Reduce chances of race conditions when processing deleted toots (mast…

…odon#9815)

* Reduce chances of race conditions when processing deleted toots

* Prevent race condition when processing deleted toots

app/lib/activitypub/activity/create.rb

@@ -5,10 +5,12 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
   CONVERTED_TYPES = %w(Image Video Article Page).freeze
 
   def perform
-    return if delete_arrived_first?(object_uri) || unsupported_object_type? || invalid_origin?(@object['id'])
+    return if unsupported_object_type? || invalid_origin?(@object['id'])
 
     RedisLock.acquire(lock_options) do |lock|
       if lock.acquired?
+        return if delete_arrived_first?(object_uri)
+
         @status = find_existing_status
 
         if @status.nil?

app/lib/activitypub/activity/delete.rb

@@ -21,11 +21,13 @@ def delete_person
   def delete_note
     return if object_uri.nil?
 
+    RedisLock.acquire(lock_options) do |_lock|
+      delete_later!(object_uri)
+    end
+
     @status   = Status.find_by(uri: object_uri, account: @account)
     @status ||= Status.find_by(uri: @object['atomUri'], account: @account) if @object.is_a?(Hash) && @object['atomUri'].present?
 
-    delete_later!(object_uri)
-
     return if @status.nil?
 
     if @status.public_visibility? || @status.unlisted_visibility?
@@ -68,4 +70,8 @@ def delete_now!
   def payload
     @payload ||= Oj.dump(@json)
   end
+
+  def lock_options
+    { redis: Redis.current, key: "create:#{object_uri}" }
+  end
 end