Kordant/tasks/ios-production/10-memory-leak-audit.md

10. Memory Management & Leak Audit

meta: id: ios-production-10 feature: ios-production priority: P2 depends_on: [] tags: [performance, memory, production]

objective:

• Audit and fix memory leaks and retain cycles to ensure stable app performance over long sessions

deliverables:

• Memory leak audit report
• Fixed retain cycles in ViewModels and Services
• Instruments leak check passing
• Memory usage optimization

steps:

1. Audit ViewModels for retain cycles:
   • Review all ViewModels in iOS/Kordant/ViewModels/
   • Check for strong references in closures
   • Verify cancellables properly stored and cleaned up
   • Check for delegate patterns causing cycles
2. Audit Services for leaks:
   • Review APIClient, AuthService, CacheManager
   • Check singleton patterns don't retain view controllers
   • Verify notification observers removed on deinit
   • Check timer/interval cleanup
3. Run Instruments leak check:
   • Profile app with Leaks instrument
   • Perform all critical user journeys
   • Record and categorize all leaks
   • Fix leaks in priority order (critical first)
4. Optimize memory usage:
   • Reduce image cache size if needed
   • Limit number of cached API responses
   • Clear unused ViewModels from navigation stack
   • Optimize large data structures
5. Add memory warnings handling:
   • Clear caches on UIApplication.didReceiveMemoryWarningNotification
   • Reduce quality of background operations
   • Cancel non-essential network requests
6. Test long-running sessions:
   • Leave app running for 24 hours
   • Monitor memory growth
   • Verify no crashes from memory pressure

tests:

• Instruments: Leaks instrument shows 0 leaks
• Performance: Memory stable after 1 hour of use
• Stress: No crashes after extended usage

acceptance_criteria:

• 0 memory leaks detected in Instruments
• No retain cycles in ViewModels or Services
• Memory usage stable over 1 hour session
• Memory warnings handled appropriately
• Caches cleared on low memory
• No strong reference cycles in closures
• Notification observers removed on deinit
• Long-running session (24h) without memory-related crashes

validation:

• Profile with Instruments → 0 leaks after full app navigation
• Monitor memory in Xcode → flat line during idle
• Trigger memory warning → caches cleared, app responsive
• Extended use test → no memory growth over time

notes:

• SwiftUI @StateObject and @ObservedObject can cause leaks if misused
• Use [weak self] in all async closures
• Combine subscribers must be stored in Set
• Test on physical device — simulator behaves differently