ZeroSeek v1.2.0: Batch Region Rebase & Non-Destructive TPS Governor

ZeroSeek v1.2.0 delivers an architectural overhaul of the delta persistence subsystem, complete multi-dimension isolation, a non-destructive rewrite of the TPS Governor using MixinExtras, and full alignment with Java 22 Foreign Function & Memory (FFM) APIs on Minecraft 1.21.11 (Fabric).

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What's New

1. Batch Rebase Pattern for Delta Chunk Storage

The asynchronous delta persistence subsystem has been redesigned to eliminate file descriptor thrashing and off-heap memory churn during delta merges:

• Region-Grouped Batch Writes: Modified chunk delta files (world/**/region_delta/r.X.Z/c.x.z.raw) are now aggregated and grouped by destination region before executing rebase tasks.
• Single Descriptor Allocation: ZeroSeek opens the target RegionFile handle exactly once per batch, writes all pending chunk deltas sequentially, and closes the handle in a single atomic cycle.
• Single Cache Invalidation: Native off-heap MmapLruCache handles are invalidated exactly once per region file prior to write injection, eliminating cache eviction loops and stale virtual memory pages.
• Full Multi-Dimension Architecture: Added automatic dimension hierarchy resolution supporting:
  • Overworld (world/region/r.X.Z.mca)
  • The Nether (world/DIM-1/region/r.X.Z.mca)
  • The End (world/DIM1/region/r.X.Z.mca)
  • Custom & Modded Dimensions (world/dimensions/<namespace>/<dimension_path>/region/r.X.Z.mca)
• High-Throughput Delta Discovery: ExternalDeltaManager.getAllDeltaFiles() uses a pruned directory scanner that explicitly skips heavy vanilla trees (region/, poi/, entities/, playerdata/, stats/, advancements/), dropping filesystem traversal overhead on servers with large worlds.

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Bug Fixes & Safety (Non-Destructive TPS Governor)

Prior releases throttled server load by aggressively suppressing core entity and network ticking, which caused physics desyncs and rubberbanding. Version 1.2.0 replaces all destructive hooks with a non-destructive governor architecture:

1. Complete Restoration of Vanilla LivingEntity.aiStep()

• Root Cause Fixed: Cancelling aiStep() previously bypassed gravity integration, suffocation checks, fall damage counters, fluid drag, status effect updates, and vehicle/mount synchronization.
• Invariant: LivingEntity.aiStep() is now executed unconditionally without interception.

2. Surgical Mob AI Decimation via @WrapOperation

• Safe Goal Throttling: Implemented MobMixin using @WrapOperation on serverAiStep() targeting GoalSelector.tick() and GoalSelector.tickRunningGoals(boolean).
• Player Proximity Immunity: Mobs within 48 blocks of any alive player (level.hasNearbyAlivePlayer(x, y, z, 48.0)) are strictly immune to AI skipping.
• Adaptive Load Throttling: Distant mobs only experience probabilistic AI decimation under verified server degradation:
  • NORMAL state (TPS >= 15.0): 0% skip (Vanilla execution).
  • STRESS state (10.0 <= TPS < 15.0): 25% skip (stressSkipAiChance = 0.25).
  • CRITICAL state (TPS < 10.0): 75% skip (criticalSkipAiChance = 0.75).

3. Removal of Movement Packet Drops

• Fix: Removed destructive mixins on ServerGamePacketListenerImpl (ServerboundMovePlayerPacket).
• Result: Complete elimination of client rubberbanding, server-client coordinate divergence, and false-positive anticheat kicks during low TPS conditions.

4. Removal of Chunk Ticket Interference

• Fix: Removed throttling hooks on DistanceManager.addPlayer() and DistanceManager.updatePlayerTickets().
• Result: Players will no longer fall through unloaded chunks or get stranded in void boundaries when server load spikes.

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Technical Improvements & Architecture

Platform & Toolchain Upgrades

• Minecraft Target: Standardized on Minecraft 1.21.11.
• Loader Target: Fabric Loader >=0.16.0 (tested on 0.18.2) and Fabric API 0.139.4+1.21.11.
• Java 22 FFM API: Memory segment management fully integrated with java.lang.foreign.MemorySegment and java.lang.foreign.Arena.ofShared().
• Bytecode Compliance: Set "compatibilityLevel": "JAVA_22" in zeroseek.mixins.json.

Test Suite Integration

• Added unit test coverage via JUnit 5 in RebaseWorkerTest:
  • testComputeBaseFilePath: Validates .mca path derivation across Overworld, Nether, End, and custom dimensions.
  • testDetectDimension: Asserts exact ResourceKey<Level> parsing from path structures.
  • testGroupingDeltaFiles: Verifies batch partition counts per region file.
  • testExternalDeltaManagerScan: Validates directory exclusion rules and .raw file filtering under temporary filesystems.