fix(responses): backfill empty chat completion output

Author: masterkain

lib/codex_pooler/gateway/openai_compatibility/responses/sse.ex

@@ -71,8 +71,9 @@ defmodule CodexPooler.Gateway.OpenAICompatibility.Responses.SSE do
     end
   end
 
-  defp maybe_backfill_output(%{"output" => output} = response, _events) when is_list(output),
-    do: response
+  defp maybe_backfill_output(%{"output" => output} = response, _events)
+       when is_list(output) and output != [],
+       do: response
 
   defp maybe_backfill_output(response, events) do
     output_items =

test/codex_pooler_web/controllers/v1/chat_completions_controller_test.exs

@@ -154,7 +154,11 @@ defmodule CodexPoolerWeb.V1.ChatCompletionsControllerTest do
           {"response.completed",
            %{
              "type" => "response.completed",
-             "response" => %{"id" => "resp_chat_delta_collect", "status" => "completed"}
+             "response" => %{
+               "id" => "resp_chat_delta_collect",
+               "status" => "completed",
+               "output" => []
+             }
            }}
         ])
       )