'ObjectChange' is not subscriptable on upgrade to 3.1-beta1

[rodvand]

NetBox version

v3.1-beta1

Python version

3.8

Steps to Reproduce

Unsure on the full steps to reproduce, but I believe it relates to having a Changelog entry from a cable creation. Upgraded from NetBox 3.0.9 to 3.1-beta1.

Expected Behavior

Front page to load with no issue.

Observed Behavior

I can load pages where Changelogs are not fetched, so it' definitely related to changelog entries.

Apologies for providing error message by screenshot... it was just the easiest way here.

[jeremystretch]

I believe it relates to having a Changelog entry from a cable creation.

I suspect you're right, but I haven't been able to reproduce this. It would help to see the full stack trace; are you able to post that? (If you click "Switch to copy-and-paste view" next to the "Traceback" heading it will show a plaintext traceback.)

[rodvand]

This is the error text from the email notification. As I've deleted all the change logs I'm unable to reproduce the issue right now.

Internal Server Error: /

AttributeError at /
'NoneType' object has no attribute '_base_manager'

Request Method: GET
Request URL: https://****/ Django Version: 3.2.9 Python Executable: /opt/netbox-3.1-beta1/venv/bin/python3
Python Version: 3.8.3
Python Path: ['/opt/netbox/netbox', '/opt/netbox-3.1-beta1/netbox', '/opt/netbox-3.1-beta1/venv/bin', '/usr/lib64/python38.zip', '/usr/lib64/python3.8', '/usr/lib64/python3.8/lib-dynload', '/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages', '/opt/netbox-3.1-beta1/venv/lib/python3.8/site-packages']
Server time: Mon, 08 Nov 2021 19:35:54 +0100 Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.humanize',
 'corsheaders',
 'debug_toolbar',
 'graphiql_debug_toolbar',
 'django_filters',
 'django_tables2',
 'django_prometheus',
 'graphene_django',
 'mptt',
 'rest_framework',
 'social_django',
 'taggit',
 'timezone_field',
 'circuits',
 'dcim',
 'ipam',
 'extras',
 'tenancy',
 'users',
 'utilities',
 'virtualization',
 'wireless',
 'django_rq',
 'drf_yasg']
Installed Middleware:
['graphiql_debug_toolbar.middleware.DebugToolbarMiddleware',
 'django_prometheus.middleware.PrometheusBeforeMiddleware',
 'corsheaders.middleware.CorsMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'django.middleware.security.SecurityMiddleware',
 'netbox.middleware.ExceptionHandlingMiddleware',
 'netbox.middleware.RemoteUserMiddleware',
 'netbox.middleware.LoginRequiredMiddleware',
 'netbox.middleware.DynamicConfigMiddleware',
 'netbox.middleware.APIVersionMiddleware',
 'netbox.middleware.ObjectChangeMiddleware',
 'django_prometheus.middleware.PrometheusAfterMiddleware']

Traceback (most recent call last):
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/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-3.1-beta1/venv/lib64/python3.8/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/views/generic/base.py", line 70, in view
    return self.dispatch(request, *args, **kwargs)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/views/generic/base.py", line 98, in dispatch
    return handler(request, *args, **kwargs)
  File "/opt/netbox/netbox/netbox/views/__init__.py", line 150, in get
    return render(request, self.template_name, {
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/shortcuts.py", line 19, in render
    content = loader.render_to_string(template_name, context, request, using=using)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/loader.py", line 62, in render_to_string
    return template.render(context, request)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 170, in render
    return self._render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/defaulttags.py", line 312, in render
    return nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django_tables2/templatetags/django_tables2.py", line 167, in render
    return template.render(context={"table": table}, request=request)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 170, in render
    return self._render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/defaulttags.py", line 211, in render
    nodelist.append(node.render_annotated(context))
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/defaulttags.py", line 167, in render
    values = list(values)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django_tables2/rows.py", line 244, in items
    column.current_value = self.get_cell(column.name)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django_tables2/rows.py", line 197, in get_cell
    return self._get_and_render_with(
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django_tables2/rows.py", line 173, in _get_and_render_with
    return render_func(bound_column, value)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django_tables2/rows.py", line 206, in _call_render
    content = call_with_appropriate(bound_column.render, render_kwargs)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django_tables2/utils.py", line 572, in call_with_appropriate
    return fn(**kwargs)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django_tables2/columns/templatecolumn.py", line 66, in render
    return Template(self.template_code).render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 172, in render
    return self._render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/test/utils.py", line 100, in instrumented_test_render
    return self.nodelist.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/defaulttags.py", line 305, in render
    match = condition.eval(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/defaulttags.py", line 889, in eval
    return self.value.resolve(context, ignore_failures=True)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 671, in resolve
    obj = self.var.resolve(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 796, in resolve
    value = self._resolve_lookup(context)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/site-packages/django/template/base.py", line 837, in _resolve_lookup
    current = getattr(current, bit)
  File "/opt/netbox-3.1-beta1/venv/lib64/python3.8/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-3.1-beta1/venv/lib64/python3.8/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 /
Exception Value: 'NoneType' object has no attribute '_base_manager'

[jeremystretch]

Unfortunately I still haven't been able to reproduce this. I've been populating the changelog under v3.0 with all types of changes that might be relevant and then upgrading to v3.1, but I never encounter an error. @rodvand can you think of anything else to try?

[DanSheps]

@rodvand I know this is a long shot, but... Would you happen to have a pre-upgrade db snapshot?

[rodvand]

I can revert to an older install and try upgrading again. Can you give me some pointers on what would be useful info to collect when I do so? We do have "unlimited" change log retention enabled so there would be stuff there from 2.8 and onward.

[jeremystretch]

I'd love to see if we can narrow it down to the specific change record that's causing the error. Maybe try navigating to the change log with ?per_page=1 and trying clicking through one by one? If the exception is showing on the home page, it should be in the top 15.

[DanSheps]

Good point. I was thinking revert and get an export of the content types so we could see what type ID is up, then get a list of content types from the DB.

[jeremystretch]

@rodvand any luck reproducing this? I still haven't been able to, and I've been jumping between develop and feature pretty frequently.

[rodvand]

I managed to reproduce it with the backup of my database. It was due to change log entries by a plugin (netbox-bgp). I had disabled the plugin for the upgrade, but the change log entries were still lurking behind creating havoc. Apologies for the confusion.

[jeremystretch]

Ahh, that makes sense. Thanks for following up!