Hello. I extend sale.order model with a field. As result I want to get a tree view with a char field that contains a string made of all product names of an order.

class SaleOrderInherit(models.Model):
    _inherit = 'sale.order'

    order_products = fields.Char(string='Order products', compute='_compute_order_products')

    @api.depends('order_line.product_id')
    def _compute_order_products(self):
        for _order in self:
            s_order_products = ''
            for _order_line in _order.order_line:
                s_order_products += str(_order_line.product_id.name) + ', '
            _order.order_products = s_order_products[:-2]

I get this error:

The requested operation ("read" on "Product" (product.product)) was rejected because of the following rules: 

 (Records: False (id=3), User: Administrator (id=2))

Implicitly accessed through 'Product' (product.product).