[16.0] partner_invoicing_mode: Using _get_invoice_grouping_keys() in read_group() leads to incompatibility with other modules

[AungKoKoLin1997]

Module

partner_invoicing_mode

Affected versions: 16.0
Didn't check in other versions.

Describe the bug

Using _get_invoice_grouping_keys() in read_group() of sale.order leads to incompatibility with other modules if they want to add new keys from the account.move model.

IIUC, this method is for defining grouping keys for the invoice values (i.e., keys from _prepare_invoice()), not necessarily fields from the sale.order model itself.

However, in partner_invoicing_mode, these keys are passed directly to read_group(), which requires them to be actual fields on sale.order.

account-invoicing/partner_invoicing_mode/models/sale_order.py

Lines 75 to 80 in 97f2065

	saleorder_groups = self.read_group(
	domain,
	["partner_invoice_id", "sale_ids:array_agg(id)"],
	groupby=self._get_invoice_grouping_keys(),
	lazy=False,
	)

You can see the incompatibility in this PR:
#2071

@qrtl

[AungKoKoLin1997]

@rousseldenis
Could you please take a look at this issue?
I noticed that _get_invoice_grouping_keys() was introduced in your PR. Shouldn't a dedicated method be used instead of the standard Odoo one? I'm not fully familiar with the background of the partner_invoicing_mode module, so I might be missing some context.

#1515