Use engine and session in future=True mode in till client

See #310 on github.

quicktill/delivery.py

@@ -520,6 +520,8 @@ def accept(self):
                 f"{delivery.logref}")
             stocktype.saleprice = saleprice
         qty = int(self.qtyfield.f)
+        # add_items() creates the StockItem instances and leaves them
+        # pending in the current ORM session
         items = delivery.add_items(stocktype, stockunit, qty, cost, bestbefore)
         td.s.flush()
         for item in items:

quicktill/models.py

@@ -1303,6 +1303,9 @@ def void(self, transaction, user, source):
         (not necessarily the same as this line's transaction) that
         voids this line and return it.
 
+        The new transaction line is not automatically placed in the
+        ORM session; the caller must do this if desired.
+
         If this transaction line has already been voided, returns
         None.
         """
@@ -1925,22 +1928,17 @@ def add_items(self, stocktype, stockunit, qty, cost, bestbefore=None):
         costper = (cost / qty).quantize(penny) if cost else None
         remaining_cost = cost
         items = []
-        # It's necessary to disable autoflush here, otherwise some of
-        # the new StockItem rows may be autoflushed with deliveryid
-        # still set to None if sqlalchemy has to issue a query to load
-        # stocktype
-        with object_session(self).no_autoflush:
-            while qty > 0:
-                thiscost = remaining_cost if qty == 1 else costper
-                remaining_cost = remaining_cost - thiscost if cost else None
-                item = StockItem(stocktype=stocktype,
-                                 description=description,
-                                 size=size,
-                                 costprice=thiscost,
-                                 bestbefore=bestbefore)
-                self.items.append(item)
-                items.append(item)
-                qty -= 1
+        while qty > 0:
+            thiscost = remaining_cost if qty == 1 else costper
+            remaining_cost = remaining_cost - thiscost if cost else None
+            item = StockItem(stocktype=stocktype,
+                             description=description,
+                             size=size,
+                             costprice=thiscost,
+                             bestbefore=bestbefore)
+            self.items.append(item)  # adds item to object_session(self)
+            items.append(item)
+            qty -= 1
         return items
 
 

quicktill/td.py

@@ -195,8 +195,8 @@ def init(database):
     log.info("init database \'%s\'", database)
     database = parse_database_name(database)
     log.info("sqlalchemy engine URL \'%s\'", database)
-    engine = create_engine(database)
-    session_factory = sessionmaker(bind=engine, future=False)
+    engine = create_engine(database, future=True)
+    session_factory = sessionmaker(bind=engine, future=True)
     s = scoped_session(session_factory)
 
 

quicktill/test_models.py

@@ -13,14 +13,14 @@ class ModelTest(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         # Create the test database
-        engine = create_engine("postgresql+psycopg2:///postgres")
+        engine = create_engine("postgresql+psycopg2:///postgres", future=True)
         raw_connection = engine.raw_connection()
         with raw_connection.cursor() as cursor:
             cursor.execute('commit')
             cursor.execute(f'create database "{TEST_DATABASE_NAME}"')
         raw_connection.close()
         cls._engine = create_engine(
-            f"postgresql+psycopg2:///{TEST_DATABASE_NAME}")
+            f"postgresql+psycopg2:///{TEST_DATABASE_NAME}", future=True)
         models.metadata.create_all(cls._engine)
         cls._sm = sessionmaker(cls._engine, future=True)
 
@@ -29,7 +29,7 @@ def tearDownClass(cls):
         # Dispose of the connection pool, closing all checked-in connections
         cls._engine.dispose()
         del cls._engine
-        engine = create_engine("postgresql+psycopg2:///postgres")
+        engine = create_engine("postgresql+psycopg2:///postgres", future=True)
         raw_connection = engine.raw_connection()
         with raw_connection.cursor() as cursor:
             cursor.execute('commit')

quicktill/user.py

@@ -519,7 +519,8 @@ def add_token(self):
         if not token:
             token = UserToken(token=t)
         token.last_seen = None
-        user.tokens.append(token)
+        user.tokens.append(token)  # adds token to ORM session if not present
+        td.s.flush()
         self.tokenfield.set(None)
         self.description.set("")
         self.reload_tokens()