Should be possible to change and save money back to default currency

.pre-commit-config.yaml

@@ -11,7 +11,7 @@
     -   id: end-of-file-fixer
     -   id: fix-encoding-pragma
 - repo: git://github.com/FalconSocial/pre-commit-python-sorter
-  sha: d044ff27300a6dc8b1a56cd22552e3a810dc6f49
+  sha: 1.0.1
   hooks:
   - id: python-import-sorter
     args:

CHANGES.rst

@@ -3,6 +3,7 @@ Changes in 0.10
 
 - Fixed ``understands_money`` behaviour. Now it can be used as a decorator `#215`_ (`Stranger6667`_)
 - Do not fail comparisons because of different currency. Just return ``False`` `#225`_ (`benjaoming`_ and `ivirabyan`_)
+- Fixed: Not possible to revert MoneyField currency back to default `#221`_ (`benjaoming`_)
 
 Changes in 0.9.1
 ----------------
@@ -219,4 +220,7 @@ Changes in 0.3
 .. _tsouvarev: https://github.com/tsouvarev
 .. _w00kie: https://github.com/w00kie
 .. _willhcr: https://github.com/willhcr
+<<<<<<< e6efad2071e1281609732cc5c9d5c1cbf5c17c18
 .. _ivirabyan: https://github.com/ivirabyan
+=======
+>>>>>>> Add release note

djmoney/apps.py

@@ -1,4 +1,4 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-
 from django.apps import AppConfig
 
 

djmoney/contrib/__init__.py

@@ -1 +1 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-

djmoney/contrib/django_rest_framework/__init__.py

@@ -1,3 +1,3 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-
 from .fields import MoneyField, register_money_field  # noqa
 from .helpers import VERSION  # noqa

djmoney/contrib/django_rest_framework/fields.py

@@ -1,8 +1,8 @@
-# coding: utf-8
-from moneyed import Money
+# -*- coding: utf-8 -*-
 from rest_framework.serializers import DecimalField, ModelSerializer
 
 from djmoney.models.fields import MoneyField as ModelField
+from moneyed import Money
 
 from .helpers import IS_DRF_3
 

djmoney/contrib/django_rest_framework/helpers.py

@@ -1,4 +1,4 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-
 from rest_framework import VERSION
 
 

djmoney/models/fields.py

@@ -12,11 +12,10 @@
 from django.db.models.signals import class_prepared
 from django.utils import translation
 
+from djmoney import forms
 from moneyed import Currency, Money
 from moneyed.localization import _FORMATTER, format_money
 
-from djmoney import forms
-
 from .._compat import (
     BaseExpression,
     Expression,
@@ -258,9 +257,13 @@ def set_currency(self, obj, value):
         # then the currency is already set up, before this code hits
         # __set__ of MoneyField. This is because the currency field
         # has less creation counter than money field.
+        #
+        # Gotcha:
+        # But we should also allow setting a field back to its original default
+        # value!
+        # https://github.com/django-money/django-money/issues/221
         object_currency = obj.__dict__[self.currency_field_name]
-        default_currency = str(self.field.default_currency)
-        if object_currency != value and (object_currency == default_currency or value != default_currency):
+        if object_currency != value:
             # in other words, update the currency only if it wasn't
             # changed before.
             setattr(obj, self.currency_field_name, value)

djmoney/models/managers.py

@@ -9,7 +9,7 @@
 
 from .._compat import LOOKUP_SEP, BaseExpression, smart_unicode, wraps
 from ..utils import get_currency_field_name, prepare_expression
-from .fields import MoneyField
+from .fields import CurrencyField, MoneyField
 
 
 def _get_clean_name(name):
@@ -124,22 +124,31 @@ def _expand_money_kwargs(model, args=(), kwargs=None, exclusions=()):
     """
     Augments kwargs so that they contain _currency lookups.
     """
+    involved_fields = [_get_clean_name(name) for name in kwargs]
     for name, value in list(kwargs.items()):
         if name in exclusions:
             continue
         if isinstance(value, Money):
             clean_name = _get_clean_name(name)
             kwargs[name] = value.amount
             kwargs[get_currency_field_name(clean_name)] = smart_unicode(value.currency)
-        elif isinstance(_get_field(model, name), MoneyField):
-            if isinstance(value, (BaseExpression, F)):
-                clean_name = _get_clean_name(name)
-                if not isinstance(value, F):
-                    value = prepare_expression(value)
-                kwargs[get_currency_field_name(clean_name)] = F(get_currency_field_name(value.name))
-            if is_in_lookup(name, value):
-                args += (_convert_in_lookup(model, name, value), )
-                del kwargs[name]
+        else:
+            field = _get_field(model, name)
+            if isinstance(field, MoneyField):
+                if isinstance(value, (BaseExpression, F)):
+                    clean_name = _get_clean_name(name)
+                    if not isinstance(value, F):
+                        value = prepare_expression(value)
+                    kwargs[get_currency_field_name(clean_name)] = F(get_currency_field_name(value.name))
+                if is_in_lookup(name, value):
+                    args += (_convert_in_lookup(model, name, value), )
+                    del kwargs[name]
+            elif isinstance(field, CurrencyField):
+                money_field_name = name[:-9]  # Remove '_currency'
+                if money_field_name not in involved_fields:
+                    money_field = _get_field(model, money_field_name)
+                    kwargs[money_field_name] = money_field.default.amount
+
     return args, kwargs
 
 

setup.cfg

@@ -5,7 +5,7 @@ universal = 1
 line_length = 79
 combine_as_imports = true
 known_django = django
-known_first_party = tests, djmoney
+known_first_party = tests, djmoney, moneyed
 known_third_party = pytest, rest_framework
 sections=FUTURE,STDLIB,DJANGO,THIRDPARTY,FIRSTPARTY,LOCALFOLDER
 include_trailing_comma = true

tests/contrib/__init__.py

@@ -1 +1 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-

tests/contrib/test_django_rest_framework.py

@@ -1,4 +1,4 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-
 import pytest
 from moneyed import Money
 

tests/test_form.py

@@ -8,8 +8,9 @@
 
 from django import VERSION
 
-import moneyed
 import pytest
+
+import moneyed
 from moneyed import Money
 
 from .testapp.forms import (

tests/test_managers.py

@@ -2,11 +2,11 @@
 from django.db.models import F, Q
 
 import pytest
-from moneyed import Money
 
 from djmoney._compat import split_expression
 from djmoney.models.managers import _expand_money_args, _expand_money_kwargs
 from djmoney.utils import get_amount
+from moneyed import Money
 
 from .testapp.models import ModelWithNonMoneyField
 

tests/test_migrations.py

@@ -1,4 +1,4 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-
 from textwrap import dedent
 
 from django import VERSION

tests/test_models.py

@@ -4,6 +4,7 @@
 
 @author: jake
 """
+from copy import copy
 from decimal import Decimal
 
 from django import VERSION
@@ -12,12 +13,12 @@
 from django.db.models import F, Q
 from django.utils.six import PY2
 
-import moneyed
 import pytest
-from moneyed import Money
 
+import moneyed
 from djmoney._compat import Case, Func, Value, When
 from djmoney.models.fields import MoneyField, MoneyPatched, NotSupportedLookup
+from moneyed import Money
 
 from .testapp.models import (
     AbstractModel,
@@ -75,6 +76,35 @@ def test_create_defaults(self, model_class, kwargs, expected):
         retrieved = model_class.objects.get(pk=instance.pk)
         assert retrieved.money == expected
 
+    @pytest.mark.parametrize(
+        'model_class, other_value',
+        (
+            (ModelWithVanillaMoneyField, Money('100.0')),
+            (BaseModel, Money(0, 'USD')),
+            (ModelWithDefaultAsMoney, Money('0.01', 'RUB')),
+            (ModelWithDefaultAsFloat, Money('12.05', 'PLN')),
+        )
+    )
+    def test_revert_to_default(self, model_class, other_value):
+        if hasattr(model_class._meta, 'get_field'):
+            default_instance = model_class._meta.get_field('money').get_default()
+        else:
+            default_instance = model_class._meta.get_field_by_name('money').default
+        instance1 = model_class.objects.create()
+        pk = instance1.pk
+        # Grab a fresh instance, change the currency to something non-default
+        # and unexpected
+        instance2 = model_class.objects.get(id=pk)
+        instance2.money = Money(other_value.amount, "DKK")
+        instance2.save()
+        instance3 = model_class.objects.get(id=pk)
+        assert instance3.money == Money(other_value.amount, "DKK")
+        # Now change the field back to the default currency
+        instance3.money = copy(default_instance)
+        instance3.save()
+        instance4 = model_class.objects.get(id=pk)
+        assert instance4.money == default_instance
+
     def test_not_supported_lookup(self):
         with pytest.raises(NotSupportedLookup) as exc:
             ModelWithVanillaMoneyField.objects.filter(money__regex='\d+').count()

tests/test_serialization.py

@@ -1,4 +1,4 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-
 import pytest
 
 from djmoney.serializers import Deserializer, Serializer

tests/test_settings.py

@@ -1,4 +1,4 @@
-# coding: utf-8
+# -*- coding: utf-8 -*-
 import pytest
 
 

tests/test_tags.py

@@ -5,9 +5,9 @@
 from django.utils.translation import override
 
 import pytest
-from moneyed import Money
 
 from djmoney.models.fields import MoneyPatched
+from moneyed import Money
 
 
 def assert_template(string, result, context=None):