Fix issue where collection deletion success message was not correct

- Fixes #10813

CHANGELOG.txt

@@ -16,6 +16,7 @@ Changelog
  * Remove `wagtail.unpublish` log action on aliases when source page is unpublished (Dan Braghis)
  * Fix: Ensure that StreamField's `FieldBlock`s correctly set the `required` and `aria-describedby` attributes (Storm Heg)
  * Fix: Avoid an error when the moderation panel (admin dashboard) contains both snippets and private pages (Matt Westcott)
+ * Fix: When deleting collections, ensure the collection name is correctly shown in the success message (LB (Ben) Johnston)
  * Docs: Document `WAGTAILADMIN_BASE_URL` on "Integrating Wagtail into a Django project" page (Shreshth Srivastava)
  * Docs: Replace incorrect screenshot for authors listing on tutorial (Shreshth Srivastava)
  * Maintenance: Fix snippet search test to work on non-fallback database backends (Matt Westcott)

docs/releases/5.2.md

@@ -29,6 +29,7 @@ depth: 1
 
  * Ensure that StreamField's `FieldBlock`s correctly set the `required` and `aria-describedby` attributes (Storm Heg)
  * Avoid an error when the moderation panel (admin dashboard) contains both snippets and private pages (Matt Westcott)
+ * When deleting collections, ensure the collection name is correctly shown in the success message (LB (Ben) Johnston)
 
 ### Documentation
 

wagtail/admin/tests/test_collections_views.py

@@ -600,6 +600,12 @@ class TestDeleteCollectionAsSuperuser(WagtailTestUtils, TestCase):
         # Should redirect back to index
         self.assertRedirects(response, reverse("wagtailadmin_collections:index"))
 
+        # Check the message content
+        self.assertEqual(
+            response.context["message"],
+            "Collection 'Holiday snaps' deleted.",
+        )
+
         # Check that the collection was deleted
         with self.assertRaises(Collection.DoesNotExist):
             Collection.objects.get(id=self.collection.id)

wagtail/admin/views/collections.py

@@ -182,6 +182,6 @@ class Delete(DeleteView):
             # collection is non-empty; refuse to delete it
             return HttpResponseForbidden()
 
+        messages.success(request, self.get_success_message())
         self.object.delete()
-        messages.success(request, self.success_message.format(self.object))
         return redirect(self.index_url_name)