[18.0] sale: Bug when applying discount in a sale.order.line

[mpascuall]

Odoo Version

• 16.0
• 17.0
• 18.0
• Other (specify)

Steps to Reproduce

• Discounts must be activated
• Go to sale order and create a new one.
• Select a product and apply a discount.
• Save the changes.
• Change product quantity and the discount will be setted to 0.

Grabacion-de-pantalla-desde-2025-05-29-12-20-43.mp4

Log Output

Support Ticket

No response

Possible solution: I think that changing this conditional and adding a not before the discount_enabled variable would solve this:
https://github.com/odoo/odoo/blob/18.0/addons/sale/models/sale_order_line.py#L732

In v17 this works checking the discount_policy to see if its without discount:
https://github.com/odoo/odoo/blob/17.0/addons/sale/models/sale_order_line.py#L577

So i think that makes sense.

[mpascuall]

Sorry for pinging you @pedrobaeza but what do you think about this?

[pedrobaeza]

@Feyensv, which is the sales team leader can tell you about this, but the process would be to propose a PR into odoo/odoo, not here.