Pin Python SDK app-server stdio to UTF-8

sdk/python/src/codex_app_server/client.py

@@ -181,6 +181,7 @@ class AppServerClient:
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
             text=True,
+            encoding="utf-8",
             cwd=self.config.cwd,
             env=env,
             bufsize=1,

sdk/python/tests/test_client_process_launch.py

@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+from typing import Any
+
+import pytest
+
+import codex_app_server.client as client_module
+from codex_app_server.client import AppServerClient, AppServerConfig
+
+
+def test_start_launches_subprocess_with_utf8_text_io(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    launched: dict[str, Any] = {}
+
+    class FakeProc:
+        stdin = None
+        stdout = None
+        stderr = None
+
+    def fake_popen(args: list[str], **kwargs: Any) -> FakeProc:
+        launched["args"] = args
+        launched["kwargs"] = kwargs
+        return FakeProc()
+
+    monkeypatch.setattr(client_module.subprocess, "Popen", fake_popen)
+
+    client = AppServerClient(
+        config=AppServerConfig(
+            launch_args_override=("codex", "app-server", "--listen", "stdio://")
+        )
+    )
+
+    client.start()
+
+    assert launched["args"] == ["codex", "app-server", "--listen", "stdio://"]
+    assert launched["kwargs"]["text"] is True
+    assert launched["kwargs"]["encoding"] == "utf-8"