Anonymize reporter before federating

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -415,6 +415,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     with flag_data <- make_flag_data(params, additional),
          {:ok, activity} <- insert(flag_data, local),
          {:ok, stripped_activity} <- strip_report_status_data(activity),
+         stripped_activity <- maybe_anonymize_reporter(stripped_activity),
          _ <- notify_and_stream(activity),
          :ok <-
            maybe_federate(stripped_activity) do

lib/pleroma/web/activity_pub/utils.ex

@@ -875,15 +875,29 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     {:ok, %{activity | data: new_data}}
   end
 
-  def maybe_anonymize_reporter(activity) do
+  def get_anonymized_reporter do
     with true <- Pleroma.Config.get([:activitypub, :anonymize_reporter]),
          nickname when is_binary(nickname) <-
            Pleroma.Config.get([:activitypub, :anonymize_reporter_local_nickname]),
          %User{ap_id: ap_id, local: true} <- User.get_cached_by_nickname(nickname) do
+      ap_id
+    else
+      _ -> nil
+    end
+  end
+
+  def maybe_anonymize_reporter(%Activity{data: data} = activity) do
+    %Activity{activity | data: maybe_anonymize_reporter(data)}
+  end
+
+  def maybe_anonymize_reporter(activity) do
+    ap_id = get_anonymized_reporter()
+
+    if is_binary(ap_id) do
       activity
       |> Map.put("actor", ap_id)
     else
-      _ -> activity
+      activity
     end
   end
 

test/pleroma/web/activity_pub/activity_pub_test.exs

@@ -1707,6 +1707,41 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubTest do
       assert_called(Utils.maybe_federate(%{activity | data: new_data}))
     end
 
+    test "anonymize reporter from Flag, before federating it, if configured so",
+         %{
+           reporter: reporter,
+           context: context,
+           target_account: target_account,
+           reported_activity: reported_activity,
+           object_ap_id: object_ap_id,
+           content: content
+         } do
+      placeholder = insert(:user)
+      clear_config([:activitypub, :anonymize_reporter], true)
+      clear_config([:activitypub, :anonymize_reporter_local_nickname], placeholder.nickname)
+      # Workaround "could not checkout connection" problem
+      # https://elixirforum.com/t/ecto-timeout-errors-when-wrapping-into-cachex-calls-in-tests/19078/11
+      %User{} = User.get_cached_by_nickname(placeholder.nickname)
+
+      with_mock Utils, [:passthrough], [] do
+        {:ok, activity} =
+          ActivityPub.flag(%{
+            actor: reporter,
+            context: context,
+            account: target_account,
+            statuses: [reported_activity],
+            content: content
+          })
+
+        new_data =
+          activity.data
+          |> put_in(["object"], [target_account.ap_id, object_ap_id])
+          |> Map.put("actor", placeholder.ap_id)
+
+        assert_called(Utils.maybe_federate(%{activity | data: new_data}))
+      end
+    end
+
     test_with_mock "reverts on error",
                    %{
                      reporter: reporter,