[FIX] fields, test_new_api: monetary related custom

This commit allows for not copying the currency_field attribute
of a monetary field when the monetary field is related,
and when the currency_field attribute is not explicit

Before this commit, the currency_field attribute on the related monetary
was set as the one on the distant model

After this commit, the currency_field attribute takes the field on the
current model

Though the test may appear like an incoherent use case,
it is on the contrary totally legit, as web_studio allows it

OPW 1903113

closes odoo/odoo#28144

1 files changed, 11 insertions, 3 deletions

diff --git a/odoo/fields.py b/odoo/fields.py
index a146a1bfa07..00923886d0a 100644
--- a/odoo/fields.py
+++ b/odoo/fields.py
@@ -1276,11 +1276,9 @@ class Monetary(Field):
     def __init__(self, string=Default, currency_field=Default, **kwargs):
         super(Monetary, self).__init__(string=string, currency_field=currency_field, **kwargs)
 
-    _related_currency_field = property(attrgetter('currency_field'))
     _description_currency_field = property(attrgetter('currency_field'))
 
-    def _setup_regular_full(self, model):
-        super(Monetary, self)._setup_regular_full(model)
+    def _setup_currency_field(self, model):
         if not self.currency_field:
             # pick a default, trying in order: 'currency_id', 'x_currency_id'
             if 'currency_id' in model._fields:
@@ -1290,6 +1288,16 @@ class Monetary(Field):
         assert self.currency_field in model._fields, \
             "Field %s with unknown currency_field %r" % (self, self.currency_field)
 
+    def _setup_regular_full(self, model):
+        super(Monetary, self)._setup_regular_full(model)
+        self._setup_currency_field(model)
+
+    def _setup_related_full(self, model):
+        super(Monetary, self)._setup_related_full(model)
+        if self.inherited:
+            self.currency_field = self.related_field.currency_field
+        self._setup_currency_field(model)
+
     def convert_to_column(self, value, record, values=None, validate=True):
         # retrieve currency from values or record
         if values and self.currency_field in values: