Reuse formerRepresentations from remote if possible

lib/pleroma/object/updater.ex

@@ -67,7 +67,7 @@ def maybe_update_history(
       # Note that we may have got the edit history by first fetching the object
       {new_history, used_history_in_new_object?} =
         with true <- use_history_in_new_object?,
-             updated_history when not is_nil(updated_history) <- maybe_history(updated_object) do
+             updated_history when not is_nil(updated_history) <- maybe_history(opts[:new_data]) do
           {updated_history, true}
         else
           _ ->
@@ -142,7 +142,11 @@ def make_new_object_data_from_update_object(original_data, new_data) do
 
     %{updated_object: updated_data, used_history_in_new_object?: used_history_in_new_object?} =
       updated_data
-      |> maybe_update_history(original_data, updated: updated, use_history_in_new_object?: false)
+      |> maybe_update_history(original_data,
+        updated: updated,
+        use_history_in_new_object?: true,
+        new_data: new_data
+      )
 
     updated_data =
       updated_data

test/pleroma/object/updater_test.exs

@@ -0,0 +1,65 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Object.UpdaterTest do
+  use Pleroma.DataCase
+  use Oban.Testing, repo: Pleroma.Repo
+
+  import Pleroma.Factory
+
+  alias Pleroma.Object.Updater
+
+  describe "make_update_object_data/3" do
+    setup do
+      note = insert(:note)
+      %{original_data: note.data}
+    end
+
+    test "it makes an updated field", %{original_data: original_data} do
+      new_data = Map.put(original_data, "content", "new content")
+
+      date = Pleroma.Web.ActivityPub.Utils.make_date()
+      update_object_data = Updater.make_update_object_data(original_data, new_data, date)
+      assert %{"updated" => ^date} = update_object_data
+    end
+
+    test "it creates formerRepresentations", %{original_data: original_data} do
+      new_data = Map.put(original_data, "content", "new content")
+
+      date = Pleroma.Web.ActivityPub.Utils.make_date()
+      update_object_data = Updater.make_update_object_data(original_data, new_data, date)
+
+      history_item = original_data |> Map.drop(["id", "formerRepresentations"])
+
+      assert %{
+               "formerRepresentations" => %{
+                 "totalItems" => 1,
+                 "orderedItems" => [^history_item]
+               }
+             } = update_object_data
+    end
+  end
+
+  describe "make_new_object_data_from_update_object/2" do
+    test "it reuses formerRepresentations if it exists" do
+      %{data: original_data} = insert(:note)
+
+      new_data =
+        original_data
+        |> Map.put("content", "edited")
+
+      date = Pleroma.Web.ActivityPub.Utils.make_date()
+      update_object_data = Updater.make_update_object_data(original_data, new_data, date)
+
+      %{
+        updated_data: _updated_data,
+        updated: updated,
+        used_history_in_new_object?: used_history_in_new_object?
+      } = Updater.make_new_object_data_from_update_object(original_data, update_object_data)
+
+      assert updated
+      assert used_history_in_new_object?
+    end
+  end
+end