Hello everyone,

I am having a problem on solving a workflow on Odoo 12 for the invoicing module.

When we pay several invoices on Odoo 12, Odoo sets every selected invoice as paid which is the correct approach.
Problem is that the default order is not the one I need. That is, Odoo pays the invoices starting from the last one (which usually is the newest one) and the oldest one is left for the end.

When the invoices are paid in full, there is no problem, but when the amount to be paid does is not equal to the total value of all selected invoices, the oldest one will be left open.

In my specific case, the order should be changed, that is, oldest invoices should be paid first.

I found that on Odoo core account model we have:
       class AccountInvoice(models.Model):
              _order = "date_invoice desc, number desc, id desc"

I have tested and manually changed this default order to:

      _order = "date_invoice asc, number asc, id asc"

This worked as expected and using this approach, invoices are paid on the desired order.

Since it is not advisable to make direct changes on core odoo modules, I have tried to inherit this class from my module using the following code:

      class AccountInvoice(models.Model):
              _inherit = "account.invoice"
              _order = "date_invoice asc, number asc, id asc"

This change is working because I can see on the invoices list view that the order is changed.

Problem is that even changing the default order, using a custom module, invoice payments are still on the "wrong" order.
So, I get lost here because I was expecting that inheriting the class and changing the order, this will be effective and change core Odoo behaviour.

Can anyone help me change this default order for my specific case?

Thank you all in advance

Best regards

Paulo