How do I make Magento theme templates update friendly?

Question

Imagine this scenario:

1. User creates app\design\frontend\default\mytheme\template\checkout\cart.phtml
2. User updates from 1.7.0 to 1.8.1
3. Cart page item qty updating does not work
4. User compares both base template file and his theme template file, finds out it's missing the new line <?php echo $this->getBlockHtml('formkey'); ?>

The process above has to be repeated for every template file that the theme overrides.

Is there a better workflow for theming magento?

Answer 1

That's a very good question.
I had issues like this on almost every upgrade and I didn't find a clean solution to make this fast and simple.
Here is what I do now to minimize the time of making a theme work on other versions.

• try to make most of the design changes using css.
• copy to the new theme only the files you modify. - this reduces the code you may need to modify later.
• put a comment at the top of the files you copy to your theme (or above some lines) with the reason to why you needed to move it. Use a special markup so it's easier to grep.
• use local.xml (when possible) for layout changes to have them all in the same place. Again comment everything you add/remove/change so you will remember easily why you did it.
• after the upgrade, look in your theme folders and see what you changed. Then test the functionality related to your changes.

I guess all of these things sound like common sense, but if you stick to them it will make your upgrade a bit faster and safer but not "lightning speed" fast.