AP ingest: accept object type as list

lib/pleroma/web/activity_pub/transmogrifier.ex

@@ -433,9 +433,15 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   def handle_incoming(data, options \\ []) do
     data
     |> fix_recursive(&strip_internal_fields/1)
+    |> fix_recursive(&fix_type_as_string/1)
     |> handle_incoming_normalized(options)
   end
 
+  defp fix_type_as_string(%{"type" => [type | _]} = data) when is_binary(type),
+    do: Map.put(data, "type", type)
+
+  defp fix_type_as_string(data), do: data
+
   # Flag objects are placed ahead of the ID check because Mastodon 2.8 and earlier send them
   # with nil ID.
   defp handle_incoming_normalized(

test/fixtures/fedidev.fun/object_type_list.json

@@ -0,0 +1,28 @@
+{
+  "@context": [
+    "https://www.w3.org/ns/activitystreams"
+  ],
+  "type": "Create",
+  "id": "https://fedidev.fun/activity/object-type-list",
+  "actor": "https://fedidev.fun/users/alice",
+  "to": [
+    "https://www.w3.org/ns/activitystreams#Public"
+  ],
+  "cc": [],
+  "published": "2025-11-21T14:43:32Z",
+  "object": {
+    "type": [
+      "Note"
+    ],
+    "id": "https://fedidev.fun/objects/note-object-type-list",
+    "attributedTo": "https://fedidev.fun/users/alice",
+    "to": [
+      "https://www.w3.org/ns/activitystreams#Public"
+    ],
+    "cc": [],
+    "published": "2025-11-21T14:43:32Z",
+    "name": "name",
+    "summary": "summary",
+    "content": "content"
+  }
+}

test/pleroma/web/activity_pub/transmogrifier/fedidev_fun_object_type_list_test.exs

@@ -0,0 +1,53 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.Transmogrifier.FedidevFunObjectTypeListTest do
+  use Oban.Testing, repo: Pleroma.Repo
+  use Pleroma.DataCase
+
+  alias Pleroma.Object
+  alias Pleroma.User
+  alias Pleroma.Web.ActivityPub.Transmogrifier
+
+  import Pleroma.Factory
+
+  setup_all do
+    Tesla.Mock.mock_global(fn env -> apply(HttpRequestMock, :request, [env]) end)
+    :ok
+  end
+
+  defp ensure_remote_actor!(ap_id) when is_binary(ap_id) do
+    case User.get_cached_by_ap_id(ap_id) do
+      %User{} ->
+        :ok
+
+      _ ->
+        insert(:user,
+          local: false,
+          ap_id: ap_id,
+          follower_address: ap_id <> "/followers",
+          following_address: ap_id <> "/following",
+          featured_address: ap_id <> "/collections/featured",
+          inbox: ap_id <> "/inbox"
+        )
+
+        :ok
+    end
+  end
+
+  defp ingest_fixture!(rel_path) do
+    data = rel_path |> File.read!() |> Jason.decode!()
+    ensure_remote_actor!(data["actor"])
+
+    assert {:ok, activity} = Transmogrifier.handle_incoming(data)
+    object = Object.normalize(activity.data["object"], fetch: false)
+
+    {activity, object}
+  end
+
+  test "accepts object type as a list and stores the first type" do
+    {_activity, object} = ingest_fixture!("test/fixtures/fedidev.fun/object_type_list.json")
+    assert object.data["type"] == "Note"
+  end
+end