# 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<AnyCancellable>
- Test on physical device — simulator behaves differently