fix(wecom): guard null quote fields in _on_ws_text to prevent AttributeError (#4069)

* fix(wecom): guard null quote fields in _on_ws_text to prevent AttributeError

* test(wecom): regression for null quote fields in _on_ws_text

backend/app/channels/wecom.py

@@ -199,7 +199,7 @@ class WeComChannel(Channel):
     async def _on_ws_text(self, frame: dict[str, Any]) -> None:
         body = frame.get("body", {}) or {}
         text = ((body.get("text") or {}).get("content") or "").strip()
-        quote = body.get("quote", {}).get("text", {}).get("content", "").strip()
+        quote = (((body.get("quote") or {}).get("text") or {}).get("content") or "").strip()
         if not text and not quote:
             return
         await self._publish_ws_inbound(frame, text + (f"\nQuote message: {quote}" if quote else ""))

backend/tests/test_wecom_ws_text.py

@@ -0,0 +1,72 @@
+"""Regression tests for WeComChannel._on_ws_text quote parsing.
+
+A quoted non-text message (or any payload where ``quote``/``quote.text``/
+``quote.text.content`` is JSON ``null``) must not crash the text handler.
+``dict.get(key, default)`` returns the stored ``None`` when the key is present
+with a null value, so chaining ``.get``/``.strip`` on it raised
+``AttributeError`` before the fix.
+"""
+
+from __future__ import annotations
+
+import asyncio
+from typing import Any
+from unittest.mock import AsyncMock
+
+from app.channels.message_bus import MessageBus
+from app.channels.wecom import WeComChannel
+
+
+def _run(coro):
+    """Run an async coroutine synchronously."""
+    loop = asyncio.new_event_loop()
+    try:
+        return loop.run_until_complete(coro)
+    finally:
+        loop.close()
+
+
+def _channel() -> WeComChannel:
+    ch = WeComChannel(bus=MessageBus(), config={})
+    # Bypass the real websocket publish path so the test exercises only the
+    # frame-parsing logic in _on_ws_text.
+    ch._publish_ws_inbound = AsyncMock()  # type: ignore[method-assign]
+    return ch
+
+
+class TestOnWsTextQuoteParsing:
+    def test_quote_is_null_does_not_crash(self):
+        ch = _channel()
+        frame: dict[str, Any] = {"body": {"quote": None}}
+        _run(ch._on_ws_text(frame))
+        # Empty text and empty quote -> handler returns early, no publish.
+        ch._publish_ws_inbound.assert_not_called()
+
+    def test_quote_text_is_null_does_not_crash(self):
+        ch = _channel()
+        frame: dict[str, Any] = {"body": {"quote": {"text": None}}}
+        _run(ch._on_ws_text(frame))
+        ch._publish_ws_inbound.assert_not_called()
+
+    def test_quote_content_is_null_does_not_crash(self):
+        ch = _channel()
+        frame: dict[str, Any] = {"body": {"quote": {"text": {"content": None}}}}
+        _run(ch._on_ws_text(frame))
+        ch._publish_ws_inbound.assert_not_called()
+
+    def test_text_with_null_quote_still_publishes(self):
+        # This is the crash the fix targets: a real text message that also
+        # carries a null ``quote`` (e.g. quoting a non-text message) used to
+        # raise AttributeError before reaching _publish_ws_inbound.
+        ch = _channel()
+        frame: dict[str, Any] = {"body": {"text": {"content": "hello"}, "quote": None}}
+        _run(ch._on_ws_text(frame))
+        ch._publish_ws_inbound.assert_called_once_with(frame, "hello")
+
+    def test_text_and_valid_quote_are_combined(self):
+        ch = _channel()
+        frame: dict[str, Any] = {
+            "body": {"text": {"content": "T"}, "quote": {"text": {"content": "Q"}}},
+        }
+        _run(ch._on_ws_text(frame))
+        ch._publish_ws_inbound.assert_called_once_with(frame, "T\nQuote message: Q")