[IMP] point_of_sale: get login_number in the same transaction as update it

Otherwise, if two POS stations are using the same user with the same pos.config,
i.e. create two session AND if you have bad luck, then those sessions will get
same login_number, which leads to losing half of orders, because POS stations
will generate same pos_reference and only first order from the POSes is saved,
while another order is lost without let know to cashier.

closes odoo/odoo#24486

Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

addons/point_of_sale/controllers/main.py

@@ -34,12 +34,12 @@ class PosController(http.Controller):
         pos_session = request.env['pos.session'].sudo().search(domain, limit=1)
         if not pos_session:
             return werkzeug.utils.redirect('/web#action=point_of_sale.action_client_pos_menu')
-        pos_session.login()
         # The POS only work in one company, so we enforce the one of the session in the context
         session_info = request.env['ir.http'].session_info()
         session_info['user_context']['allowed_company_ids'] = pos_session.company_id.ids
         context = {
-            'session_info': session_info
+            'session_info': session_info,
+            'login_number': pos_session.login(),
         }
         return request.render('point_of_sale.index', qcontext=context)
 

addons/point_of_sale/models/pos_session.py

@@ -220,9 +220,11 @@ class PosSession(models.Model):
 
     def login(self):
         self.ensure_one()
+        login_number = self.login_number + 1
         self.write({
-            'login_number': self.login_number + 1,
+            'login_number': login_number,
         })
+        return login_number
 
     def action_pos_session_open(self):
         # second browse because we need to refetch the data from the DB for cash_register_id

addons/point_of_sale/static/src/js/models.js

@@ -242,7 +242,7 @@ exports.PosModel = Backbone.Model.extend({
         },
     },{
         model:  'pos.session',
-        fields: ['id', 'name', 'user_id', 'config_id', 'start_at', 'stop_at', 'sequence_number', 'login_number', 'payment_method_ids'],
+        fields: ['id', 'name', 'user_id', 'config_id', 'start_at', 'stop_at', 'sequence_number', 'payment_method_ids'],
         domain: function(self){
             var domain = [
                 ['state','=','opened'],
@@ -253,6 +253,7 @@ exports.PosModel = Backbone.Model.extend({
         },
         loaded: function(self, pos_sessions, tmp){
             self.pos_session = pos_sessions[0];
+            self.pos_session.login_number = odoo.login_number;
             self.config_id = self.config_id || self.pos_session && self.pos_session.config_id[0];
             tmp.payment_method_ids = pos_sessions[0].payment_method_ids;
         },

addons/point_of_sale/views/pos_templates.xml

@@ -31,6 +31,7 @@
             var odoo = <t t-raw="json.dumps({
                 'csrf_token': request.csrf_token(None),
                 'session_info': session_info,
+                'login_number': login_number,
                 'debug': debug,
             })"/>;
         </script>