Missing attribute: published_at after updating to a recent nightly

[renchap]

Steps to reproduce the problem

When a nightly/main update containing #26153, timeline request result in 500 errors:

ActiveModel::MissingAttributeError (missing attribute: published_at):
app/controllers/api/v1/favourites_controller.rb:10:in `index'
app/controllers/concerns/localized.rb:11:in `set_locale'
lib/mastodon/rack_middleware.rb:9:in `call'
lib/public_file_server_middleware.rb:18:in `call'

ActiveModel::MissingAttributeError (missing attribute: published_at):
app/controllers/api/v1/notifications_controller.rb:17:in `index'
app/controllers/concerns/localized.rb:11:in `set_locale'
lib/mastodon/rack_middleware.rb:9:in `call'

ActiveModel::MissingAttributeError (missing attribute: published_at):
app/controllers/api/v1/trends/statuses_controller.rb:12:in `index'
app/controllers/concerns/localized.rb:11:in `set_locale'
lib/mastodon/rack_middleware.rb:9:in `call'

Expected behaviour

The update does not cause errors

Actual behaviour

We get 500 errors on timelines

Detailed description

Purging the Rails cache fixes the issues, there are most probably items in cache without this new published_at attribute, and rendering those fail until the cache expires.

Mastodon instance

No response

Mastodon version

nightly

Technical details

No response

[ClearlyClaire]

Something like the following should fix it, but I wonder if there's a cleaner solution:

diff --git a/app/serializers/rest/preview_card_serializer.rb b/app/serializers/rest/preview_card_serializer.rb
index cf700ff24e..2eb67214c9 100644
--- a/app/serializers/rest/preview_card_serializer.rb
+++ b/app/serializers/rest/preview_card_serializer.rb
@@ -15,4 +15,8 @@ class REST::PreviewCardSerializer < ActiveModel::Serializer
   def html
     Sanitize.fragment(object.html, Sanitize::Config::MASTODON_OEMBED)
   end
+
+  def published_at
+    object.published_at if object.respond_to?(:published_at)
+  end
 end

An alternative is to bump the appropriate cache key (but we need to figure out which ones).