Magento – Magento 1.9.0.1 to 1.9.1.1 upgrade fails, existing tables

Finally found the cause of the above issue: shopping cart rules with a category condition

First I installed xdebug to try to find out what was going on. I found out that the the Subselect.php and Combine.php files were in an infinite loop when adding a configurable product to the cart. Looking for that issue I found this post: Magento debug trace That post refers to "have a sales rule with a subselection of categories, I ran into the OPs issue with an infinite loop."

So I removed the shopping cart rules that had a category condition and then it work perfectly. I was able to add any configurable product to the cart again. But I need the shopping rules I used. Adding a new one didn't work: if the shopping cart rule had a category condition, impossible to add configurable product to the cart. Without a category condition, no issues.

The fix module from Briand Litzinger (or Husseycoding) didn't fix the issue for me. But by changing the core file:

app/code/core/Mage/SalesRule/Model/Rule/Condition/Product/Subselect.php

From:

if (parent::validate($item)) {

To:

if (Mage_Rule_Model_Condition_Combine::validate($item)) {

Fixed the issue and I'm able to use cart rules with a category condition and add a configurable product to the cart.

There seems to ba several bug reports open against 1.9.1 that are not fixed yet.

That means you already have the mage_permission_variable table in your database.
Don't delete the file instead of you can drop mage_permission_variable and mage_permission_block table then continue you upgrading process

it will do the trick....

Don't forget to backup the database before dropping those tables

Hope it helps