Check price_decimal configuration

The price_decimal stored in ir.configuration is checked against the current
configuration value. We do not allow to start serving a database for which the
values are different as it may be due to a misconfiguration which can lead to
data corruption.

issue9324
review317381002

CHANGELOG

@@ -1,3 +1,5 @@
+* Check price_decimal configuration
+
 Version 5.6.0 - 2020-05-04
 * Bug fixes (see mercurial logs for details)
 * Add round_price

__init__.py

@@ -2,6 +2,7 @@
 # this repository contains the full copyright notices and license terms.
 
 from trytond.pool import Pool
+from . import ir
 from . import uom
 from . import category
 from . import product
@@ -14,6 +15,7 @@ __all__ = [price_digits, round_price, uom_conversion_digits]
 
 def register():
     Pool.register(
+        ir.Configuration,
         uom.UomCategory,
         uom.Uom,
         category.Category,

ir.py

@@ -0,0 +1,24 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+from trytond.config import config
+from trytond.model import fields
+from trytond.pool import PoolMeta
+
+price_decimal = config.getint('product', 'price_decimal', default=4)
+
+
+class Configuration(metaclass=PoolMeta):
+    __name__ = 'ir.configuration'
+    product_price_decimal = fields.Integer("Product Price Decimal")
+
+    @classmethod
+    def default_product_price_decimal(cls):
+        return price_decimal
+
+    def check(self):
+        super().check()
+        if self.product_price_decimal != price_decimal:
+            raise ValueError(
+                "The price_decimal %s in [product] configuration section "
+                "is different from the value %s in 'ir.configuration'." % (
+                    self.product_price_decimal, price_decimal))

product.py

@@ -18,12 +18,12 @@ from trytond.pyson import Eval
 from trytond.transaction import Transaction
 from trytond.pool import Pool
 from trytond import backend
-from trytond.config import config
 from trytond.tools import lstrip_wildcard
 from trytond.tools.multivalue import migrate_property
 from trytond.modules.company.model import (
     CompanyMultiValueMixin, CompanyValueMixin)
 from .exceptions import InvalidIdentifierCode
+from .ir import price_decimal
 
 
 __all__ = ['price_digits', 'round_price', 'TemplateFunction']
@@ -39,7 +39,7 @@ COST_PRICE_METHODS = [
     ('average', 'Average'),
     ]
 
-price_digits = (16, config.getint('product', 'price_decimal', default=4))
+price_digits = (16, price_decimal)
 
 
 def round_price(value, rounding=None):