Account Invoice Triple Discount does not compute correctly price_subtotal

[c-amara]

The module does not compute correctly the price_subtotal field because the price rounding feature.

Module

account_invoice_triple_discount

Describe the bug

When the invoice has a price and a discount (just one discount can reproduce the issue) that produce a discounted price with more decimals than price rounding setting so the price_subtotal is wrong.

To Reproduce

An example is:
qty price discount discount2 discount3 subtotal
9950 0.139 15% 0 0 1176.09

but the right subtotal is 1175.59 because 0.139 minus 15% is 0.11815 * 9950 = 1175.5925 -> Rounded = 1175.59.

Affected versions:

• 12.0

[legalsylvain]

Could you add in a PR a test that is failing ?
Thanks !

[c-amara]

Just added
#1242

[ramiadavid]

@legalsylvain @c-amara

I have the same problem, even using only Odoo's default discount field and the problem is here

        for line in self.line_ids:
            aggregated_discount = line._compute_aggregated_discount(line.discount)
            old_values_by_line_id[line.id] = {
                "price_unit": line.price_unit,
                "discount": line.discount,
            }
            price_unit = line.price_unit * (1 - aggregated_discount / 100)
            line.update({"price_unit": price_unit, "discount": 0})**

To calculate the taxes here the unit price with the aggregated discounts is computed, but when saving the value in the line Odoo rounds to the decimals by default and this produces an inaccuracy when calculating the taxes and the base especially when the line contains many units.

[github-actions]

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