Override/remove XML Config node/value?

Question

I want to remove some XML value without touching core XML files, is it possible ?

The scenario is the following.

In /app/code/core/Mage/Tax/etc/config.xml we have some config value for the totals (<sales><quote><totals>). I want to comment out the tax one so the tax line is not displayed in the frontend.

• commenting the node in the core XML file works fine but it is not the best approach.
• If I have put new empy values in a separate module I have a different effect ( it is not like remove the declaration)

In particular I want to do something like:

• <!--<renderer>tax/checkout_tax</renderer>-->

• Peter O'Callaghan: Is there some reason you can't change the settings under System > Configuration > Tax > Shopping Cart Display Settings to not show tax?

Answer 1

Theoretically inside of your module you can:

1. in config.xml reset the node to something like <renderer>0</renderer>
2. register an observer and Mage::getConfig()->setNode('path', NULL)

• Fra: <renderer>0</renderer> is giving me a different result: removing the node from core XML file return null while <renderer>0</renderer> return a string with value 0
• Tim Bezhashvyly: Try putting null instead of 0. If it will not work try option 2.
• Fra: I have already tried both ( 0 and null ) the issue is that they are converted to string ... I think solution 2 is the only one working
• Tim Bezhashvyly: @Francesco, not quite. Solution 1 can be still valid for some cases where setting the value to 0 or something else will do the job.
• Fra: Hi Tim, I think it is good idea to improve the answer specifying that method 1 is not equivalent to comment out the line in the core file