Fixed #29010, Fixed #29138 -- Added limit_choices_to and to_field support to autocomplete fields.

* Fixed #29010 -- Added limit_choices_to support to autocomplete fields.
* Fixed #29138 -- Allowed autocomplete fields to target a custom
  to_field rather than the PK.

django/contrib/admin/options.py

@@ -19,7 +19,6 @@ from django.contrib.admin.utils import (
     get_deleted_objects, lookup_needs_distinct, model_format_dict,
     model_ngettext, quote, unquote,
 )
-from django.contrib.admin.views.autocomplete import AutocompleteJsonView
 from django.contrib.admin.widgets import (
     AutocompleteSelect, AutocompleteSelectMultiple,
 )
@@ -225,7 +224,7 @@ class BaseModelAdmin(metaclass=forms.MediaDefiningClass):
 
         if 'widget' not in kwargs:
             if db_field.name in self.get_autocomplete_fields(request):
-                kwargs['widget'] = AutocompleteSelect(db_field.remote_field, self.admin_site, using=db)
+                kwargs['widget'] = AutocompleteSelect(db_field, self.admin_site, using=db)
             elif db_field.name in self.raw_id_fields:
                 kwargs['widget'] = widgets.ForeignKeyRawIdWidget(db_field.remote_field, self.admin_site, using=db)
             elif db_field.name in self.radio_fields:
@@ -255,7 +254,7 @@ class BaseModelAdmin(metaclass=forms.MediaDefiningClass):
             autocomplete_fields = self.get_autocomplete_fields(request)
             if db_field.name in autocomplete_fields:
                 kwargs['widget'] = AutocompleteSelectMultiple(
-                    db_field.remote_field,
+                    db_field,
                     self.admin_site,
                     using=db,
                 )
@@ -622,7 +621,6 @@ class ModelAdmin(BaseModelAdmin):
         return [
             path('', wrap(self.changelist_view), name='%s_%s_changelist' % info),
             path('add/', wrap(self.add_view), name='%s_%s_add' % info),
-            path('autocomplete/', wrap(self.autocomplete_view), name='%s_%s_autocomplete' % info),
             path('<path:object_id>/history/', wrap(self.history_view), name='%s_%s_history' % info),
             path('<path:object_id>/delete/', wrap(self.delete_view), name='%s_%s_delete' % info),
             path('<path:object_id>/change/', wrap(self.change_view), name='%s_%s_change' % info),
@@ -1652,9 +1650,6 @@ class ModelAdmin(BaseModelAdmin):
 
         return self.render_change_form(request, context, add=add, change=not add, obj=obj, form_url=form_url)
 
-    def autocomplete_view(self, request):
-        return AutocompleteJsonView.as_view(model_admin=self)(request)
-
     def add_view(self, request, form_url='', extra_context=None):
         return self.changeform_view(request, None, form_url, extra_context)
 

django/contrib/admin/sites.py

@@ -4,6 +4,7 @@ from weakref import WeakSet
 
 from django.apps import apps
 from django.contrib.admin import ModelAdmin, actions
+from django.contrib.admin.views.autocomplete import AutocompleteJsonView
 from django.contrib.auth import REDIRECT_FIELD_NAME
 from django.core.exceptions import ImproperlyConfigured
 from django.db.models.base import ModelBase
@@ -255,6 +256,7 @@ class AdminSite:
                 wrap(self.password_change_done, cacheable=True),
                 name='password_change_done',
             ),
+            path('autocomplete/', wrap(self.autocomplete_view), name='autocomplete'),
             path('jsi18n/', wrap(self.i18n_javascript, cacheable=True), name='jsi18n'),
             path(
                 'r/<int:content_type_id>/<path:object_id>/',
@@ -401,6 +403,9 @@ class AdminSite:
         request.current_app = self.name
         return LoginView.as_view(**defaults)(request)
 
+    def autocomplete_view(self, request):
+        return AutocompleteJsonView.as_view(admin_site=self)(request)
+
     def _build_app_dict(self, request, label=None):
         """
         Build the app dictionary. The optional `label` parameter filters models

django/contrib/admin/static/admin/js/autocomplete.js

@@ -7,7 +7,10 @@
                 data: function(params) {
                     return {
                         term: params.term,
-                        page: params.page
+                        page: params.page,
+                        app_label: $element.data('app-label'),
+                        model_name: $element.data('model-name'),
+                        field_name: $element.data('field-name')
                     };
                 }
             }

django/contrib/admin/views/autocomplete.py

@@ -1,3 +1,5 @@
+from django.apps import apps
+from django.core.exceptions import FieldDoesNotExist, PermissionDenied
 from django.http import Http404, JsonResponse
 from django.views.generic.list import BaseListView
 
@@ -5,7 +7,7 @@ from django.views.generic.list import BaseListView
 class AutocompleteJsonView(BaseListView):
     """Handle AutocompleteWidget's AJAX requests for data."""
     paginate_by = 20
-    model_admin = None
+    admin_site = None
 
     def get(self, request, *args, **kwargs):
         """
@@ -15,20 +17,16 @@ class AutocompleteJsonView(BaseListView):
             pagination: {more: true}
         }
         """
-        if not self.model_admin.get_search_fields(request):
-            raise Http404(
-                '%s must have search_fields for the autocomplete_view.' %
-                type(self.model_admin).__name__
-            )
-        if not self.has_perm(request):
-            return JsonResponse({'error': '403 Forbidden'}, status=403)
+        self.term, self.model_admin, self.source_field, to_field_name = self.process_request(request)
+
+        if not self.has_perm(request):
+            raise PermissionDenied
 
-        self.term = request.GET.get('term', '')
         self.object_list = self.get_queryset()
         context = self.get_context_data()
         return JsonResponse({
             'results': [
-                {'id': str(obj.pk), 'text': str(obj)}
+                {'id': str(getattr(obj, to_field_name)), 'text': str(obj)}
                 for obj in context['object_list']
             ],
             'pagination': {'more': context['page_obj'].has_next()},
@@ -41,11 +39,63 @@ class AutocompleteJsonView(BaseListView):
     def get_queryset(self):
         """Return queryset based on ModelAdmin.get_search_results()."""
         qs = self.model_admin.get_queryset(self.request)
+        qs = qs.complex_filter(self.source_field.get_limit_choices_to())
         qs, search_use_distinct = self.model_admin.get_search_results(self.request, qs, self.term)
         if search_use_distinct:
             qs = qs.distinct()
         return qs
 
+    def process_request(self, request):
+        """
+        Validate request integrity, extract and return request parameters.
+
+        Since the subsequent view permission check requires the target model
+        admin, which is determined here, raise PermissionDenied if the
+        requested app, model or field are malformed.
+
+        Raise Http404 if the target model admin is not configured properly with
+        search_fields.
+        """
+        term = request.GET.get('term', '')
+        try:
+            app_label = request.GET['app_label']
+            model_name = request.GET['model_name']
+            field_name = request.GET['field_name']
+        except KeyError as e:
+            raise PermissionDenied from e
+
+        # Retrieve objects from parameters.
+        try:
+            source_model = apps.get_model(app_label, model_name)
+        except LookupError as e:
+            raise PermissionDenied from e
+
+        try:
+            source_field = source_model._meta.get_field(field_name)
+        except FieldDoesNotExist as e:
+            raise PermissionDenied from e
+        try:
+            remote_model = source_field.remote_field.model
+        except AttributeError as e:
+            raise PermissionDenied from e
+        try:
+            model_admin = self.admin_site._registry[remote_model]
+        except KeyError as e:
+            raise PermissionDenied from e
+
+        # Validate suitability of objects.
+        if not model_admin.get_search_fields(request):
+            raise Http404(
+                '%s must have search_fields for the autocomplete_view.' %
+                type(model_admin).__qualname__
+            )
+
+        to_field_name = getattr(source_field.remote_field, 'field_name', model_admin.model._meta.pk.name)
+        if not model_admin.to_field_allowed(request, to_field_name):
+            raise PermissionDenied
+
+        return term, model_admin, source_field, to_field_name
+
     def has_perm(self, request, obj=None):
         """Check if user has permission to access the related model."""
         return self.model_admin.has_view_permission(request, obj=obj)

django/contrib/admin/widgets.py

@@ -380,18 +380,17 @@ class AutocompleteMixin:
     Renders the necessary data attributes for select2 and adds the static form
     media.
     """
-    url_name = '%s:%s_%s_autocomplete'
+    url_name = '%s:autocomplete'
 
-    def __init__(self, rel, admin_site, attrs=None, choices=(), using=None):
-        self.rel = rel
+    def __init__(self, field, admin_site, attrs=None, choices=(), using=None):
+        self.field = field
         self.admin_site = admin_site
         self.db = using
         self.choices = choices
         self.attrs = {} if attrs is None else attrs.copy()
 
     def get_url(self):
-        model = self.rel.model
-        return reverse(self.url_name % (self.admin_site.name, model._meta.app_label, model._meta.model_name))
+        return reverse(self.url_name % self.admin_site.name)
 
     def build_attrs(self, base_attrs, extra_attrs=None):
         """
@@ -408,6 +407,9 @@ class AutocompleteMixin:
             'data-ajax--delay': 250,
             'data-ajax--type': 'GET',
             'data-ajax--url': self.get_url(),
+            'data-app-label': self.field.model._meta.app_label,
+            'data-model-name': self.field.model._meta.model_name,
+            'data-field-name': self.field.name,
             'data-theme': 'admin-autocomplete',
             'data-allow-clear': json.dumps(not self.is_required),
             'data-placeholder': '',  # Allows clearing of the input.
@@ -426,9 +428,10 @@ class AutocompleteMixin:
         }
         if not self.is_required and not self.allow_multiple_selected:
             default[1].append(self.create_option(name, '', '', False, 0))
+        to_field_name = getattr(self.field.remote_field, 'field_name', self.field.model._meta.pk.name)
         choices = (
-            (obj.pk, self.choices.field.label_from_instance(obj))
-            for obj in self.choices.queryset.using(self.db).filter(pk__in=selected_choices)
+            (getattr(obj, to_field_name), self.choices.field.label_from_instance(obj))
+            for obj in self.choices.queryset.using(self.db).filter(**{'%s__in' % to_field_name: selected_choices})
         )
         for option_value, option_label in choices:
             selected = (

docs/releases/3.2.txt

@@ -119,6 +119,12 @@ Minor features
 
 * The admin now supports theming. See :ref:`admin-theming` for more details.
 
+* :attr:`.ModelAdmin.autocomplete_fields` now respects
+  :attr:`ForeignKey.to_field <django.db.models.ForeignKey.to_field>` and
+  :attr:`ForeignKey.limit_choices_to
+  <django.db.models.ForeignKey.limit_choices_to>` when searching a related
+  model.
+
 :mod:`django.contrib.admindocs`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/admin_views/models.py

@@ -629,6 +629,7 @@ class Question(models.Model):
     posted = models.DateField(default=datetime.date.today)
     expires = models.DateTimeField(null=True, blank=True)
     related_questions = models.ManyToManyField('self')
+    uuid = models.UUIDField(default=uuid.uuid4, unique=True)
 
     def __str__(self):
         return self.question
@@ -636,6 +637,13 @@ class Question(models.Model):
 
 class Answer(models.Model):
     question = models.ForeignKey(Question, models.PROTECT)
+    question_with_to_field = models.ForeignKey(
+        Question, models.SET_NULL,
+        blank=True, null=True, to_field='uuid',
+        related_name='uuid_answers',
+        limit_choices_to=~models.Q(question__istartswith='not'),
+    )
+    related_answers = models.ManyToManyField('self')
     answer = models.CharField(max_length=20)
 
     def __str__(self):

tests/admin_views/test_autocomplete_view.py

@@ -6,6 +6,7 @@ from django.contrib.admin.tests import AdminSeleniumTestCase
 from django.contrib.admin.views.autocomplete import AutocompleteJsonView
 from django.contrib.auth.models import Permission, User
 from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import PermissionDenied
 from django.http import Http404
 from django.test import RequestFactory, override_settings
 from django.urls import reverse, reverse_lazy
@@ -38,10 +39,28 @@ site.register(Author, AuthorAdmin)
 site.register(Book, BookAdmin)
 
 
+@contextmanager
+def model_admin(model, model_admin, admin_site=site):
+    org_admin = admin_site._registry.get(model)
+    if org_admin:
+        admin_site.unregister(model)
+    admin_site.register(model, model_admin)
+    try:
+        yield
+    finally:
+        if org_admin:
+            admin_site._registry[model] = org_admin
+
+
 class AutocompleteJsonViewTests(AdminViewBasicTestCase):
-    as_view_args = {'model_admin': QuestionAdmin(Question, site)}
+    as_view_args = {'admin_site': site}
+    opts = {
+        'app_label': Answer._meta.app_label,
+        'model_name': Answer._meta.model_name,
+        'field_name': 'question'
+    }
     factory = RequestFactory()
-    url = reverse_lazy('autocomplete_admin:admin_views_question_autocomplete')
+    url = reverse_lazy('autocomplete_admin:autocomplete')
 
     @classmethod
     def setUpTestData(cls):
@@ -53,7 +72,7 @@ class AutocompleteJsonViewTests(AdminViewBasicTestCase):
 
     def test_success(self):
         q = Question.objects.create(question='Is this a question?')
-        request = self.factory.get(self.url, {'term': 'is'})
+        request = self.factory.get(self.url, {'term': 'is', **self.opts})
         request.user = self.superuser
         response = AutocompleteJsonView.as_view(**self.as_view_args)(request)
         self.assertEqual(response.status_code, 200)
@@ -63,11 +82,56 @@ class AutocompleteJsonViewTests(AdminViewBasicTestCase):
             'pagination': {'more': False},
         })
 
+    def test_custom_to_field(self):
+        q = Question.objects.create(question='Is this a question?')
+        request = self.factory.get(self.url, {'term': 'is', **self.opts, 'field_name': 'question_with_to_field'})
+        request.user = self.superuser
+        response = AutocompleteJsonView.as_view(**self.as_view_args)(request)
+        self.assertEqual(response.status_code, 200)
+        data = json.loads(response.content.decode('utf-8'))
+        self.assertEqual(data, {
+            'results': [{'id': str(q.uuid), 'text': q.question}],
+            'pagination': {'more': False},
+        })
+
+    def test_field_does_not_exist(self):
+        request = self.factory.get(self.url, {'term': 'is', **self.opts, 'field_name': 'does_not_exist'})
+        request.user = self.superuser
+        with self.assertRaises(PermissionDenied):
+            AutocompleteJsonView.as_view(**self.as_view_args)(request)
+
+    def test_field_no_related_field(self):
+        request = self.factory.get(self.url, {'term': 'is', **self.opts, 'field_name': 'answer'})
+        request.user = self.superuser
+        with self.assertRaises(PermissionDenied):
+            AutocompleteJsonView.as_view(**self.as_view_args)(request)
+
+    def test_field_does_not_allowed(self):
+        request = self.factory.get(self.url, {'term': 'is', **self.opts, 'field_name': 'related_questions'})
+        request.user = self.superuser
+        with self.assertRaises(PermissionDenied):
+            AutocompleteJsonView.as_view(**self.as_view_args)(request)
+
+    def test_limit_choices_to(self):
+        # Answer.question_with_to_field defines limit_choices_to to "those not
+        # starting with 'not'".
+        q = Question.objects.create(question='Is this a question?')
+        Question.objects.create(question='Not a question.')
+        request = self.factory.get(self.url, {'term': 'is', **self.opts, 'field_name': 'question_with_to_field'})
+        request.user = self.superuser
+        response = AutocompleteJsonView.as_view(**self.as_view_args)(request)
+        self.assertEqual(response.status_code, 200)
+        data = json.loads(response.content.decode('utf-8'))
+        self.assertEqual(data, {
+            'results': [{'id': str(q.uuid), 'text': q.question}],
+            'pagination': {'more': False},
+        })
+
     def test_must_be_logged_in(self):
-        response = self.client.get(self.url, {'term': ''})
+        response = self.client.get(self.url, {'term': '', **self.opts})
         self.assertEqual(response.status_code, 200)
         self.client.logout()
-        response = self.client.get(self.url, {'term': ''})
+        response = self.client.get(self.url, {'term': '', **self.opts})
         self.assertEqual(response.status_code, 302)
 
     def test_has_view_or_change_permission_required(self):
@@ -75,13 +139,12 @@ class AutocompleteJsonViewTests(AdminViewBasicTestCase):
         Users require the change permission for the related model to the
         autocomplete view for it.
         """
-        request = self.factory.get(self.url, {'term': 'is'})
+        request = self.factory.get(self.url, {'term': 'is', **self.opts})
         self.user.is_staff = True
         self.user.save()
         request.user = self.user
-        response = AutocompleteJsonView.as_view(**self.as_view_args)(request)
-        self.assertEqual(response.status_code, 403)
-        self.assertJSONEqual(response.content.decode('utf-8'), {'error': '403 Forbidden'})
+        with self.assertRaises(PermissionDenied):
+            AutocompleteJsonView.as_view(**self.as_view_args)(request)
         for permission in ('view', 'change'):
             with self.subTest(permission=permission):
                 self.user.user_permissions.clear()
@@ -104,14 +167,14 @@ class AutocompleteJsonViewTests(AdminViewBasicTestCase):
         q2.related_questions.add(q1)
         q3 = Question.objects.create(question='question 3')
         q3.related_questions.add(q1)
-        request = self.factory.get(self.url, {'term': 'question'})
+        request = self.factory.get(self.url, {'term': 'question', **self.opts})
         request.user = self.superuser
 
         class DistinctQuestionAdmin(QuestionAdmin):
             search_fields = ['related_questions__question', 'question']
 
-        model_admin = DistinctQuestionAdmin(Question, site)
-        response = AutocompleteJsonView.as_view(model_admin=model_admin)(request)
+        with model_admin(Question, DistinctQuestionAdmin):
+            response = AutocompleteJsonView.as_view(**self.as_view_args)(request)
         self.assertEqual(response.status_code, 200)
         data = json.loads(response.content.decode('utf-8'))
         self.assertEqual(len(data['results']), 3)
@@ -120,20 +183,22 @@ class AutocompleteJsonViewTests(AdminViewBasicTestCase):
         class EmptySearchAdmin(QuestionAdmin):
             search_fields = []
 
-        model_admin = EmptySearchAdmin(Question, site)
-        msg = 'EmptySearchAdmin must have search_fields for the autocomplete_view.'
-        with self.assertRaisesMessage(Http404, msg):
-            model_admin.autocomplete_view(self.factory.get(self.url))
+        with model_admin(Question, EmptySearchAdmin):
+            msg = 'EmptySearchAdmin must have search_fields for the autocomplete_view.'
+            with self.assertRaisesMessage(Http404, msg):
+                site.autocomplete_view(self.factory.get(self.url, {'term': '', **self.opts}))
 
     def test_get_paginator(self):
         """Search results are paginated."""
+        class PKOrderingQuestionAdmin(QuestionAdmin):
+            ordering = ['pk']
+
         Question.objects.bulk_create(Question(question=str(i)) for i in range(PAGINATOR_SIZE + 10))
-        model_admin = QuestionAdmin(Question, site)
-        model_admin.ordering = ['pk']
         # The first page of results.
-        request = self.factory.get(self.url, {'term': ''})
+        request = self.factory.get(self.url, {'term': '', **self.opts})
         request.user = self.superuser
-        response = AutocompleteJsonView.as_view(model_admin=model_admin)(request)
+        with model_admin(Question, PKOrderingQuestionAdmin):
+            response = AutocompleteJsonView.as_view(**self.as_view_args)(request)
         self.assertEqual(response.status_code, 200)
         data = json.loads(response.content.decode('utf-8'))
         self.assertEqual(data, {
@@ -141,9 +206,10 @@ class AutocompleteJsonViewTests(AdminViewBasicTestCase):
             'pagination': {'more': True},
         })
         # The second page of results.
-        request = self.factory.get(self.url, {'term': '', 'page': '2'})
+        request = self.factory.get(self.url, {'term': '', 'page': '2', **self.opts})
         request.user = self.superuser
-        response = AutocompleteJsonView.as_view(model_admin=model_admin)(request)
+        with model_admin(Question, PKOrderingQuestionAdmin):
+            response = AutocompleteJsonView.as_view(**self.as_view_args)(request)
         self.assertEqual(response.status_code, 200)
         data = json.loads(response.content.decode('utf-8'))
         self.assertEqual(data, {

tests/admin_widgets/models.py

@@ -19,6 +19,7 @@ class Member(models.Model):
 
 
 class Band(models.Model):
+    uuid = models.UUIDField(unique=True, default=uuid.uuid4)
     name = models.CharField(max_length=100)
     style = models.CharField(max_length=20)
     members = models.ManyToManyField(Member)
@@ -36,7 +37,7 @@ class UnsafeLimitChoicesTo(models.Model):
 
 
 class Album(models.Model):
-    band = models.ForeignKey(Band, models.CASCADE)
+    band = models.ForeignKey(Band, models.CASCADE, to_field='uuid')
     featuring = models.ManyToManyField(Band, related_name='featured')
     name = models.CharField(max_length=100)
     cover_art = models.FileField(upload_to='albums')

tests/admin_widgets/test_autocomplete_widget.py

@@ -14,12 +14,12 @@ class AlbumForm(forms.ModelForm):
         fields = ['band', 'featuring']
         widgets = {
             'band': AutocompleteSelect(
-                Album._meta.get_field('band').remote_field,
+                Album._meta.get_field('band'),
                 admin.site,
                 attrs={'class': 'my-class'},
             ),
             'featuring': AutocompleteSelect(
-                Album._meta.get_field('featuring').remote_field,
+                Album._meta.get_field('featuring'),
                 admin.site,
             )
         }
@@ -54,9 +54,12 @@ class AutocompleteMixinTests(TestCase):
             'data-ajax--cache': 'true',
             'data-ajax--delay': 250,
             'data-ajax--type': 'GET',
-            'data-ajax--url': '/admin_widgets/band/autocomplete/',
+            'data-ajax--url': '/autocomplete/',
             'data-theme': 'admin-autocomplete',
             'data-allow-clear': 'false',
+            'data-app-label': 'admin_widgets',
+            'data-field-name': 'band',
+            'data-model-name': 'album',
             'data-placeholder': ''
         })
 
@@ -76,19 +79,19 @@ class AutocompleteMixinTests(TestCase):
         self.assertJSONEqual(attrs['data-allow-clear'], False)
 
     def test_get_url(self):
-        rel = Album._meta.get_field('band').remote_field
+        rel = Album._meta.get_field('band')
         w = AutocompleteSelect(rel, admin.site)
         url = w.get_url()
-        self.assertEqual(url, '/admin_widgets/band/autocomplete/')
+        self.assertEqual(url, '/autocomplete/')
 
     def test_render_options(self):
         beatles = Band.objects.create(name='The Beatles', style='rock')
         who = Band.objects.create(name='The Who', style='rock')
         # With 'band', a ForeignKey.
-        form = AlbumForm(initial={'band': beatles.pk})
+        form = AlbumForm(initial={'band': beatles.uuid})
         output = form.as_table()
-        selected_option = '<option value="%s" selected>The Beatles</option>' % beatles.pk
-        option = '<option value="%s">The Who</option>' % who.pk
+        selected_option = '<option value="%s" selected>The Beatles</option>' % beatles.uuid
+        option = '<option value="%s">The Who</option>' % who.uuid
         self.assertIn(selected_option, output)
         self.assertNotIn(option, output)
         # With 'featuring', a ManyToManyField.

tests/admin_widgets/tests.py

@@ -539,13 +539,13 @@ class ForeignKeyRawIdWidgetTest(TestCase):
 
         w = widgets.ForeignKeyRawIdWidget(rel, widget_admin_site)
         self.assertHTMLEqual(
-            w.render('test', band.pk, attrs={}),
-            '<input type="text" name="test" value="%(bandpk)s" '
+            w.render('test', band.uuid, attrs={}),
+            '<input type="text" name="test" value="%(banduuid)s" '
             'class="vForeignKeyRawIdAdminField">'
-            '<a href="/admin_widgets/band/?_to_field=id" class="related-lookup" '
+            '<a href="/admin_widgets/band/?_to_field=uuid" class="related-lookup" '
             'id="lookup_id_test" title="Lookup"></a>&nbsp;<strong>'
             '<a href="/admin_widgets/band/%(bandpk)s/change/">Linkin Park</a>'
-            '</strong>' % {'bandpk': band.pk}
+            '</strong>' % {'banduuid': band.uuid, 'bandpk': band.pk}
         )
 
     def test_relations_to_non_primary_key(self):