Purchase Order No Zero Price

This module adds a validation rule to purchase order lines. When a line's unit price is zero, Odoo checks whether the line is a real product line (not a section or note), whether the purchase order is already confirmed or done (not draft or cancelled), and whether any of the three discount fields (if the triple discount module is installed) is set to 100%. If all these conditions are met, Odoo raises an error message listing the affected products and prevents saving the line.

• The check runs automatically whenever the unit price, the line type, or the order status changes.
• It applies to confirmed and done purchase orders, not to draft or cancelled ones.
• Lines that are sections or notes are ignored.
• If a line is fully discounted (100% on any discount field), a zero price is allowed.
• The error message shows the names of the products missing a price.

The rule appears directly on the purchase order form when editing lines. It touches the purchase.order.line model and works together with the standard Purchase app. No new menus or reports are added.