[IMP] point_of_sale: verbose logging when dealing with 'rescue' sessions

When dealing with issues related to 'rescue' sessions we are very
limited in what we can do because the actual orders sent to the backend
exist only in localStorage in the browser on the device of the
user. Because of this it is important that we log some data about the
orders we receive in the backend to have an idea of what's going on.

opw-676497

addons/point_of_sale/point_of_sale.py

@@ -689,9 +689,21 @@ class pos_order(osv.osv):
                                                  ('user_id', '=', closed_session.user_id.id)],
                                        limit=1, order="start_at DESC", context=context)
 
+        _logger.warning('session %s (ID: %s) was closed but received order %s (total: %s) belonging to it',
+                        closed_session.name,
+                        closed_session.id,
+                        order['name'],
+                        order['amount_total'])
+
         if open_sessions:
-            return open_sessions[0]
+            open_session = session.browse(cr, uid, open_sessions[0], context=context)
+            _logger.warning('using session %s (ID: %s) for order %s instead',
+                            open_session.name,
+                            open_session.id,
+                            order['name'])
+            return open_session.id
         else:
+            _logger.warning('attempting to create new session for order %s', order['name'])
             new_session_id = session.create(cr, uid, {
                 'config_id': closed_session.config_id.id,
             }, context=context)