Fixed #28529 -- Fixed VariableDoesNotExist warnings in admin templates.

django/contrib/admin/sites.py

@@ -300,6 +300,7 @@ class AdminSite:
             'site_url': site_url,
             'has_permission': self.has_permission(request),
             'available_apps': self.get_app_list(request),
+            'is_popup': False,
         }
 
     def password_change(self, request, extra_context=None):
@@ -431,6 +432,8 @@ class AdminSite:
                 'name': capfirst(model._meta.verbose_name_plural),
                 'object_name': model._meta.object_name,
                 'perms': perms,
+                'admin_url': None,
+                'add_url': None,
             }
             if perms.get('change') or perms.get('view'):
                 model_dict['view_only'] = not perms.get('change')

django/contrib/admin/templates/admin/change_list.html

@@ -46,7 +46,7 @@
           {% endblock %}
         </ul>
     {% endblock %}
-    {% if cl.formset.errors %}
+    {% if cl.formset and cl.formset.errors %}
         <p class="errornote">
         {% if cl.formset.total_error_count == 1 %}{% trans "Please correct the error below." %}{% else %}{% trans "Please correct the errors below." %}{% endif %}
         </p>
@@ -54,7 +54,7 @@
     {% endif %}
     <div class="module{% if cl.has_filters %} filtered{% endif %}" id="changelist">
       {% block search %}{% search_form cl %}{% endblock %}
-      {% block date_hierarchy %}{% date_hierarchy cl %}{% endblock %}
+      {% block date_hierarchy %}{% if cl.date_hierarchy %}{% date_hierarchy cl %}{% endif %}{% endblock %}
 
       {% block filters %}
         {% if cl.has_filters %}
@@ -65,7 +65,7 @@
         {% endif %}
       {% endblock %}
 
-      <form id="changelist-form" method="post"{% if cl.formset.is_multipart %} enctype="multipart/form-data"{% endif %} novalidate>{% csrf_token %}
+      <form id="changelist-form" method="post"{% if cl.formset and cl.formset.is_multipart %} enctype="multipart/form-data"{% endif %} novalidate>{% csrf_token %}
       {% if cl.formset %}
         <div>{{ cl.formset.management_form }}</div>
       {% endif %}

django/contrib/admin/templates/admin/change_list_results.html

@@ -27,7 +27,7 @@
 </thead>
 <tbody>
 {% for result in results %}
-{% if result.form.non_field_errors %}
+{% if result.form and result.form.non_field_errors %}
     <tr><td colspan="{{ result|length }}">{{ result.form.non_field_errors }}</td></tr>
 {% endif %}
 <tr class="{% cycle 'row1' 'row2' %}">{% for item in result %}{{ item }}{% endfor %}</tr>

django/contrib/admin/templates/admin/edit_inline/stacked.html

@@ -19,7 +19,7 @@
     {% include "admin/includes/fieldset.html" %}
   {% endfor %}
   {% if inline_admin_form.needs_explicit_pk_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
-  {{ inline_admin_form.fk_field.field }}
+  {% if inline_admin_form.fk_field %}{{ inline_admin_form.fk_field.field }}{% endif %}
 </div>{% endfor %}
 </fieldset>
 </div>

django/contrib/admin/templates/admin/edit_inline/tabular.html

@@ -36,12 +36,12 @@
           {% if inline_admin_form.show_url %}<a href="{{ inline_admin_form.absolute_url }}">{% trans "View on site" %}</a>{% endif %}
             </p>{% endif %}
           {% if inline_admin_form.needs_explicit_pk_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
-          {{ inline_admin_form.fk_field.field }}
+          {% if inline_admin_form.fk_field %}{{ inline_admin_form.fk_field.field }}{% endif %}
           {% spaceless %}
           {% for fieldset in inline_admin_form %}
             {% for line in fieldset %}
               {% for field in line %}
-                {% if field.field.is_hidden %} {{ field.field }} {% endif %}
+                {% if not field.is_readonly and field.field.is_hidden %}{{ field.field }}{% endif %}
               {% endfor %}
             {% endfor %}
           {% endfor %}
@@ -50,7 +50,7 @@
         {% for fieldset in inline_admin_form %}
           {% for line in fieldset %}
             {% for field in line %}
-              {% if not field.field.is_hidden %}
+              {% if field.is_readonly or not field.field.is_hidden %}
               <td{% if field.field.name %} class="field-{{ field.field.name }}"{% endif %}>
               {% if field.is_readonly %}
                   <p>{{ field.contents }}</p>

django/contrib/admin/templates/admin/submit_line.html

@@ -2,7 +2,7 @@
 <div class="submit-row">
 {% block submit-row %}
 {% if show_save %}<input type="submit" value="{% trans 'Save' %}" class="default" name="_save">{% endif %}
-{% if show_delete_link %}
+{% if show_delete_link and original %}
     {% url opts|admin_urlname:'delete' original.pk|admin_urlquote as delete_url %}
     <p class="deletelink-box"><a href="{% add_preserved_filters delete_url %}" class="deletelink">{% trans "Delete" %}</a></p>
 {% endif %}

django/contrib/admin/templatetags/admin_list.py

@@ -418,6 +418,7 @@ def date_hierarchy(cl):
             years = getattr(cl.queryset, 'dates')(field_name, 'year')
             return {
                 'show': True,
+                'back': None,
                 'choices': [{
                     'link': link({year_field: str(year.year)}),
                     'title': str(year.year),

django/contrib/admin/views/main.py

@@ -46,6 +46,7 @@ class ChangeList:
         self.list_display = list_display
         self.list_display_links = list_display_links
         self.list_filter = list_filter
+        self.has_filters = None
         self.date_hierarchy = date_hierarchy
         self.search_fields = search_fields
         self.list_select_related = list_select_related

django/contrib/admin/widgets.py

@@ -154,8 +154,12 @@ class ForeignKeyRawIdWidget(forms.TextInput):
             context['link_title'] = _('Lookup')
             # The JavaScript code looks for this class.
             context['widget']['attrs'].setdefault('class', 'vForeignKeyRawIdAdminField')
+        else:
+            context['related_url'] = None
         if context['widget']['value']:
             context['link_label'], context['link_url'] = self.label_and_url_for_value(value)
+        else:
+            context['link_label'] = None
         return context
 
     def base_url_parameters(self):

docs/ref/templates/api.txt

@@ -371,9 +371,9 @@ replaced with the name of the invalid variable.
     While ``string_if_invalid`` can be a useful debugging tool, it is a bad
     idea to turn it on as a 'development default'.
 
-    Many templates, including those in the Admin site, rely upon the silence
-    of the template system when a nonexistent variable is encountered. If you
-    assign a value other than ``''`` to ``string_if_invalid``, you will
+    Many templates, including some of the Django's templates, rely upon the
+    silence of the template system when a nonexistent variable is encountered.
+    If you assign a value other than ``''`` to ``string_if_invalid``, you will
     experience rendering problems with these templates and sites.
 
     Generally, ``string_if_invalid`` should only be enabled in order to debug