Add experimental features flag for LocalizedField

With the flag set, LocalizedField will return None if there is no
database value.

README.rst

@@ -244,6 +244,16 @@ Besides ``LocalizedField``, there's also:
                    title = LocalizedField()
                    description = LocalizedBleachField()
 
+Experimental feature
+^^^^^^^^^^^^^^^^^^^^
+    Enables the following experimental features:
+        * ``LocalizedField`` will return ``None`` instead of an empty ``LocalizedValue`` if there is no database value.
+
+    .. code-block:: python
+
+         LOCALIZED_FIELDS_EXPERIMENTAL = True
+
+
 Frequently asked questions (FAQ)
 --------------------------------
 

localized_fields/fields/localized_field.py

@@ -1,8 +1,8 @@
 from django.conf import settings
 from django.db.utils import IntegrityError
+from psqlextra.fields import HStoreField
 
 from localized_fields import LocalizedFieldForm
-from psqlextra.fields import HStoreField
 
 from ..localized_value import LocalizedValue
 
@@ -36,11 +36,15 @@ class LocalizedField(HStoreField):
         """
 
         if not value:
-            return LocalizedValue()
+            if getattr(settings, 'LOCALIZED_FIELDS_EXPERIMENTAL', False):
+                return None
+            else:
+                return LocalizedValue()
 
         return LocalizedValue(value)
 
-    def to_python(self, value: dict) -> LocalizedValue:
+    @staticmethod
+    def to_python(value: dict) -> LocalizedValue:
         """Turns the specified database value into its Python
         equivalent.
 

localized_fields/models.py

@@ -15,7 +15,7 @@ class LocalizedModel(PostgresModel):
 
         Here we set all the fields that are of :see:LocalizedField
         to an instance of :see:LocalizedValue in case they are none
-        so that the user doesn't explicitely have to do so."""
+        so that the user doesn't explicitly have to do so."""
 
         super(LocalizedModel, self).__init__(*args, **kwargs)
 

settings.py

@@ -27,3 +27,5 @@ INSTALLED_APPS = (
 # set to a lower number than the default, since
 # we want the tests to be fast, default is 100
 LOCALIZED_FIELDS_MAX_RETRIES = 3
+
+LOCALIZED_FIELDS_EXPERIMENTAL = False

tests/test_localized_field.py

@@ -1,9 +1,9 @@
 from django.conf import settings
+from django.db.utils import IntegrityError
 from django.test import TestCase
 from django.utils import translation
-from django.db.utils import IntegrityError
 
-from localized_fields import LocalizedField, LocalizedValue, LocalizedFieldForm
+from localized_fields import LocalizedField, LocalizedFieldForm, LocalizedValue
 
 
 def get_init_values() -> dict:
@@ -179,7 +179,7 @@ class LocalizedFieldTestCase(TestCase):
 
     @staticmethod
     def test_from_db_value_none():
-        """Tests whether the :see:from_db_valuei function
+        """Tests whether the :see:from_db_value function
         correctly handles None values."""
 
         localized_value = LocalizedField.from_db_value(None)
@@ -187,6 +187,18 @@ class LocalizedFieldTestCase(TestCase):
         for lang_code, _ in settings.LANGUAGES:
             assert localized_value.get(lang_code) is None
 
+    @staticmethod
+    def test_from_db_value_none_return_none():
+        """Tests whether the :see:from_db_value function
+        correctly handles None values when LOCALIZED_FIELDS_EXPERIMENTAL
+        is set to True."""
+
+        settings.LOCALIZED_FIELDS_EXPERIMENTAL = True
+        localized_value = LocalizedField.from_db_value(None)
+        settings.LOCALIZED_FIELDS_EXPERIMENTAL = False
+
+        assert localized_value is None
+
     @staticmethod
     def test_to_python():
         """Tests whether the :see:to_python function