Fixes/do not override timestamps (#7336)

* Revert "Fixes/do not override timestamps (#7331)"

This reverts commit 581a5c9d29.

* Document Snowflake ID corner-case a bit more

Snowflake IDs are used for two purposes: making object identifiers harder to
guess and ensuring they are in chronological order. For this reason, they
are based on the `created_at` attribute of the object.

Unfortunately, inserting items with older snowflakes IDs will break the
assumption of consumers of the paging APIs that new items will always have
a greater identifier than the last seen one.

* Add `override_timestamps` virtual attribute to not correlate snowflake ID with created_at

app/lib/activitypub/activity.rb

@@ -78,9 +78,11 @@ class ActivityPub::Activity
     notify_about_reblog(status) if reblog_of_local_account?(status)
     notify_about_mentions(status)
 
-    # Only continue if the status is supposed to have
-    # arrived in real-time
-    return unless status.within_realtime_window?
+    # Only continue if the status is supposed to have arrived in real-time.
+    # Note that if @options[:override_timestamps] isn't set, the status
+    # may have a lower snowflake id than other existing statuses, potentially
+    # "hiding" it from paginated API calls
+    return unless @options[:override_timestamps] || status.within_realtime_window?
 
     distribute_to_followers(status)
   end

app/lib/activitypub/activity/announce.rb

@@ -16,6 +16,7 @@ class ActivityPub::Activity::Announce < ActivityPub::Activity
       reblog: original_status,
       uri: @json['id'],
       created_at: @json['published'],
+      override_timestamps: @options[:override_timestamps],
       visibility: original_status.visibility
     )
 

app/lib/activitypub/activity/create.rb

@@ -48,6 +48,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
       language: detected_language,
       spoiler_text: @object['summary'] || '',
       created_at: @object['published'],
+      override_timestamps: @options[:override_timestamps],
       reply: @object['inReplyTo'].present?,
       sensitive: @object['sensitive'] || false,
       visibility: visibility_from_audience,