swiftdata▌

SwiftData migration failures manifest as production crashes, data loss, corrupted relationships, or simulator-only success. Core principle 90% of migration failures stem from missing models in VersionedSchema, relationship inverse issues, or untested migration paths—not SwiftData bugs.

SwiftData schema migrations move your data safely when models change. Core principle SwiftData's willMigrate sees only OLD models, didMigrate sees only NEW models—you can never access both simultaneously. This limitation shapes all migration strategies.

Apple's native persistence framework using @Model classes and declarative queries. Built on Core Data, designed for SwiftUI.

Write, review, and improve SwiftData code using modern APIs and best practices. \n \n Validates code against core SwiftData rules including relationships, delete rules, autosaving, and FetchDescriptor patterns \n Checks predicates for safety and runtime crashes, with special handling for CloudKit constraints and unsupported operations \n Targets Swift 6.2+ with modern concurrency; recommends indexing strategies for iOS 18+ and class inheritance patterns for iOS 26+ \n Reports only genuine issues

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