Cannot view changelog after upgrade from v3.0.8 to v3.1.6 and postgresql upgrade from 9.5 to 10.0

[michael-edobor]

NetBox version

v3.1.6

Python version

3.9

Steps to Reproduce

1. Upon sign-in on Netbox
2. Click on the 'Change Log' https://{my_domain_name}/extras/changelog/

Expected Behavior

I should be able to view all changelogs as I could before the upgrade. It was working before my upgrade.

Observed Behavior

An AttributeError is raised.

<class 'AttributeError'>

'NoneType' object has no attribute '_base_manager'

Python version: 3.9.4
NetBox version: 3.1.6

[michael-edobor]

I just noticed something ODD. I am able to view this same page on this exact netbox instance with a different superuser account. There are no permissions to restrict access to the changelog view so it is quite strange that this is happening

[candlerb]

Can you get a full backtrace? Set EMAIL and ADMINS in configuration.py, restart, and repeat the problem. The backtrace should be E-mailed to you.

[DanSheps]

I suspect @michael-edobor had a plugin installed before, and now that the plugin is gone because of the upgrade you cannot see it.

I get this quite frequently and it has been something I have been meaning to address

[michael-edobor]

Oh yes, I had 'phonebox-plugin' installed in v3.0.8 but I removed it during the upgrade to v3.1.6 because I was getting some errors during the upgrade. Perhaps, the plugin's maintainer had not updated the codebase to support the version 3.1.6.

@candlerb : See below.

Template error:
In template <unknown source>, error at line 2
   'NoneType' object has no attribute '_base_manager'
   1 : 
   2 :  {% if record.changed_object.get_absolute_url %} 
   3 :     <a href="{{ record.changed_object.get_absolute_url }}">{{ record.object_repr }}</a>
   4 : {% else %}
   5 :     {{ record.object_repr }}
   6 : {% endif %}
   7 : 

Traceback (most recent call last):
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 829, in _resolve_lookup
    current = current[bit]

During handling of the above exception ('ObjectChange' object is not subscriptable), another exception occurred:
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/views/generic/base.py", line 70, in view
    return self.dispatch(request, *args, **kwargs)
  File "/opt/netbox/netbox/utilities/views.py", line 93, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/views/generic/base.py", line 98, in dispatch
    return handler(request, *args, **kwargs)
  File "/opt/netbox/netbox/netbox/views/generic.py", line 274, in get
    return render(request, self.template_name, context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/shortcuts.py", line 19, in render
    content = loader.render_to_string(template_name, context, request, using=using)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/loader.py", line 62, in render_to_string
    return template.render(context, request)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 170, in render
    return self._render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/loader_tags.py", line 195, in render
    return template.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 172, in render
    return self._render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django_tables2/templatetags/django_tables2.py", line 167, in render
    return template.render(context={"table": table}, request=request)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 170, in render
    return self._render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/defaulttags.py", line 211, in render
    nodelist.append(node.render_annotated(context))
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/defaulttags.py", line 167, in render
    values = list(values)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django_tables2/rows.py", line 244, in items
    column.current_value = self.get_cell(column.name)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django_tables2/rows.py", line 197, in get_cell
    return self._get_and_render_with(
  File "/opt/netbox/venv/lib/python3.9/site-packages/django_tables2/rows.py", line 173, in _get_and_render_with
    return render_func(bound_column, value)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django_tables2/rows.py", line 206, in _call_render
    content = call_with_appropriate(bound_column.render, render_kwargs)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django_tables2/utils.py", line 572, in call_with_appropriate
    return fn(**kwargs)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django_tables2/columns/templatecolumn.py", line 66, in render
    return Template(self.template_code).render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 172, in render
    return self._render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/defaulttags.py", line 305, in render
    match = condition.eval(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/defaulttags.py", line 889, in eval
    return self.value.resolve(context, ignore_failures=True)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 671, in resolve
    obj = self.var.resolve(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 796, in resolve
    value = self._resolve_lookup(context)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/template/base.py", line 837, in _resolve_lookup
    current = getattr(current, bit)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/contrib/contenttypes/fields.py", line 241, in __get__
    rel_obj = ct.get_object_for_this_type(pk=pk_val)
  File "/opt/netbox/venv/lib/python3.9/site-packages/django/contrib/contenttypes/models.py", line 175, in get_object_for_this_type
    return self.model_class()._base_manager.using(self._state.db).get(**kwargs)

Exception Type: AttributeError at /extras/changelog/
Exception Value: 'NoneType' object has no attribute '_base_manager'`

[jeremystretch]

I've opened #8425 as a bug report to capture this as a reproducible error.