Fix resource leaks: unclosed file handles and sockets

[hobostay]

Summary

• Fix multiple resource leaks where file handles and sockets were never properly closed
• Use with statements for file operations and try/finally for socket cleanup

Issues Fixed

File handle leaks:

• helpers.py capture_screenshot(): open().write() pattern never closed the file handle
• daemon.py log(): open().write() leaked a file descriptor on every log call — critical in a long-running daemon
• daemon.py __main__: PID file write leaked a file handle

Socket leaks:

• helpers.py _send(): socket leaked if an exception occurred before s.close()
• admin.py ensure_daemon(): stale-daemon probe socket never closed in any code path (success or exception)
• admin.py restart_daemon(): socket leaked if an exception occurred before s.close()

Test plan

• Existing tests still pass
• Manual verification: run the daemon and confirm no file descriptor growth over time

🤖 Generated with Claude Code

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Summary by cubic

Fixes file and socket resource leaks to stop file descriptor growth and improve daemon stability. All file handles and UNIX sockets are now properly closed.

• Bug Fixes
  • Use with for file writes in daemon.log, PID creation, and helpers.capture_screenshot.
  • Close sockets with try/finally in helpers._send, admin.ensure_daemon, and admin.restart_daemon.
  • No behavior changes; improves reliability under load.

^{Written for commit f04d753. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 3 files

[Qodo-Free-For-OSS]

Hi, admin.restart_daemon() still reads the PID file via open(pid_path).read() without closing the file handle, leaking a descriptor on the success path. This undermines the PR’s stated goal of eliminating resource leaks and can accumulate if restart_daemon() is called repeatedly (e.g., from ensure_daemon()).

Severity: remediation recommended | Category: reliability

How to fix: Use context manager for PID

Agent prompt to fix - you can give this to your LLM of choice:

Issue description

admin.restart_daemon() reads the PID file using open(pid_path).read() without closing the handle.

Issue Context

This PR fixes multiple resource leaks, but this remaining open() call still leaks a file descriptor on the success path.

Fix Focus Areas

• admin.py[156-160]

Suggested change

Replace:

pid = int(open(pid_path).read())

with either:

with open(pid_path) as f:
    pid = int(f.read())

(or pid = int(Path(pid_path).read_text()) if you prefer pathlib and already import it in this file).

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Found by Qodo code review