Fix processing of remote Delete activities (#16084)

* Add tests

* Ensure deleted statuses are marked as such

* Save some redis memory by not storing URIs in delete_upon_arrival values

* Avoid possible race condition when processing incoming Deletes

* Avoid potential duplicate Delete forwards

* Lower lock durations to reduce issues in case of hard crash of the Rails process

* Check for `lock.aquired?` and improve comment

* Refactor RedisLock usage in app/lib/activitypub

* Fix using incorrect or non-existent sender for relaying Deletes

1 files changed, 14 insertions, 22 deletions

diff --git a/app/lib/activitypub/activity/announce.rb b/app/lib/activitypub/activity/announce.rb
index ae8b2db754e..a1081522eb1 100644
--- a/app/lib/activitypub/activity/announce.rb
+++ b/app/lib/activitypub/activity/announce.rb
@@ -4,29 +4,25 @@ class ActivityPub::Activity::Announce < ActivityPub::Activity
   def perform
     return reject_payload! if delete_arrived_first?(@json['id']) || !related_to_local_activity?
 
-    RedisLock.acquire(lock_options) do |lock|
-      if lock.acquired?
-        original_status = status_from_object
+    lock_or_fail("announce:#{@object['id']}") do
+      original_status = status_from_object
 
-        return reject_payload! if original_status.nil? || !announceable?(original_status)
+      return reject_payload! if original_status.nil? || !announceable?(original_status)
 
-        @status = Status.find_by(account: @account, reblog: original_status)
+      @status = Status.find_by(account: @account, reblog: original_status)
 
-        return @status unless @status.nil?
+      return @status unless @status.nil?
 
-        @status = Status.create!(
-          account: @account,
-          reblog: original_status,
-          uri: @json['id'],
-          created_at: @json['published'],
-          override_timestamps: @options[:override_timestamps],
-          visibility: visibility_from_audience
-        )
+      @status = Status.create!(
+        account: @account,
+        reblog: original_status,
+        uri: @json['id'],
+        created_at: @json['published'],
+        override_timestamps: @options[:override_timestamps],
+        visibility: visibility_from_audience
+      )
 
-        distribute(@status)
-      else
-        raise Mastodon::RaceConditionError
-      end
+      distribute(@status)
     end
 
     @status
@@ -69,8 +65,4 @@ class ActivityPub::Activity::Announce < ActivityPub::Activity
   def reblog_of_local_status?
     status_from_uri(object_uri)&.account&.local?
   end
-
-  def lock_options
-    { redis: Redis.current, key: "announce:#{@object['id']}" }
-  end
 end