fix(webui): suppress restart handshake noise

tests/channels/test_websocket_channel.py

@@ -3,6 +3,7 @@
 import asyncio
 import functools
 import json
+import logging
 import time
 from typing import Any
 from unittest.mock import AsyncMock, MagicMock
@@ -16,6 +17,7 @@ from websockets.frames import Close
 from nanobot.bus.events import OUTBOUND_META_AGENT_UI, OutboundMessage
 from nanobot.bus.queue import MessageBus
 from nanobot.channels.websocket import (
+    _OPENING_HANDSHAKE_FAILED_MESSAGE,
     WebSocketChannel,
     WebSocketConfig,
     _is_valid_chat_id,
@@ -26,6 +28,7 @@ from nanobot.channels.websocket import (
     _parse_inbound_payload,
     _parse_query,
     _parse_request_path,
+    _WebSocketHandshakeNoiseFilter,
     publish_runtime_model_update,
 )
 from nanobot.config.loader import load_config, save_config
@@ -39,6 +42,18 @@ from nanobot.webui.settings_api import settings_payload, update_provider_setting
 _PORT = 29876
 
 
+def _log_record(message: str, exc: BaseException) -> logging.LogRecord:
+    return logging.LogRecord(
+        name="websockets.server",
+        level=logging.ERROR,
+        pathname=__file__,
+        lineno=1,
+        msg=message,
+        args=(),
+        exc_info=(type(exc), exc, exc.__traceback__),
+    )
+
+
 def _ch(bus: Any, **kw: Any) -> WebSocketChannel:
     cfg: dict[str, Any] = {
         "enabled": True,
@@ -113,6 +128,22 @@ def test_websocket_config_rejects_relative_unix_socket() -> None:
         WebSocketConfig(unix_socket_path="engine.sock")
 
 
+def test_websocket_handshake_noise_filter_suppresses_disconnects() -> None:
+    filter_ = _WebSocketHandshakeNoiseFilter()
+    wrapped = RuntimeError("wrapped")
+    wrapped.__cause__ = BrokenPipeError(32, "Broken pipe")
+
+    assert not filter_.filter(_log_record(_OPENING_HANDSHAKE_FAILED_MESSAGE, BrokenPipeError()))
+    assert not filter_.filter(_log_record(_OPENING_HANDSHAKE_FAILED_MESSAGE, wrapped))
+
+
+def test_websocket_handshake_noise_filter_keeps_real_errors() -> None:
+    filter_ = _WebSocketHandshakeNoiseFilter()
+
+    assert filter_.filter(_log_record(_OPENING_HANDSHAKE_FAILED_MESSAGE, RuntimeError("boom")))
+    assert filter_.filter(_log_record("connection handler failed", BrokenPipeError()))
+
+
 def test_parse_query_extracts_token_and_client_id() -> None:
     query = _parse_query("/?token=secret&client_id=u1")
     assert query.get("token") == ["secret"]