Fix repr of a json field in field changes (#489)

CHANGELOG.md

@@ -8,6 +8,7 @@
 
 #### Improvements
 
+- Changes the view when it has changes in fields `JSONField`. The `JSONField.encoder` is assigned to `json.dumps`. ([#489](https://github.com/jazzband/django-auditlog/pull/489))
 - feat: Added support for Correlation ID. ([#481](https://github.com/jazzband/django-auditlog/pull/481))
 - feat: Added pre-log and post-log signals. ([#483](https://github.com/jazzband/django-auditlog/pull/483))
 

auditlog/diff.py

@@ -1,3 +1,4 @@
+import json
 from datetime import timezone
 from typing import Optional
 
@@ -74,6 +75,7 @@ def get_field_value(obj, field):
                 value = django_timezone.make_naive(value, timezone=timezone.utc)
         elif isinstance(field, JSONField):
             value = field.to_python(getattr(obj, field.name, None))
+            value = json.dumps(value, sort_keys=True, cls=field.encoder)
         elif (field.one_to_one or field.many_to_one) and hasattr(field, "rel_class"):
             value = smart_str(
                 getattr(obj, field.get_attname(), None), strings_only=True

auditlog_tests/models.py

@@ -1,6 +1,7 @@
 import uuid
 
 from django.contrib.postgres.fields import ArrayField
+from django.core.serializers.json import DjangoJSONEncoder
 from django.db import models
 
 from auditlog.models import AuditlogHistoryField
@@ -260,7 +261,7 @@ class NoDeleteHistoryModel(models.Model):
 
 
 class JSONModel(models.Model):
-    json = models.JSONField(default=dict)
+    json = models.JSONField(default=dict, encoder=DjangoJSONEncoder)
 
     history = AuditlogHistoryField(delete_related=False)
 

auditlog_tests/tests.py

@@ -1601,7 +1601,7 @@ class JSONModelTest(TestCase):
 
         self.assertDictEqual(
             history.changes,
-            {"json": ["{}", "{'quantity': '1'}"]},
+            {"json": ["{}", '{"quantity": "1"}']},
             msg="The change is correctly logged",
         )
 
@@ -1693,6 +1693,34 @@ class ModelInstanceDiffTest(TestCase):
             msg="ObjectDoesNotExist should be handled",
         )
 
+    def test_diff_models_with_json_fields(self):
+        first = JSONModel.objects.create(
+            json={
+                "code": "17",
+                "date": datetime.date(2022, 1, 1),
+                "description": "first",
+            }
+        )
+        first.refresh_from_db()  # refresh json data from db
+        second = JSONModel.objects.create(
+            json={
+                "code": "17",
+                "description": "second",
+                "date": datetime.date(2023, 1, 1),
+            }
+        )
+        diff = model_instance_diff(first, second, ["json"])
+
+        self.assertDictEqual(
+            diff,
+            {
+                "json": (
+                    '{"code": "17", "date": "2022-01-01", "description": "first"}',
+                    '{"code": "17", "date": "2023-01-01", "description": "second"}',
+                )
+            },
+        )
+
 
 class TestRelatedDiffs(TestCase):
     def setUp(self):