Make ActivityPub.Publisher aware of the actor change by Transmogrifier

lib/pleroma/web/activity_pub/publisher.ex

@@ -92,6 +92,19 @@ defmodule Pleroma.Web.ActivityPub.Publisher do
     uri = %{path: path} = URI.parse(inbox)
 
     {:ok, data} = Transmogrifier.prepare_outgoing(activity.data)
+    {actor, activity, data} =
+      with {_, false} <- {:actor_changed?, data["actor"] != activity.data["actor"]} do
+        {orig_actor, activity, data}
+      else
+        {:actor_changed?, true} ->
+          # If prepare_outgoing changes the actor, re-get it from the db
+          actor = User.get_cached_by_ap_id(data["actor"])
+
+          activity = %Activity{activity | actor: actor.ap_id}
+
+          {actor, activity, data}
+    end
+
 
     param_cc = Map.get(params, :cc, [])