Fixed #28414 -- Fixed ClearableFileInput rendering as a subwidget of MultiWidget.

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

-{% if is_initial %}<p class="file-upload">{{ initial_text }}: <a href="{{ widget.value.url }}">{{ widget.value }}</a>{% if not widget.required %}
+{% if widget.is_initial %}<p class="file-upload">{{ widget.initial_text }}: <a href="{{ widget.value.url }}">{{ widget.value }}</a>{% if not widget.required %}
 <span class="clearable-file-input">
-<input type="checkbox" name="{{ checkbox_name }}" id="{{ checkbox_id }}" />
-<label for="{{ checkbox_id }}">{{ clear_checkbox_label }}</label></span>{% endif %}<br />
-{{ input_text }}:{% endif %}
-<input type="{{ widget.type }}" name="{{ widget.name }}"{% include "django/forms/widgets/attrs.html" %} />{% if is_initial %}</p>{% endif %}
+<input type="checkbox" name="{{ widget.checkbox_name }}" id="{{ widget.checkbox_id }}" />
+<label for="{{ widget.checkbox_id }}">{{ widget.clear_checkbox_label }}</label></span>{% endif %}<br />
+{{ widget.input_text }}:{% endif %}
+<input type="{{ widget.type }}" name="{{ widget.name }}"{% include "django/forms/widgets/attrs.html" %} />{% if widget.is_initial %}</p>{% endif %}

django/forms/jinja2/django/forms/widgets/clearable_file_input.html

-{% if is_initial %}{{ initial_text }}: <a href="{{ widget.value.url }}">{{ widget.value }}</a>{% if not widget.required %}
-<input type="checkbox" name="{{ checkbox_name }}" id="{{ checkbox_id }}" />
-<label for="{{ checkbox_id }}">{{ clear_checkbox_label }}</label>{% endif %}<br />
-{{ input_text }}:{% endif %}
+{% if widget.is_initial %}{{ widget.initial_text }}: <a href="{{ widget.value.url }}">{{ widget.value }}</a>{% if not widget.required %}
+<input type="checkbox" name="{{ widget.checkbox_name }}" id="{{ widget.checkbox_id }}" />
+<label for="{{ widget.checkbox_id }}">{{ widget.clear_checkbox_label }}</label>{% endif %}<br />
+{{ widget.input_text }}:{% endif %}
 <input type="{{ widget.type }}" name="{{ widget.name }}"{% include "django/forms/widgets/attrs.html" %} />

django/forms/templates/django/forms/widgets/clearable_file_input.html

-{% if is_initial %}{{ initial_text }}: <a href="{{ widget.value.url }}">{{ widget.value }}</a>{% if not widget.required %}
-<input type="checkbox" name="{{ checkbox_name }}" id="{{ checkbox_id }}" />
-<label for="{{ checkbox_id }}">{{ clear_checkbox_label }}</label>{% endif %}<br />
-{{ input_text }}:{% endif %}
+{% if widget.is_initial %}{{ widget.initial_text }}: <a href="{{ widget.value.url }}">{{ widget.value }}</a>{% if not widget.required %}
+<input type="checkbox" name="{{ widget.checkbox_name }}" id="{{ widget.checkbox_id }}" />
+<label for="{{ widget.checkbox_id }}">{{ widget.clear_checkbox_label }}</label>{% endif %}<br />
+{{ widget.input_text }}:{% endif %}
 <input type="{{ widget.type }}" name="{{ widget.name }}"{% include "django/forms/widgets/attrs.html" %} />

django/forms/widgets.py

@@ -392,7 +392,7 @@ class ClearableFileInput(FileInput):
         context = super().get_context(name, value, attrs)
         checkbox_name = self.clear_checkbox_name(name)
         checkbox_id = self.clear_checkbox_id(checkbox_name)
-        context.update({
+        context['widget'].update({
             'checkbox_name': checkbox_name,
             'checkbox_id': checkbox_id,
             'is_initial': self.is_initial(value),

docs/releases/1.11.4.txt

@@ -28,3 +28,10 @@ Bugfixes
 
 * Fixed ``QuerySet.count()`` for ``union()``, ``difference()``, and
   ``intersection()`` queries. (:ticket:`28399`).
+
+* Fixed ``ClearableFileInput`` rendering as a subwidget of ``MultiWidget``
+  (:ticket:`28414`). Custom ``clearable_file_input.html`` widget templates
+  will need to adapt for the fact that context values
+  ``checkbox_name``, ``checkbox_id``, ``is_initial``, ``input_text``,
+  ``initial_text``, and ``clear_checkbox_label`` are now attributes of
+  ``widget`` rather than appearing in the top-level context.

docs/spelling_wordlist

@@ -696,6 +696,7 @@ subtransactions
 subtree
 subtype
 subviews
+subwidget
 subwidgets
 superclass
 superset

tests/forms_tests/widget_tests/test_clearablefileinput.py

 from django.core.files.uploadedfile import SimpleUploadedFile
-from django.forms import ClearableFileInput
+from django.forms import ClearableFileInput, MultiWidget
 
 from .base import WidgetTest
 
@@ -74,6 +74,18 @@ class ClearableFileInputTest(WidgetTest):
         """
         self.check_html(self.widget, 'myfile', None, html='<input type="file" name="myfile" />')
 
+    def test_render_as_subwidget(self):
+        """A ClearableFileInput as a subwidget of MultiWidget."""
+        widget = MultiWidget(widgets=(self.widget,))
+        self.check_html(widget, 'myfile', [FakeFieldFile()], html=(
+            """
+            Currently: <a href="something">something</a>
+            <input type="checkbox" name="myfile_0-clear" id="myfile_0-clear_id" />
+            <label for="myfile_0-clear_id">Clear</label><br />
+            Change: <input type="file" name="myfile_0" />
+            """
+        ))
+
     def test_clear_input_checked_returns_false(self):
         """
         ClearableFileInput.value_from_datadict returns False if the clear