[FIX] account: make import of discounts thread safe

The patch method is not thread safe, which is very annoying for SH users
for instance.

One obvious issue is that during one thread patching the method, other
threads will also be impacted and have 100 decimal places for the
discount.
But it is even worse:
* thread A start: original = real_original; new = patchedA
* thread B start: original = patchedA; new = patchedB
* thread A end: reset original to real_original
* thread B end: reset original to patchedA

Now at the end of the transaction, the original method simply doesn't
exist anymore, and we only have one of the patches, which forces a
restart of the server to fix it.

opw-3552839

closes odoo/odoo#152168

X-original-commit: 9239ee3a95b474ce2eea92747b64f17f58c5c4cc
Signed-off-by: Quentin De Paoli <qdp@odoo.com>
Signed-off-by: William André (wan) <wan@odoo.com>

addons/account/models/__init__.py

@@ -30,6 +30,7 @@ from . import company
 from . import res_config_settings
 from . import account_cash_rounding
 from . import account_incoterms
+from . import decimal_precision
 from . import digest
 from . import res_users
 from . import ir_attachment

addons/account/models/account_move.py

@@ -11,10 +11,8 @@ from psycopg2 import OperationalError
 import math
 import re
 from textwrap import shorten
-from unittest.mock import patch
 
 from odoo import api, fields, models, _, Command
-from odoo.addons.base.models.decimal_precision import DecimalPrecision
 from odoo.addons.account.tools import format_structured_reference_iso
 from odoo.exceptions import UserError, ValidationError, AccessError, RedirectWarning
 from odoo.tools import (
@@ -3065,12 +3063,7 @@ class AccountMove(models.Model):
         The reasonning is that if the document that we are importing has a discount, it
         shouldn't be rounded to the local settings.
         """
-        original_precision_get = DecimalPrecision.precision_get
-        def precision_get(self, application):
-            if application == 'Discount':
-                return 100
-            return original_precision_get(self, application)
-        with patch('odoo.addons.base.models.decimal_precision.DecimalPrecision.precision_get', new=precision_get):
+        with self._disable_recursion({'records': self}, 'ignore_discount_precision'):
             yield
 
     def _get_edi_decoder(self, file_data, new=False):

addons/account/models/decimal_precision.py

@@ -0,0 +1,9 @@
+from odoo import models
+
+class DecimalPrecision(models.Model):
+    _inherit = 'decimal.precision'
+
+    def precision_get(self, application):
+        if application == 'Discount' and self.env.context.get('ignore_discount_precision'):
+            return 100
+        return super().precision_get(application)