feat: implement transaction-level session locking in pos_order and idempotent payment creation in pos_payment

models/__init__.py

@@ -2,4 +2,5 @@
 from . import pos_config
 from . import res_config_settings
 from . import pos_order
+from . import pos_payment
 

models/pos_order.py

@@ -106,7 +106,34 @@ class PosOrder(models.Model):
         Override to prevent concurrent processing of the same order uuid.
         Uses pg_advisory_xact_lock on the order's uuid to force subsequent
         duplicate requests to wait until the first request completes/commits.
+        Also, locks the session associated with the incoming orders at the database
+        transaction level to serialize updates affecting the same session and prevent
+        serialization failures (concurrent updates on pos.session).
         """
+        # Extract unique session IDs from the orders list
+        session_ids = set()
+        for order in orders:
+            session_id = order.get('session_id')
+            if session_id:
+                session_ids.add(session_id)
+
+        if session_ids:
+            # Also find if any of these sessions are closed/closing, and if so, their potential open rescue/config sessions
+            sessions = self.env['pos.session'].browse(session_ids).exists()
+            closed_or_closing = sessions.filtered(lambda s: s.state in ('closing_control', 'closed'))
+            if closed_or_closing:
+                # Find open sessions for those configs
+                open_sessions = self.env['pos.session'].search([
+                    ('state', '=', 'opened'),
+                    ('config_id', 'in', closed_or_closing.mapped('config_id').ids)
+                ])
+                session_ids.update(open_sessions.ids)
+
+            # De-duplicate, filter to existing, sort to prevent deadlocks, and lock using FOR UPDATE
+            resolved_session_ids = sorted(list(session_ids))
+            if resolved_session_ids:
+                self.env.cr.execute("SELECT id FROM pos_session WHERE id IN %s FOR UPDATE", (tuple(resolved_session_ids),))
+
         # Sort orders by uuid to prevent potential deadlocks when locking multiple orders
         sorted_orders = sorted(orders, key=lambda x: x.get('uuid') or '')
         for order in sorted_orders:

models/pos_payment.py

@@ -0,0 +1,53 @@
+# -*- coding: utf-8 -*-
+from odoo import models, api
+
+class PosPayment(models.Model):
+    _inherit = 'pos.payment'
+
+    @api.model_create_multi
+    def create(self, vals_list):
+        # 1. Extract and sort unique uuids to prevent deadlocks
+        uuids = []
+        for vals in vals_list:
+            if isinstance(vals, dict) and vals.get('uuid'):
+                uuids.append(vals['uuid'])
+
+        sorted_uuids = sorted(list(set(uuids)))
+
+        # 2. Acquire transaction-level PostgreSQL advisory locks on the sorted hashes of uuids
+        for uuid in sorted_uuids:
+            self.env.cr.execute("SELECT pg_advisory_xact_lock(hashtext(%s))", (uuid,))
+
+        # 3. Check which payments already exist in the database
+        existing_payments_map = {}
+        if sorted_uuids:
+            existing_payments = self.search([('uuid', 'in', sorted_uuids)])
+            for payment in existing_payments:
+                existing_payments_map[payment.uuid] = payment
+
+        # 4. Prepare values to create (only those that don't already exist)
+        final_payments_list = [None] * len(vals_list)
+        vals_to_create = []
+        create_indices = []
+
+        for i, vals in enumerate(vals_list):
+            uuid = vals.get('uuid') if isinstance(vals, dict) else None
+            if uuid and uuid in existing_payments_map:
+                final_payments_list[i] = existing_payments_map[uuid]
+            else:
+                vals_to_create.append(vals)
+                create_indices.append(i)
+
+        # 5. Create new payments
+        if vals_to_create:
+            created_payments = super(PosPayment, self).create(vals_to_create)
+            for idx, payment in zip(create_indices, created_payments):
+                final_payments_list[idx] = payment
+
+        # 6. Reconstruct and return the final combined recordset
+        final_payments = self.env['pos.payment']
+        for payment in final_payments_list:
+            if payment:
+                final_payments += payment
+
+        return final_payments