Strange output in diff visualization when applying a tag

[LucaNicosia]

Plugin Version

0.5.2

NetBox Version

4.1.6

Python Version

3.10.2

Steps to Reproduce

1. Create a branch
2. Checkout into the branch
3. Create an object (f.e. a site) w/out a tag
4. Go into the diff tab of the branch page
5. The object will be created (as expected)
6. Edit the object created at point 3 and add a tag
7. Go back into the diff tab of the branch page
8. The object column is now None (FIRST PROBLEM)
9. Create a new object and assign it a tag this time
10. Go into the Changes ahead tab of the branch page
11. The creation of an object resulted into 2 different operations: object creation & object update with the tag (SECOND PROBLEM)
12. Due to problem at point 8, the object column in the diff page is None also for this record

Expected Behavior

1. Always see the object in the diff page
2. When I create a new record with a tag, I expect one single action

Observed Behavior

I've attached to this message reproducing all the steps above

show-netbox-tag-problems.mp4

[cruse1977]

On point 8 - this occurs on adding a tag and the object_repr in the ChangeDiff objects is set to None.

Currently the ChangeDiff save method always updates the object_repr:

    def save(self, *args, **kwargs):
        self._update_conflicts()
        super().save(*args, **kwargs)

Wrapping this in a conditional (as per below) prevents the object_repr from being updated thus shown the correct object rather than None - however, this may be better resolved by a change in the signal receivers.

    def save(self, *args, **kwargs):
        self._update_conflicts()
        if self.object:
            self.object_repr = str(self.object)

        super().save(*args, **kwargs)