Stock Picking Product Interchangeable

This module adds a way to define substitute products and use them automatically on outgoing deliveries.

On a product form you get an "Interchangeable" tab where you list the products that can replace it (and that it can replace). For single-variant products this is also available on the product template.

On each operation type (for example your delivery orders) you can choose a "Substitute Products" mode: "If all available" or "If any available". The field only appears for outgoing operation types.

When a delivery is confirmed, if the ordered product does not have enough immediately usable stock, Odoo looks at its interchangeable products, takes the available quantities and creates extra stock moves for them in the same transfer. The original line quantity is reduced by the substituted quantity, and a note is added to the transfer explaining which product was missing and what replaced it.

On the transfer itself a "Pass Interchangeable" checkbox lets you skip this automatic substitution for that specific delivery; it is only shown when the operation type is outgoing and a substitute mode is set.

Business rules: substitution only applies to outgoing transfers, only when a substitute mode is configured, and only for the missing quantity. With "If all available" the substitution happens only if the full missing quantity can be covered; with "If any available" partial coverage is accepted.