CloudKit Code Review

Quick Reference

Issue Type	Reference
CKContainer, databases, zones, entitlements	references/container-setup.md
CKRecord, references, assets, batch operations	references/records.md
CKSubscription, push notifications, silent sync	references/subscriptions.md
CKShare, participants, permissions, acceptance	references/sharing.md

Review Checklist

• Account status checked before private/shared database operations
• Custom zones used (not default zone) for production data
• All CloudKit errors handled with retryAfterSeconds respected
• serverRecordChanged conflicts handled with proper merge logic
• CKErrorPartialFailure parsed for individual record errors
• Batch operations used (CKModifyRecordsOperation) not individual saves
• Large binary data stored as CKAsset (records have 1MB limit)
• Record keys type-safe (enums) not string literals
• UI updates dispatched to main thread from callbacks
• CKAccountChangedNotification observed for account switches
• Subscriptions have unique IDs to prevent duplicates
• CKShare uses custom zone (sharing requires custom zones)

When to Load References

• Reviewing container/database setup or zones -> container-setup.md
• Reviewing record CRUD or relationships -> records.md
• Reviewing push notifications or sync triggers -> subscriptions.md
• Reviewing sharing or collaboration features -> sharing.md

Output Format

Report issues using: [FILE:LINE] ISSUE_TITLE

Examples:

• [AppDelegate.swift:24] CKContainer not in custom zone
• [SyncManager.swift:156] Unhandled CKErrorPartialFailure
• [DataStore.swift:89] Missing retryAfterSeconds backoff

Review Questions

1. What happens when the user is signed out of iCloud?
2. Does error handling respect rate limiting (retryAfterSeconds)?
3. Are conflicts resolved or does data get overwritten silently?
4. Is the schema deployed to production before App Store release?
5. Are shared records in custom zones (required for CKShare)?