Magento code/local case sensitivness

I found an odd behaviour, and I need some help if someone knows the answers.

Behaviour seems different between app/code/local/Mage and app/code/local/MyCompany (or whatever)

If I have a module Mymodule in app/code/local/Mage wit开发者_开发问答h a Model Mymodel (app/code/local/Mage/Mymodule/Model/Mymodel) I can load it with :

Mage::getModel('*M*ymodule/Mymodel') or Mage::getModel('*m*ymodule/Mymodel') both are working ...

But If the module is in app/code/local/Mycompany the name is case sensitive and only one will work, depending on config.xml

<model>
            <**m**ymodule&gt;
                <class>Mycompany_Mymodule_Model</class>
                <resourceModel>cybermut_mysql4</resourceModel>
            </**m**ymodule>
</models>

will allows Mage::getModel('*m*ymodule/Mymodel')

and

<models>
            <**M**ymodule&gt;
                <class>Mycompany_Mymodule_Model</class>
                <resourceModel>cybermut_mysql4</resourceModel>
            </**M**ymodule>
</models>

will allows Mage::getModel('*M*ymodule/Mymodel')

Why is there this different behaviour between local/Mage and local/Alltheothers ???

PS: It's not a rewriting it's a home made module and I'm using CE 1.4.2 Best Regards

The difference is that when your module is under Mage/Mymodule with a shortname of mymodule and you call Mage::getModel('Mymodule/mymodel') you end up hitting the fall-back behavior.

If the resolver does not find an entry for the shortname Mymodule (case-sensitive), then it defaults to a classname of mage_mymodule_model_mymodel and since your module is under the Mage namespace that works.

By moving your module into a company specific namespace you end up with a classname that does not work if it hit the fall-back. You need mycompany_mymodule_model_mymodel and instead end up with mage_mymodule_model_mymodel.

The relevant code is in Mage_Core_Model_Config::getGroupedClassName()

public function getGroupedClassName($groupType, $classId, $groupRootNode=null)
{
    if (empty($groupRootNode)) {
        $groupRootNode = 'global/'.$groupType.'s';
    }

    $classArr = explode('/', trim($classId));
    $group = $classArr[0];
    $class = !empty($classArr[1]) ? $classArr[1] : null;

    if (isset($this->_classNameCache[$groupRootNode][$group][$class])) {
        return $this->_classNameCache[$groupRootNode][$group][$class];
    }

    //$config = $this->getNode($groupRootNode.'/'.$group);
    $config = $this->_xml->global->{$groupType.'s'}->{$group};

    if (isset($config->rewrite->$class)) {
        $className = (string)$config->rewrite->$class;
    } else {
        if (!empty($config)) {
            $className = $config->getClassName();
        }
        if (empty($className)) {
            $className = 'mage_'.$group.'_'.$groupType;
        }
        if (!empty($class)) {
            $className .= '_'.$class;
        }
        $className = uc_words($className);
    }

    $this->_classNameCache[$groupRootNode][$group][$class] = $className;
    return $className;
}

NB: Magento calls uc_words on $classname.

function uc_words($str, $destSep='_', $srcSep='_')
{
    return str_replace(' ', $destSep, ucwords(str_replace($srcSep, ' ', $str)));
}