Merge pull request #576 from marcanuy/master

fix #575 use django model_to_dict to detect changes in parent models

Author: kseever

AUTHORS.rst

@@ -58,6 +58,7 @@ Authors
 - Leticia Portella
 - Lucas Wiman
 - Maciej "RooTer" Urbański
+- Marcelo Canina (`marcanuy <https://github.com/marcanuy>`_)
 - Mark Davidoff
 - Martin Bachwerk
 - Marty Alchin

CHANGES.rst

@@ -4,6 +4,9 @@ Changes
 Unreleased
 ----------
 - Fixed DoesNotExist error when trying to get instance if object is deleted (gh-571)
+- Fix `model_to_dict` to detect changes in a parent model when using
+  `inherit=True` (backwards-incompatible for users who were directly
+  using previous version) (gh-576)
 
 2.7.3 (2019-07-15)
 ------------------

simple_history/models.py

@@ -16,6 +16,7 @@
 from django.db import models
 from django.db.models import Q
 from django.db.models.fields.proxy import OrderWrt
+from django.forms.models import model_to_dict
 from django.urls import reverse
 from django.utils.encoding import python_2_unicode_compatible, smart_text
 from django.utils.text import format_lazy
@@ -32,10 +33,6 @@
 registered_models = {}
 
 
-def _model_to_dict(model):
-    return json.loads(serialize("json", [model]))[0]["fields"]
-
-
 def _default_get_user(request, **kwargs):
     try:
         return request.user
@@ -576,8 +573,8 @@ def diff_against(self, old_history):
 
         changes = []
         changed_fields = []
-        old_values = _model_to_dict(old_history.instance)
-        current_values = _model_to_dict(self.instance)
+        old_values = model_to_dict(old_history.instance)
+        current_values = model_to_dict(self.instance)
         for field, new_value in current_values.items():
             if field in old_values:
                 old_value = old_values[field]

simple_history/tests/models.py

@@ -483,6 +483,15 @@ class InheritTracking4(TrackedAbstractBaseA):
     pass
 
 
+class BasePlace(models.Model):
+    name = models.CharField(max_length=50)
+    history = HistoricalRecords(inherit=True)
+
+
+class InheritedRestaurant(BasePlace):
+    serves_hot_dogs = models.BooleanField(default=False)
+
+
 class BucketMember(models.Model):
     name = models.CharField(max_length=30)
     user = models.OneToOneField(

simple_history/tests/tests/test_models.py

@@ -35,6 +35,7 @@
 from ..models import (
     AbstractBase,
     AdminProfile,
+    BasePlace,
     Book,
     Bookcase,
     BucketData,
@@ -62,6 +63,7 @@
     HistoricalPoll,
     HistoricalPollWithHistoricalIPAddress,
     HistoricalState,
+    InheritedRestaurant,
     OverrideModelNameAsCallable,
     OverrideModelNameUsingBaseModel1,
     MyOverrideModelNameRegisterMethod1,
@@ -594,6 +596,19 @@ def test_history_diff_does_not_include_unchanged_fields(self):
         delta = new_record.diff_against(old_record)
         self.assertNotIn("pub_date", delta.changed_fields)
 
+    def test_history_diff_includes_changed_fields_of_base_model(self):
+        r = InheritedRestaurant.objects.create(name="McDonna", serves_hot_dogs=False)
+        # change base model field
+        r.name = "DonnutsKing"
+        r.save()
+        new_record, old_record = r.history.all()
+        delta = new_record.diff_against(old_record)
+        expected_change = ModelChange("name", "McDonna", "DonnutsKing")
+        self.assertEqual(delta.changed_fields, ["name"])
+        self.assertEqual(delta.old_record, old_record)
+        self.assertEqual(delta.new_record, new_record)
+        self.assertEqual(expected_change.field, delta.changes[0].field)
+
     def test_history_diff_with_incorrect_type(self):
         p = Poll.objects.create(question="what's up?", pub_date=today)
         p.question = "what's up, man?"