Changelog

v1.1.0 — 2026-05-14

Mega-update: 16 new features across security, performance, UX, and testing. No breaking changes — all v1.0 code compiles and runs unchanged.

Security & Anti-Cheat

• HMAC-SHA256 Save-Signatures (Z.1) — tamper-evident format byte 0x07; HmacVerificationFailedException on mismatch
• Machine-Bound Key-Derivation (Z.2) — HKDF-SHA256 + IMachineIdentityProvider; files non-transferable between devices
• Save-File-Repair Tool (Z.3) — EditorWindow + headless CLI with 5 repair checks (header / HMAC / encryption / migration version / slot meta)

Performance

• Streaming Save/Load (P.1) — chunked I/O for 100 MB+ payloads; IProgress<StreamProgress> pattern for loading-bar integration
• Save-Batching / Transactions (P.2) — atomic multi-slot writes via 2-phase commit; SaveBatch / TrySaveBatch / SaveBatchAsync
• In-Memory LRU Cache (V.3) — configurable maxEntries + maxByteSize with hit-rate statistics

Foundation

• UnityEngine.Object References (V.1) — JsonConverter chain for assets, scene-objects, and sub-assets
• [Save] Attribute (V.2) — opt-in field marker with auto-discovery via AutoSaveAttributeSaver
• Backup Auto-Schedule (B.1) — count-triggered rolling FIFO snapshots with configurable retention depth

Testing & Quality

• Migration TestBed (M.1) — fluent Given/When/Then with handler chains; JSON-path assertions
• Stress-Test Suite (Q.1) — 10 000+ iteration framework with P50/P95/P99/StdDev latency metrics
• Fuzz-Test Suite (Q.2) — 5 modular mutators (BitFlip / ByteDeletion / RandomInjection / HeaderCorruption / Truncation)

UX & Onboarding

• Genre Recipes (R.1) — 4 drop-in schemas: RPG, Roguelike, Open-World, Arcade
• Code Snippets (R.2) — 7 ready-to-use templates: Settings, SaveSlotUI, AutoSave, QuickSave, Migration, LoadingScreen, BackupRestore
• i18n for Error Messages (L.1) — opt-in ILocalizationProvider with 22 message keys across en / de / ja / zh
• DocFX API Docs Pipeline (D.1) — docfx.json config + 6 handwritten articles; ready for tools.avanatro.com/savestack/api

Stats

• +245 tests (493 → 738 total, all green)
• 16 features across 4 fulldev sessions
• 0 new NuGet dependencies — pure C# stack
• 0 breaking changes to public API surface

v1.0.0 — pre-submit, 2026 Q2

The shipping foundation. Engineering complete; pending Asset Store submission after an in-house dogfood pilot and a 2-week external beta.

Core save & load

• Static facade SaveSystem — Save / Load / TryLoad / HasKey / HasValidSlot with slot-based API
• Async paths — SaveAsync / LoadAsync / TryLoadAsync with CancellationToken; native async I/O via IAsyncStorageProvider
• Per-slot lock (SemaphoreSlim) — concurrent Save / SaveAsync on the same slot are safe; different slots run in parallel

Storage backends

• FileStorage — atomic writes (tmp + File.Replace + .bak fallback). Async via IAsyncStorageProvider.
• PlayerPrefsStorage — WebGL / mobile fallback when filesystem access is restricted
• In-memory storage — for tests + transient slots

Encryption

• AesEncryption — AES-256-CBC, per-encrypt IV. Production default for Mono + IL2CPP.
• AesGcmEncryption — AES-256-GCM with format-version byte (0x01). IL2CPP-only in v1.0; Backwards-Compat with un-prefixed legacy bytes.
• NoEncryption — opt-out pass-through

Versioning & migration

• MigrationHandler — opt-in envelope (__sspVersion / __sspData) with registered IMigration steps
• Pre-migration backups — every stale-version Load mirrors original cipher to <key>.premigration_v{N}.bak once, idempotent
• RestoreBackup / ListBackupVersions — recovery API for migrations gone wrong
• Legacy saves recognized as VersionInfo.Unversioned — drop-in upgrade path from pre-versioning saves

Slot inventory & metadata

• SlotMeta — SlotIndex / LastScene / SavedAt / Description / CustomFields / TotalPlaytimeTicks
• GetAllSlots / GetSlotInfo — load-game-menu listings without full-decrypt of each value
• SetSlotDescription / SetSlotMetaField — atomic Read-Modify-Write on __meta
• PlaytimeTracker — monotonic Stopwatch.GetTimestamp + 24h sanity cap

Game systems

• QuestStore (sub-namespace, separate asmdef) — start / advance / complete / fail with counters + variables; persists under __quests
• Flag store — SetFlag / GetFlag / HasFlag / ClearFlag / GetAllFlags; persists under __flags; corrupt-store-tolerant
• SettingsSystem — parallel facade, separate storage root, exception-free Get, thread-safe

Saver components

• Saver abstract base — GetUniqueKey = scene+hierarchy+type or overrideKey; auto-register via Awake
• 6 built-in savers — Position / Rotation / Active / Enabled / AnimatorParameters / Rigidbody
• SaveSystemSceneController — static Dictionary<Saver, byte> registry, OnSceneLoaded auto-restore, DontDestroyOnLoad-safe via build-index filter
• Cross-scene state bucket — __scene_<sceneName>; SaveSystem.GetSceneState / SetSceneState
• AutoSaver — periodic + OnApplicationQuit + OnApplicationPause + OnDisable save triggers
• SlotSave / SlotLoad — one-call high-level scene capture / restore

Production hardening

• Path-traversal validation — SaveSlot.ValidateUserKey public for caller pre-validation
• Concurrent-save lock + 5+ regression tests
• IOException + corrupt-JSON recovery suites — 8 + 6 tests respectively
• Performance benchmarks — 1 MB ~22 ms, 10 MB ~80 ms, 50 MB ~350–660 ms (Win11, NVMe)
• Build test matrix — Standalone Win/Mac/Linux + WebGL + Android + iOS-IL2CPP (pre-submit checklist)
• Unity 6000 minimum — modern Rigidbody.linearVelocity API + UPM Samples~ convention

Editor tools

• SaveSystemWindow — slot inspector with JSON preview, delete, export (testable SaveSystemWindowViewModel)
• SaveWizard — bulk-add savers to Selection, ToggleRow preserves state, overrideKey applied only to newly-added components

Tests

• 300+ dotnet NUnit tests — Concurrent-Save, IOException-Recovery, CorruptJsonRecovery, PathTraversal, Async, Performance benchmarks
• 17 Unity Test Runner tests — EditMode (PlayerPrefs + AES-GCM smoke) + PlayMode (AutoSaver, PlaytimeTracker)
• Test code shipped separately via UNITY_INCLUDE_TESTS constraint — Asset Store package excludes test sources

Stabilization pass (2026-05-11)

• Export-crash fix in SaveSystemWindowViewModel (JSON > 300 chars)
• Lost-update race fixes: SetSlotDescription, SetSlotMetaField, SaveAsync, QuestStore active-check + Persist bypass
• PlaytimeTracker moved to monotonic clock
• FileStorage .bak fallback on 0-byte primary (mid-File.Replace crash recovery)
• SaveSystemSceneController DontDestroyOnLoad fix + dead-entry sweep
• GetSlotInfo via IStorageSizeProvider (no full read + decrypt)
• UPM refactor → Packages/com.avanatrotools.savestack/ embedded package
• One-call SlotSave / SlotLoad high-level API + trigger MonoBehaviours
• Stabilization follow-ups — SettingsSystem static-lock hygiene + 7 concurrency tests; Load backup side-effect explicitly documented in user-facing XML-doc

v1.2 — planned

Additive features. No breaking changes. Public-API surface from v1.1 keeps working.

• Compression — ICompressionProvider + GzipCompression default. Pre-encryption gzip squeezes JSON to ~25–35% on typical RPG saves.
• Screenshot preview per slot — SnapshotCamera + SetSlotPreview for thumbnails in the load menu
• AES-GCM on Mono — BouncyCastle-backed implementation, finally usable in non-IL2CPP builds. Format-version byte already in place; existing IL2CPP saves keep loading.
• Inspector bundle — custom Inspectors for every Saver component (live preview, status badges), expanded SaveSystemWindow (Quest / Flag tabs, slot diff), optional ReflectionSaver with field-picker for explicit auto-capture