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.

1 files changed, 10 insertions, 7 deletions

diff --git a/django/contrib/admin/widgets.py b/django/contrib/admin/widgets.py
index 59d1004d2d..1f438daf2d 100644
--- a/django/contrib/admin/widgets.py
+++ b/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 = (