Reuse Supplier Invoice References

By default, Odoo refuses to save a vendor bill when its supplier reference already exists on another bill. This module removes that restriction, so several bills can share the same supplier reference number.

• It changes the duplicate-reference check on account.move, the model behind invoices and vendor bills.
• The check is simply skipped, so no warning or error is raised when a reference is reused.
• The only exception is during automated tests, where the original duplicate check is still applied unless a special test flag is set.

There are no new menus, buttons, reports or settings. The change is automatic and applies to all vendor bills: users can enter the same reference on multiple bills and save them normally. This is useful when a supplier sends recurring invoices that carry the same reference, such as the same BVR/ESR payment slip number.

Because the restriction is removed globally, Odoo no longer warns about duplicate supplier references at all. Users who need to spot repeated references must check them manually.