I have a condition that I have to change/decrease the stock only when the order status changes to processing. By default it is changed as soon as order is placed. But, this is what I need to achieve.
First,read the question When does Magento decrement quantity
Let do some tricky code this requirement.
First,in order to stop decrement rewrite the Observer class
At this class add this code for revert the stock which just decrease.
$items = $this->_getProductsQty($quote->getAllItems()); Mage::getSingleton('cataloginventory/stock')->revertProductsSale($items);
sales_order_save_after with checking order status process you can deducted the stock