Add round_price

We add a common method to round prices that are stored using the price digits.
It is useless to use the digits from the field because it can not be changed in
any other way than by configuration.

issue9146
review299521002

move.py

@@ -19,7 +19,7 @@ from trytond.tools import reduce_ids
 from trytond.transaction import Transaction
 from trytond.pool import Pool
 
-from trytond.modules.product import price_digits
+from trytond.modules.product import price_digits, round_price
 
 from .exceptions import MoveOriginWarning
 
@@ -477,7 +477,6 @@ class Move(Workflow, ModelSQL, ModelView):
         """
         pool = Pool()
         Uom = pool.get('product.uom')
-        Product = pool.get('product.product')
         Currency = pool.get('currency.currency')
 
         if direction == 'in':
@@ -505,10 +504,7 @@ class Move(Workflow, ModelSQL, ModelView):
             new_cost_price = unit_price
         elif direction == 'out':
             new_cost_price = cost_price
-
-        digits = Product.cost_price.digits
-        return new_cost_price.quantize(
-            Decimal(str(10.0 ** -digits[1])))
+        return round_price(new_cost_price)
 
     @staticmethod
     def _get_internal_quantity(quantity, uom, product):

product.py

@@ -23,6 +23,8 @@ from trytond.transaction import Transaction
 from trytond.pool import Pool, PoolMeta
 from trytond.tools import grouped_slice
 
+from trytond.modules.product import round_price
+
 from .exceptions import ProductCostPriceError
 from .move import StockMixin
 
@@ -226,7 +228,6 @@ class Product(StockMixin, object, metaclass=PoolMeta):
     def recompute_cost_price(cls, products, start=None):
         pool = Pool()
         Move = pool.get('stock.move')
-        digits = cls.cost_price.digits
         costs = defaultdict(list)
         for product in products:
             if product.type == 'service':
@@ -234,7 +235,7 @@ class Product(StockMixin, object, metaclass=PoolMeta):
             cost = getattr(
                 product, 'recompute_cost_price_%s' %
                 product.cost_price_method)(start)
-            cost = cost.quantize(Decimal(str(10.0 ** -digits[1])))
+            cost = round_price(cost)
             costs[cost].append(product)
 
         updated = []
@@ -298,7 +299,6 @@ class Product(StockMixin, object, metaclass=PoolMeta):
         Currency = pool.get('currency.currency')
         Uom = pool.get('product.uom')
         Revision = pool.get('product.cost_price.revision')
-        digits = self.__class__.cost_price.digits
 
         domain = [
             ('product', '=', self.id),
@@ -371,8 +371,7 @@ class Product(StockMixin, object, metaclass=PoolMeta):
                         ) / (quantity + qty)
                 elif qty > 0:
                     cost_price = unit_price
-                current_cost_price = cost_price.quantize(
-                    Decimal(str(10.0 ** -digits[1])))
+                current_cost_price = round_price(cost_price)
             quantity += qty
 
         Move.write([