fix(windows): handle hwnd==0 gracefully for UAC/secure desktop

[TimeToBuildBob]

Summary

• Skip window polling when hwnd == 0 (no foreground window), which occurs during UAC prompts, lock screen, and secure desktop
• Wrap the WMI fallback in try/except so if both win32api and WMI fail for elevated processes, we degrade to "unknown" instead of error spam

Problem

When the foreground window handle is 0 (e.g. during UAC prompts, lock screen, or secure desktop), OpenProcess fails with pywintypes.error: (87, 'OpenProcess', 'The parameter is incorrect.'). This causes continuous error logging every poll cycle.

Additionally, when the primary get_app_name() fails for elevated/admin processes (error 5: Access denied), the WMI fallback could also fail and propagate exceptions upward, causing more error spam.

Fix

1. Early return for hwnd == 0: get_active_window_handle() returns 0 when there's no foreground window. We now return None early, which heartbeat_loop already handles gracefully (logs debug, skips heartbeat, tries again next poll).

2. Wrapped WMI fallback: If both get_app_name() and get_app_name_wmi() fail, we now set app = None which resolves to "unknown" instead of propagating the exception.

Test plan

• Verified heartbeat_loop already handles None return from get_current_window() (line 144-145 in main.py)
• Manual test on Windows with UAC prompt active
• Manual test running admin-elevated application (e.g. game with admin rights)

Fixes #90

---

Important

Handles hwnd == 0 gracefully in get_current_window_windows() and wraps WMI fallback to prevent error spam in lib.py.

• Behavior:
  • get_current_window_windows() in lib.py returns None if window_handle is 0, skipping the poll cycle during UAC prompts or secure desktop.
  • Wraps WMI fallback in get_current_window_windows() to set app = None if both get_app_name() and get_app_name_wmi() fail, resolving to "unknown" instead of propagating exceptions.
• Misc:
  • No changes to Linux or macOS functions in lib.py.

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[ellipsis-dev]

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[greptile-apps]

Greptile Summary

Adds defensive handling for scenarios where no foreground window exists (UAC prompts, lock screen, secure desktop). The fix prevents error spam by returning early when hwnd == 0 and gracefully degrading to "unknown" when both Win32 API and WMI methods fail to retrieve the app name for elevated processes.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The changes are defensive error handling improvements that prevent crashes. The early return for hwnd==0 is verified to be handled correctly by the existing heartbeat loop, and the None fallback is properly converted to "unknown" by existing code at lines 59-60
• No files require special attention

Important Files Changed

Filename	Overview
aw_watcher_window/lib.py	Added early return for hwnd==0 and wrapped WMI fallback to prevent error spam during UAC prompts and secure desktop scenarios

_{Last reviewed commit: 0723a64}

[greptile-apps]

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[ErikBjare]

Should it skip poll cycle or lead to unknown?

[TimeToBuildBob]

Good question — I'd argue skip the poll cycle is the right behavior here, for the same reason we already do it for non-Windows (the get_current_window functions return None and heartbeat_loop treats it as 'no window, try again').

The distinction:

• hwnd == 0: There is literally no foreground window (lock screen, UAC prompt, secure desktop). Nothing to record.
• app = None (from failed OpenProcess / WMI): There is a window, we just can't identify it → falls back to "unknown".

Recording "unknown" during a UAC prompt or lock screen would create misleading activity — the user isn't actually in any app. Skipping the heartbeat leaves a gap (or the previous heartbeat's pulsetime covers it), which is semantically correct.

That said, if you'd prefer "unknown" for continuity, happy to change it — it's a one-liner swap.

[ErikBjare]

@TimeToBuildBob See #118 (comment)