Contact group assignments are not recorded in changelog

[jeremystretch]

Deployment Type

Self-hosted

NetBox Version

v4.3.0

Python Version

3.10

Steps to Reproduce

1. Create a contact group named Group 1
2. Create a contact named Contact 1 and assign it to the group
3. Inspect the creation record for the contact in the changelog

Expected Behavior

The assigned group should appear in a groups list in the serialized representation of the contact.

Observed Behavior

There is no groups field in the changelog data:

{
    'link': '',
    'name': 'Contact 1',
    'tags': [],
    'email': '',
    'phone': '',
    'title': '',
    'address': '',
    'created': '2025-05-08T19:14:40.686Z',
    'comments': '',
    'description': '',
    'custom_fields': {}
}

[jeremystretch]

The root cause here is that Django's PythonSerializer doesn't know how to handle many-to-many fields which use a custom through model (see handle_m2m_field()).