Ferrite

[0.6.5-alpha] - 2026-06-26

Changed

• Walkability cache default off. -Dferrite.nav.cache now defaults to false. Session 5's first live counters showed the pre-fill box thrashing the 512-slot direct-mapped cache (hit rate 1-17%, ~4400 snapshots per 5 s, net regression in casual play). The default path stays vanilla until the session 6 fill-strategy fix lands; set -Dferrite.nav.cache=true to opt in for measurement.

Added

• Walkability cache session 4. WalkNodeEvaluatorMixin intercepts WalkNodeEvaluator.getPathTypeFromState(BlockGetter, BlockPos) at HEAD. For sections already snapshotted, returns PathType directly from a Java-side direct-mapped section cache (512 slots, ~5-10 ns per lookup) instead of calling level.getBlockState followed by the 50-line classification chain. The Java-side cache is filled in snapshotSection alongside the Rust store and evicted on block-kind changes.

  kindToPathType maps the unambiguous kinds: AIR/LADDER/SCAFFOLDING/CARPET to OPEN; OPAQUE_FULL/SLAB/STAIRS to BLOCKED; FENCE/WALL to FENCE; TRAPDOOR to TRAPDOOR; WATER to WATER; LAVA to LAVA; LEAVES to LEAVES. DOOR, FENCE_GATE, and OTHER fall through to vanilla (state-dependent).

  encodeBlockKind now redirects MAGMA_BLOCK, HONEY_BLOCK, POWDER_SNOW, lit campfires, and LAVA_CAULDRON to KIND_OTHER to prevent false BLOCKED returns for those blocks.

  Parity correction: LiquidBlock.isPathfindable(LAND) is true in 26.1.x (water blocks return PathType.WATER, not BLOCKED). Updated kindToPathType and predictCategory accordingly.

• Walkability cache session 5: A/B flags and hit-rate counters. -Dferrite.nav.cache (default true) gates the whole cache for clean vanilla-baseline measurement runs; -Dferrite.nav.parity (default false) gates the parity validator, which had been running per-node JNI and string work on every ground-mob findPath after validation was already complete. Hit/ambiguous/miss/snapshot counters in NavigationCacheBridge feed a [nav-cache] line in the 5 s monitor report, so measurement runs report hit rate alongside timing deltas.

Fixed

• Nav-cache snapshot gate desync. The section-snapshot gate in PathFinderMixin checked the Rust store while the hot path reads the Java 512-slot kind cache. A slot collision or door eviction emptied the Java slot while Rust still reported cached, so the section never refilled and went permanently cold. The gate now checks the Java cache (hasJavaSection), which also drops the per-section JNI call from the pre-fill loop.
• Asymmetric door eviction. Placing or removing a door evicted the Java cache slot but not the Rust section store (empty match arms in nav_cache.rs). Eviction is now symmetric: any kind-crossing change evicts both stores; door open/close (DOOR to DOOR) is still filtered.
• Snapshot box could cache wrong-AIR sections. The pre-fill bounding box extended past the chunks PathNavigationRegion actually backs, where the region serves EmptyLevelChunk (all AIR). Those sections were cached as permanently wrong AIR data invisible to the parity gate, which only checks in-region path nodes. The box is now clamped to region-backed chunks (new PathNavigationRegionAccessor) and world build height, and null getChunkNow entries are skipped.