Add tombstones for remote statuses (#9830)

* Add Tombstone model to remember object deletion

* Do not recreate a status if it has been deleted

* Record Tombstone for remote deleted items

Also, only record deleted items from same-host actors

* Clear an user's tombstones when their key change

1 files changed, 6 insertions, 0 deletions

diff --git a/app/services/activitypub/process_account_service.rb b/app/services/activitypub/process_account_service.rb
index d6c791b44..487456f3a 100644
--- a/app/services/activitypub/process_account_service.rb
+++ b/app/services/activitypub/process_account_service.rb
@@ -33,6 +33,8 @@ class ActivityPub::ProcessAccountService < BaseService
 
     after_protocol_change! if protocol_changed?
     after_key_change! if key_changed? && !@options[:signed_with_known_key]
+    clear_tombstones! if key_changed?
+
     unless @options[:only_key]
       check_featured_collection! if @account.featured_collection_url.present?
       check_links! unless @account.fields.empty?
@@ -209,6 +211,10 @@ class ActivityPub::ProcessAccountService < BaseService
     !@old_public_key.nil? && @old_public_key != @account.public_key
   end
 
+  def clear_tombstones!
+    Tombstone.delete_all(account_id: @account.id)
+  end
+
   def protocol_changed?
     !@old_protocol.nil? && @old_protocol != @account.protocol
   end