Get django-reversion to work with django-money

src/ralph/apps.py

@@ -2,6 +2,7 @@
 from importlib import import_module
 
 from django.apps import AppConfig
+from django.core import serializers
 
 
 class RalphAppConfig(AppConfig):
@@ -15,6 +16,8 @@ def ready(self):
         """
         super().ready()
 
+        serializers.register_serializer("json", "ralph.lib.serializers")
+
         package = self.module.__name__
         for module in self.get_load_modules_when_ready():
             try:

src/ralph/lib/serializers/__init__.py

@@ -0,0 +1,78 @@
+# -*- coding: utf-8 -*-
+import json
+import sys
+
+from django.core.serializers.base import DeserializationError
+from django.core.serializers.json import Serializer as JSONSerializer
+from django.utils import six
+from djmoney.models.fields import MoneyField
+
+from djmoney.money import Money
+from djmoney.utils import get_currency_field_name
+
+from ralph.settings import DEFAULT_CURRENCY_CODE
+
+Serializer = JSONSerializer
+
+
+def Deserializer(stream_or_string, **options):  # noqa
+    """
+    Deserialize a stream or string of JSON data.
+    """
+    # Copied almost without changes from djmoney.serializers (django-money).
+    # Adding support for situation where old models to be deserialized have
+    # price field, but not price_currency field.
+    # In Ralph, price field existed before in various models as
+    # a Decimal field. All price fields were migrated to MoneyField
+    # without changing the original field name. This can cause problems
+    # in original django-money's implementation of Deserializer.
+    # This updated Deserializer is needed to get reversion (django-reversion)
+    # to work in circumstances described above.
+
+    from django.core.serializers.python import \
+        Deserializer as PythonDeserializer, _get_model
+
+    ignore = options.pop("ignorenonexistent", False)
+
+    if not isinstance(stream_or_string, (bytes, six.string_types)):
+        stream_or_string = stream_or_string.read()
+    if isinstance(stream_or_string, bytes):
+        stream_or_string = stream_or_string.decode("utf-8")
+    try:
+        for obj in json.loads(stream_or_string):
+            try:
+                Model = _get_model(obj["model"])
+            except DeserializationError:
+                if ignore:
+                    continue
+                else:
+                    raise
+            money_fields = {}
+            fields = {}
+            field_names = {field.name for field in Model._meta.get_fields()}
+            for (field_name, field_value) in six.iteritems(obj["fields"]):
+                if ignore and field_name not in field_names:
+                    # skip fields no longer on model
+                    continue
+                field = Model._meta.get_field(field_name)
+                if isinstance(field, MoneyField) and field_value is not None:
+                    try:
+                        currency = \
+                            obj["fields"][get_currency_field_name(field_name)]
+                    except KeyError:
+                        currency = DEFAULT_CURRENCY_CODE
+                    money_fields[field_name] = Money(field_value, currency)
+                else:
+                    fields[field_name] = field_value
+            obj["fields"] = fields
+
+            for inner_obj in PythonDeserializer([obj], **options):
+                for field, value in money_fields.items():
+                    setattr(inner_obj.object, field, value)
+                yield inner_obj
+    except (GeneratorExit, DeserializationError):
+        raise
+    except Exception as exc:
+        six.reraise(
+            DeserializationError, DeserializationError(exc), sys.exc_info()[2]
+        )