prod_lot_seq: Fix sequence incrementation opening detailed operations

When opening the detailed operations view of a stock move, Odoo is calling
stock.production.lot._get_next_serial to set stock.move.next_serial field
anytime the product is tracked by serial and the move is assigned.

If we use this module with product or global policy, the respective sequence
will therefore be called and incremented anytime this view is open, even
if the picking is not creating lots (e.g. delivery orders or internal transfers)

To avoid incrementing the sequence unnecessarily, we only allow to get the next
sequence number the first time this view is opened and if the move has
to create new serial numbers.
Otherwise, we force the value to be set to stock.move.next_serial field to
an empty string if no serial has to be created through this move, or to the
next_serial value assigned on the first opening of the view.

product_lot_sequence/models/__init__.py

@@ -1,2 +1,3 @@
 from . import product
 from . import stock_production_lot
+from . import stock_move

product_lot_sequence/models/stock_move.py

@@ -0,0 +1,23 @@
+# Copyright 2023 Camptocamp SA
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl)
+from odoo import models
+
+
+class StockMove(models.Model):
+    _inherit = "stock.move"
+
+    def action_show_details(self):
+        """Avoid calling and incrementing the sequence if not needed or already done"""
+        seq_policy = self.env["stock.production.lot"]._get_sequence_policy()
+        if seq_policy in ("product", "global"):
+            # If move is not supposed to assign serial pass empty string for next serial
+            if not self.display_assign_serial:
+                return super(
+                    StockMove, self.with_context(force_next_serial="")
+                ).action_show_details()
+            # If the sequence was already called once, avoid calling it another time
+            elif self.next_serial:
+                return super(
+                    StockMove, self.with_context(force_next_serial=self.next_serial)
+                ).action_show_details()
+        return super().action_show_details()

product_lot_sequence/models/stock_production_lot.py

@@ -56,6 +56,8 @@ def create(self, vals_list):
 
     @api.model
     def _get_next_serial(self, company, product):
+        if "force_next_serial" in self.env.context:
+            return self.env.context.get("force_next_serial")
         seq_policy = self._get_sequence_policy()
         if seq_policy == "product":
             seq = product.product_tmpl_id.lot_sequence_id

product_lot_sequence/tests/test_product_lot_sequence.py

@@ -9,6 +9,22 @@ def setUp(self):
         super(TestProductLotSequence, self).setUp()
         self.product_product = self.env["product.product"]
         self.stock_production_lot = self.env["stock.production.lot"]
+        self.receipt_type = self.env.ref("stock.picking_type_in")
+        self.delivery_type = self.env.ref("stock.picking_type_out")
+
+    def _create_picking(self, picking_type, move_vals_list):
+        picking_form = Form(self.env["stock.picking"])
+        picking_form.picking_type_id = picking_type
+        for move_vals in move_vals_list:
+            with picking_form.move_ids_without_package.new() as move_form:
+                move_form.product_id = move_vals.get("product_id")
+                move_form.product_uom_qty = move_vals.get("product_uom_qty", 1.0)
+                move_form.product_uom = move_vals.get(
+                    "product_uom", self.env.ref("uom.product_uom_unit")
+                )
+        picking = picking_form.save()
+        picking.action_confirm()
+        return picking
 
     def test_product_sequence(self):
         self.assertEqual(self.stock_production_lot._get_sequence_policy(), "product")
@@ -88,3 +104,36 @@ def test_lot_onchange_product_id_global(self):
         lot_form.product_id = product
         lot = lot_form.save()
         self.assertEqual(lot.name, next_sequence_number)
+
+    def test_open_detailed_operations(self):
+        self.env["ir.config_parameter"].set_param(
+            "product_lot_sequence.policy", "global"
+        )
+        seq = self.env["ir.sequence"].search([("code", "=", "stock.lot.serial")])
+        first_next_sequence_number = seq.get_next_char(seq.number_next_actual)
+        product = self.product_product.create(
+            {"name": "Test global", "tracking": "serial"}
+        )
+        delivery_picking = self._create_picking(
+            self.delivery_type, [{"product_id": product}]
+        )
+        delivery_move = delivery_picking.move_lines
+        self.assertFalse(delivery_move.next_serial)
+        delivery_move.action_show_details()
+        self.assertFalse(delivery_move.next_serial)
+        self.assertEqual(
+            seq.get_next_char(seq.number_next_actual), first_next_sequence_number
+        )
+        receipt_picking = self._create_picking(
+            self.receipt_type, [{"product_id": product}]
+        )
+        receipt_move = receipt_picking.move_lines
+        self.assertFalse(receipt_move.next_serial)
+        receipt_move.action_show_details()
+        self.assertEqual(receipt_move.next_serial, first_next_sequence_number)
+        new_next_sequence_number = seq.get_next_char(seq.number_next_actual)
+        self.assertNotEqual(new_next_sequence_number, first_next_sequence_number)
+        receipt_move.action_show_details()
+        self.assertEqual(
+            new_next_sequence_number, seq.get_next_char(seq.number_next_actual)
+        )