- The route-and-reject hydrology system and its probes are removed
- Hydrology is configured under dimension hydrology and per biome, region and dimension hydrologyPolicy
- riverPolicy and the old hydrology config types are gone
- Grid kernels cover priority flood, D8 routing, flow accumulation, basin extraction, breaching and stream burning
- A basin spills at its pour point and an interior bump can never be the spill
- Region plans cover 4096-block regions on a 64-block grid for major rivers and lakes
- Window plans cover 512-block windows on an 8-block grid for reaches and ponds
- Plans are cached in memory, persisted per world under iris/hydrology and keyed by pack, seed, world height and settings
- Only the main runtime of an engine persists plans and stores swap on hotload and default runtime change
- Demand rasters outrank prefetch and stopping pregen withdraws its queued prefetch
- Ponds come from natural basins, seeded cups and chained cups with strictly falling levels
- A pond level never exceeds its rim plus maxFill or the end grade of any inflow
- Pond outlet loops are opened at their lowest pond
- Reaches split at junctions, pond outlets and 256-block grid lines
- Reaches meander, fit the valley, grade to a running minimum and smooth with Chaikin passes
- Drops of two blocks or more get a lip and one-block corner steps become dry rim ledges
- Cascades and waterfalls write falling fluid from the mantle at level eight
- Inflows into region lakes end at the lake level
- River mouths and water beside the sea sit at the sea surface
- The per-chunk raster gives terrain height, water head, role, tier, fluid, cave ceiling and shore distance
- WaterRole codes are stable and exposed to packs through the WATER_ROLE engine stream
- WATER_HEAD replaces the old river engine streams and an unknown stream name fails the pack load
- Banks take SMOOTH, LINEAR, CONCAVE, TERRACED or CLIFF profiles
- Containment berms grow as tall as the water needs
- Columns within two blocks of water stay solid and keep no Terrain3D overhang
- Seam dams hold water where new chunks meet chunks generated earlier
- The transition blend skips hydrology-owned columns
- Caves stay at least two blocks below river and pond beds
- The painter is the only writer of still water
- Objects cannot open water, falls or bank ground and solid objects may stand in water
- On-water objects need fluid at their anchor column
- Floating child islands stay out of channels
- Sea inlets run inland from cliff coasts at sea level and end in a chamber pool
- Inlet passages are sealed against carvers, subterrain features and the post pass
- Cave pools settle into carved lows, keep one fluid and stay out of inlet space
- Pool and inlet cells use their own cave actions in mantle data
- Water vegetation lists sit on tiers, ponds and hydrologyPolicy with SEA_FLOOR, SEA_SURFACE and SHORE_LINE parts
- Pack validation compiles hydrology settings and rejects empty or water-holding palettes
- Chunk generation fails closed when its 3x3 water rasters are not planned
- /iris find covers stream, river, major river, cascade, waterfall, mouth, pond, lake, dam, sea inlet and cave pool
- Generation history records the new feature types and drops old hydrology entries
- The studio map draws water from rasters up close and from plans when zoomed out
- Pregen prepares the current region and one region ahead
- hydrologyProbe, riverTransectProbe, hydrologyBlockProbe, seaInletProbe and cavePoolProbe report containment, rises, seams, tick conversion and missing surface
- Test forks run with a 2 GB heap, a 60-minute timeout and the Mockito agent loaded explicitly
- Generation with hydrology off is unchanged
- Added DeferredPlacementRecords to gate tracking on Identifier and TileWrapper slices
- Cleared deferred custom and tile records at positions native structure placement changed
- Implemented block change tracking in the Bukkit and modded structure policies
- Covered invalidation through the custom block materialization pass
- Covered modded wrapper change tracking and protected cells
- Passed disabled change sets in existing wrapper tests
- Generated registry validation always re-renders recorded semantics with the current fixer
- Validation canonicalizes the rendering like the installer
- Renderer changes need no version bump
- The renderer identity SPI, both identity strings and the identity-based source preference are gone
- New captures record the fixer class as an informational renderer identity
- The v1 history format is unchanged
- The modded forced datapack, world check and datapack command use the runtime data version
- That is the same data version validation uses
- Tests cover a renderer change under an unchanged identity
- Tests cover 26.3 bare natural_mob_spawns history against the overlay rendering
- Tests cover semantic round trips for every supported fixer
- 26.3 custom biomes write natural_mob_spawns as an overlay modifier with its argument, matching vanilla biomes
- NeoForge biome modifiers can add spawns to Iris biomes again
- The 26.3 custom biome codec test checks the overlay modifier
- PregenChunkRetention holds every chunk in a FULL request's dependency square until all in-area regions reaching it drained; drained regions keep only the border strips undrained neighbours need
- Removes the unload/reload churn (about 1.5 reloads per generated chunk at r1000: lattice passes, next region's border, future-region and ring protos)
- Capped at one chunk per MB of heap; over the cap the drained strips farthest from the active region are released; heap pressure and close release everything
- Regions still save and unload at drain; the early-unload test now pins that plus border retention
- Limit terrain cleanup to affected columns and batch cave boundary reads.
- Reuse offline generation workers and native air states.
- Gather history writes and defer unpublished append synchronization until atomic publication.
- Cover terrain parity, worker lifecycle, history durability, and publication failures.
Brian Neumann-Fopiano