite passing both of the \"tests\" mentioned in the

Answer 1

Just change

<company_onepagecheckout before="IWD_OnepageCheckout">Company_OnepageCheckout</company_onepagecheckout> 

to

<Company_OnepageCheckout before="IWD_OnepageCheckout">Company_OnepageCheckout</Company_OnepageCheckout>

If it is not working then used

<global>
        <!-- This rewrite rule could be added to the database instead -->
        <rewrite>
            <!-- This is an identifier for your rewrite that should be unique -->
            <!-- THIS IS THE CLASSNAME IN YOUR OWN CONTROLLER -->
            <mynamespace_mymodule_onepage_iwd>
                <from><![CDATA[#^/onepagecheckout/index/#]]></from>
                <!--
                    - mymodule matches the router frontname below
                    - checkout_cart matches the path to your controller

                    Considering the router below, "/mymodule/checkout_car/" will be
                    "translated" to "/MyNameSpace/MyModule/controllers/Checkout/CartController.php" (?)
                -->
                <to>/comonepagecheckout/index/</to>
            </mynamespace_mymodule_onepage_iwd>
        </rewrite>
    </global>
<frontend>
        <routers>
            <comonepagecheckout>
                <!-- should be set to "admin" when overloading admin stuff (?) -->
                <use>standard</use>
                <args>
                    <module>Company_OnepageCheckout</module>
                    <!-- This is used when "catching" the rewrite above -->
                    <frontName>comonepagecheckout</frontName>
                </args>
            </comonepagecheckout>
        </routers>
    </frontend>

See more at

Answer 2

Your best bet is to drop some debugging code into the standard router (temporarily, of course).

#File: app/code/core/Mage/Core/Controller/Varien/Router/Standard.php
protected function _validateControllerClassName($realModule, $controller)
{
    $controllerFileName = $this->getControllerFileName($realModule, $controller);
    if (!$this->validateControllerFileName($controllerFileName)) {
        return false;
    }

    $controllerClassName = $this->getControllerClassName($realModule, $controller);
    if (!$controllerClassName) {
        return false;
    }

    // include controller file if needed
    if (!$this->_includeControllerClass($controllerFileName, $controllerClassName)) {
        return false;
    }

    return $controllerClassName;
}

Each return false is an instance where the router considers a configured controller and rejects it based on an improper name, not being able to find or include the file, etc.