Magento Module Depends Throws Exception

Question

I'm building an extension, following the official Magento developer's guide, here: http://info.magento.com/rs/magentocommerce/images/Magento-Extension-Developers-Guide-v1.0.pdf

In the app/etc/modules/Mage_Extension.xml file, the following code results in a fatal error:

<config>
    <modules>
        <Mage_Extension>
            <active>true</active>
            <codePool>community</codePool>
            <depends>
                <Mage_adminhtml />
            </depends>
        </Mage_Extension>
    </modules>
</config>

However, this is stipulated as a recommendation by Magento on page 8 of the guide. If I comment out the depends code, all is well:

<config>
    <modules>
        <Mage_Extension>
            <active>true</active>
            <codePool>community</codePool>
            <!--
            <depends>
                <Mage_adminhtml />
            </depends>
            -->
        </Mage_Extension>
    </modules>
</config>

Can anyone tell me why this throws an exception and whether I should just leave it out?

Thanks.

Answer 1

The error comes from the fact that adminhtml is all lowercase.
It should be:

<depends>
   <Mage_Adminhtml />
</depends>

Off topic: I hope Mage_Extension is just a placeholder you used for the extension name in this question. Do not use Mage as a namespace. Even if it works is not a good practice.