LITE-20982 return latest db value in previous data instead of the value before the latest save

Author: Francesco Faraone

dj_cqrs/mixins.py

@@ -118,11 +118,12 @@ def save(self, *args, **kwargs):
     def save_tracked_fields(self):
         if hasattr(self, FIELDS_TRACKER_FIELD_NAME):
             tracker = getattr(self, FIELDS_TRACKER_FIELD_NAME)
-            if self._state.adding:
-                data = tracker.changed_initial()
-            else:
-                data = tracker.changed()
-            setattr(self, TRACKED_FIELDS_ATTR_NAME, data)
+            if self.is_initial_cqrs_save:
+                if self._state.adding:
+                    data = tracker.changed_initial()
+                else:
+                    data = tracker.changed()
+                setattr(self, TRACKED_FIELDS_ATTR_NAME, data)
 
     @property
     def _update_cqrs_fields_default(self):

requirements/dev.txt

@@ -1,4 +1,4 @@
-Django >= 1.11.20
+Django>= 1.11.20,<4
 pika>=1.0.0
 kombu==4.6.*
 ujson==3.0.0

tests/test_master/test_mixin.py

@@ -734,7 +734,7 @@ def test_transaction_instance_saved_once_simple_case(mocker):
 
     mapper = (
         (i0.pk, 0, 'old', None),
-        (i1.pk, 0, '2', '1'),
+        (i1.pk, 0, '2', None),
         (i2.pk, 0, 'a', None),
         (i3.pk, 0, '.', None),
         (i0.pk, 1, 'new', 'old'),
@@ -749,6 +749,27 @@ def test_transaction_instance_saved_once_simple_case(mocker):
         assert payload.previous_data['char_field'] == expected_data[3]
 
 
+@pytest.mark.django_db(transaction=True)
+def test_transaction_instance_saved_multiple_times_previous_data(mocker):
+    publisher_mock = mocker.patch('dj_cqrs.controller.producer.produce')
+    instance = models.TrackedFieldsParentModel.objects.create(char_field='db_value')
+
+    with transaction.atomic():
+        instance.refresh_from_db()
+        instance.char_field = 'save_1'
+        instance.save()
+        instance.char_field = 'save_2'
+        instance.save()
+
+    assert publisher_mock.call_count == 2
+    payload_create = publisher_mock.call_args_list[0][0][0]
+    payload_update = publisher_mock.call_args_list[1][0][0]
+    assert payload_create.instance_data['char_field'] == 'db_value'
+    assert payload_create.previous_data['char_field'] is None
+    assert payload_update.instance_data['char_field'] == 'save_2'
+    assert payload_update.previous_data['char_field'] == 'db_value'
+
+
 @pytest.mark.django_db(transaction=True)
 def test_cqrs_saves_count_lifecycle():
     instance = models.TrackedFieldsParentModel(char_field='1')