Add conversation-based forwarding for limited visibility statuses through bearcaps

app/workers/activitypub/distribution_worker.rb

@@ -12,8 +12,10 @@ class ActivityPub::DistributionWorker
 
     return if skip_distribution?
 
-    ActivityPub::DeliveryWorker.push_bulk(inboxes) do |inbox_url|
-      [payload, @account.id, inbox_url]
+    if delegate_distribution?
+      deliver_to_parent!
+    else
+      deliver_to_inboxes!
     end
 
     relay! if relayable?
@@ -24,22 +26,44 @@ class ActivityPub::DistributionWorker
   private
 
   def skip_distribution?
-    @status.direct_visibility? || @status.limited_visibility?
+    @status.direct_visibility?
+  end
+
+  def delegate_distribution?
+    @status.limited_visibility? && @status.reply? && !@status.conversation.local?
   end
 
   def relayable?
     @status.public_visibility?
   end
 
+  def deliver_to_parent!
+    return if @status.conversation.inbox_url.blank?
+
+    ActivityPub::DeliveryWorker.perform_async(payload, @account.id, @status.conversation.inbox_url)
+  end
+
+  def deliver_to_inboxes!
+    ActivityPub::DeliveryWorker.push_bulk(inboxes) do |inbox_url|
+      [payload, @account.id, inbox_url]
+    end
+  end
+
   def inboxes
-    # Deliver the status to all followers.
-    # If the status is a reply to another local status, also forward it to that
-    # status' authors' followers.
-    @inboxes ||= if @status.reply? && @status.thread.account.local? && @status.distributable?
-                   @account.followers.or(@status.thread.account.followers).inboxes
-                 else
-                   @account.followers.inboxes
-                 end
+    # Deliver the status to all followers. If the status is a reply
+    # to another local status, also forward it to that status'
+    # authors' followers. If the status has limited visibility,
+    # deliver it to inboxes of people mentioned (no shared ones)
+
+    @inboxes ||= begin
+      if @status.limited_visibility?
+        DeliveryFailureTracker.without_unavailable(Account.remote.joins(:mentions).merge(@status.mentions).pluck(:inbox_url))
+      elsif @status.reply? && @status.thread.account.local? && @status.distributable?
+        @account.followers.or(@status.thread.account.followers).inboxes
+      else
+        @account.followers.inboxes
+      end
+    end
   end
 
   def payload

app/workers/activitypub/forward_distribution_worker.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class ActivityPub::ForwardDistributionWorker < ActivityPub::DistributionWorker
+  include Sidekiq::Worker
+
+  sidekiq_options queue: 'push'
+
+  def perform(conversation_id, json)
+    conversation = Conversation.find(conversation_id)
+
+    @status  = conversation.parent_status
+    @account = conversation.parent_account
+    @json    = json
+
+    return if @status.nil? || @account.nil?
+
+    deliver_to_inboxes!
+  rescue ActiveRecord::RecordNotFound
+    true
+  end
+
+  private
+
+  def payload
+    @json
+  end
+end