fix: serialize non-resource struct values in generic action results

lib/ash_json_api/serializer.ex

@@ -1258,11 +1258,23 @@ defmodule AshJsonApi.Serializer do
           req = %{fields: %{}, route: %{}, domain: domain}
           serialize_attributes(req, value, opts)
         else
-          value
+          dump_struct_value(value, type, constraints)
         end
     end
   end
 
+  # A struct whose type is a non-resource Ash type (e.g. a TypedStruct or an
+  # embedded type) isn't JSON-encodable as-is. Dump it through the type into a
+  # native map; non-struct values pass through unchanged.
+  defp dump_struct_value(value, type, constraints) when is_struct(value) do
+    case Ash.Type.dump_to_embedded(type, value, constraints || []) do
+      {:ok, dumped} -> dumped
+      _ -> value
+    end
+  end
+
+  defp dump_struct_value(value, _type, _constraints), do: value
+
   defp flatten_new_type(type, constraints) do
     if Ash.Type.NewType.new_type?(type) do
       new_constraints = Ash.Type.NewType.constraints(type, constraints)

test/acceptance/route_test.exs

@@ -5,6 +5,15 @@
 defmodule Test.Acceptance.RouteTest do
   use ExUnit.Case, async: true
 
+  defmodule Greeting do
+    use Ash.TypedStruct
+
+    typed_struct do
+      field(:message, :string, allow_nil?: false)
+      field(:count, :integer)
+    end
+  end
+
   defmodule Actions do
     use Ash.Resource,
       domain: Test.Acceptance.RouteTest.Domain,
@@ -16,6 +25,7 @@ defmodule Test.Acceptance.RouteTest do
         route(:get, "/say_hello", :say_hello, query_params: [:to])
         route(:post, "/required_say_hello/:to", :with_required)
         route(:post, "/trigger_job", :trigger_job)
+        route(:get, "/say_hello_struct/:to", :say_hello_struct)
       end
     end
 
@@ -42,6 +52,15 @@ defmodule Test.Acceptance.RouteTest do
           :ok
         end)
       end
+
+      action :say_hello_struct, Test.Acceptance.RouteTest.Greeting do
+        argument(:to, :string, allow_nil?: false)
+
+        run(fn input, _ ->
+          {:ok,
+           %Test.Acceptance.RouteTest.Greeting{message: "Hello, #{input.arguments.to}!", count: 1}}
+        end)
+      end
     end
   end
 
@@ -94,6 +113,13 @@ defmodule Test.Acceptance.RouteTest do
            |> Kernel.==(%{"success" => true})
   end
 
+  test "generic actions returning a TypedStruct are serialized without a Jason encoder" do
+    assert Domain
+           |> get("/say_hello_struct/fred", status: 200)
+           |> Map.get(:resp_body)
+           |> Kernel.==(%{"message" => "Hello, fred!", "count" => 1})
+  end
+
   test "generic actions with required inputs" do
     assert Domain
            |> post(