We are finding problems when unistalling one of our modules. This module inherits from product.product model in the "inheritance by prototyping" (we need this type of inheritance) way as follows:

_name = "product.product.costs"
_inherit = "product.product"

In the dependencies of the module (__openerp__.py file, the dependency with "product_cost_incl_bom" module has been set, -we understand that indirectly this also includes the dependency with product module-).

The module installs correctly and works ok, the problem comes when unistalling it, since this operation causes the deletion of the references to product.template in product.product model, leaving the system non-operative (it is no longer possible to access the list of products since it is left blank).

Do you have any idea of what could be happening?