From fff5663ae108eecdc53203928d1c1cada8258e15 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Tue, 8 Apr 2025 09:59:33 +0200
Subject: [PATCH] Add DecimalNull as tools

---
 modules/product_price_list/price_list.py | 27 ++----------------------
 trytond/CHANGELOG                        |  1 +
 trytond/doc/ref/tools/decimal.rst        | 13 ++++++++++++
 trytond/doc/ref/tools/index.rst          |  1 +
 trytond/trytond/tools/decimal_.py        | 26 +++++++++++++++++++++++
 5 files changed, 43 insertions(+), 25 deletions(-)
 create mode 100644 trytond/doc/ref/tools/decimal.rst

diff --git a/modules/product_price_list/price_list.py b/modules/product_price_list/price_list.py
index f0469178dc..ea23a3da24 100644
--- a/modules/product_price_list/price_list.py
+++ b/modules/product_price_list/price_list.py
@@ -1,7 +1,6 @@
 # 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 decimal import Decimal
-from functools import total_ordering
 
 from simpleeval import simple_eval
 
@@ -11,35 +10,13 @@ from trytond.model import (
     sequence_ordered)
 from trytond.modules.product import round_price
 from trytond.pool import Pool
-from trytond.tools import decistmt
+from trytond.tools.decimal_ import DecimalNull as Null
+from trytond.tools.decimal_ import decistmt
 from trytond.transaction import Transaction
 
 from .exceptions import FormulaError
 
 
-@total_ordering
-class Null(Decimal):
-    def __eq__(self, other):
-        if isinstance(other, Null) or other is None:
-            return True
-        return False
-
-    def __lt__(self, other):
-        return 0 < other
-
-
-def _return_self(self, *args, **kwargs):
-    return self
-
-
-_OPERATORS = (
-    'add sub mul matmul truediv floordiv mod divmod pow lshift rshift and xor '
-    'or'.split())
-for op in _OPERATORS:
-    setattr(Null, '__%s__' % op, _return_self)
-    setattr(Null, '__r%s__' % op, _return_self)
-
-
 class PriceList(DeactivableMixin, ModelSQL, ModelView):
     __name__ = 'product.price_list'
 
diff --git a/trytond/CHANGELOG b/trytond/CHANGELOG
index 42a8013af6..501f45d438 100644
--- a/trytond/CHANGELOG
+++ b/trytond/CHANGELOG
@@ -1,3 +1,4 @@
+* Add DecimalNull as tools
 * Add chat backend
 * Transaction.check_warnings is now a directory mapping the key to the warnings
 * Store target of field as relation
diff --git a/trytond/doc/ref/tools/decimal.rst b/trytond/doc/ref/tools/decimal.rst
new file mode 100644
index 0000000000..7b1c966a77
--- /dev/null
+++ b/trytond/doc/ref/tools/decimal.rst
@@ -0,0 +1,13 @@
+.. _ref-tools-decimal:
+.. module:: trytond.tools.decimal_
+
+decimal_
+========
+
+.. function:: decistmt(string)
+
+   Substitute Decimals for floats and integers in the string statements.
+
+.. class:: DecimalNull
+
+   A Decimal that behaves like the SQL ``NULL``.
diff --git a/trytond/doc/ref/tools/index.rst b/trytond/doc/ref/tools/index.rst
index 7eb9f20ed7..c8b887bbd4 100644
--- a/trytond/doc/ref/tools/index.rst
+++ b/trytond/doc/ref/tools/index.rst
@@ -11,6 +11,7 @@ Tools API reference.
 
    barcode
    chart
+   decimal
    email
    immutabledict
    logging
diff --git a/trytond/trytond/tools/decimal_.py b/trytond/trytond/tools/decimal_.py
index c418ae9890..7652c905d3 100644
--- a/trytond/trytond/tools/decimal_.py
+++ b/trytond/trytond/tools/decimal_.py
@@ -1,5 +1,8 @@
 # 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 decimal import Decimal
+from functools import total_ordering
 from io import BytesIO
 from tokenize import NAME, NUMBER, OP, STRING, tokenize, untokenize
 
@@ -45,3 +48,26 @@ def decistmt(s):
         else:
             result.append((toknum, tokval))
     return untokenize(result).decode('utf-8')
+
+
+@total_ordering
+class DecimalNull(Decimal):
+    def __eq__(self, other):
+        if isinstance(other, DecimalNull) or other is None:
+            return True
+        return False
+
+    def __lt__(self, other):
+        return 0 < other
+
+
+def _return_self(self, *args, **kwargs):
+    return self
+
+
+_OPERATORS = (
+    'add sub mul matmul truediv floordiv mod divmod pow lshift rshift and xor '
+    'or'.split())
+for op in _OPERATORS:
+    setattr(DecimalNull, '__%s__' % op, _return_self)
+    setattr(DecimalNull, '__r%s__' % op, _return_self)