Adding TrackerField to model makes django-extensions list_signals crash

[jlandercy]

Problem

Dear JazzBand,

I just discovered this package and I was happy to find the TrackerField object which definitely brings a lot of value for cleaning and checking logics.

I have some CI quality flow running on my projects and unfortunately using this object in my model breaks this check from django-extensions:

python manage.py list_signals

With the following trace:

Traceback (most recent call last):
  File ".\project\manage.py", line 29, in <module>
    main()
  File ".\project\manage.py", line 25, in main
    execute_from_command_line(sys.argv)
  File ".\lib\site-packages\django\core\management\__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File ".\lib\site-packages\django\core\management\__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File ".\lib\site-packages\django\core\management\base.py", line 330, in run_from_argv
    self.execute(*args, **cmd_options)
  File ".\lib\site-packages\django\core\management\base.py", line 371, in execute
    output = self.handle(*args, **options)
  File ".\Python\Python39\site-packages\django_extensions-3.1.3-py3.9.egg\django_extensions\management\commands\list_signals.py", line 65, in han
dle
    verbose_name = force_str(key._meta.verbose_name)
AttributeError: 'str' object has no attribute '_meta'

I can see the problem occurs on the django-extensions package, so it might not be the right place to raise this issue.

Anyway, I was surprised to not need to migrate my schema once I have added the TrackerField so my first guess is that issue is somehow related with the fact that the TrackerField is not a full fledged field because it does not have any _meta registered.

I raise this issue to keep a track of it and gently raise your attention on it (maybe you have some useful input to add).
At this stage I am not sure if it is something missing at the TrackerField object or if the list_signals feature should be more careful on fields he wants to extract meta.

Once I have found a solution, I'll update this issue.
Feel free to add your observations.

Thank you anyway.

Environment

• Django Model Utils version: django-model-utils==4.2.0
• Django version: django==3.2.5
• Python version: Python 3.9.7
• Other libraries used, if any: django-extensions==3.1.3

Tested on several environments and OS.

Code examples

Add a simple tracker on a model:

# models.py
from django.db import models
from model_utils import FieldTracker

class Dummy(models.Model):
    # ...
    tracker = FieldTracker()

Run the list_signals on the project:

python manage.py list_signals