out_of_stock patch

class sale_order_line(osv.osv):
    _inherit = 'sale.order.line'

    def product_id_change(self, cr, uid, ids, pricelist, product, qty=0,
            uom=False, qty_uos=0, uos=False, name='', partner_id=False,
            lang=False, update_tax=True, date_order=False, packaging=False, fiscal_position=False, flag=False):
        result = super(sale_order_line, self).product_id_change(cr, uid, ids, pricelist, product, qty,
            uom, qty_uos, uos, name, partner_id,
            lang, update_tax, date_order, packaging, fiscal_position, flag)
        if product and self.pool.get('product.product').browse(cr, uid, product, {}).virtual_available < 1:
            if result['warning'] and result['warning']['message']:
                result['warning']['message'] += "\n\n" + _('Not available in stock!')
            else:
                result['warning'] = {'title':_('Not available in stock!'),'message':_('Not available in stock!')}

        return result


sale_order_line()