webdrop-bridge/UPDATE_FIX_SUMMARY.md

Update Feature Fixes - Final Summary

Problem Identified

The update feature was causing the application to hang indefinitely when clicked. The issue had two components:

1. UI Thread Blocking: The original code was running download operations synchronously on the UI thread
2. Network Timeout Issues: Even with timeouts set, the socket-level network calls would hang indefinitely if the server didn't respond

Solutions Implemented

1. Background Threading (First Fix)

• Created UpdateDownloadWorker class to run download operations in a background thread
• Moved blocking network calls off the UI thread
• This prevents the UI from freezing while waiting for network operations

2. Aggressive Timeout Strategy (Second Fix)

Applied timeouts at multiple levels to ensure the app never hangs:

A. Socket-Level Timeout (Most Important)

• File: src/webdrop_bridge/core/updater.py
• Reduced urlopen() timeout from 10 seconds to 5 seconds
• This is the first line of defense against hanging socket connections
• Applied in _fetch_release() method

B. Asyncio-Level Timeout

• File: src/webdrop_bridge/ui/main_window.py and src/webdrop_bridge/core/updater.py
• UpdateCheckWorker: 10-second timeout on entire check operation
• UpdateDownloadWorker: 300-second timeout on download, 30-second on verification
• check_for_updates(): 8-second timeout on async executor
• These catch any remaining hangs in the asyncio operations

C. Qt-Level Timeout (Final Safety Net)

• File: src/webdrop_bridge/ui/main_window.py
• Update check: 30-second QTimer safety timeout (_run_async_check())
• Download: 10-minute QTimer safety timeout (_perform_update_async())
• If nothing else works, Qt's event loop will forcefully close the operation

3. Error Handling Improvements

• Added proper exception handling for asyncio.TimeoutError
• Better logging to identify where hangs occur
• User-friendly error messages like "no server response" or "Operation timed out"
• Graceful degradation: operations fail fast instead of hanging

Timeout Hierarchy (in seconds)

Update Check Flow:
  QTimer safety net: 30s ─┐
                          ├─ Asyncio timeout: 10s ─┐
                                                   ├─ Socket timeout: 5s (first to trigger)
Download Flow:
  QTimer safety net: 600s ─┐
                           ├─ Asyncio timeout: 300s ─┐
                                                     ├─ Socket timeout: 5s (first to trigger)

Files Modified

1. src/webdrop_bridge/ui/main_window.py

   • Updated UpdateCheckWorker.run() with timeout handling
   • Updated UpdateDownloadWorker.run() with timeout handling
   • Added QTimer safety timeouts in _run_async_check() and _perform_update_async()
   • Proper event loop cleanup in finally blocks

2. src/webdrop_bridge/core/updater.py

   • Reduced socket timeout in _fetch_release() from 10s to 5s
   • Added timeout to check_for_updates() async operation
   • Added timeout to download_update() async operation
   • Added timeout to verify_checksum() async operation
   • Better error logging with exception types

Testing

• All 7 integration tests pass
• Timeout verification script confirms all timeout mechanisms are in place
• No syntax errors in modified code

Result

The application will no longer hang indefinitely when checking for or downloading updates. Instead:

• Operations timeout quickly (5-30 seconds depending on operation type)
• User gets clear feedback about what went wrong
• User can retry or cancel without force-killing the app
• Background threads are properly cleaned up to avoid resource leaks