Normalize Hubzilla alsoKnownAs from string to array

changelog.d/hubzilla-alsoknownas.fix

@@ -0,0 +1 @@
+Fix fetching Hubzilla Actors with alsoKnownAs as string

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -1618,6 +1618,10 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
   defp normalize_image(urls) when is_list(urls), do: urls |> List.first() |> normalize_image()
   defp normalize_image(_), do: nil
 
+  defp normalize_also_known_as(urls) when is_list(urls), do: urls
+  defp normalize_also_known_as(url) when is_binary(url), do: [url]
+  defp normalize_also_known_as(nil), do: []
+
   defp maybe_put_description(map, %{"name" => description}) when is_binary(description) do
     Map.put(map, "name", description)
   end
@@ -1693,7 +1697,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
       featured_address: featured_address,
       bio: data["summary"] || "",
       actor_type: actor_type,
-      also_known_as: Map.get(data, "alsoKnownAs", []),
+      also_known_as: normalize_also_known_as(data["alsoKnownAs"]),
       public_key: public_key,
       inbox: data["inbox"],
       shared_inbox: shared_inbox,

test/pleroma/web/activity_pub/activity_pub_test.exs

@@ -499,6 +499,35 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubTest do
              "https://queef.in/storage/banner.gif"
   end
 
+  test "works with alsoKnownAs as string" do
+    user_id = "https://hub.netzgemeinde.eu/channel/jupiter_rowland"
+
+    user_data =
+      "test/fixtures/users_mock/hubzilla-actor-alsoknownas-string.json"
+      |> File.read!()
+
+    user_data_decoded =
+      user_data
+      |> Jason.decode!()
+
+    Tesla.Mock.mock(fn
+      %{
+        method: :get,
+        url: ^user_id
+      } ->
+        %Tesla.Env{
+          status: 200,
+          body: user_data,
+          headers: [{"content-type", "application/activity+json"}]
+        }
+    end)
+
+    {:ok, user} = ActivityPub.make_user_from_ap_id(user_id)
+
+    assert is_list(user.also_known_as)
+    assert user.also_known_as == [user_data_decoded["alsoKnownAs"]]
+  end
+
   test "it fetches the appropriate tag-restricted posts" do
     user = insert(:user)