Add support for showing on delete information on generic usage view

wagtail/admin/templates/wagtailadmin/tables/references_cell.html

@@ -5,8 +5,7 @@
                 {% if edit_url %}
                     <a href="{{ edit_url }}#content-path-{{ reference.content_path }}">
                 {% endif %}
-                {{ reference.describe_source_field }}
-                {% if edit_url %}</a>{% endif %}
+                {{ reference.describe_source_field }}{% if edit_url %}</a>{% endif %}{% if describe_on_delete %}: {{ reference.describe_on_delete }}{% endif %}
             </li>
         {% endfor %}
     </ul>

wagtail/admin/ui/tables.py

@@ -290,9 +290,11 @@ class ReferencesColumn(Column):
         sort_key=None,
         width=None,
         get_url=None,
+        describe_on_delete=False,
     ):
         super().__init__(name, label, accessor, classname, sort_key, width)
         self._get_url_func = get_url
+        self.describe_on_delete = describe_on_delete
 
     def get_edit_url(self, instance):
         if self._get_url_func:
@@ -301,6 +303,7 @@ class ReferencesColumn(Column):
     def get_cell_context_data(self, instance, parent_context):
         context = super().get_cell_context_data(instance, parent_context)
         context["edit_url"] = self.get_edit_url(instance)
+        context["describe_on_delete"] = self.describe_on_delete
         return context
 
 

wagtail/admin/views/generic/usage.py

@@ -1,3 +1,4 @@
+from django.utils.functional import cached_property
 from django.utils.text import capfirst
 from django.utils.translation import gettext as _
 from django.utils.translation import gettext_lazy
@@ -19,6 +20,10 @@ class UsageView(BaseObjectMixin, IndexView):
     is_searchable = False
     page_title = gettext_lazy("Usage of")
 
+    @cached_property
+    def describe_on_delete(self):
+        return bool(self.request.GET.get("describe_on_delete"))
+
     def get_object(self):
         object = super().get_object()
         if isinstance(object, DraftStateMixin):
@@ -49,9 +54,12 @@ class UsageView(BaseObjectMixin, IndexView):
             ),
             tables.ReferencesColumn(
                 "field",
-                label=_("Field"),
+                label=_("If you confirm deletion")
+                if self.describe_on_delete
+                else _("Field"),
                 accessor="references",
                 get_url=lambda r: r["edit_url"],
+                describe_on_delete=self.describe_on_delete,
             ),
         ]