catalog_product_collection_load_before and getLoadedProductCollection

Question

I have a strange problem, which gives me the feeling i missed some concept:

In an observer triggered via event dispatch <catalog_product_collection_load_before> i fetch the collection and do a join:

        $select->joinLeft(
            array('partner_stock' => Mage::getSingleton('core/resource')->getTableName('xxx_partner_stock')),
            "`e`.`sku`=`partner_stock`.`sku` AND `partner_stock`.`customer_id`={$partnerId}",
            array('stock_id'=>'stock_id')
        );

In a later observer listening to <catalog_product_collection_load_after> i fetch the select and its missing the join. Any clou why?

Answer 1

Take a look at the catalog_block_product_list_collection observer used in Mage_Review (review/observer::catalogBlockProductCollectionBeforeToHtml). Within this observer method, Magento loads the collection ($productCollection->load()). Better to use this event to do what you want: catalog_product_collection_apply_limitations_after.

Order of events:

1. catalog_block_product_list_collection (used by review module, after collection is loaded its not editable anymore)
2. catalog_product_collection_load_before
3. catalog_product_collection_load_after