Use correct activity for undo

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -142,7 +142,7 @@ def announce(
 
   def unannounce(%User{} = actor, %Object{} = object, local \\ true) do
     with %Activity{} = activity <- get_existing_announce(actor.ap_id, object),
-         unannounce_data <- make_unannounce_data(actor, object),
+         unannounce_data <- make_unannounce_data(actor, activity),
          {:ok, unannounce_activity} <- insert(unannounce_data, local),
          :ok <- maybe_federate(activity),
          {:ok, _activity} <- Repo.delete(activity),

lib/pleroma/web/activity_pub/utils.ex

@@ -283,13 +283,13 @@ def make_announce_data(
   """
   def make_unannounce_data(
         %User{ap_id: ap_id} = user,
-        %Object{data: %{"id" => id, "context" => context}} = object
+        %Activity{data: %{"id" => id, "context" => context}} = activity
       ) do
     %{
       "type" => "Undo",
       "actor" => ap_id,
       "object" => id,
-      "to" => [user.follower_address, object.data["actor"]],
+      "to" => [user.follower_address, activity.data["actor"]],
       "cc" => ["https://www.w3.org/ns/activitystreams#Public"],
       "context" => context
     }

test/web/activity_pub/activity_pub_test.exs

@@ -291,12 +291,12 @@ test "unannouncing a previously announced object" do
 
       assert unannounce_activity.data["to"] == [
                User.ap_followers(user),
-               note_activity.data["actor"]
+               announce_activity.data["actor"]
       ]
       assert unannounce_activity.data["type"] == "Undo"
-      assert unannounce_activity.data["object"] == object.data["id"]
+      assert unannounce_activity.data["object"] == announce_activity.data["id"]
       assert unannounce_activity.data["actor"] == user.ap_id
-      assert unannounce_activity.data["context"] == object.data["context"]
+      assert unannounce_activity.data["context"] == announce_activity.data["context"]
 
       assert Repo.get(Activity, announce_activity.id) == nil
     end