[Django] #36935: ContentType.app_labeled_name fallback omits app label when model_class() is None

[Django]

#36935: ContentType.app_labeled_name fallback omits app label when model_class() is
None
-------------------------------------+-------------------------------------
Reporter: Marco Aurélio da | Type: Bug
Rosa Haubrich | Component:
Status: new | contrib.contenttypes
Version: 5.0 | Severity: Normal
Keywords: contenttypes | Triage Stage:
app_labeled_name admin ui/ux | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 1
-------------------------------------+-------------------------------------
= ContentType.app_labeled_name fallback omits app label when model_class()
is None =

== Environment ==

* Django version: 5.0 (also reproduced on latest `main` as of 2026‑02‑18)
* Python: 3.x
* Database: Oracle (others likely affected)

== Summary ==

`django.contrib.contenttypes.models.ContentType.app_labeled_name` is
intended to provide a human‑readable label combining the app label and
model name, typically used in admin UIs and other tooling to disambiguate
models with the same name.

Its current implementation is roughly:

{{{
@property
def app_labeled_name(self):
model = self.model_class()
if not model:
return self.model
return '%s | %s' % (model._meta.app_label, model._meta.verbose_name)
}}}

When `model_class()` returns a model, this works as expected and returns:

{{{
<app_label> | <model verbose_name>
}}}

However, when `model_class()` returns `None` (for example, for stale or
external content types), the property falls back to returning only
`self.model`, which drops the app label and makes the label ambiguous. In
projects with many apps, this makes it hard to distinguish entries that
share the same model name. It is also inconsistent with the name
*app_labeled_name*, which suggests that the app label is always present.

This degraded behaviour can be seen in admin UI elements or APIs that rely
on `app_labeled_name` when the underlying content type cannot be resolved
to a concrete model.

== Steps to reproduce ==

1. Create a `ContentType` whose model cannot be resolved in the current
project (for example, by creating a content type for an app/model that is
no longer installed, or by inserting a row with a bogus model name).
2. In a Django shell, access that instance’s `app_labeled_name`.
3. Use that `ContentType` in any UI or API that displays
`app_labeled_name` (for example, a custom admin widget or permission
management screen).

Example (simplified):

{{{
from django.contrib.contenttypes.models import ContentType

ct = ContentType.objects.create(
app_label='external_app',
model='externalmodel',
)

ct.model_class() # returns None
ct.app_labeled_name # returns 'externalmodel'
}}}

== Actual behavior ==

For content types whose `model_class()` is `None`, `app_labeled_name`
returns only the raw model string:

{{{
'externalmodel'
}}}

The app label is omitted, which makes the label ambiguous in UIs that list
many models from many apps.

== Expected behavior ==

Even when `model_class()` is `None`, `app_labeled_name` should still
include the app label so that the label remains informative and consistent
with its name. A more helpful and still backwards‑compatible fallback
would be:

{{{
@property
def app_labeled_name(self):
model = self.model_class()
if not model:
return '%s | %s' % (self.app_label, self.model)
return '%s | %s' % (model._meta.app_label, model._meta.verbose_name)
}}}

This keeps the current behaviour when the model exists (using the
translated `verbose_name`) and improves the fallback when it does not, by
returning:

{{{
'external_app | externalmodel'
}}}

This matches the intent of ticket #16027 (Include app_label in
ContentType.^^_^^_str^^_^^_()) to disambiguate models with the same name
by always including the app label.

== Rationale / backwards compatibility ==

* For existing, valid content types (`model_class()` not `None`),
behaviour is unchanged.
* For invalid/stale/external content types, behaviour becomes *more*
informative; currently they return just the model name, which is rarely
desirable in user‑facing lists.
* The change is therefore backwards compatible and strictly improves the
degraded code path.

== Possible patch ==

If this proposal is accepted, a patch could:

* Update `ContentType.app_labeled_name` as shown above.
* Add tests for both cases:
* A content type with a real model (assert the current behaviour is
preserved).
* A content type whose `model_class()` is `None` (assert that
`app_labeled_name` returns `'app_label | model'`).

I’m happy to submit a pull request with implementation and tests once
there is agreement on the desired behaviour.
--
Ticket URL: <https://code.djangoproject.com/ticket/36935>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.

[Django]

#36935: ContentType.app_labeled_name fallback omits app label when model_class() is
None
-------------------------------------+-------------------------------------

Reporter: Marco Aurélio da | Owner: (none)
Rosa Haubrich |
Type: Bug | Status: new
Component: | Version: 5.0
contrib.contenttypes |
Severity: Normal | Resolution:

Keywords: contenttypes | Triage Stage:
app_labeled_name admin ui/ux | Unreviewed

Has patch: 1 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 1
-------------------------------------+-------------------------------------

Changes (by Marco Aurélio da Rosa Haubrich):

* has_patch: 0 => 1

--
Ticket URL: <https://code.djangoproject.com/ticket/36935#comment:1>

[Django]

#36935: ContentType.app_labeled_name fallback omits app label when model_class() is
None
-------------------------------------+-------------------------------------
Reporter: Marco Aurélio da | Owner:

Rosa Haubrich | SnippyCodes
Type: Bug | Status: assigned

Component: | Version: 5.0
contrib.contenttypes |
Severity: Normal | Resolution:
Keywords: contenttypes | Triage Stage:
app_labeled_name admin ui/ux | Unreviewed
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 1
-------------------------------------+-------------------------------------

Changes (by SnippyCodes):

* owner: (none) => SnippyCodes
* status: new => assigned

--
Ticket URL: <https://code.djangoproject.com/ticket/36935#comment:2>