Fix: Remove redundant exception logging to eliminate pytest shutdown errors

[danielaskdd]

🐛 Fix: Remove redundant exception logging to eliminate pytest shutdown errors

Problem

During pytest execution, a "Logging Error in ConsoleHandler" was occurring at shutdown:

--- Logging Error in ConsoleHandler ---
Error flushing stream during close
--- Traceback ---
Traceback (most recent call last):
  File "/Users/ydh/mycode/ai/paper-RAG/.venv/lib/python3.12/site-packages/ascii_colors/__init__.py", line 998, in close
    self.stream.flush()
ValueError: I/O operation on closed file.
--- End Logging Error ---

Root Cause: The log_trace_exception function attempted to use ascii_colors logging after pytest had already closed output streams during shutdown.

Solution

Removed the redundant log_trace_exception exception logging layer:

1. Deleted log_trace_exception function from lightrag/utils.py
2. Removed all imports and usages from:
   • lightrag/api/routers/query_routes.py (3 occurrences)
   • lightrag/api/routers/ollama_api.py (4 occurrences)
3. Cleaned up redundant exception handling:
   • Removed empty except Exception as e: raise blocks that served no purpose
4. Preserved defensive safeguards:
   • Kept SafeStreamHandler for graceful stream closure handling
   • Kept _patch_ascii_colors_console_handler() monkey-patch as a defensive measure

Why This Works

• FastAPI automatically logs exceptions with full stack traces - no additional logging layer needed
• Standard Python logging with SafeStreamHandler and ascii_colors patch provides robust error handling
• Simpler code path reduces potential for shutdown-related race conditions

Impact

• ✅ Cleaner, more maintainable code
• ✅ Eliminates annoying shutdown error messages
• ✅ Reduces logging complexity
• ✅ Maintains full error visibility through FastAPI's built-in logging
• ✅ No behavioral changes for end users

Backward Compatibility

✅ Fully backward compatible - This change only affects internal error logging; all external APIs and behaviors remain unchanged.

[danielaskdd]

@codex review

[danielaskdd]

@codex review

[chatgpt-codex-connector[bot]]

Codex Review: Didn't find any major issues. Another round soon, please!

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".