feat: add dlv_account_move_copy_ref — copy customer ref on duplicate of customer invoice/credit note, with OK-popup warning

dlv_account_move_copy_ref/models/account_move.py

@@ -0,0 +1,20 @@
+from odoo import fields, models
+
+CUSTOMER_MOVE_TYPES = ("out_invoice", "out_refund")
+
+
+class AccountMove(models.Model):
+    _inherit = "account.move"
+
+    # Core has copy=False. Flipped to True here; copy_data() below limits the
+    # effect to customer invoices and credit notes.
+    ref = fields.Char(copy=True)
+
+    def copy_data(self, default=None):
+        data_list = super().copy_data(default)
+        if default and "ref" in default:
+            return data_list
+        for move, data in zip(self, data_list):
+            if move.move_type not in CUSTOMER_MOVE_TYPES:
+                data.pop("ref", None)
+        return data_list