Improve Python reliability in channel retries and thread typing (#1776)

Agent-Logs-Url: https://github.com/0xxy0/deer-flow/sessions/95336da6-e16d-43b4-834a-e5534c9396c5

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

backend/app/channels/feishu.py

@@ -206,7 +206,9 @@ class FeishuChannel(Channel):
                     await asyncio.sleep(delay)
 
         logger.error("[Feishu] send failed after %d attempts: %s", _max_retries, last_exc)
-        raise last_exc  # type: ignore[misc]
+        if last_exc is None:
+            raise RuntimeError("Feishu send failed without an exception from any attempt")
+        raise last_exc
 
     async def send_file(self, msg: OutboundMessage, attachment: ResolvedAttachment) -> bool:
         if not self._api_client:

backend/app/channels/slack.py

@@ -126,7 +126,9 @@ class SlackChannel(Channel):
                 )
             except Exception:
                 pass
-        raise last_exc  # type: ignore[misc]
+        if last_exc is None:
+            raise RuntimeError("Slack send failed without an exception from any attempt")
+        raise last_exc
 
     async def send_file(self, msg: OutboundMessage, attachment: ResolvedAttachment) -> bool:
         if not self._web_client:

backend/app/channels/telegram.py

@@ -125,7 +125,9 @@ class TelegramChannel(Channel):
                     await asyncio.sleep(delay)
 
         logger.error("[Telegram] send failed after %d attempts: %s", _max_retries, last_exc)
-        raise last_exc  # type: ignore[misc]
+        if last_exc is None:
+            raise RuntimeError("Telegram send failed without an exception from any attempt")
+        raise last_exc
 
     async def send_file(self, msg: OutboundMessage, attachment: ResolvedAttachment) -> bool:
         if not self._application:

backend/app/gateway/routers/threads.py

@@ -488,16 +488,19 @@ async def get_thread(thread_id: str, request: Request) -> ThreadResponse:
             "metadata": {k: v for k, v in ckpt_meta.items() if k not in ("created_at", "updated_at", "step", "source", "writes", "parents")},
         }
 
-    status = _derive_thread_status(checkpoint_tuple) if checkpoint_tuple is not None else record.get("status", "idle")  # type: ignore[union-attr]
+    if record is None:
+        raise HTTPException(status_code=404, detail=f"Thread {thread_id} not found")
+
+    status = _derive_thread_status(checkpoint_tuple) if checkpoint_tuple is not None else record.get("status", "idle")
     checkpoint = getattr(checkpoint_tuple, "checkpoint", {}) or {} if checkpoint_tuple is not None else {}
     channel_values = checkpoint.get("channel_values", {})
 
     return ThreadResponse(
         thread_id=thread_id,
         status=status,
-        created_at=str(record.get("created_at", "")),  # type: ignore[union-attr]
-        updated_at=str(record.get("updated_at", "")),  # type: ignore[union-attr]
-        metadata=record.get("metadata", {}),  # type: ignore[union-attr]
+        created_at=str(record.get("created_at", "")),
+        updated_at=str(record.get("updated_at", "")),
+        metadata=record.get("metadata", {}),
         values=serialize_channel_values(channel_values),
     )