[1.11.x] Fixed #27850 -- Made RelatedFieldWidgetWrapper call render() of the wrapped widget.

Backport of fb7e0e01af from master

django/contrib/admin/templates/admin/widgets/related_widget_wrapper.html

@@ -1,24 +1,24 @@
 {% load i18n static %}
 <div class="related-widget-wrapper">
-    {% include widget.template_name %}
+    {{ rendered_widget }}
     {% block links %}
         {% spaceless %}
         {% if can_change_related %}
-        <a class="related-widget-wrapper-link change-related" id="change_id_{{ widget.name }}"
+        <a class="related-widget-wrapper-link change-related" id="change_id_{{ name }}"
             data-href-template="{{ change_related_template_url }}?{{ url_params }}"
             title="{% blocktrans %}Change selected {{ model }}{% endblocktrans %}">
             <img src="{% static 'admin/img/icon-changelink.svg' %}" alt="{% trans 'Change' %}"/>
         </a>
         {% endif %}
         {% if can_add_related %}
-        <a class="related-widget-wrapper-link add-related" id="add_id_{{ widget.name }}"
+        <a class="related-widget-wrapper-link add-related" id="add_id_{{ name }}"
             href="{{ add_related_url }}?{{ url_params }}"
             title="{% blocktrans %}Add another {{ model }}{% endblocktrans %}">
             <img src="{% static 'admin/img/icon-addlink.svg' %}" alt="{% trans 'Add' %}"/>
         </a>
         {% endif %}
         {% if can_delete_related %}
-        <a class="related-widget-wrapper-link delete-related" id="delete_id_{{ widget.name }}"
+        <a class="related-widget-wrapper-link delete-related" id="delete_id_{{ name }}"
             data-href-template="{{ delete_related_template_url }}?{{ url_params }}"
             title="{% blocktrans %}Delete selected {{ model }}{% endblocktrans %}">
             <img src="{% static 'admin/img/icon-deletelink.svg' %}" alt="{% trans 'Delete' %}"/>

django/contrib/admin/widgets.py

@@ -269,18 +269,20 @@ class RelatedFieldWidgetWrapper(forms.Widget):
                        current_app=self.admin_site.name, args=args)
 
     def get_context(self, name, value, attrs=None):
-        with self.widget.override_choices(self.choices):
-            context = self.widget.get_context(name, value, attrs)
-
         from django.contrib.admin.views.main import IS_POPUP_VAR, TO_FIELD_VAR
         rel_opts = self.rel.model._meta
         info = (rel_opts.app_label, rel_opts.model_name)
+        self.widget.choices = self.choices
         url_params = '&'.join("%s=%s" % param for param in [
             (TO_FIELD_VAR, self.rel.get_related_field().name),
             (IS_POPUP_VAR, 1),
         ])
-        context['url_params'] = url_params
-        context['model'] = rel_opts.verbose_name
+        context = {
+            'rendered_widget': self.widget.render(name, value, attrs),
+            'name': name,
+            'url_params': url_params,
+            'model': rel_opts.verbose_name,
+        }
         if self.can_change_related:
             change_related_template_url = self.get_related_url(info, 'change', '__fk__')
             context.update(

django/forms/widgets.py

@@ -7,7 +7,6 @@ from __future__ import unicode_literals
 import copy
 import datetime
 import re
-from contextlib import contextmanager
 from itertools import chain
 
 from django.conf import settings
@@ -647,13 +646,6 @@ class ChoiceWidget(Widget):
                 pass
         return getter(name)
 
-    @contextmanager
-    def override_choices(self, choices):
-        old = self.choices
-        self.choices = choices
-        yield
-        self.choices = old
-
     def format_value(self, value):
         """Return selected values as a set."""
         if not isinstance(value, (tuple, list)):

tests/admin_widgets/tests.py

@@ -599,6 +599,7 @@ class ManyToManyRawIdWidgetTest(TestCase):
         )
 
 
+@override_settings(ROOT_URLCONF='admin_widgets.urls')
 class RelatedFieldWidgetWrapperTests(SimpleTestCase):
     def test_no_can_add_related(self):
         rel = Individual._meta.get_field('parent').remote_field
@@ -633,6 +634,21 @@ class RelatedFieldWidgetWrapperTests(SimpleTestCase):
         self.assertTrue(wrapper.can_change_related)
         self.assertFalse(wrapper.can_delete_related)
 
+    def test_custom_widget_render(self):
+        class CustomWidget(forms.Select):
+            def render(self, *args, **kwargs):
+                return 'custom render output'
+        rel = Album._meta.get_field('band').remote_field
+        widget = CustomWidget()
+        wrapper = widgets.RelatedFieldWidgetWrapper(
+            widget, rel, widget_admin_site,
+            can_add_related=True,
+            can_change_related=True,
+            can_delete_related=True,
+        )
+        output = wrapper.render('name', 'value')
+        self.assertIn('custom render output', output)
+
 
 @override_settings(ROOT_URLCONF='admin_widgets.urls')
 class AdminWidgetSeleniumTestCase(AdminSeleniumTestCase):