July 15, 2026·Lizhaowen
I Added 150ms of Latency on Purpose. It Fixed the Start Sound.
The recording start sound played before the system muted. The fix: delay the mute by 150ms. Not 50ms, not 300ms. Here's how I found the number.
macOSAudioUXTiming
Engineering Blog
Building a voice input app on macOS — what broke, how we fixed it, and what we learned.
July 3, 2026·Lizhaowen
When the Keyboard Lies: Recovering Phantom Key State After macOS Wake
macOS Secure Input swallows keyUp events during screen lock. Your pressingKeys map fills with ghost keys. Exact-set shortcut matching fails silently. CGEventSource.keyState reads hardware truth—even when Secure Input is active.
macOSHIDCGEventKeyboardSecure InputDebugging
April 16, 2026·Lizhaowen
SwiftData on macOS: Your Default Store Location Is a Data Loss Trap
SwiftData's default ModelContainer stores at ~/Library/Application Support/default.store. It's shared by any non-sandboxed app. Another app triggered a migration. All 207 records gone.
SwiftDatamacOSData LossCoreDataSQLite
April 14, 2026·Lizhaowen
CGEventTap + Swift Concurrency: The Module-Level Globals Pattern
CGEventTap callbacks are C function pointers. Swift ARC can eat the objects they capture. The fix: module-level globals, not instance properties.
macOSSwiftCGEventTapConcurrencyKeyboard