Refs #9602 -- Moved AlreadyRegistered/NotRegistered exceptions to django.contrib.admin.exceptions.

django/contrib/admin/checks.py

@@ -3,6 +3,7 @@ from itertools import chain
 
 from django.apps import apps
 from django.conf import settings
+from django.contrib.admin.exceptions import NotRegistered
 from django.contrib.admin.utils import NotRelationField, flatten, get_fields_from_path
 from django.core import checks
 from django.core.exceptions import FieldDoesNotExist
@@ -220,8 +221,6 @@ class BaseModelAdminChecks:
         ManyToManyField and that the item has a related ModelAdmin with
         search_fields defined.
         """
-        from django.contrib.admin.sites import NotRegistered
-
         try:
             field = obj.model._meta.get_field(field_name)
         except FieldDoesNotExist:

django/contrib/admin/exceptions.py

@@ -11,3 +11,15 @@ class DisallowedModelAdminToField(SuspiciousOperation):
     """Invalid to_field was passed to admin view via URL query string"""
 
     pass
+
+
+class AlreadyRegistered(Exception):
+    """The model is already registered."""
+
+    pass
+
+
+class NotRegistered(Exception):
+    """The model is not registered."""
+
+    pass

django/contrib/admin/filters.py

@@ -7,6 +7,7 @@ certain test -- e.g. being a DateField or ForeignKey.
 """
 import datetime
 
+from django.contrib.admin.exceptions import NotRegistered
 from django.contrib.admin.options import IncorrectLookupParameters
 from django.contrib.admin.utils import (
     build_q_object_from_lookup_parameters,
@@ -257,8 +258,6 @@ class RelatedFieldListFilter(FieldListFilter):
         """
         Return the model admin's ordering for related field, if provided.
         """
-        from django.contrib.admin.sites import NotRegistered
-
         try:
             related_admin = model_admin.admin_site.get_model_admin(
                 field.remote_field.model

django/contrib/admin/options.py

@@ -14,7 +14,7 @@ from django.contrib.admin.checks import (
     InlineModelAdminChecks,
     ModelAdminChecks,
 )
-from django.contrib.admin.exceptions import DisallowedModelAdminToField
+from django.contrib.admin.exceptions import DisallowedModelAdminToField, NotRegistered
 from django.contrib.admin.templatetags.admin_urls import add_preserved_filters
 from django.contrib.admin.utils import (
     NestedObjects,
@@ -160,8 +160,6 @@ class BaseModelAdmin(metaclass=forms.MediaDefiningClass):
 
         If kwargs are given, they're passed to the form Field's constructor.
         """
-        from django.contrib.admin.sites import NotRegistered
-
         # If the field specifies choices, we don't need to look for special
         # admin widgets - we just need to use a select widget of some kind.
         if db_field.choices:
@@ -252,8 +250,6 @@ class BaseModelAdmin(metaclass=forms.MediaDefiningClass):
         ordering.  Otherwise don't specify the queryset, let the field decide
         (return None in that case).
         """
-        from django.contrib.admin.sites import NotRegistered
-
         try:
             related_admin = self.admin_site.get_model_admin(db_field.remote_field.model)
         except NotRegistered:

django/contrib/admin/sites.py

@@ -4,6 +4,7 @@ from weakref import WeakSet
 from django.apps import apps
 from django.conf import settings
 from django.contrib.admin import ModelAdmin, actions
+from django.contrib.admin.exceptions import AlreadyRegistered, NotRegistered
 from django.contrib.admin.views.autocomplete import AutocompleteJsonView
 from django.contrib.auth import REDIRECT_FIELD_NAME
 from django.core.exceptions import ImproperlyConfigured
@@ -25,14 +26,6 @@ from django.views.i18n import JavaScriptCatalog
 all_sites = WeakSet()
 
 
-class AlreadyRegistered(Exception):
-    pass
-
-
-class NotRegistered(Exception):
-    pass
-
-
 class AdminSite:
     """
     An AdminSite object encapsulates an instance of the Django admin application, ready

django/contrib/admin/views/autocomplete.py

@@ -1,4 +1,5 @@
 from django.apps import apps
+from django.contrib.admin.exceptions import NotRegistered
 from django.core.exceptions import FieldDoesNotExist, PermissionDenied
 from django.http import Http404, JsonResponse
 from django.views.generic.list import BaseListView
@@ -74,8 +75,6 @@ class AutocompleteJsonView(BaseListView):
         Raise Http404 if the target model admin is not configured properly with
         search_fields.
         """
-        from django.contrib.admin.sites import NotRegistered
-
         term = request.GET.get("term", "")
         try:
             app_label = request.GET["app_label"]

docs/ref/contrib/admin/index.txt

@@ -3014,14 +3014,14 @@ Templates can override or extend base admin templates as described in
     as options to the admin class.
 
     Raises :class:`~django.core.exceptions.ImproperlyConfigured` if a model is
-    abstract. and ``django.contrib.admin.sites.AlreadyRegistered`` if a model
+    abstract. and ``django.contrib.admin.exceptions.AlreadyRegistered`` if a
-    is already registered.
+    model is already registered.
 
 .. method:: AdminSite.unregister(model_or_iterable)
 
     Unregisters the given model class (or iterable of classes).
 
-    Raises ``django.contrib.admin.sites.NotRegistered`` if a model isn't
+    Raises ``django.contrib.admin.exceptions.NotRegistered`` if a model isn't
     already registered.
 
 .. method:: AdminSite.get_model_admin(model)
@@ -3029,7 +3029,7 @@ Templates can override or extend base admin templates as described in
     .. versionadded:: 5.0
 
     Returns an admin class for the given model class. Raises
-    ``django.contrib.admin.sites.NotRegistered`` if a model isn't registered.
+    ``django.contrib.admin.exceptions.NotRegistered`` if a model isn't registered.
 
 .. method:: AdminSite.get_log_entries(request)
 

docs/releases/5.0.txt

@@ -487,6 +487,9 @@ Miscellaneous
 * The minimum supported version of ``selenium`` is increased from 3.8.0 to
   4.8.0.
 
+* The ``AlreadyRegistered`` and ``NotRegistered`` exceptions are moved from
+  ``django.contrib.admin.sites`` to ``django.contrib.admin.exceptions``.
+
 .. _deprecated-features-5.0:
 
 Features deprecated in 5.0

tests/admin_registration/tests.py

@@ -1,5 +1,6 @@
 from django.contrib import admin
 from django.contrib.admin.decorators import register
+from django.contrib.admin.exceptions import AlreadyRegistered, NotRegistered
 from django.contrib.admin.sites import site
 from django.core.exceptions import ImproperlyConfigured
 from django.test import SimpleTestCase
@@ -35,7 +36,7 @@ class TestRegistration(SimpleTestCase):
     def test_prevent_double_registration(self):
         self.site.register(Person)
         msg = "The model Person is already registered in app 'admin_registration'."
-        with self.assertRaisesMessage(admin.sites.AlreadyRegistered, msg):
+        with self.assertRaisesMessage(AlreadyRegistered, msg):
             self.site.register(Person)
 
     def test_prevent_double_registration_for_custom_admin(self):
@@ -47,12 +48,12 @@ class TestRegistration(SimpleTestCase):
             "The model Person is already registered with "
             "'admin_registration.PersonAdmin'."
         )
-        with self.assertRaisesMessage(admin.sites.AlreadyRegistered, msg):
+        with self.assertRaisesMessage(AlreadyRegistered, msg):
             self.site.register(Person, PersonAdmin)
 
     def test_unregister_unregistered_model(self):
         msg = "The model Person is not registered"
-        with self.assertRaisesMessage(admin.sites.NotRegistered, msg):
+        with self.assertRaisesMessage(NotRegistered, msg):
             self.site.unregister(Person)
 
     def test_registration_with_star_star_options(self):
@@ -61,7 +62,7 @@ class TestRegistration(SimpleTestCase):
 
     def test_get_model_admin_unregister_model(self):
         msg = "The model Person is not registered."
-        with self.assertRaisesMessage(admin.sites.NotRegistered, msg):
+        with self.assertRaisesMessage(NotRegistered, msg):
             self.site.get_model_admin(Person)
 
     def test_star_star_overrides(self):

tests/admin_views/test_autocomplete_view.py

@@ -3,7 +3,7 @@ import json
 from contextlib import contextmanager
 
 from django.contrib import admin
-from django.contrib.admin.sites import NotRegistered
+from django.contrib.admin.exceptions import NotRegistered
 from django.contrib.admin.tests import AdminSeleniumTestCase
 from django.contrib.admin.views.autocomplete import AutocompleteJsonView
 from django.contrib.auth.models import Permission, User