Magento show empty grouped product - magento

Question

I want tot display the grouped products in magento(version 1.9.1.1) even if they don't have a active simple product attached to them.
It's possible for me to view the grouped product on the frontend if i visit the product by using the direct url, but when I use the search form or check the category page I don't see the product.
If I activate the simple product that is associated to the grouped product the grouped product does appears in the category page and search form.
Thanks in advance!

Answer 1

This is due to a bug in Magento's grouped product price indexer (Mage_Catalog_Model_Resource_Product_Indexer_Price_Grouped).
The indexing process only takes into account grouped products that have simple products associated, see Mage_Catalog_Model_Resource_Product_Indexer_Price_Grouped Line 118:
if (!is_null($entityIds)) {
$select->where('l.product_id IN(?)', $entityIds);
}
This needs to be changed to
if (!is_null($entityIds)) {
$select->where('e.entity_id IN(?)', $entityIds);
}
to make it work. Also, the mass indexing of product prices (via admin interface or via shell) fixes the problem because the reindexAll() function of the named class does not limit to grouped products that have associated simple products either.
Please note that you shouldn't make those changes within the core file but overwrite the class instead.
The issue has also been reported to Magento.