Update Mage_SalesRule_Model_Quote_Discount (#4293)

* DiscountDescription should only be string or null (not array)
* strlen needs a type check for string before
* sales_quote_address_discount_item needs to be done after calculator->process

Author: Hanmac

app/code/core/Mage/SalesRule/Model/Quote/Discount.php

@@ -64,7 +64,7 @@ public function collect(Mage_Sales_Model_Quote_Address $address)
         $this->_calculator->init($store->getWebsiteId(), $quote->getCustomerGroupId(), $quote->getCouponCode());
         $this->_calculator->initTotals($items, $address);
 
-        $address->setDiscountDescription([]);
+        $address->setDiscountDescription('');
         /** @var Mage_Sales_Model_Quote_Item[] $items */
         $items = $this->_calculator->sortItemsByPriority($items);
         foreach ($items as $item) {
@@ -79,9 +79,6 @@ public function collect(Mage_Sales_Model_Quote_Address $address)
                     continue;
                 }
 
-                $eventArgs['item'] = $item;
-                Mage::dispatchEvent('sales_quote_address_discount_item', $eventArgs);
-
                 if ($item->getHasChildren() && $item->isChildrenCalculated()) {
                     foreach ($item->getChildren() as $child) {
                         $this->_calculator->process($child);
@@ -92,6 +89,8 @@ public function collect(Mage_Sales_Model_Quote_Address $address)
                     }
                 } else {
                     $this->_calculator->process($item);
+                    $eventArgs['item'] = $item;
+                    Mage::dispatchEvent('sales_quote_address_discount_item', $eventArgs);
                     $this->_aggregateItemDiscount($item);
                 }
             }
@@ -143,7 +142,7 @@ public function fetch(Mage_Sales_Model_Quote_Address $address)
 
         if ($amount != 0) {
             $description = $address->getDiscountDescription();
-            if (strlen($description)) {
+            if (is_string($description) && strlen($description)) {
                 $title = Mage::helper('sales')->__('Discount (%s)', $description);
             } else {
                 $title = Mage::helper('sales')->__('Discount');