Research: gaps against current-version saves (Saved/SaveGames deep dive)

Probe: tests/AbioticEditor.Tests/NewSaveDeepDiveTests.cs (run 2026-06-11). Subject: the game's own save tree at D:\Development\uesave\Saved\SaveGames - newer than the checked-in tests/fixtures/Cascade/ fixture. All 88 non-backup .sav files were parsed, round-tripped, and schema-walked.

1. File tree

SaveGames/
└─ 76561197993781479/                      (steamid64 account folder)
   ├─ Admin.ini                            171 B   (non-GVAS, ini)
   ├─ PlayerStatsSave.sav                  2.8 KB  [/Script/AbioticFactor.PlayerStatsSave]   ← NATIVE class
   ├─ ScientistCustomization_1.sav         2.5 KB  [Abiotic_CustomizationSave_C]
   ├─ Unlocks.sav                          2.4 KB  [Abiotic_CustomizationUnlocks_Save_C]     ← not modeled
   ├─ UserSettings.sav                     3.0 KB  [Abiotic_SettingsSave_C]                  ← not modeled
   ├─ steam_autocloud.vdf
   ├─ Backups/Cascade/1..5/                306 .sav (rolling copies of Worlds/Cascade, same build)
   └─ Worlds/
      ├─ Cascade/                          62 .sav - engine 5.4.4 build -2146453646 (same build as fixture,
      │                                    newer data: 14.8 MB Facility, story=DarkLens, 40 127 min)
      │  ├─ PlayerData/Player_*.sav        ×4 [Abiotic_CharacterSave_C]
      │  ├─ WorldSave_MetaData.sav         [Abiotic_WorldMetadataSave_C]
      │  └─ WorldSave_*.sav                [Abiotic_WorldSave_C]
      └─ Chrissie/                         22 .sav - engine 5.4.4 build **-2146453647** (NEWEST build,
         │                                 fresh world: story=Labs, 176 min)
         ├─ PlayerData/Player_76561197993781479.sav
         └─ WorldSave_*.sav

Every .sav is GVAS v3, UE4 pkg 522 / UE5 pkg 1012, 74 custom format entries. The only build difference is the Worlds/Chrissie tree (build id -2146453647 vs -2146453646).

2. Parse results (typed readers)

Reader	Files	Result
PlayerSaveReader	5 (4 Cascade + 1 Chrissie)	All OK. Skills=15, equip=13, hotbar=8 everywhere.
WorldSaveReader	79 (incl. both MetaData)	All OK. Containers/flags/doors/dropped/NPCs/deployables all read.
CustomizationSaveFile	ScientistCustomization_1.sav	OK - 13/13 known fields, zero unknown properties.
raw SaveGame.LoadFrom	PlayerStatsSave / Unlocks / UserSettings	All OK (header-only classes, no custom header).

No parse failures anywhere, including the newest-build Chrissie files.

3. Binary round-trip (corruption canary)

All 88 non-backup saves round-trip byte-identical through SaveGame.LoadFrom -> WriteTo - including the newest-build Chrissie saves and the native-class PlayerStatsSave.sav. Loading + saving with the typed editors will not corrupt current-version saves.

4. JSON round-trip - BROKEN (would corrupt on JSON import)

SaveGameSerializer (used by SaveJsonBridge / the raw-JSON tab) is not byte-identical for any character/world save, old or new:

DIFF [new] Chrissie/Player_*.sav            first diff 0x640
DIFF [new] Chrissie/WorldSave_*.sav         first diff 0x64D
DIFF [new] Chrissie/WorldSave_MetaData.sav  first diff 0x65D
DIFF [old-fixture control] same offsets     ← pre-existing, not a new-version regression
OK   ScientistCustomization_1.sav           (no custom header on this class)

Cause: AbioticWorldSave/AbioticCharacterSave carry a custom header (ABF_SAVE_VERSION marker + Version=3, Id=1 for world saves; Version int for character saves), but no JSON ISaveClassSerializer is registered for these classes, so ConvertToJson never emits a CustomHeader block and ConvertFromJson re-creates the class with Version=0/Id=0. A save edited through the raw-JSON import path is silently downgraded to save-version 0 - the game's load-time migration logic then sees a "version 0" save. The byte length is unchanged, which makes the corruption invisible until the game reads the version field.

Fix: add SaveClassSerializerBase<AbioticWorldSave> / ...<AbioticCharacterSave> implementations (in a JSON-aware assembly) that write/read Version/Id in a CustomHeader JSON object. Until then the raw-JSON import feature is unsafe for character and world saves.

5. Player save schema gaps (CharacterSaveData, newest build)

Chrissie player save: 32 properties, 24 consumed by PlayerSaveReader, 8 not:

Unconsumed property	Type	Notes
CompletedIntro_	Bool	Listed in no docs; trivially modelable.
LastControlRotation_	Struct (Vector)	Documented as known-unmodeled.
TransmogDisabledArray_	Array<Bool>[13]	Documented as known-unmodeled.
RecipesRequiringResearch_	Array<Name>[120]	Documented as known-unmodeled; pairs with RecipesUnlock_.
LastHotbarSelection_	Int	NEW in build -2146453647 (absent from every -646 save). Cosmetic.
NewestRecipes_	Array<Name>	"NEW" badge list; should be cleared/extended when editing recipes.
Compendium_Unread_	Array<Name>[48]	Unread-badge list; pairs with compendium edits.
Journal_Unread_	Array<Name>[23]	Unread-badge list; pairs with JournalEntries_.

Key-set diff vs old fixture player save (hash suffixes stripped):

• Added: LastHotbarSelection (only genuinely new field).
• "Removed": FavoritedSlots, Compendium_Fish, Fish_Unread, ItemsDistilled - not removed by the game; UE skips properties equal to blueprint defaults (delta-serialization). A fresh character simply never favorited/fished/distilled.
• Top-level keys unchanged (CharacterSaveData, SaveIdentifier, SaveVersion).

Delta-serialization pitfall (editor bugs, not corruption)

The Chrissie save's CurrentSurvivalStats_ struct contains only Thirst/Sanity/Fatigue/Continence - Hunger_ is absent (it sits at the blueprint default). Consequences with the current code:

1. PlayerSaveReader.GetDouble(..., "Hunger_") falls back to 0 -> the editor shows Hunger 0 for a character whose hunger is actually full. Same risk for any default-valued stat (the default should be 100, not 0).
2. Every PlayerSaveWriter.Set* helper silently no-ops when the property is absent (ApplyStats -> Hunger edit lost; ApplyFishCaught on a save without Compendium_Fish_ -> entire edit lost). Nothing is corrupted, but the user's edit doesn't stick. Writers should create the missing FPropertyTag (clone type/hash name from a donor save or the blueprint) instead of skipping.

JSON exports for manual diffing were written to %TEMP%\abiotic-newsave-deepdive\player-{new,old}.json.

6. World save schema (largest new save: Worlds/Cascade/WorldSave_Facility.sav, 14.9 MB)

Top-level keys: all reader-consumed keys present with expected shapes (DeployedObjectMap Map[937], WorldFlags Array[191] of FString, SimpleDoorMap, SecurityDoorMap, DroppedItemMap Map[230], NarrativeNPCMap Map[3], CustomInventoryMap Map[2]).

• NEW key: DestructibleMap (Map<Str,Struct>, value = ActorPath + Broken bool; sample entry ...PersistentLevel.IceWall_BP_C_1). Absent from the old fixture. Round-trips fine (preserved untouched); model it if destructible state editing is wanted.
• Case change: PortalMap -> portalmap. Harmless today (unmodeled), but a warning: top-level key matching must be case-insensitive if PortalMap is ever modeled, and FindByPrefix is case-sensitive (Ordinal).
• Chrissie (newest build) Facility has no extra keys - it's just missing ResourceNodeMap/DestructibleMap/NarrativeNPCMap/NPCSpawnMap/PetNPC because the fresh world hasn't populated them. No keys were added by build -647.
• TimeOfDay struct: TimeOfDaySeconds, CurrentDay, LastAssaultDay, LastWeatherDay, LastPowerLeechDay.

DeployedObjectMap value struct (937/937 uniform)

Matches the reader's expectations. Two corrections to docs/world-save-schema.md (stale doc, not a game change - old fixture has the same types):

• ConstructionMode_82_* is BoolProperty (doc says ByteProperty enum).
• ConstructionLevel_85_* is DoubleProperty (doc says ByteProperty enum).

NarrativeNPCMap value struct

Reader consumes IsDead (Bool), NarrativeState (Byte), Location (Vector). Also present but unmodeled: ActorPath (Struct), NPCClass (SoftObject), CurrentHealthMap (Map), CustomName (Text), DynamicProperties (Array).

Inventory slot struct (ChangeableData) census

Across all container slots: AssetID, CurrentAmmoInMagazine, CurrentItemDurability, CurrentLiquid, CurrentStack, DynamicState, LiquidLevel, MaxItemDurability, PlayerMadeString (all modeled) plus unmodeled DynamicProperties (Array), GameplayTags (GameplayTagContainer struct), TextureVariantRow (DataTableRowHandle). All three already exist in the old fixture; they survive editing because slot writers patch in place. TextureVariantRow matters if item-skin editing is ever added.

7. Account-level files not yet modeled

• PlayerStatsSave.sav (/Script/AbioticFactor.PlayerStatsSave, native): Stats_Int Map<Name,Int> (10 kill-stat counters, e.g. STAT_KILLS_PEST=418) + Achievements Array[51] - local achievement mirror; would pair with SteamAchievements.
• Unlocks.sav (Abiotic_CustomizationUnlocks_Save_C): single CustomizationUnlocks Array<Name>[38] - unlocked appearance rows; pairs with CustomizationCatalog to show locked/unlocked options.
• UserSettings.sav (Abiotic_SettingsSave_C): FavouriteRecipesList, HasCreatedACharacter, HasPlayedTutorial, UIPopupsSeen, HostPreferences (struct: SinglePlayer, Password), TutorialHintPopupsSeen, TutorialPanelsSeen, PinnedRecipeList, RecentServers. Low editing value.

All three load and round-trip byte-identical with plain SaveGame.

8. Prioritized gap list

Round-trip breaks / corruption risks

1. JSON import zeroes ABF_SAVE_VERSION (§4) - affects every character/world save, old and new. Register JSON save-class serializers or disable JSON import for these classes. Highest priority: this is the only path that actively damages a save.

Fields that changed meaning / behave differently on new saves

2. Delta-serialized stats (§5) - Hunger (and any default-valued property) absent on fresh characters: editor shows 0 instead of the default, and edits silently no-op. Writers should create missing tags; reader defaults should match blueprint defaults (100, not 0).
3. PortalMap -> portalmap casing change - make any future top-level key lookups case-insensitive.

Fields we should model next

4. LastHotbarSelection_ (new in current build, Int - trivial).
5. Unread/NEW-badge arrays: NewestRecipes_, Compendium_Unread_, Journal_Unread_ (and Fish_Unread when present) - should be updated alongside the recipe/compendium/ journal editors so edited entries don't show stale badges.
6. RecipesRequiringResearch_ - complements the recipe editor.
7. DestructibleMap (world) - new map, ActorPath+Broken.
8. TransmogDisabledArray_, CompletedIntro_, LastControlRotation_ (player).
9. NarrativeNPC extras (CurrentHealthMap, CustomName) and slot TextureVariantRow/GameplayTags if skin/NPC editing is pursued.
10. Account files: Unlocks.sav (customization unlocks), PlayerStatsSave.sav (stat counters/achievements).

Doc corrections

11. world-save-schema.md: ConstructionMode is Bool, ConstructionLevel is Double; add DestructibleMap, TimeOfDay field list, and the portalmap casing note.