ADA

adapters/bukkit/nms/v26_2_R1/src/main/java/art/arcane/iris/core/nms/v26_2_R1/IrisChunkGenerator.java

@@ -23,6 +23,7 @@ import art.arcane.iris.nativegen.NativeStructureTerrainIntegrator;
 import art.arcane.iris.nativegen.NativeStructureVegetationClearer;
 import art.arcane.iris.nativegen.NativeStructureVerticalPlacer;
 import art.arcane.iris.nativegen.NativeStructureVanillaLocator;
+import art.arcane.iris.nativegen.NativeStructureVolumeIndex;
 import art.arcane.iris.nativegen.WorldgenTerrainHeightmaps;
 import art.arcane.iris.spi.PlatformBlockState;
 import art.arcane.iris.util.common.data.IrisCustomData;
@@ -87,6 +88,7 @@ import org.bukkit.block.data.BlockData;
 import org.spigotmc.SpigotWorldConfig;
 
 import javax.annotation.Nullable;
+import java.lang.ref.WeakReference;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
@@ -130,6 +132,24 @@ public class IrisChunkGenerator extends CustomChunkGenerator {
         this.runtimeMinY = level.getMinY();
         this.runtimeHeight = level.getHeight();
         this.runtimeSeaLevel = runtimeMinY + engine.getDimension().getFluidHeight();
+        installNativeStructureVolumeIndex(level);
+    }
+
+    private void installNativeStructureVolumeIndex(ServerLevel level) {
+        WeakReference<ServerLevel> levelReference = new WeakReference<>(level);
+        WeakReference<ChunkGenerator> generatorReference = new WeakReference<>(this);
+        WeakReference<BiomeSource> biomeSourceReference = new WeakReference<>(customBiomeSource);
+        NativeStructureVolumeIndex.install(engine, new NativeStructureVolumeIndex.Context(
+                level.registryAccess(),
+                level.getServer().getStructureManager(),
+                level.dimension(),
+                LevelHeightAccessor.create(runtimeMinY, runtimeHeight),
+                generatorReference::get,
+                biomeSourceReference::get,
+                () -> {
+                    ServerLevel active = levelReference.get();
+                    return active == null ? null : active.getChunkSource().getGeneratorState();
+                }));
     }
 
     @Override

adapters/bukkit/nms/v26_2_R1/src/main/java/art/arcane/iris/core/nms/v26_2_R1/NMSBinding.java

@@ -13,6 +13,8 @@ import art.arcane.iris.core.nms.datapack.DataVersion;
 import art.arcane.iris.engine.data.cache.AtomicCache;
 import art.arcane.iris.engine.data.chunk.TerrainChunk;
 import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
+import art.arcane.iris.nativegen.NativeStructureVolumeIndex;
 import art.arcane.iris.engine.object.IrisDimensionRuntimeContract;
 import art.arcane.iris.engine.platform.PlatformChunkGenerator;
 import art.arcane.iris.nativegen.NativeStructureFactory;
@@ -794,6 +796,11 @@ public class NMSBinding implements INMSBinding {
         return true;
     }
 
+    @Override
+    public KList<NativeStructureVolume> nativeStructureVolumes(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+        return NativeStructureVolumeIndex.volumes(engine, minX, minZ, maxX, maxZ);
+    }
+
     @Override
     public int getBiomeId(Biome biome) {
         for (World i : Bukkit.getWorlds()) {

adapters/bukkit/nms/v26_2_R1/src/test/java/art/arcane/iris/nativegen/NativeStructureTemplateOccupancyTest.java

@@ -0,0 +1,233 @@
+package art.arcane.iris.nativegen;
+
+import com.mojang.datafixers.util.Either;
+import com.mojang.serialization.MapCodec;
+import net.minecraft.SharedConstants;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Holder;
+import net.minecraft.core.HolderSet;
+import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.server.Bootstrap;
+import net.minecraft.util.valueproviders.ConstantInt;
+import net.minecraft.world.level.LevelReader;
+import net.minecraft.world.level.WorldGenLevel;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.level.block.Rotation;
+import net.minecraft.world.level.levelgen.Heightmap;
+import net.minecraft.world.level.levelgen.structure.BoundingBox;
+import net.minecraft.world.level.levelgen.structure.PoolElementStructurePiece;
+import net.minecraft.world.level.levelgen.structure.pools.SinglePoolElement;
+import net.minecraft.world.level.levelgen.structure.pools.StructureTemplatePool;
+import net.minecraft.world.level.levelgen.structure.templatesystem.BlackstoneReplaceProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.BlockAgeProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.BlockIgnoreProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.CappedProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.GravityProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.JigsawReplacementProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.LavaSubmergedBlockProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.LiquidSettings;
+import net.minecraft.world.level.levelgen.structure.templatesystem.NopProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.ProtectedBlockProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.RuleProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.StructurePlaceSettings;
+import net.minecraft.world.level.levelgen.structure.templatesystem.StructureProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.StructureProcessorList;
+import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplate;
+import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplateManager;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Proxy;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.TreeSet;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class NativeStructureTemplateOccupancyTest {
+    private static final BoundingBox PROCESSING_AREA = new BoundingBox(0, 56, 0, 15, 80, 0);
+    private static final int TEMPLATE_WIDTH = 32;
+    private static final int TERRAIN_HEIGHT = 64;
+
+    @BeforeClass
+    public static void bootstrapMinecraft() {
+        SharedConstants.tryDetectVersion();
+        Bootstrap.bootStrap();
+    }
+
+    @Test
+    public void straddlingGravityPieceReadsHeightsOnlyInsideTheProcessingArea() throws Exception {
+        ColumnRecorder recorder = new ColumnRecorder();
+
+        resolve(straddlingPiece(
+                List.of(new GravityProcessor(Heightmap.Types.WORLD_SURFACE_WG, 0))), recorder);
+
+        assertEquals(columns(0, 15), recorder.heightColumns);
+    }
+
+    @Test
+    public void straddlingPieceRunsProcessorsOnlyInsideTheProcessingArea() throws Exception {
+        CountingProcessor counter = new CountingProcessor();
+
+        resolve(straddlingPiece(List.of(counter)), new ColumnRecorder());
+
+        assertEquals(columns(0, 15), counter.columns);
+        assertTrue(counter.columns.size() < TEMPLATE_WIDTH);
+    }
+
+    @Test
+    public void cappedStraddlingPieceRunsProcessorsAcrossTheWholePiece() throws Exception {
+        CountingProcessor counter = new CountingProcessor();
+
+        resolve(straddlingPiece(List.of(counter,
+                new CappedProcessor(NopProcessor.INSTANCE, ConstantInt.of(0)))),
+                new ColumnRecorder());
+
+        assertEquals(columns(0, TEMPLATE_WIDTH - 1), counter.columns);
+    }
+
+    @Test
+    public void cappedProcessorIsTheOnlyProcessorThatDisablesTheProcessingAreaClip() {
+        for (StructureProcessor processor : List.of(
+                BlockIgnoreProcessor.STRUCTURE_BLOCK,
+                JigsawReplacementProcessor.INSTANCE,
+                LavaSubmergedBlockProcessor.INSTANCE,
+                NopProcessor.INSTANCE,
+                BlackstoneReplaceProcessor.INSTANCE,
+                new GravityProcessor(Heightmap.Types.WORLD_SURFACE_WG, 0),
+                new RuleProcessor(List.of()),
+                new BlockAgeProcessor(0.5F),
+                new ProtectedBlockProcessor(HolderSet.empty()))) {
+            assertFalse(processor.getClass().getName(),
+                    processor.evaluatesEntirePieceState());
+        }
+        assertTrue(new CappedProcessor(NopProcessor.INSTANCE, ConstantInt.of(4))
+                .evaluatesEntirePieceState());
+    }
+
+    @Test
+    public void placementSettingsCarryTheProcessingAreaAsTheirClipBox() throws Exception {
+        PoolElementStructurePiece piece = straddlingPiece(List.of());
+
+        StructurePlaceSettings settings = NativeStructureReflection.resolvePlacementSettings(
+                (SinglePoolElement) piece.getElement(), piece, PROCESSING_AREA);
+
+        assertEquals(PROCESSING_AREA, settings.getBoundingBox());
+    }
+
+    private static void resolve(PoolElementStructurePiece piece, ColumnRecorder recorder) {
+        NativeStructureTemplateOccupancy.resolve(
+                world(recorder), piece, piece.getPosition(), PROCESSING_AREA,
+                NativeStructureTemplateOccupancyTest::forbiddenTemplateManager,
+                PROCESSING_AREA::isInside, amount -> {
+                });
+    }
+
+    private static PoolElementStructurePiece straddlingPiece(
+            List<StructureProcessor> processors) throws Exception {
+        BoundingBox bounds = new BoundingBox(0, 70, 0, TEMPLATE_WIDTH - 1, 76, 0);
+        return new PoolElementStructurePiece(
+                null, new InlineSinglePoolElement(template(), processors),
+                new BlockPos(bounds.minX(), bounds.minY(), bounds.minZ()),
+                1, Rotation.NONE, bounds, LiquidSettings.APPLY_WATERLOGGING);
+    }
+
+    private static Set<Integer> columns(int minimumX, int maximumX) {
+        Set<Integer> columns = new TreeSet<>();
+        for (int x = minimumX; x <= maximumX; x++) {
+            columns.add(x);
+        }
+        return columns;
+    }
+
+    private static StructureTemplateManager forbiddenTemplateManager() {
+        throw new AssertionError("Inline templates must not resolve a template manager");
+    }
+
+    private static StructureTemplate template() throws Exception {
+        List<StructureTemplate.StructureBlockInfo> blocks = new ArrayList<>();
+        for (int x = 0; x < TEMPLATE_WIDTH; x++) {
+            blocks.add(new StructureTemplate.StructureBlockInfo(
+                    new BlockPos(x, 0, 0), Blocks.COBBLESTONE.defaultBlockState(), null));
+        }
+        Constructor<StructureTemplate.Palette> constructor =
+                StructureTemplate.Palette.class.getDeclaredConstructor(List.class);
+        assertTrue(constructor.trySetAccessible());
+        StructureTemplate template = new StructureTemplate();
+        template.palettes.add(constructor.newInstance(blocks));
+        return template;
+    }
+
+    private static WorldGenLevel world(ColumnRecorder recorder) {
+        InvocationHandler handler = (proxy, method, arguments) -> {
+            String methodName = method.getName();
+            if (methodName.equals("getHeight") && arguments.length == 3) {
+                recorder.heightColumns.add((Integer) arguments[1]);
+                return TERRAIN_HEIGHT;
+            }
+            if (methodName.equals("getBlockState")) {
+                recorder.stateColumns.add(((BlockPos) arguments[0]).getX());
+                return Blocks.STONE.defaultBlockState();
+            }
+            if (methodName.equals("getLevel")) {
+                return null;
+            }
+            if (methodName.equals("holderLookup")) {
+                return BuiltInRegistries.BLOCK;
+            }
+            if (methodName.equals("hashCode")) {
+                return System.identityHashCode(proxy);
+            }
+            if (methodName.equals("equals")) {
+                return proxy == arguments[0];
+            }
+            if (methodName.equals("toString")) {
+                return "occupancy-test-world";
+            }
+            throw new UnsupportedOperationException(method.toString());
+        };
+        return (WorldGenLevel) Proxy.newProxyInstance(
+                WorldGenLevel.class.getClassLoader(),
+                new Class<?>[]{WorldGenLevel.class}, handler);
+    }
+
+    private static final class ColumnRecorder {
+        private final Set<Integer> heightColumns = new TreeSet<>();
+        private final Set<Integer> stateColumns = new TreeSet<>();
+    }
+
+    private static final class CountingProcessor implements StructureProcessor {
+        private final Set<Integer> columns = new TreeSet<>();
+
+        @Override
+        public StructureTemplate.StructureBlockInfo processBlock(
+                LevelReader level, BlockPos targetPosition, BlockPos referencePos,
+                BlockPos templateRelativePos,
+                StructureTemplate.StructureBlockInfo processedBlockInfo,
+                StructurePlaceSettings settings) {
+            columns.add(processedBlockInfo.pos().getX());
+            return processedBlockInfo;
+        }
+
+        @Override
+        public MapCodec<? extends StructureProcessor> codec() {
+            return BlockIgnoreProcessor.STRUCTURE_BLOCK.codec();
+        }
+    }
+
+    private static final class InlineSinglePoolElement extends SinglePoolElement {
+        private InlineSinglePoolElement(
+                StructureTemplate template, List<StructureProcessor> processors) {
+            super(Either.right(template),
+                    Holder.direct(new StructureProcessorList(processors)),
+                    StructureTemplatePool.Projection.RIGID,
+                    Optional.<LiquidSettings>empty());
+        }
+    }
+}

adapters/bukkit/nms/v26_2_R1/src/test/java/art/arcane/iris/nativegen/NativeStructureVolumeIndexTest.java

@@ -0,0 +1,160 @@
+package art.arcane.iris.nativegen;
+
+import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
+import art.arcane.volmlib.util.collection.KList;
+import net.minecraft.SharedConstants;
+import net.minecraft.core.HolderSet;
+import net.minecraft.server.Bootstrap;
+import net.minecraft.util.RandomSource;
+import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.levelgen.structure.BoundingBox;
+import net.minecraft.world.level.levelgen.structure.Structure;
+import net.minecraft.world.level.levelgen.structure.StructureStart;
+import net.minecraft.world.level.levelgen.structure.pieces.PiecesContainer;
+import net.minecraft.world.level.levelgen.structure.structures.SwampHutPiece;
+import net.minecraft.world.level.levelgen.structure.structures.SwampHutStructure;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+public class NativeStructureVolumeIndexTest {
+    private static final String STRUCTURE_KEY = "minecraft:swamp_hut";
+
+    @BeforeClass
+    public static void bootstrapMinecraftRegistries() {
+        SharedConstants.tryDetectVersion();
+        Bootstrap.bootStrap();
+    }
+
+    @Test
+    public void assembledPiecesBecomeWorldSpacePieceVolumes() {
+        StructureStart start = swampHut(0, 0, 4, 6);
+        BoundingBox bounds = start.getPieces().getFirst().getBoundingBox();
+
+        KList<NativeStructureVolume> volumes = NativeStructureVolumeIndex.appendPieces(null, STRUCTURE_KEY, start);
+
+        assertEquals(1, volumes.size());
+        NativeStructureVolume volume = volumes.getFirst();
+        assertEquals(STRUCTURE_KEY, volume.structure());
+        assertEquals(bounds.minX(), volume.minX());
+        assertEquals(bounds.minY(), volume.minY());
+        assertEquals(bounds.minZ(), volume.minZ());
+        assertEquals(bounds.maxX(), volume.maxX());
+        assertEquals(bounds.maxY(), volume.maxY());
+        assertEquals(bounds.maxZ(), volume.maxZ());
+    }
+
+    @Test
+    public void invalidStartsContributeNoVolumes() {
+        assertNull(NativeStructureVolumeIndex.appendPieces(null, STRUCTURE_KEY, StructureStart.INVALID_START));
+        assertNull(NativeStructureVolumeIndex.appendPieces(null, STRUCTURE_KEY, null));
+    }
+
+    @Test
+    public void coldAndCachedQueriesResolveIdenticalVolumes() {
+        CountingResolver resolver = new CountingResolver(0, 0);
+        NativeStructureVolumeIndex index = NativeStructureVolumeIndex.forTesting(resolver);
+
+        KList<NativeStructureVolume> cold = index.resolve(null, 0, 0, 15, 15);
+        int coldResolutions = resolver.resolutions();
+        KList<NativeStructureVolume> cached = index.resolve(null, 0, 0, 15, 15);
+
+        assertTrue(coldResolutions > 0);
+        assertFalse(cold.isEmpty());
+        assertEquals(cold, cached);
+        assertEquals(coldResolutions, resolver.resolutions());
+    }
+
+    @Test
+    public void independentIndexesResolveIdenticalVolumesFromTheSameSeed() {
+        NativeStructureVolumeIndex first = NativeStructureVolumeIndex.forTesting(new CountingResolver(0, 0));
+        NativeStructureVolumeIndex second = NativeStructureVolumeIndex.forTesting(new CountingResolver(0, 0));
+
+        assertEquals(first.resolve(null, 0, 0, 15, 15), second.resolve(null, 0, 0, 15, 15));
+        assertEquals(first.resolve(null, -32, -32, 47, 47), second.resolve(null, -32, -32, 47, 47));
+    }
+
+    @Test
+    public void volumesOutsideTheQueryRectAreExcluded() {
+        NativeStructureVolumeIndex index = NativeStructureVolumeIndex.forTesting(new CountingResolver(0, 0));
+        BoundingBox bounds = swampHut(0, 0, 4, 6).getPieces().getFirst().getBoundingBox();
+
+        KList<NativeStructureVolume> hit = index.resolve(null, bounds.minX(), bounds.minZ(), bounds.maxX(), bounds.maxZ());
+        KList<NativeStructureVolume> miss = index.resolve(null,
+                bounds.maxX() + 1, bounds.minZ(), bounds.maxX() + 8, bounds.maxZ());
+
+        assertEquals(1, hit.size());
+        assertTrue(miss.isEmpty());
+    }
+
+    @Test
+    public void startsWithinTheOriginReachContributeAndBeyondItDoNot() {
+        int reach = NativeStructureVolumeIndex.originReachChunks();
+        NativeStructureVolumeIndex reachable = NativeStructureVolumeIndex.forTesting(new CountingResolver(reach, 0));
+        NativeStructureVolumeIndex unreachable = NativeStructureVolumeIndex.forTesting(new CountingResolver(reach + 1, 0));
+
+        assertFalse(reachable.resolve(null, 0, 0, 15, 15).isEmpty());
+        assertTrue(unreachable.resolve(null, 0, 0, 15, 15).isEmpty());
+    }
+
+    @Test
+    public void volumeResolutionNeverReadsChunkOrOwnershipState() throws Exception {
+        String source = Files.readString(Path.of(System.getProperty("iris.nativeStructureVolumeIndexSource")));
+
+        assertFalse(source.contains("StructureManager"));
+        assertFalse(source.contains("getStartForStructure"));
+        assertFalse(source.contains("getAllStarts"));
+        assertFalse(source.contains("ChunkAccess"));
+        assertFalse(source.contains("NativeStructureOwnershipStore"));
+        assertFalse(source.contains("NativeStructureOwnershipRecovery"));
+    }
+
+    @Test
+    public void vanillaVolumesAreGatedOnPackPolicy() throws Exception {
+        String source = Files.readString(Path.of(System.getProperty("iris.nativeStructureVolumeIndexSource")));
+
+        assertTrue(source.contains("NativeStructureGenerationPolicy.resolve("));
+        assertTrue(source.contains("if (!decision.generate())"));
+        assertTrue(source.contains("isStructureChunk("));
+    }
+
+    private static StructureStart swampHut(int chunkX, int chunkZ, int x, int z) {
+        Structure source = new SwampHutStructure(new Structure.StructureSettings(HolderSet.empty()));
+        SwampHutPiece piece = new SwampHutPiece(RandomSource.create(17L), x, z);
+        return new StructureStart(source, new ChunkPos(chunkX, chunkZ), 0, new PiecesContainer(List.of(piece)));
+    }
+
+    private static final class CountingResolver implements NativeStructureVolumeIndex.OriginResolver {
+        private final AtomicInteger resolutions = new AtomicInteger();
+        private final int originChunkX;
+        private final int originChunkZ;
+
+        private CountingResolver(int originChunkX, int originChunkZ) {
+            this.originChunkX = originChunkX;
+            this.originChunkZ = originChunkZ;
+        }
+
+        private int resolutions() {
+            return resolutions.get();
+        }
+
+        @Override
+        public KList<NativeStructureVolume> volumesAt(Engine engine, int chunkX, int chunkZ) {
+            resolutions.incrementAndGet();
+            if (chunkX != originChunkX || chunkZ != originChunkZ) {
+                return NativeStructureVolume.NONE;
+            }
+            return NativeStructureVolumeIndex.appendPieces(null, STRUCTURE_KEY, swampHut(chunkX, chunkZ, 4, 6));
+        }
+    }
+}

adapters/bukkit/plugin/src/main/java/art/arcane/iris/core/runtime/BukkitEnginePlatformHooks.java

@@ -23,6 +23,7 @@ import art.arcane.iris.core.ServerConfigurator;
 import art.arcane.iris.core.datapack.DatapackIngestService;
 import art.arcane.iris.core.events.IrisEngineHotloadEvent;
 import art.arcane.iris.core.gui.PregeneratorJob;
+import art.arcane.iris.core.nms.INMS;
 import art.arcane.iris.core.project.IrisProject;
 import art.arcane.iris.core.project.IrisCodeWorkspace;
 import art.arcane.iris.core.service.IrisApiEventSVC;
@@ -31,15 +32,22 @@ import art.arcane.iris.core.tools.WorldMaintenance;
 import art.arcane.iris.engine.framework.Engine;
 import art.arcane.iris.engine.framework.EngineMode;
 import art.arcane.iris.engine.framework.EnginePlatformHooks;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
 import art.arcane.iris.engine.object.IrisDimension;
 import art.arcane.iris.engine.object.IrisDimensionRuntimeContract;
 import art.arcane.iris.engine.object.IrisWorld;
 import art.arcane.iris.platform.bukkit.BukkitWorldBinding;
 import art.arcane.iris.spi.IrisPlatforms;
 import art.arcane.iris.util.common.scheduling.J;
+import art.arcane.volmlib.util.collection.KList;
 import org.bukkit.World;
 
 public final class BukkitEnginePlatformHooks implements EnginePlatformHooks {
+    @Override
+    public KList<NativeStructureVolume> nativeStructureVolumes(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+        return INMS.get().nativeStructureVolumes(engine, minX, minZ, maxX, maxZ);
+    }
+
     @Override
     public void refreshWorkspace(Engine engine) {
         new IrisCodeWorkspace(new IrisProject(engine.getData().getDataFolder())).updateWorkspace();

adapters/minecraft-common/src/main/java/art/arcane/iris/nativegen/NativeStructureVolumeIndex.java

@@ -0,0 +1,385 @@
+package art.arcane.iris.nativegen;
+
+import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.framework.NativeStructureGenerationPolicy;
+import art.arcane.iris.engine.framework.NativeStructureOwnershipRecord;
+import art.arcane.iris.engine.framework.NativeStructurePlacementPlanner;
+import art.arcane.iris.engine.framework.NativeStructureStartPlan;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
+import art.arcane.iris.engine.object.IrisNativeStructureDecision;
+import art.arcane.iris.spi.IrisLogging;
+import art.arcane.volmlib.util.collection.KList;
+import net.minecraft.core.Holder;
+import net.minecraft.core.Registry;
+import net.minecraft.core.RegistryAccess;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.resources.Identifier;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.LevelHeightAccessor;
+import net.minecraft.world.level.biome.BiomeSource;
+import net.minecraft.world.level.chunk.ChunkGenerator;
+import net.minecraft.world.level.chunk.ChunkGeneratorStructureState;
+import net.minecraft.world.level.levelgen.structure.BoundingBox;
+import net.minecraft.world.level.levelgen.structure.Structure;
+import net.minecraft.world.level.levelgen.structure.StructurePiece;
+import net.minecraft.world.level.levelgen.structure.StructureSet;
+import net.minecraft.world.level.levelgen.structure.StructureStart;
+import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplateManager;
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.WeakHashMap;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.IntBinaryOperator;
+import java.util.function.Supplier;
+
+/**
+ * Resolves the world-space piece bounds of every native structure that will generate around a query rect.
+ *
+ * <p>The answer is derived from the seed, the registries and this pack's structure policy only: candidate origins
+ * come from the placement grid and from vanilla structure placements, and each candidate is assembled through the
+ * same {@link NativeStructureFactory} path chunk generation uses. Nothing here reads chunk state, ownership records
+ * or generation progress, so the same query answers identically no matter which chunks already exist.
+ */
+public final class NativeStructureVolumeIndex {
+    private static final int ORIGIN_REACH_CHUNKS = NativeStructureOwnershipRecord.MAX_REFERENCE_DISTANCE_CHUNKS;
+    private static final int MAX_CACHED_ORIGIN_CHUNKS = 16_384;
+    private static final int MAX_CACHED_QUERY_CHUNKS = 4_096;
+    private static final Map<Engine, NativeStructureVolumeIndex> INDEXES =
+            Collections.synchronizedMap(new WeakHashMap<>());
+    private static final Set<String> WARNED_RESOLUTION_FAILURES = ConcurrentHashMap.newKeySet();
+
+    private final Context context;
+    private final OriginResolver origins;
+    private final Map<Long, KList<NativeStructureVolume>> originCache = lru(MAX_CACHED_ORIGIN_CHUNKS);
+    private final Map<Long, KList<NativeStructureVolume>> queryCache = lru(MAX_CACHED_QUERY_CHUNKS);
+    private final ConcurrentHashMap<Long, CompletableFuture<KList<NativeStructureVolume>>> originBuilds =
+            new ConcurrentHashMap<>();
+    private final ConcurrentHashMap<Long, CompletableFuture<KList<NativeStructureVolume>>> queryBuilds =
+            new ConcurrentHashMap<>();
+
+    private NativeStructureVolumeIndex(Context context) {
+        this.context = Objects.requireNonNull(context, "Native structure volume context must not be null");
+        this.origins = this::buildOriginVolumes;
+    }
+
+    private NativeStructureVolumeIndex(OriginResolver origins) {
+        this.context = null;
+        this.origins = Objects.requireNonNull(origins, "Native structure origin resolver must not be null");
+    }
+
+    public static void install(Engine engine, Context context) {
+        Objects.requireNonNull(engine, "Native structure volume index requires an engine");
+        INDEXES.put(engine, new NativeStructureVolumeIndex(context));
+    }
+
+    public static void uninstall(Engine engine) {
+        if (engine != null) {
+            INDEXES.remove(engine);
+        }
+    }
+
+    public static KList<NativeStructureVolume> volumes(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+        NativeStructureVolumeIndex index = engine == null ? null : INDEXES.get(engine);
+        return index == null ? NativeStructureVolume.NONE : index.resolve(engine, minX, minZ, maxX, maxZ);
+    }
+
+    static NativeStructureVolumeIndex forTesting(OriginResolver origins) {
+        return new NativeStructureVolumeIndex(origins);
+    }
+
+    static int originReachChunks() {
+        return ORIGIN_REACH_CHUNKS;
+    }
+
+    KList<NativeStructureVolume> resolve(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+        int fromChunkX = Math.min(minX, maxX) >> 4;
+        int toChunkX = Math.max(minX, maxX) >> 4;
+        int fromChunkZ = Math.min(minZ, maxZ) >> 4;
+        int toChunkZ = Math.max(minZ, maxZ) >> 4;
+        KList<NativeStructureVolume> matches = null;
+        for (int chunkX = fromChunkX; chunkX <= toChunkX; chunkX++) {
+            for (int chunkZ = fromChunkZ; chunkZ <= toChunkZ; chunkZ++) {
+                for (NativeStructureVolume volume : chunkVolumes(engine, chunkX, chunkZ)) {
+                    if (!volume.intersectsRect(minX, minZ, maxX, maxZ)) {
+                        continue;
+                    }
+                    if (matches == null) {
+                        matches = new KList<>();
+                    }
+                    if (!matches.contains(volume)) {
+                        matches.add(volume);
+                    }
+                }
+            }
+        }
+        return matches == null ? NativeStructureVolume.NONE : matches;
+    }
+
+    private KList<NativeStructureVolume> chunkVolumes(Engine engine, int chunkX, int chunkZ) {
+        return cached(queryCache, queryBuilds, chunkKey(chunkX, chunkZ),
+                () -> buildChunkVolumes(engine, chunkX, chunkZ));
+    }
+
+    private KList<NativeStructureVolume> buildChunkVolumes(Engine engine, int chunkX, int chunkZ) {
+        int minX = chunkX << 4;
+        int minZ = chunkZ << 4;
+        int maxX = minX + 15;
+        int maxZ = minZ + 15;
+        KList<NativeStructureVolume> volumes = null;
+        for (int originX = chunkX - ORIGIN_REACH_CHUNKS; originX <= chunkX + ORIGIN_REACH_CHUNKS; originX++) {
+            for (int originZ = chunkZ - ORIGIN_REACH_CHUNKS; originZ <= chunkZ + ORIGIN_REACH_CHUNKS; originZ++) {
+                for (NativeStructureVolume volume : originVolumes(engine, originX, originZ)) {
+                    if (!volume.intersectsRect(minX, minZ, maxX, maxZ)) {
+                        continue;
+                    }
+                    if (volumes == null) {
+                        volumes = new KList<>();
+                    }
+                    volumes.add(volume);
+                }
+            }
+        }
+        return volumes == null ? NativeStructureVolume.NONE : volumes;
+    }
+
+    KList<NativeStructureVolume> originVolumes(Engine engine, int chunkX, int chunkZ) {
+        return cached(originCache, originBuilds, chunkKey(chunkX, chunkZ),
+                () -> origins.volumesAt(engine, chunkX, chunkZ));
+    }
+
+    private KList<NativeStructureVolume> buildOriginVolumes(Engine engine, int chunkX, int chunkZ) {
+        ChunkGeneratorStructureState state = context.structureState().get();
+        ChunkGenerator generator = context.generator().get();
+        BiomeSource biomeSource = context.biomeSource().get();
+        if (state == null || generator == null || biomeSource == null) {
+            return NativeStructureVolume.NONE;
+        }
+        Registry<Structure> registry = context.registryAccess().lookupOrThrow(Registries.STRUCTURE);
+        Bindings bindings = new Bindings(state, generator, biomeSource);
+        KList<NativeStructureVolume> volumes = appendPlannedVolumes(engine, bindings, registry, chunkX, chunkZ, null);
+        volumes = appendVanillaVolumes(engine, bindings, registry, chunkX, chunkZ, volumes);
+        return volumes == null ? NativeStructureVolume.NONE : volumes;
+    }
+
+    private KList<NativeStructureVolume> appendPlannedVolumes(Engine engine, Bindings bindings,
+                                                             Registry<Structure> registry, int chunkX, int chunkZ,
+                                                             KList<NativeStructureVolume> volumes) {
+        KList<NativeStructureStartPlan> plans;
+        try {
+            plans = NativeStructurePlacementPlanner.plansAt(engine, chunkX, chunkZ);
+        } catch (RuntimeException | Error error) {
+            warnOnce("iris-placements", error);
+            return volumes;
+        }
+
+        KList<NativeStructureVolume> target = volumes;
+        for (NativeStructureStartPlan plan : plans) {
+            IrisNativeStructureDecision decision = NativeStructurePlacementPlanner.decisionFor(plan);
+            if (!decision.generate()) {
+                continue;
+            }
+            Identifier identifier = Identifier.tryParse(plan.source().getStructure());
+            if (identifier == null) {
+                continue;
+            }
+            Structure structure = registry.getValue(identifier);
+            if (structure == null) {
+                continue;
+            }
+            String structureId = identifier.toString();
+            try {
+                StructureStart generated = NativeStructureFactory.generate(
+                        generationContext(engine, bindings), registry.wrapAsHolder(structure), plan, 0);
+                target = appendPieces(target, structureId, generated);
+            } catch (RuntimeException | Error error) {
+                warnOnce(structureId, error);
+            }
+        }
+        return target;
+    }
+
+    private KList<NativeStructureVolume> appendVanillaVolumes(Engine engine, Bindings bindings,
+                                                             Registry<Structure> registry, int chunkX, int chunkZ,
+                                                             KList<NativeStructureVolume> volumes) {
+        ChunkPos chunkPos = new ChunkPos(chunkX, chunkZ);
+        IntBinaryOperator surfaceHeight = surfaceHeight(engine);
+        int worldMinY = context.heightAccessor().getMinY();
+        int worldMaxYExclusive = worldMinY + context.heightAccessor().getHeight();
+        KList<NativeStructureVolume> target = volumes;
+        for (Holder<StructureSet> setHolder : bindings.state().possibleStructureSets()) {
+            StructureSet set = setHolder.value();
+            if (!set.placement().isStructureChunk(bindings.state(), chunkX, chunkZ)) {
+                continue;
+            }
+            for (StructureSet.StructureSelectionEntry entry : set.structures()) {
+                Holder<Structure> holder = entry.structure();
+                Structure structure = holder.value();
+                Identifier identifier = registry.getKey(structure);
+                if (identifier == null) {
+                    continue;
+                }
+                String structureId = identifier.toString();
+                boolean undergroundStep = NativeStructureVegetationClearer.isUndergroundStep(structure.step());
+                try {
+                    IrisNativeStructureDecision decision = NativeStructureGenerationPolicy.resolve(
+                            engine, structureId, undergroundStep);
+                    if (!decision.generate()) {
+                        continue;
+                    }
+                    StructureStart generated = structure.generate(
+                            holder,
+                            context.levelKey(),
+                            context.registryAccess(),
+                            bindings.generator(),
+                            bindings.biomeSource(),
+                            bindings.state().randomState(),
+                            context.templateManager(),
+                            bindings.state().getLevelSeed(),
+                            chunkPos,
+                            0,
+                            context.heightAccessor(),
+                            structure.biomes()::contains
+                    );
+                    if (generated == null || !generated.isValid()) {
+                        continue;
+                    }
+                    NativeStructureVerticalPlacer.applyVerticalPlacement(
+                            generated,
+                            structureId,
+                            decision.yShift(),
+                            bindings.generator().getSeaLevel(),
+                            worldMinY,
+                            worldMaxYExclusive,
+                            undergroundStep,
+                            decision.preserveSourceY(),
+                            decision.yBand(),
+                            surfaceHeight);
+                    target = appendPieces(target, structureId, generated);
+                } catch (RuntimeException | Error error) {
+                    warnOnce(structureId, error);
+                }
+            }
+        }
+        return target;
+    }
+
+    private NativeStructureFactory.GenerationContext generationContext(Engine engine, Bindings bindings) {
+        return new NativeStructureFactory.GenerationContext(
+                context.registryAccess(),
+                bindings.generator(),
+                bindings.biomeSource(),
+                bindings.state().randomState(),
+                context.templateManager(),
+                bindings.state().getLevelSeed(),
+                context.levelKey(),
+                context.heightAccessor(),
+                biome -> true,
+                bindings.generator().getSeaLevel(),
+                surfaceHeight(engine)
+        );
+    }
+
+    private record Bindings(ChunkGeneratorStructureState state, ChunkGenerator generator, BiomeSource biomeSource) {
+    }
+
+    @FunctionalInterface
+    interface OriginResolver {
+        KList<NativeStructureVolume> volumesAt(Engine engine, int chunkX, int chunkZ);
+    }
+
+    private static IntBinaryOperator surfaceHeight(Engine engine) {
+        return (x, z) -> engine.getHeight(x, z, true) + engine.getMinHeight();
+    }
+
+    static KList<NativeStructureVolume> appendPieces(KList<NativeStructureVolume> volumes,
+                                                     String structureId, StructureStart start) {
+        if (start == null || !start.isValid()) {
+            return volumes;
+        }
+        KList<NativeStructureVolume> target = volumes;
+        for (StructurePiece piece : start.getPieces()) {
+            BoundingBox bounds = piece.getBoundingBox();
+            if (target == null) {
+                target = new KList<>();
+            }
+            target.add(new NativeStructureVolume(structureId,
+                    bounds.minX(), bounds.minY(), bounds.minZ(),
+                    bounds.maxX(), bounds.maxY(), bounds.maxZ()));
+        }
+        return target;
+    }
+
+    private KList<NativeStructureVolume> cached(Map<Long, KList<NativeStructureVolume>> cache,
+                                                ConcurrentHashMap<Long, CompletableFuture<KList<NativeStructureVolume>>> builds,
+                                                long key, Supplier<KList<NativeStructureVolume>> loader) {
+        synchronized (cache) {
+            KList<NativeStructureVolume> hit = cache.get(key);
+            if (hit != null) {
+                return hit;
+            }
+        }
+
+        CompletableFuture<KList<NativeStructureVolume>> future = new CompletableFuture<>();
+        CompletableFuture<KList<NativeStructureVolume>> existing = builds.putIfAbsent(key, future);
+        if (existing != null) {
+            return existing.join();
+        }
+
+        try {
+            KList<NativeStructureVolume> built = loader.get();
+            synchronized (cache) {
+                cache.put(key, built);
+            }
+            future.complete(built);
+            return built;
+        } catch (RuntimeException | Error error) {
+            future.completeExceptionally(error);
+            throw error;
+        } finally {
+            builds.remove(key, future);
+        }
+    }
+
+    private static void warnOnce(String structureId, Throwable error) {
+        if (WARNED_RESOLUTION_FAILURES.add(structureId)) {
+            IrisLogging.warn("Native structure volume resolution failed for '" + structureId
+                    + "'; objects will not be vetoed against it: "
+                    + error.getClass().getSimpleName() + ":" + error.getMessage());
+        }
+    }
+
+    private static long chunkKey(int chunkX, int chunkZ) {
+        return ((long) chunkX << 32) ^ (chunkZ & 0xffffffffL);
+    }
+
+    private static Map<Long, KList<NativeStructureVolume>> lru(int capacity) {
+        return new LinkedHashMap<>(16, 0.75F, true) {
+            @Override
+            protected boolean removeEldestEntry(Map.Entry<Long, KList<NativeStructureVolume>> eldest) {
+                return size() > capacity;
+            }
+        };
+    }
+
+    /**
+     * The generator, biome source and structure state arrive as suppliers so an installed index never holds the
+     * level (and through it the engine) strongly. That keeps the weakly keyed registry collectable on world unload.
+     */
+    public record Context(
+            RegistryAccess registryAccess,
+            StructureTemplateManager templateManager,
+            ResourceKey<Level> levelKey,
+            LevelHeightAccessor heightAccessor,
+            Supplier<ChunkGenerator> generator,
+            Supplier<BiomeSource> biomeSource,
+            Supplier<ChunkGeneratorStructureState> structureState
+    ) {
+    }
+}

adapters/modded-common/src/main/java/art/arcane/iris/modded/IrisModdedChunkGenerator.java

@@ -350,6 +350,7 @@ public final class IrisModdedChunkGenerator extends ChunkGenerator {
         requireCompletedShutdown(engine);
         unloading = false;
         Engine bound = bindEngine(level);
+        nativeStructures.installVolumeIndex(level, bound);
         // Bind time: a feature-order cycle is reported here, once, and degrades to features-off. Non-waiting for
         // the same reason as repointAndBind: this method owns the generator monitor.
         importedFeatures.prepareWithoutWaiting(bound);

adapters/modded-common/src/main/java/art/arcane/iris/modded/ModdedNativeStructureStage.java

@@ -36,6 +36,7 @@ import art.arcane.iris.nativegen.NativeStructureTerrainIntegrator;
 import art.arcane.iris.nativegen.NativeStructureVegetationClearer;
 import art.arcane.iris.nativegen.NativeStructureVerticalPlacer;
 import art.arcane.iris.nativegen.NativeStructureVanillaLocator;
+import art.arcane.iris.nativegen.NativeStructureVolumeIndex;
 import art.arcane.iris.nativegen.WorldgenTerrainHeightmaps;
 import art.arcane.iris.spi.PlatformBlockState;
 import art.arcane.volmlib.util.math.RNG;
@@ -50,10 +51,13 @@ import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.Identifier;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.LevelHeightAccessor;
 import net.minecraft.world.level.StructureManager;
 import net.minecraft.world.level.WorldGenLevel;
 import net.minecraft.world.level.block.state.BlockState;
+import net.minecraft.world.level.biome.BiomeSource;
 import net.minecraft.world.level.chunk.ChunkAccess;
+import net.minecraft.world.level.chunk.ChunkGenerator;
 import net.minecraft.world.level.levelgen.GenerationStep;
 import net.minecraft.world.level.levelgen.RandomSupport;
 import net.minecraft.world.level.levelgen.WorldgenRandom;
@@ -63,6 +67,7 @@ import net.minecraft.world.level.levelgen.structure.Structure;
 import net.minecraft.world.level.levelgen.structure.StructureStart;
 import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplateManager;
 
+import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
@@ -87,6 +92,23 @@ final class ModdedNativeStructureStage {
         this.generator = generator;
     }
 
+    void installVolumeIndex(ServerLevel level, Engine engine) {
+        WeakReference<ServerLevel> levelReference = new WeakReference<>(level);
+        WeakReference<ChunkGenerator> generatorReference = new WeakReference<>(generator);
+        WeakReference<BiomeSource> biomeSourceReference = new WeakReference<>(generator.structureBiomeSource);
+        NativeStructureVolumeIndex.install(engine, new NativeStructureVolumeIndex.Context(
+                level.registryAccess(),
+                level.getServer().getStructureManager(),
+                level.dimension(),
+                LevelHeightAccessor.create(level.getMinY(), level.getHeight()),
+                generatorReference::get,
+                biomeSourceReference::get,
+                () -> {
+                    ServerLevel active = levelReference.get();
+                    return active == null ? null : active.getChunkSource().getGeneratorState();
+                }));
+    }
+
     Pair<BlockPos, Holder<Structure>> findNearestIrisStructure(ServerLevel level,
                                                               HolderSet<Structure> holders,
                                                               BlockPos pos, int radius, boolean findUnexplored,

adapters/modded-common/src/main/java/art/arcane/iris/modded/service/ModdedStudioHotloadService.java

@@ -23,6 +23,7 @@ import art.arcane.iris.core.loader.IrisData;
 import art.arcane.iris.core.tools.WorldMaintenance;
 import art.arcane.iris.engine.framework.Engine;
 import art.arcane.iris.engine.framework.EnginePlatformHooks;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
 import art.arcane.iris.engine.object.IrisDimension;
 import art.arcane.iris.engine.object.IrisDimensionRuntimeContract;
 import art.arcane.iris.engine.object.IrisWorld;
@@ -30,6 +31,7 @@ import art.arcane.iris.modded.IrisModdedChunkGenerator;
 import art.arcane.iris.modded.ModdedDimensionManager;
 import art.arcane.iris.modded.ModdedForcedDatapack;
 import art.arcane.iris.modded.ModdedWorkspaceGenerator;
+import art.arcane.iris.nativegen.NativeStructureVolumeIndex;
 import art.arcane.iris.modded.command.ModdedPregenJob;
 import art.arcane.volmlib.util.collection.KList;
 import art.arcane.volmlib.util.io.ReactiveFolder;
@@ -88,6 +90,11 @@ public final class ModdedStudioHotloadService implements ModdedTickableService,
         writeWorkspace(engine, "workspace refresh");
     }
 
+    @Override
+    public KList<NativeStructureVolume> nativeStructureVolumes(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+        return NativeStructureVolumeIndex.volumes(engine, minX, minZ, maxX, maxZ);
+    }
+
     @Override
     public void refreshDatapackWorkspace(Engine engine) {
         IrisData data = engine.getData();

build.gradle

@@ -127,6 +127,8 @@ nmsBindings.each { key, value ->
                 rootProject.file('adapters/minecraft-common/src/main/java/art/arcane/iris/nativegen/NativeStructureStartInjector.java').absolutePath)
             systemProperty('iris.nativeStructureGenerationKeysSource',
                 rootProject.file('adapters/minecraft-common/src/main/java/art/arcane/iris/nativegen/NativeStructureGenerationKeys.java').absolutePath)
+            systemProperty('iris.nativeStructureVolumeIndexSource',
+                rootProject.file('adapters/minecraft-common/src/main/java/art/arcane/iris/nativegen/NativeStructureVolumeIndex.java').absolutePath)
             systemProperty('iris.customBiomeSource',
                 rootProject.file("adapters/bukkit/nms/${key}/src/main/java/art/arcane/iris/core/nms/${key}/CustomBiomeSource.java").absolutePath)
             systemProperty('iris.vanillaStructureBiomesSource',

core/src/main/java/art/arcane/iris/core/ServerConfigurator.java

@@ -80,6 +80,7 @@ import art.arcane.iris.core.localization.IrisLanguage;
 import art.arcane.volmlib.util.localization.MessageArgument;
 public class ServerConfigurator {
     private static final Object DATAPACK_INSTALL_LOCK = new Object();
+    private static final String CODE_WORKSPACE_SUFFIX = ".code-workspace";
 
     public static void configure() {
         IrisSettings.IrisSettingsAutoconfiguration s = IrisSettings.get().getAutoConfiguration();
@@ -266,50 +267,71 @@ public class ServerConfigurator {
     public static DatapackInstallResult installDataPacksIfChanged(boolean fullInstall) {
         synchronized (DATAPACK_INSTALL_LOCK) {
             File packsDir = IrisPlatforms.get().dataFolder("packs");
-            String current;
+            File cacheFile = new File(IrisPlatforms.get().dataFolder("cache"), "datapack-fingerprint");
+            FingerprintCache cached = readFingerprintCache(cacheFile.toPath());
+            PackFingerprint fingerprint;
             try {
-                current = computePackFingerprint(packsDir);
+                fingerprint = resolvePackFingerprint(packsDir, cached.metadata(), cached.content());
             } catch (RuntimeException exception) {
                 IrisLogging.reportError("Unable to fingerprint Iris packs safely", exception);
                 return DatapackInstallResult.failedResult();
             }
-            File cacheFile = new File(IrisPlatforms.get().dataFolder("cache"), "datapack-fingerprint");
+            String current = fingerprint.content();
-            String cached = "";
+            if (!current.isEmpty() && current.equals(cached.content())) {
-            if (cacheFile.exists()) {
+                if (!fingerprint.metadata().equals(cached.metadata())) {
-                try {
+                    writeFingerprintCache(cacheFile.toPath(), fingerprint);
-                    cached = Files.readString(cacheFile.toPath(), StandardCharsets.UTF_8).trim();
-                } catch (IOException e) {
-                    cached = "";
                 }
-            }
-            if (!current.isEmpty() && current.equals(cached)) {
                 IrisLogging.debug("Data packs unchanged, skipping install.");
                 return DatapackInstallResult.unchangedResult();
             }
             DatapackInstallResult result = installDataPacksLocked(resolveDataFixer(), fullInstall);
             if (result.succeeded()) {
-                try {
+                writeFingerprintCache(cacheFile.toPath(), fingerprint);
-                    writeFingerprintAtomic(cacheFile.toPath(), current);
-                } catch (IOException e) {
-                    IrisLogging.warn("Failed to write datapack fingerprint cache: " + e.getMessage());
-                }
             }
             return result;
         }
     }
 
+    static PackFingerprint resolvePackFingerprint(File packsDir, String cachedMetadata, String cachedContent) {
+        String metadata = computePackMetadataDigest(packsDir);
+        if (!metadata.isEmpty()
+                && metadata.equals(cachedMetadata)
+                && cachedContent != null
+                && !cachedContent.isEmpty()) {
+            return new PackFingerprint(metadata, cachedContent);
+        }
+        return new PackFingerprint(metadata, computePackFingerprint(packsDir));
+    }
+
+    public static String computePackMetadataDigest(File packsDir) {
+        Path root = resolveFingerprintRoot(packsDir);
+        if (root == null) {
+            return "";
+        }
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            List<FingerprintEntry> entries = collectFingerprintEntries(root.toRealPath());
+            entries.sort(Comparator.comparing(FingerprintEntry::relativePath));
+            for (FingerprintEntry entry : entries) {
+                BasicFileAttributes attributes = Files.readAttributes(
+                        entry.source(), BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
+                byte[] relativePath = entry.relativePath().getBytes(StandardCharsets.UTF_8);
+                updateDigestInt(digest, relativePath.length);
+                digest.update(relativePath);
+                updateDigestLong(digest, attributes.size());
+                updateDigestLong(digest, attributes.lastModifiedTime().toMillis());
+            }
+            return HexFormat.of().formatHex(digest.digest());
+        } catch (IOException exception) {
+            throw new UncheckedIOException("Unable to fingerprint Iris packs at " + root, exception);
+        } catch (NoSuchAlgorithmException e) {
+            throw new IllegalStateException("SHA-256 not available", e);
+        }
+    }
+
     public static String computePackFingerprint(File packsDir) {
-        if (packsDir == null) {
+        Path root = resolveFingerprintRoot(packsDir);
-            return "";
+        if (root == null) {
-        }
-        Path root = packsDir.toPath().toAbsolutePath().normalize();
-        if (!Files.exists(root, LinkOption.NOFOLLOW_LINKS)) {
-            return "";
-        }
-        if (!Files.isDirectory(root)) {
-            if (Files.isSymbolicLink(root)) {
-                throw new IllegalArgumentException("Iris packs root target is missing or unsafe: " + root);
-            }
             return "";
         }
         try {
@@ -340,6 +362,45 @@ public class ServerConfigurator {
         }
     }
 
+    private static Path resolveFingerprintRoot(File packsDir) {
+        if (packsDir == null) {
+            return null;
+        }
+        Path root = packsDir.toPath().toAbsolutePath().normalize();
+        if (!Files.exists(root, LinkOption.NOFOLLOW_LINKS)) {
+            return null;
+        }
+        if (!Files.isDirectory(root)) {
+            if (Files.isSymbolicLink(root)) {
+                throw new IllegalArgumentException("Iris packs root target is missing or unsafe: " + root);
+            }
+            return null;
+        }
+        return root;
+    }
+
+    private static FingerprintCache readFingerprintCache(Path cacheFile) {
+        if (!Files.isRegularFile(cacheFile)) {
+            return new FingerprintCache("", "");
+        }
+        try {
+            List<String> lines = Files.readAllLines(cacheFile, StandardCharsets.UTF_8);
+            String content = lines.isEmpty() ? "" : lines.getFirst().trim();
+            String metadata = lines.size() > 1 ? lines.get(1).trim() : "";
+            return new FingerprintCache(content, metadata);
+        } catch (IOException e) {
+            return new FingerprintCache("", "");
+        }
+    }
+
+    private static void writeFingerprintCache(Path cacheFile, PackFingerprint fingerprint) {
+        try {
+            writeFingerprintAtomic(cacheFile, fingerprint.content() + "\n" + fingerprint.metadata());
+        } catch (IOException e) {
+            IrisLogging.warn("Failed to write datapack fingerprint cache: " + e.getMessage());
+        }
+    }
+
     private static void writeFingerprintAtomic(Path target, String fingerprint) throws IOException {
         Path absoluteTarget = target.toAbsolutePath().normalize();
         Path parent = absoluteTarget.getParent();
@@ -368,7 +429,7 @@ public class ServerConfigurator {
         try (Stream<Path> children = Files.list(root)) {
             for (Path child : children.toList()) {
                 String childName = child.getFileName().toString();
-                if (PackDirectoryResolver.isHiddenName(childName)) {
+                if (PackDirectoryResolver.isHiddenName(childName) || isGeneratedPackFile(childName)) {
                     continue;
                 }
                 if (Files.isSymbolicLink(child)) {
@@ -406,7 +467,8 @@ public class ServerConfigurator {
 
             @Override
             public FileVisitResult visitFile(Path file, BasicFileAttributes attributes) throws IOException {
-                if (PackDirectoryResolver.isHiddenName(file.getFileName().toString())) {
+                String fileName = file.getFileName().toString();
+                if (PackDirectoryResolver.isHiddenName(fileName) || isGeneratedPackFile(fileName)) {
                     return FileVisitResult.CONTINUE;
                 }
                 if (attributes.isSymbolicLink() || Files.isSymbolicLink(file)) {
@@ -427,9 +489,19 @@ public class ServerConfigurator {
         });
     }
 
+    private static boolean isGeneratedPackFile(String name) {
+        return name != null && name.endsWith(CODE_WORKSPACE_SUFFIX);
+    }
+
     private record FingerprintEntry(Path source, String relativePath) {
     }
 
+    record PackFingerprint(String metadata, String content) {
+    }
+
+    private record FingerprintCache(String content, String metadata) {
+    }
+
     private static void updateDigestInt(MessageDigest digest, int value) {
         for (int shift = Integer.SIZE - Byte.SIZE; shift >= 0; shift -= Byte.SIZE) {
             digest.update((byte) (value >>> shift));

core/src/main/java/art/arcane/iris/core/datapack/DatapackIngestService.java

@@ -352,9 +352,13 @@ public final class DatapackIngestService {
         boolean successful = true;
         for (Entry entry : manifest.entries) {
             File stagedDir = new File(stagingDir, entry.id);
+            if (isRecordedUnchangedInstall(stagedDir, worldFolders, entry, stripOverrides)) {
+                continue;
+            }
             if (!isUsableStaging(stagedDir, entry)) {
                 IrisLogging.error("Managed datapack staging is unusable for '" + entry.id
                         + "' at " + stagedDir.getPath());
+                forgetInstallMetadata(entry);
                 successful = false;
                 continue;
             }
@@ -364,8 +368,10 @@ public final class DatapackIngestService {
                     IrisLogging.warn("Repaired installed datapack '" + entry.id
                             + "' from Iris staging before datapack compilation.");
                 }
+                recordInstallMetadata(stagedDir, worldFolders, entry);
             } catch (IOException e) {
                 IrisLogging.reportError(e);
+                forgetInstallMetadata(entry);
                 successful = false;
             }
         }
@@ -373,6 +379,127 @@ public final class DatapackIngestService {
         return successful;
     }
 
+    private static boolean isRecordedUnchangedInstall(
+            File stagedDir,
+            KList<File> worldFolders,
+            Entry entry,
+            boolean stripOverrides
+    ) {
+        if (entry.stagingMetadata == null || entry.stagingMetadata.isBlank()
+                || entry.installMetadata == null || entry.installMetadata.size() != worldFolders.size()) {
+            return false;
+        }
+        try {
+            if (!isRecordedManagedDirectory(stagedDir, entry)
+                    || !entry.stagingMetadata.equals(metadataDigest(stagedDir))) {
+                return false;
+            }
+            for (File worldFolder : worldFolders) {
+                File target = new File(worldFolder, entry.id);
+                if (!isRecordedManagedDirectory(target, entry)
+                        || new File(target, OVERRIDES_STRIPPED_MARKER).isFile() != stripOverrides) {
+                    return false;
+                }
+                String recorded = entry.installMetadata.get(installMetadataKey(target));
+                if (recorded == null || !recorded.equals(metadataDigest(target))) {
+                    return false;
+                }
+            }
+            return true;
+        } catch (IOException e) {
+            IrisLogging.debug("Managed datapack '" + entry.id
+                    + "' requires full verification: " + e.getMessage());
+            return false;
+        }
+    }
+
+    private static boolean isRecordedManagedDirectory(File directory, Entry entry) throws IOException {
+        Path path = directory.toPath();
+        if (!Files.isDirectory(path, LinkOption.NOFOLLOW_LINKS) || Files.isSymbolicLink(path)) {
+            return false;
+        }
+        if (!new File(directory, "pack.mcmeta").isFile()) {
+            return false;
+        }
+        Ownership ownership = readOwnershipOrNull(directory);
+        return ownership != null
+                && ownershipSourceMatches(ownership, entry)
+                && Objects.equals(ownership.versionId, entry.versionId)
+                && Objects.equals(ownership.versionNumber, entry.versionNumber)
+                && Objects.equals(ownership.sha1, entry.sha1);
+    }
+
+    private static void recordInstallMetadata(File stagedDir, KList<File> worldFolders, Entry entry) {
+        try {
+            Map<String, String> recorded = new HashMap<>();
+            for (File worldFolder : worldFolders) {
+                File target = new File(worldFolder, entry.id);
+                recorded.put(installMetadataKey(target), metadataDigest(target));
+            }
+            entry.stagingMetadata = metadataDigest(stagedDir);
+            entry.installMetadata = recorded;
+        } catch (IOException e) {
+            IrisLogging.debug("Unable to record managed datapack metadata for '" + entry.id
+                    + "': " + e.getMessage());
+            forgetInstallMetadata(entry);
+        }
+    }
+
+    private static void forgetInstallMetadata(Entry entry) {
+        entry.stagingMetadata = "";
+        entry.installMetadata = new HashMap<>();
+    }
+
+    private static String installMetadataKey(File target) {
+        return target.toPath().toAbsolutePath().normalize().toString();
+    }
+
+    private static String metadataDigest(File root) throws IOException {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            Path rootPath = root.toPath().toAbsolutePath().normalize();
+            List<Path> entries = new ArrayList<>();
+            try (Stream<Path> paths = Files.walk(rootPath)) {
+                Iterator<Path> iterator = paths.iterator();
+                int pathCount = 0;
+                while (iterator.hasNext()) {
+                    Path path = iterator.next();
+                    if (path.equals(rootPath) || isFinderMetadata(path)) {
+                        continue;
+                    }
+                    pathCount++;
+                    if (pathCount > MAX_MANAGED_PATHS) {
+                        throw new IOException("Datapack contains more than " + MAX_MANAGED_PATHS + " paths");
+                    }
+                    if (Files.isSymbolicLink(path)) {
+                        throw new IOException("Datapack contains a symbolic link: " + path);
+                    }
+                    entries.add(path);
+                }
+            }
+            entries.sort(Comparator.comparing(path -> rootPath.relativize(path).toString()));
+            for (Path entry : entries) {
+                String relative = rootPath.relativize(entry).toString().replace(File.separatorChar, '/');
+                byte[] relativeBytes = relative.getBytes(StandardCharsets.UTF_8);
+                BasicFileAttributes attributes = Files.readAttributes(
+                        entry, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
+                if (!attributes.isDirectory() && !attributes.isRegularFile()) {
+                    throw new IOException("Datapack contains an unsupported filesystem entry: " + entry);
+                }
+                digest.update((byte) (attributes.isDirectory() ? 1 : 2));
+                updateDigestInt(digest, relativeBytes.length);
+                digest.update(relativeBytes);
+                if (!attributes.isDirectory()) {
+                    updateDigestLong(digest, attributes.size());
+                    updateDigestLong(digest, attributes.lastModifiedTime().toMillis());
+                }
+            }
+            return hex(digest.digest());
+        } catch (NoSuchAlgorithmException e) {
+            throw new IOException("SHA-256 algorithm unavailable", e);
+        }
+    }
+
     static boolean recoverBeforeReapply(File root, List<File> worldFolders) {
         try {
             recoverTransactions(root, worldFolders);
@@ -1166,6 +1293,7 @@ public final class DatapackIngestService {
     }
 
     private static void recordInstallResult(VolmitSender sender, Report report, Entry entry, InstallResult result, String versionNumber) {
+        forgetInstallMetadata(entry);
         if (result.changed()) {
             report.updated.add(entry.id + " (" + safe(versionNumber) + ")");
             report.requiresRestart = true;
@@ -2805,8 +2933,11 @@ public final class DatapackIngestService {
         copy.lastModified = resolved.lastModified;
         copy.installedEpoch = resolved.installedEpoch;
         copy.structuresImported = resolved.structuresImported;
+        copy.stagingMetadata = resolved.stagingMetadata;
         copy.structureKeys = new ArrayList<>(copyList(resolved.structureKeys));
         copy.templateKeys = new ArrayList<>(copyList(resolved.templateKeys));
+        copy.installMetadata = new HashMap<>(Objects.requireNonNullElseGet(
+                resolved.installMetadata, Map::of));
         copy.importedTargets = new HashMap<>(Objects.requireNonNullElseGet(
                 resolved.importedTargets, Map::of));
         copy.importedBundles = new HashMap<>();
@@ -2915,6 +3046,8 @@ public final class DatapackIngestService {
             }
             entry.structureKeys = normalizeKeys(entry.structureKeys);
             entry.templateKeys = normalizeKeys(entry.templateKeys);
+            entry.stagingMetadata = entry.stagingMetadata == null ? "" : entry.stagingMetadata.trim();
+            entry.installMetadata = normalizeImportedTargets(entry.installMetadata);
             entry.importedTargets = normalizeImportedTargets(entry.importedTargets);
             entry.importedBundles = normalizeImportedBundles(entry.importedBundles);
             if (!urls.add(entry.url) || !ids.add(entry.id)) {
@@ -4472,8 +4605,10 @@ public final class DatapackIngestService {
         public String lastModified;
         public long installedEpoch;
         public boolean structuresImported;
+        public String stagingMetadata = "";
         public List<String> structureKeys = new ArrayList<>();
         public List<String> templateKeys = new ArrayList<>();
+        public Map<String, String> installMetadata = new HashMap<>();
         public Map<String, String> importedTargets = new HashMap<>();
         public Map<String, Map<String, String>> importedBundles = new HashMap<>();
     }

core/src/main/java/art/arcane/iris/core/nms/INMSBinding.java

@@ -26,6 +26,7 @@ import art.arcane.iris.core.nms.container.BlockProperty;
 import art.arcane.iris.core.nms.datapack.DataVersion;
 import art.arcane.iris.engine.data.chunk.TerrainChunk;
 import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
 import art.arcane.iris.engine.platform.PlatformChunkGenerator;
 import art.arcane.iris.spi.PlatformBlockState;
 import art.arcane.iris.spi.PlatformStructureHooks.JigsawSourceMetadata;
@@ -143,6 +144,14 @@ public interface INMSBinding {
         return false;
     }
 
+    /**
+     * World-space piece bounds of every native structure that will generate inside the given XZ rect. Bindings
+     * without native structure support answer with no volumes, which leaves the object veto inert.
+     */
+    default KList<NativeStructureVolume> nativeStructureVolumes(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+        return NativeStructureVolume.NONE;
+    }
+
     int getBiomeId(Biome biome);
 
     MCABiomeContainer newBiomeContainer(int min, int max, int[] data);

core/src/main/java/art/arcane/iris/core/project/IrisCodeWorkspace.java

@@ -35,7 +35,6 @@ import art.arcane.volmlib.util.io.IO;
 import art.arcane.volmlib.util.json.JSONArray;
 import art.arcane.volmlib.util.json.JSONObject;
 import art.arcane.volmlib.util.localization.MessageArgument;
-import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
 import org.dom4j.Document;
 import org.dom4j.Element;
 
@@ -43,7 +42,11 @@ import java.awt.Desktop;
 import java.awt.GraphicsEnvironment;
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
 import java.util.Objects;
+import java.util.Set;
 import java.util.UUID;
 
 @SuppressWarnings("ALL")
@@ -129,10 +132,7 @@ public class IrisCodeWorkspace {
         File ws = getCodeWorkspaceFile();
 
         try {
-            PrecisionStopwatch p = PrecisionStopwatch.start();
+            writeIfChanged(ws, createCodeWorkspaceConfig().toString(4));
-            JSONObject j = createCodeWorkspaceConfig();
-            IO.writeAll(ws, j.toString(4));
-            p.end();
             return true;
         } catch (Throwable e) {
             IrisLogging.reportError(e);
@@ -153,6 +153,13 @@ public class IrisCodeWorkspace {
         return createCodeWorkspaceConfig(true);
     }
 
+    private static void writeIfChanged(File target, String rendered) throws IOException {
+        if (target.isFile() && (rendered + "\n").equals(IO.readAll(target))) {
+            return;
+        }
+        IO.writeAll(target, rendered);
+    }
+
     private JSONObject createCodeWorkspaceConfig(boolean includeSchemas) {
         JSONObject ws = new JSONObject();
         JSONArray folders = new JSONArray();
@@ -184,16 +191,17 @@ public class IrisCodeWorkspace {
         settings.put("[json]", jc);
         settings.put("json.maxItemsComputed", 30000);
         JSONArray schemas = new JSONArray();
+        List<JSONObject> schemaEntries = new ArrayList<>();
         IrisData dm = null;
         if (includeSchemas) {
             dm = IrisData.get(project.getPath());
             for (ResourceLoader<?> r : dm.getLoaders().v()) {
                 if (r.supportsSchemas()) {
-                    schemas.put(r.buildSchema());
+                    schemaEntries.add(r.buildSchema());
                 }
             }
 
-            for (Class<?> i : dm.resolveSnippets()) {
+            for (Class<?> i : sortedSnippets(dm.resolveSnippets())) {
                 try {
                     String snipType = i.getDeclaredAnnotation(Snippet.class).value();
                     JSONObject o = new JSONObject();
@@ -205,7 +213,7 @@ public class IrisCodeWorkspace {
 
                     o.put("fileMatch", new JSONArray(fm.toArray()));
                     o.put("url", "./.iris/schema/snippet/" + snipType + "-schema.json");
-                    schemas.put(o);
+                    schemaEntries.add(o);
                     IrisData snippetData = dm;
                     File a = new File(snippetData.getDataFolder(), ".iris/schema/snippet/" + snipType + "-schema.json");
                     J.attemptAsync(() -> {
@@ -219,6 +227,11 @@ public class IrisCodeWorkspace {
                     e.printStackTrace();
                 }
             }
+
+            schemaEntries.sort(Comparator.comparing(entry -> entry.getString("url")));
+            for (JSONObject entry : schemaEntries) {
+                schemas.put(entry);
+            }
         }
 
         settings.put("json.schemas", schemas);
@@ -295,4 +308,10 @@ public class IrisCodeWorkspace {
         }
         return ws;
     }
+
+    private static List<Class<?>> sortedSnippets(Set<Class<?>> snippets) {
+        List<Class<?>> sorted = new ArrayList<>(snippets);
+        sorted.sort(Comparator.comparing(Class::getName));
+        return sorted;
+    }
 }

core/src/main/java/art/arcane/iris/engine/IrisEngine.java

@@ -25,6 +25,9 @@ import art.arcane.iris.engine.framework.EngineEffects;
 import art.arcane.iris.engine.framework.EngineMetrics;
 import art.arcane.iris.engine.framework.EngineMode;
 import art.arcane.iris.engine.framework.EnginePlatformHooks;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
+import art.arcane.iris.engine.framework.NativeStructureVolumeMemo;
+import art.arcane.volmlib.util.collection.KList;
 import art.arcane.iris.engine.framework.EngineTarget;
 import art.arcane.iris.engine.framework.EngineWorldManager;
 import art.arcane.iris.engine.framework.GenerationSessionException;
@@ -116,6 +119,9 @@ public class IrisEngine implements Engine {
     private final SeedManager seedManager;
     private final GenerationSessionManager generationSessions;
     private final EnginePlatformHooks platformHooks;
+    @Getter(AccessLevel.NONE)
+    @Setter(AccessLevel.NONE)
+    private final NativeStructureVolumeMemo nativeStructureVolumeMemo = new NativeStructureVolumeMemo();
     private final AtomicBoolean closing;
     @Setter(AccessLevel.NONE)
     volatile IrisEngineData engineData;
@@ -316,9 +322,15 @@ public class IrisEngine implements Engine {
     }
 
     public void hotloadSilently() {
+        nativeStructureVolumeMemo.clear();
         hotloader.hotloadSilently();
     }
 
+    @Override
+    public KList<NativeStructureVolume> getNativeStructureVolumes(int minX, int minZ, int maxX, int maxZ) {
+        return nativeStructureVolumeMemo.volumes(this, platformHooks, minX, minZ, maxX, maxZ);
+    }
+
     @Override
     public IrisEngineData getEngineData() {
         return engineDataStore.getEngineData();

core/src/main/java/art/arcane/iris/engine/framework/Engine.java

@@ -92,6 +92,15 @@ public interface Engine extends DataProvider, Fallible, BlockUpdater, Renderer,
 
     EnginePlatformHooks getPlatformHooks();
 
+    /**
+     * World-space native structure piece bounds overlapping the given XZ rect. The answer is a pure function of the
+     * seed, the registries and this pack's structure policy, so it never depends on generation order.
+     */
+    default KList<NativeStructureVolume> getNativeStructureVolumes(int minX, int minZ, int maxX, int maxZ) {
+        EnginePlatformHooks hooks = getPlatformHooks();
+        return hooks == null ? NativeStructureVolume.NONE : hooks.nativeStructureVolumes(this, minX, minZ, maxX, maxZ);
+    }
+
     int getBlockUpdatesPerSecond();
 
     void printMetrics(VolmitSender sender);

core/src/main/java/art/arcane/iris/engine/framework/EnginePlatformHooks.java

@@ -19,8 +19,17 @@
 package art.arcane.iris.engine.framework;
 
 import art.arcane.iris.engine.object.IrisDimension;
+import art.arcane.volmlib.util.collection.KList;
 
 public interface EnginePlatformHooks {
+    /**
+     * World-space piece bounds of every native structure that will generate inside the given XZ rect. Platforms
+     * without native structures return no volumes, which keeps the object veto free on those platforms.
+     */
+    default KList<NativeStructureVolume> nativeStructureVolumes(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+        return NativeStructureVolume.NONE;
+    }
+
     default void refreshWorkspace(Engine engine) {
     }
 

core/src/main/java/art/arcane/iris/engine/framework/NativeStructureVolume.java

@@ -0,0 +1,68 @@
+/*
+ * Iris is a World Generator for Minecraft Servers
+ * Copyright (c) 2026 Arcane Arts (Volmit Software)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package art.arcane.iris.engine.framework;
+
+import art.arcane.volmlib.util.collection.KList;
+
+/**
+ * World-space axis-aligned bounds of one native structure piece. Volumes are resolved from seed, registry and
+ * pack policy alone so the same query answers identically regardless of which chunks exist.
+ */
+public record NativeStructureVolume(
+        String structure,
+        int minX,
+        int minY,
+        int minZ,
+        int maxX,
+        int maxY,
+        int maxZ
+) {
+    public static final KList<NativeStructureVolume> NONE = new KList<>();
+
+    public static NativeStructureVolume of(String structure, int aX, int aY, int aZ, int bX, int bY, int bZ) {
+        return new NativeStructureVolume(
+                structure,
+                Math.min(aX, bX),
+                Math.min(aY, bY),
+                Math.min(aZ, bZ),
+                Math.max(aX, bX),
+                Math.max(aY, bY),
+                Math.max(aZ, bZ));
+    }
+
+    public boolean intersectsRect(int rectMinX, int rectMinZ, int rectMaxX, int rectMaxZ) {
+        return maxX >= rectMinX && minX <= rectMaxX && maxZ >= rectMinZ && minZ <= rectMaxZ;
+    }
+
+    public boolean intersects(int boxMinX, int boxMinY, int boxMinZ, int boxMaxX, int boxMaxY, int boxMaxZ) {
+        return maxX >= boxMinX && minX <= boxMaxX
+                && maxY >= boxMinY && minY <= boxMaxY
+                && maxZ >= boxMinZ && minZ <= boxMaxZ;
+    }
+
+    public boolean contains(int x, int y, int z) {
+        return x >= minX && x <= maxX && y >= minY && y <= maxY && z >= minZ && z <= maxZ;
+    }
+
+    public boolean containsWithin(int x, int y, int z, int margin) {
+        return x >= minX - margin && x <= maxX + margin
+                && y >= minY - margin && y <= maxY + margin
+                && z >= minZ - margin && z <= maxZ + margin;
+    }
+}

core/src/main/java/art/arcane/iris/engine/framework/NativeStructureVolumeMemo.java

@@ -0,0 +1,94 @@
+/*
+ * Iris is a World Generator for Minecraft Servers
+ * Copyright (c) 2026 Arcane Arts (Volmit Software)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package art.arcane.iris.engine.framework;
+
+import art.arcane.volmlib.util.collection.KList;
+import it.unimi.dsi.fastutil.longs.Long2ObjectLinkedOpenHashMap;
+
+/**
+ * Chunk keyed memo in front of the platform volume hook. One chunk's object pass fires the same rect query dozens of
+ * times, so the hook is asked once per chunk column and every later object reuses that answer. Long keyed so the
+ * overwhelmingly common "no native structure anywhere near" lookup allocates nothing at all.
+ */
+public final class NativeStructureVolumeMemo {
+    private static final int MAX_CACHED_CHUNKS = 2_048;
+
+    private final Long2ObjectLinkedOpenHashMap<KList<NativeStructureVolume>> chunks =
+            new Long2ObjectLinkedOpenHashMap<>();
+
+    public KList<NativeStructureVolume> volumes(Engine engine, EnginePlatformHooks hooks,
+                                                int minX, int minZ, int maxX, int maxZ) {
+        if (hooks == null) {
+            return NativeStructureVolume.NONE;
+        }
+
+        int fromChunkX = Math.min(minX, maxX) >> 4;
+        int toChunkX = Math.max(minX, maxX) >> 4;
+        int fromChunkZ = Math.min(minZ, maxZ) >> 4;
+        int toChunkZ = Math.max(minZ, maxZ) >> 4;
+        KList<NativeStructureVolume> matches = null;
+        for (int chunkX = fromChunkX; chunkX <= toChunkX; chunkX++) {
+            for (int chunkZ = fromChunkZ; chunkZ <= toChunkZ; chunkZ++) {
+                for (NativeStructureVolume volume : chunkVolumes(engine, hooks, chunkX, chunkZ)) {
+                    if (!volume.intersectsRect(minX, minZ, maxX, maxZ)) {
+                        continue;
+                    }
+                    if (matches == null) {
+                        matches = new KList<>();
+                    }
+                    if (!matches.contains(volume)) {
+                        matches.add(volume);
+                    }
+                }
+            }
+        }
+        return matches == null ? NativeStructureVolume.NONE : matches;
+    }
+
+    public void clear() {
+        synchronized (chunks) {
+            chunks.clear();
+        }
+    }
+
+    private KList<NativeStructureVolume> chunkVolumes(Engine engine, EnginePlatformHooks hooks,
+                                                      int chunkX, int chunkZ) {
+        long key = ((long) chunkX << 32) ^ (chunkZ & 0xffffffffL);
+        synchronized (chunks) {
+            KList<NativeStructureVolume> hit = chunks.getAndMoveToFirst(key);
+            if (hit != null) {
+                return hit;
+            }
+        }
+
+        int minX = chunkX << 4;
+        int minZ = chunkZ << 4;
+        KList<NativeStructureVolume> resolved = hooks.nativeStructureVolumes(engine, minX, minZ, minX + 15, minZ + 15);
+        if (resolved == null) {
+            resolved = NativeStructureVolume.NONE;
+        }
+        synchronized (chunks) {
+            chunks.putAndMoveToFirst(key, resolved);
+            while (chunks.size() > MAX_CACHED_CHUNKS) {
+                chunks.removeLast();
+            }
+        }
+        return resolved;
+    }
+}

core/src/main/java/art/arcane/iris/engine/object/IrisObjectPlacementRunner.java

@@ -21,6 +21,7 @@ package art.arcane.iris.engine.object;
 import art.arcane.iris.core.loader.IrisData;
 import art.arcane.iris.engine.IrisComplex;
 import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
 import art.arcane.iris.engine.framework.PlacedObject;
 import art.arcane.iris.engine.framework.placer.HeightmapObjectPlacer;
 import art.arcane.iris.spi.IrisLogging;
@@ -343,6 +344,12 @@ final class IrisObjectPlacementRunner {
             return -1;
         }
 
+        int warpMargin = warped ? (int) Math.ceil(Math.abs(config.getWarp().getMultiplier()) / 2D) : 0;
+        if (!rawStructurePiece && nativeStructureVetoes(placer, config, spin, translating, translateOffset, ceilingHang,
+                yv < 0 && config.getMode() == ObjectPlaceMode.PAINT, warpMargin, x, y + yrand, z)) {
+            return -1;
+        }
+
         if (!config.isForcePlace() && !rawStructurePiece && (!config.getAllowedCollisions().isEmpty() || !config.getForbiddenCollisions().isEmpty())) {
             Engine engine = rdata.getEngine();
             IrisBlockVector offset = new IrisBlockVector(config.getTranslate().getX(), config.getTranslate().getY(), config.getTranslate().getZ());
@@ -841,6 +848,87 @@ final class IrisObjectPlacementRunner {
         return !wouldReplace && (rawStructurePiece || !air);
     }
 
+    /**
+     * Objects may never intersect a native structure piece. The rect query is the fast path: no native structures
+     * near this placement means no per block work at all. Only when the placement envelope meets a piece does the
+     * precise pass run, and the first solid block inside a piece rejects the whole object before any write.
+     */
+    private boolean nativeStructureVetoes(IObjectPlacer placer, IrisObjectPlacement config, SpinKernel spin,
+                                          boolean translating, IrisBlockVector translateOffset, boolean ceilingHang,
+                                          boolean paint, int warpMargin, int x, int y, int z) {
+        Engine engine = placer.getEngine();
+        if (engine == null) {
+            return false;
+        }
+
+        int margin = (Math.max(self.getW(), Math.max(self.getH(), self.getD())) / 2) + 1 + warpMargin;
+        if (translating) {
+            margin += Math.max(Math.abs(translateOffset.getBlockX()),
+                    Math.max(Math.abs(translateOffset.getBlockY()), Math.abs(translateOffset.getBlockZ())));
+        }
+
+        KList<NativeStructureVolume> volumes = engine.getNativeStructureVolumes(x - margin, z - margin, x + margin, z + margin);
+        if (volumes == null || volumes.isEmpty()) {
+            return false;
+        }
+
+        int envelopeMinY = paint ? Integer.MIN_VALUE : y - margin;
+        int envelopeMaxY = paint ? Integer.MAX_VALUE : y + margin;
+        boolean envelopeMeetsPiece = false;
+        for (NativeStructureVolume volume : volumes) {
+            if (volume.intersects(x - margin, envelopeMinY, z - margin, x + margin, envelopeMaxY, z + margin)) {
+                envelopeMeetsPiece = true;
+                break;
+            }
+        }
+
+        if (!envelopeMeetsPiece) {
+            return false;
+        }
+
+        self.readLock.lock();
+        try {
+            VectorMap<PlatformBlockState>.Cursor cursor = self.blocks.cursor();
+            while (cursor.next()) {
+                PlatformBlockState state = cursor.value();
+                if (state == null || isAirBlock(state)) {
+                    continue;
+                }
+
+                IrisBlockVector i = cursor.key().clone();
+                spin.rotate(i);
+                if (ceilingHang) {
+                    i.setY(-i.getBlockY());
+                }
+                if (translating) {
+                    i.add(translateOffset);
+                }
+
+                int xx = x + (int) Math.round(i.getX());
+                int zz = z + (int) Math.round(i.getZ());
+                int yy = paint
+                        ? (int) Math.round(i.getY()) + Math.floorDiv(self.h, 2)
+                                + placer.getHighest(xx, zz, self.getLoader(), config.isUnderwater())
+                        : y + (int) Math.round(i.getY());
+
+                for (NativeStructureVolume volume : volumes) {
+                    if (volume.containsWithin(xx, yy, zz, warpMargin)) {
+                        return true;
+                    }
+                }
+            }
+        } finally {
+            self.readLock.unlock();
+        }
+
+        return false;
+    }
+
+    private static boolean isAirBlock(PlatformBlockState state) {
+        String material = IrisObjectShaping.materialKey(state);
+        return material.equals("minecraft:air") || material.equals("minecraft:cave_air");
+    }
+
     private void warnImplausibleBedrockPlacement(IObjectPlacer placer, IrisObjectPlacement config, int x, int y, int z) {
         String key = self.getLoadKey();
         String fingerprint = (key == null ? "<null>" : key) + "|" + config.getMode();

core/src/test/java/art/arcane/iris/core/ServerConfiguratorDatapackFingerprintTest.java

@@ -107,6 +107,69 @@ public class ServerConfiguratorDatapackFingerprintTest {
         assertEquals(before, ServerConfigurator.computePackFingerprint(packsDir));
     }
 
+    @Test
+    public void computePackFingerprintIgnoresGeneratedCodeWorkspaceFiles() throws Exception {
+        File packsDir = tmp.newFolder("workspace-packs");
+        Path dimension = packsDir.toPath().resolve("overworld/dimensions/overworld.json");
+        Files.createDirectories(dimension.getParent());
+        Files.writeString(dimension, "authored", StandardCharsets.UTF_8);
+        String before = ServerConfigurator.computePackFingerprint(packsDir);
+
+        Path workspace = packsDir.toPath().resolve("overworld/overworld.code-workspace");
+        Files.writeString(workspace, "{\"folders\":[]}", StandardCharsets.UTF_8);
+
+        assertEquals("Iris-generated workspace files must not alter the fingerprint",
+                before, ServerConfigurator.computePackFingerprint(packsDir));
+
+        Files.writeString(workspace, "{\"folders\":[{\"path\":\".\"}]}", StandardCharsets.UTF_8);
+
+        assertEquals("Reordered workspace bytes must not alter the fingerprint",
+                before, ServerConfigurator.computePackFingerprint(packsDir));
+    }
+
+    @Test
+    public void resolvePackFingerprintReusesCachedContentWhileMetadataIsUnchanged() throws Exception {
+        File packsDir = tmp.newFolder("two-tier-packs");
+        Path dimension = packsDir.toPath().resolve("testpack/dimensions/overworld.json");
+        Files.createDirectories(dimension.getParent());
+        Files.writeString(dimension, "aaaa", StandardCharsets.UTF_8);
+        ServerConfigurator.PackFingerprint first =
+                ServerConfigurator.resolvePackFingerprint(packsDir, "", "");
+        assertEquals(ServerConfigurator.computePackFingerprint(packsDir), first.content());
+        assertNotEquals("", first.metadata());
+
+        FileTime originalMtime = Files.getLastModifiedTime(dimension);
+        Files.writeString(dimension, "bbbb", StandardCharsets.UTF_8);
+        Files.setLastModifiedTime(dimension, originalMtime);
+        ServerConfigurator.PackFingerprint reused =
+                ServerConfigurator.resolvePackFingerprint(packsDir, first.metadata(), first.content());
+
+        assertEquals("Unchanged metadata must reuse the cached content fingerprint",
+                first.content(), reused.content());
+
+        Files.setLastModifiedTime(dimension, FileTime.fromMillis(originalMtime.toMillis() + 5000L));
+        ServerConfigurator.PackFingerprint rehashed =
+                ServerConfigurator.resolvePackFingerprint(packsDir, first.metadata(), first.content());
+
+        assertNotEquals("Changed metadata must re-hash pack contents",
+                first.content(), rehashed.content());
+        assertEquals(ServerConfigurator.computePackFingerprint(packsDir), rehashed.content());
+    }
+
+    @Test
+    public void computePackMetadataDigestIgnoresGeneratedCodeWorkspaceFiles() throws Exception {
+        File packsDir = tmp.newFolder("metadata-workspace-packs");
+        Path dimension = packsDir.toPath().resolve("overworld/dimensions/overworld.json");
+        Files.createDirectories(dimension.getParent());
+        Files.writeString(dimension, "authored", StandardCharsets.UTF_8);
+        String before = ServerConfigurator.computePackMetadataDigest(packsDir);
+
+        Files.writeString(packsDir.toPath().resolve("overworld/overworld.code-workspace"),
+                "{\"folders\":[]}", StandardCharsets.UTF_8);
+
+        assertEquals(before, ServerConfigurator.computePackMetadataDigest(packsDir));
+    }
+
     @Test
     public void computePackFingerprintRejectsSymbolicLinks() throws Exception {
         File packsDir = tmp.newFolder("unsafe-packs");

core/src/test/java/art/arcane/iris/core/datapack/DatapackIngestServiceTest.java

@@ -31,6 +31,7 @@ import java.nio.channels.ServerSocketChannel;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.attribute.FileTime;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
@@ -2557,6 +2558,111 @@ public class DatapackIngestServiceTest {
         assertFalse(new File(staging, entry.id).exists());
     }
 
+    @Test
+    public void reapplyRecordsStagingAndInstallMetadataForTheNextPass() throws Exception {
+        ReapplyFixture fixture = reapplyFixture("reapply-record");
+
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+
+        assertTrue(new File(fixture.target(), ".iris-managed.json").isFile());
+        JsonObject recorded = manifestEntry(fixture.root());
+        assertFalse(recorded.get("stagingMetadata").getAsString().isBlank());
+        assertTrue(recorded.getAsJsonObject("installMetadata")
+                .has(fixture.target().toPath().toAbsolutePath().normalize().toString()));
+    }
+
+    @Test
+    public void unchangedStagingAndTargetSkipContentHashingOnReapply() throws Exception {
+        ReapplyFixture fixture = reapplyFixture("reapply-shortcircuit");
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+
+        Path staged = fixture.staging().toPath().resolve("value.txt");
+        FileTime stamp = Files.getLastModifiedTime(staged);
+        Files.writeString(staged, "wxyz", StandardCharsets.UTF_8);
+        Files.setLastModifiedTime(staged, stamp);
+
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+
+        assertEquals("abcd", Files.readString(
+                new File(fixture.target(), "value.txt").toPath(), StandardCharsets.UTF_8));
+    }
+
+    @Test
+    public void changedStagingMetadataForcesFullReapplyVerification() throws Exception {
+        ReapplyFixture fixture = reapplyFixture("reapply-staging-change");
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+
+        Path staged = fixture.staging().toPath().resolve("value.txt");
+        FileTime stamp = Files.getLastModifiedTime(staged);
+        Files.writeString(staged, "wxyz", StandardCharsets.UTF_8);
+        Files.setLastModifiedTime(staged, FileTime.fromMillis(stamp.toMillis() + 5000L));
+
+        assertFalse(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+    }
+
+    @Test
+    public void changedInstallTargetIsRepairedDespiteRecordedMetadata() throws Exception {
+        ReapplyFixture fixture = reapplyFixture("reapply-target-change");
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+
+        Path installed = fixture.target().toPath().resolve("value.txt");
+        Files.writeString(installed, "zzzz", StandardCharsets.UTF_8);
+        Files.setLastModifiedTime(installed, FileTime.fromMillis(
+                Files.getLastModifiedTime(installed).toMillis() + 5000L));
+
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+
+        assertEquals("abcd", Files.readString(installed, StandardCharsets.UTF_8));
+    }
+
+    @Test
+    public void flippedOverrideStrippingForcesFullReapplyVerification() throws Exception {
+        ReapplyFixture fixture = reapplyFixture("reapply-strip-change");
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), false));
+        assertFalse(new File(fixture.target(), ".iris-overrides-stripped").exists());
+
+        assertTrue(DatapackIngestService.reapplyStagedDirectories(
+                fixture.root(), fixture.stagingRoot(), fixture.worlds(), true));
+
+        assertTrue(new File(fixture.target(), ".iris-overrides-stripped").isFile());
+    }
+
+    private ReapplyFixture reapplyFixture(String name) throws Exception {
+        File root = temporaryFolder.newFolder(name + "-root");
+        DatapackIngestService.Entry entry = entry("managed", "v1", "1", "sha");
+        File stagingRoot = new File(root, "staging");
+        File staging = new File(stagingRoot, entry.id);
+        writeManagedDatapack(staging, entry, "abcd");
+        writeManifest(root, entry);
+        File world = temporaryFolder.newFolder(name + "-world");
+        KList<File> worlds = new KList<>();
+        worlds.add(world);
+        return new ReapplyFixture(root, stagingRoot, staging, worlds, new File(world, entry.id));
+    }
+
+    private JsonObject manifestEntry(File root) throws Exception {
+        JsonObject manifest = JsonParser.parseString(Files.readString(
+                new File(root, "manifest.json").toPath(), StandardCharsets.UTF_8)).getAsJsonObject();
+        return manifest.getAsJsonArray("entries").get(0).getAsJsonObject();
+    }
+
+    private record ReapplyFixture(
+            File root,
+            File stagingRoot,
+            File staging,
+            KList<File> worlds,
+            File target
+    ) {
+    }
+
     private LegacyStagingFixture legacyStagingFixture(
             String name,
             boolean committed,

core/src/test/java/art/arcane/iris/core/project/IrisCodeWorkspaceTest.java

@@ -0,0 +1,123 @@
+package art.arcane.iris.core.project;
+
+import art.arcane.iris.core.IrisSettings;
+import art.arcane.iris.core.loader.IrisData;
+import art.arcane.iris.engine.framework.MeteredCache;
+import art.arcane.iris.engine.framework.PreservationRegistry;
+import art.arcane.iris.spi.IrisPlatform;
+import art.arcane.iris.spi.IrisPlatforms;
+import art.arcane.iris.spi.IrisServices;
+import art.arcane.volmlib.util.json.JSONArray;
+import art.arcane.volmlib.util.json.JSONObject;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.mockito.Answers;
+
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.attribute.FileTime;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class IrisCodeWorkspaceTest {
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    private IrisPlatform previousPlatform;
+    private IrisSettings previousSettings;
+    private IrisData data;
+
+    @Before
+    public void bindPlatform() {
+        previousPlatform = IrisPlatforms.isBound() ? IrisPlatforms.get() : null;
+        previousSettings = IrisSettings.settings;
+        IrisPlatforms.unbind();
+        IrisPlatform platform = mock(IrisPlatform.class, Answers.CALLS_REAL_METHODS);
+        when(platform.dataFolder()).thenReturn(temporaryFolder.getRoot());
+        IrisPlatforms.bind(platform);
+        IrisSettings.settings = new IrisSettings();
+        IrisServices.register(PreservationRegistry.class, new NoOpPreservationRegistry());
+    }
+
+    @After
+    public void restorePlatform() {
+        if (data != null) {
+            data.close();
+            data = null;
+        }
+        IrisServices.clear();
+        IrisPlatforms.unbind();
+        if (previousPlatform != null) {
+            IrisPlatforms.bind(previousPlatform);
+        }
+        IrisSettings.settings = previousSettings;
+    }
+
+    @Test
+    public void updateWorkspaceDoesNotRewriteAnUnchangedWorkspaceFile() throws Exception {
+        File pack = temporaryFolder.newFolder("overworld");
+        IrisCodeWorkspace workspace = new IrisCodeWorkspace(new IrisProject(pack));
+
+        assertTrue(workspace.updateWorkspace());
+        data = IrisData.get(pack);
+        File file = workspace.getCodeWorkspaceFile();
+        byte[] first = Files.readAllBytes(file.toPath());
+        FileTime stamp = FileTime.fromMillis(Files.getLastModifiedTime(file.toPath()).toMillis() - 60_000L);
+        Files.setLastModifiedTime(file.toPath(), stamp);
+
+        assertTrue(workspace.updateWorkspace());
+
+        assertArrayEquals("Unchanged workspace bytes must stay identical",
+                first, Files.readAllBytes(file.toPath()));
+        assertEquals("Unchanged workspace content must not be rewritten",
+                stamp.toMillis(), Files.getLastModifiedTime(file.toPath()).toMillis());
+    }
+
+    @Test
+    public void workspaceSchemaEntriesAreEmittedInStableSortedOrder() throws Exception {
+        File pack = temporaryFolder.newFolder("sorted");
+        JSONObject configuration = new IrisCodeWorkspace(new IrisProject(pack)).createCodeWorkspaceConfig();
+        data = IrisData.get(pack);
+
+        JSONArray schemas = configuration.getJSONObject("settings").getJSONArray("json.schemas");
+        List<String> urls = new ArrayList<>();
+        for (int i = 0; i < schemas.length(); i++) {
+            urls.add(schemas.getJSONObject(i).getString("url"));
+        }
+        List<String> sorted = new ArrayList<>(urls);
+        Collections.sort(sorted);
+
+        assertFalse("Expected the workspace to declare schemas", urls.isEmpty());
+        assertEquals("Schema entries must be emitted in a boot-stable order", sorted, urls);
+    }
+
+    private static final class NoOpPreservationRegistry implements PreservationRegistry {
+        @Override
+        public void register(Thread thread) {
+        }
+
+        @Override
+        public void register(ExecutorService service) {
+        }
+
+        @Override
+        public void registerCache(MeteredCache cache) {
+        }
+
+        @Override
+        public void dereference() {
+        }
+    }
+}

core/src/test/java/art/arcane/iris/core/runtime/WorldRuntimeControlServiceTimeLockTest.java

@@ -32,7 +32,10 @@ public class WorldRuntimeControlServiceTimeLockTest {
         PluginManager pluginManager = mock(PluginManager.class);
         doReturn(pluginManager).when(server).getPluginManager();
         doReturn(Logger.getLogger("WorldRuntimeControlServiceTimeLockTest")).when(server).getLogger();
+        try {
             Bukkit.setServer(server);
+        } catch (Throwable ignored) {
+        }
     }
 
     @Test

core/src/test/java/art/arcane/iris/engine/framework/NativeStructureVolumeMemoTest.java

@@ -0,0 +1,106 @@
+package art.arcane.iris.engine.framework;
+
+import art.arcane.volmlib.util.collection.KList;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class NativeStructureVolumeMemoTest {
+    @Test
+    public void repeatedQueriesInsideOneChunkAskThePlatformOnce() {
+        RecordingHooks hooks = new RecordingHooks(volume(0, 64, 0, 15, 78, 15));
+        NativeStructureVolumeMemo memo = new NativeStructureVolumeMemo();
+
+        KList<NativeStructureVolume> first = memo.volumes(null, hooks, 2, 2, 6, 6);
+        KList<NativeStructureVolume> second = memo.volumes(null, hooks, 8, 8, 12, 12);
+
+        assertEquals(1, hooks.queries().size());
+        assertEquals(first, second);
+    }
+
+    @Test
+    public void chunkQueriesCoverTheWholeChunkColumn() {
+        RecordingHooks hooks = new RecordingHooks();
+        NativeStructureVolumeMemo memo = new NativeStructureVolumeMemo();
+
+        memo.volumes(null, hooks, 20, 36, 21, 37);
+
+        assertEquals(1, hooks.queries().size());
+        assertEquals(List.of(16, 32, 31, 47), hooks.queries().getFirst());
+    }
+
+    @Test
+    public void rectsSpanningChunksUnionWithoutDuplicates() {
+        NativeStructureVolume shared = volume(10, 64, 10, 40, 78, 40);
+        RecordingHooks hooks = new RecordingHooks(shared);
+        NativeStructureVolumeMemo memo = new NativeStructureVolumeMemo();
+
+        KList<NativeStructureVolume> volumes = memo.volumes(null, hooks, 12, 12, 20, 20);
+
+        assertEquals(4, hooks.queries().size());
+        assertEquals(1, volumes.size());
+        assertEquals(shared, volumes.getFirst());
+    }
+
+    @Test
+    public void volumesOutsideTheRectAreFiltered() {
+        RecordingHooks hooks = new RecordingHooks(volume(0, 64, 0, 3, 78, 3));
+        NativeStructureVolumeMemo memo = new NativeStructureVolumeMemo();
+
+        assertTrue(memo.volumes(null, hooks, 5, 5, 9, 9).isEmpty());
+    }
+
+    @Test
+    public void clearingTheMemoReQueriesThePlatform() {
+        RecordingHooks hooks = new RecordingHooks(volume(0, 64, 0, 15, 78, 15));
+        NativeStructureVolumeMemo memo = new NativeStructureVolumeMemo();
+
+        memo.volumes(null, hooks, 2, 2, 6, 6);
+        memo.clear();
+        memo.volumes(null, hooks, 2, 2, 6, 6);
+
+        assertEquals(2, hooks.queries().size());
+    }
+
+    @Test
+    public void missingHooksResolveNoVolumes() {
+        NativeStructureVolumeMemo memo = new NativeStructureVolumeMemo();
+
+        assertTrue(memo.volumes(null, null, 0, 0, 15, 15).isEmpty());
+    }
+
+    private static NativeStructureVolume volume(int minX, int minY, int minZ, int maxX, int maxY, int maxZ) {
+        return new NativeStructureVolume("minecraft:village_swamp", minX, minY, minZ, maxX, maxY, maxZ);
+    }
+
+    private static final class RecordingHooks implements EnginePlatformHooks {
+        private final KList<List<Integer>> queries = new KList<>();
+        private final List<NativeStructureVolume> answer = new ArrayList<>();
+
+        private RecordingHooks(NativeStructureVolume... volumes) {
+            for (NativeStructureVolume volume : volumes) {
+                answer.add(volume);
+            }
+        }
+
+        private KList<List<Integer>> queries() {
+            return queries;
+        }
+
+        @Override
+        public KList<NativeStructureVolume> nativeStructureVolumes(Engine engine, int minX, int minZ, int maxX, int maxZ) {
+            queries.add(List.of(minX, minZ, maxX, maxZ));
+            KList<NativeStructureVolume> volumes = new KList<>();
+            for (NativeStructureVolume volume : answer) {
+                if (volume.intersectsRect(minX, minZ, maxX, maxZ)) {
+                    volumes.add(volume);
+                }
+            }
+            return volumes;
+        }
+    }
+}

core/src/test/java/art/arcane/iris/engine/framework/NativeStructureVolumeSuppressionTest.java

@@ -0,0 +1,67 @@
+package art.arcane.iris.engine.framework;
+
+import art.arcane.iris.core.loader.IrisData;
+import art.arcane.iris.engine.object.IrisDimension;
+import art.arcane.iris.engine.object.IrisImportedStructureControl;
+import art.arcane.iris.engine.object.IrisNativeStructure;
+import art.arcane.iris.engine.object.IrisStructurePlacement;
+import art.arcane.iris.engine.object.StructureDistribution;
+import art.arcane.volmlib.util.collection.KList;
+import org.junit.Test;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * The gate the native structure volume index applies before it assembles anything: a structure the pack suppresses
+ * contributes no piece volumes, so it can never veto an object placement.
+ */
+public class NativeStructureVolumeSuppressionTest {
+    @Test
+    public void packDisabledStructuresContributeNoVolumes() {
+        Engine engine = engine();
+
+        assertFalse(NativeStructureGenerationPolicy
+                .resolve(engine, "minecraft:village_swamp", false).generate());
+        assertFalse(NativeStructureGenerationPolicy
+                .resolve(engine, "minecraft:village_plains", false).generate());
+    }
+
+    @Test
+    public void enabledStructuresContributeVolumes() {
+        Engine engine = engine();
+
+        assertTrue(NativeStructureGenerationPolicy
+                .resolve(engine, "towns_and_towers:village_swamp", false).generate());
+    }
+
+    @Test
+    public void plannedIrisStartsContributeVolumesThroughTheirOwnDecision() {
+        IrisStructurePlacement placement = new IrisStructurePlacement()
+                .setDistribution(StructureDistribution.DENSITY)
+                .setDensity(1D);
+        placement.getNativeStructures().add(new IrisNativeStructure()
+                .setStructure("minecraft:ancient_city")
+                .setWeight(1));
+        NativeStructureStartPlan plan = new NativeStructureStartPlan(
+                placement, placement.getNativeStructures().getFirst(), 3, 5, -30);
+
+        assertTrue(NativeStructurePlacementPlanner.decisionFor(plan).generate());
+    }
+
+    private Engine engine() {
+        IrisImportedStructureControl control = new IrisImportedStructureControl();
+        control.getDisabled().add("minecraft:village");
+        IrisDimension dimension = mock(IrisDimension.class);
+        Engine engine = mock(Engine.class);
+        when(engine.getData()).thenReturn(mock(IrisData.class));
+        when(engine.getDimension()).thenReturn(dimension);
+        when(dimension.getImportedStructures()).thenReturn(control);
+        when(dimension.getStructures()).thenReturn(new KList<>());
+        when(dimension.getAllRegions(engine)).thenReturn(new KList<>());
+        when(dimension.getReachableBiomes(engine)).thenReturn(new KList<>());
+        return engine;
+    }
+}

core/src/test/java/art/arcane/iris/engine/framework/NativeStructureVolumeTest.java

@@ -0,0 +1,54 @@
+package art.arcane.iris.engine.framework;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class NativeStructureVolumeTest {
+    private static final NativeStructureVolume PIECE =
+            new NativeStructureVolume("minecraft:village_plains", 10, 64, 20, 25, 78, 40);
+
+    @Test
+    public void rectQueriesIgnoreTheVerticalAxis() {
+        assertTrue(PIECE.intersectsRect(0, 0, 10, 20));
+        assertTrue(PIECE.intersectsRect(25, 40, 60, 60));
+        assertFalse(PIECE.intersectsRect(26, 20, 60, 40));
+        assertFalse(PIECE.intersectsRect(10, 41, 25, 60));
+    }
+
+    @Test
+    public void boxQueriesSeparateStackedVolumes() {
+        assertTrue(PIECE.intersects(0, 60, 0, 40, 70, 50));
+        assertFalse(PIECE.intersects(0, 0, 0, 40, 63, 50));
+        assertFalse(PIECE.intersects(0, 79, 0, 40, 200, 50));
+    }
+
+    @Test
+    public void containmentIsInclusiveOnEveryFace() {
+        assertTrue(PIECE.contains(10, 64, 20));
+        assertTrue(PIECE.contains(25, 78, 40));
+        assertFalse(PIECE.contains(9, 64, 20));
+        assertFalse(PIECE.contains(25, 79, 40));
+    }
+
+    @Test
+    public void marginWidensContainmentSymmetrically() {
+        assertFalse(PIECE.containsWithin(8, 64, 20, 1));
+        assertTrue(PIECE.containsWithin(8, 64, 20, 2));
+        assertTrue(PIECE.containsWithin(25, 80, 42, 2));
+    }
+
+    @Test
+    public void factoryNormalizesCornerOrder() {
+        NativeStructureVolume normalized = NativeStructureVolume.of("test:piece", 25, 78, 40, 10, 64, 20);
+
+        assertEquals(PIECE.minX(), normalized.minX());
+        assertEquals(PIECE.minY(), normalized.minY());
+        assertEquals(PIECE.minZ(), normalized.minZ());
+        assertEquals(PIECE.maxX(), normalized.maxX());
+        assertEquals(PIECE.maxY(), normalized.maxY());
+        assertEquals(PIECE.maxZ(), normalized.maxZ());
+    }
+}

core/src/test/java/art/arcane/iris/engine/object/IrisDimensionCarvingResolverParityTest.java

@@ -46,7 +46,10 @@ public class IrisDimensionCarvingResolverParityTest {
         doReturn("1.0").when(server).getBukkitVersion();
         doAnswer((InvocationOnMock invocation) -> namedBlockData(invocation.getArgument(0, Material.class).name().toLowerCase(Locale.ROOT))).when(server).createBlockData(any(Material.class));
         doAnswer((InvocationOnMock invocation) -> namedBlockData(invocation.getArgument(0, String.class))).when(server).createBlockData(anyString());
+        try {
             Bukkit.setServer(server);
+        } catch (Throwable ignored) {
+        }
     }
 
     private static BlockData namedBlockData(String key) {

core/src/test/java/art/arcane/iris/engine/object/IrisFloatingChildBiomesCarvingResolutionTest.java

@@ -38,7 +38,10 @@ public class IrisFloatingChildBiomesCarvingResolutionTest {
         doReturn("1.0").when(server).getBukkitVersion();
         doAnswer((InvocationOnMock invocation) -> namedBlockData(invocation.getArgument(0, Material.class).name().toLowerCase(Locale.ROOT))).when(server).createBlockData(any(Material.class));
         doAnswer((InvocationOnMock invocation) -> namedBlockData(invocation.getArgument(0, String.class))).when(server).createBlockData(anyString());
+        try {
             Bukkit.setServer(server);
+        } catch (Throwable ignored) {
+        }
     }
 
     private static BlockData namedBlockData(String key) {

core/src/test/java/art/arcane/iris/engine/object/NativeStructureObjectVetoTest.java

@@ -0,0 +1,320 @@
+package art.arcane.iris.engine.object;
+
+import art.arcane.iris.core.loader.IrisData;
+import art.arcane.iris.engine.IrisComplex;
+import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.framework.NativeStructureVolume;
+import art.arcane.iris.spi.IrisPlatform;
+import art.arcane.iris.spi.IrisPlatforms;
+import art.arcane.iris.spi.PlatformBlockState;
+import art.arcane.iris.spi.PlatformRegistries;
+import art.arcane.iris.util.project.stream.ProceduralStream;
+import art.arcane.volmlib.util.collection.KList;
+import art.arcane.volmlib.util.math.RNG;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class NativeStructureObjectVetoTest {
+    private static final int SURFACE_Y = 80;
+
+    private IrisData data;
+    private Engine engine;
+    private PlatformBlockState log;
+
+    @Before
+    public void bindPlatform() {
+        IrisPlatforms.unbind();
+        PlatformBlockState block = mock(PlatformBlockState.class);
+        PlatformRegistries registries = mock(PlatformRegistries.class);
+        when(registries.block(anyString())).thenReturn(block);
+        IrisPlatform platform = mock(IrisPlatform.class);
+        when(platform.registries()).thenReturn(registries);
+        IrisPlatforms.bind(platform);
+
+        log = state("minecraft:oak_log", true);
+        @SuppressWarnings("unchecked")
+        ProceduralStream<Double> heightStream = mock(ProceduralStream.class);
+        IrisComplex complex = mock(IrisComplex.class);
+        when(complex.getHeightStream()).thenReturn(heightStream);
+        engine = mock(Engine.class);
+        when(engine.getHeight()).thenReturn(256);
+        when(engine.getComplex()).thenReturn(complex);
+        when(engine.getDimension()).thenReturn(mock(IrisDimension.class));
+        volumes();
+        data = mock(IrisData.class);
+        when(data.getEngine()).thenReturn(engine);
+    }
+
+    @After
+    public void unbindPlatform() {
+        IrisPlatforms.unbind();
+    }
+
+    @Test
+    public void objectPlacesWhenNoNativeStructureIsNear() {
+        RecordingPlacer placer = new RecordingPlacer(engine);
+
+        assertTrue(place(placer) >= 0);
+        assertFalse(placer.written().isEmpty());
+    }
+
+    @Test
+    public void canopyBlockInsideAPieceRejectsTheWholeObject() {
+        int canopyY = plantedTopY();
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes(volume(-1, canopyY, -1, 1, canopyY + 4, 1));
+
+        assertEquals(-1, place(placer));
+        assertTrue(placer.written().isEmpty());
+    }
+
+    @Test
+    public void trunkBlockInsideAPieceRejectsTheWholeObject() {
+        int baseY = plantedBottomY();
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes(volume(0, baseY, 0, 0, baseY, 0));
+
+        assertEquals(-1, place(placer));
+        assertTrue(placer.written().isEmpty());
+    }
+
+    @Test
+    public void pieceOverlappingOnlyTheEnvelopeStillPlaces() {
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes(volume(2, plantedBottomY(), 2, 4, plantedTopY(), 4));
+
+        assertTrue(place(placer) >= 0);
+        assertFalse(placer.written().isEmpty());
+    }
+
+    @Test
+    public void pieceBelowTheObjectStillPlaces() {
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes(volume(-32, -60, -32, 32, plantedBottomY() - 1, 32));
+
+        assertTrue(place(placer) >= 0);
+        assertFalse(placer.written().isEmpty());
+    }
+
+    @Test
+    public void rejectionWritesNoBlocksTilesOrMarkers() {
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes(volume(-64, -64, -64, 64, 320, 64));
+
+        assertEquals(-1, place(placer));
+        assertTrue(placer.written().isEmpty());
+        assertEquals(0, placer.tiles());
+        assertEquals(0, placer.markers());
+    }
+
+    /**
+     * Iris authored structure pieces are arbitrated by the jigsaw placement scope, not by this veto: rejecting them
+     * one piece at a time would publish a partial structure. The sibling placement pins the test to the exemption
+     * rather than to geometry that simply misses every volume.
+     */
+    @Test
+    public void irisStructurePiecesBypassTheVetoUnlikeTheirSiblings() {
+        volumes(volume(-64, -64, -64, 64, 320, 64));
+
+        RecordingPlacer vetoed = new RecordingPlacer(engine);
+        assertEquals(-1, tree().place(0, SURFACE_Y, 0, vetoed, placement(), new RNG(1234L), data));
+        assertTrue(vetoed.written().isEmpty());
+
+        RecordingPlacer exempt = new RecordingPlacer(engine);
+        IrisObjectPlacement structurePiece = placement();
+        structurePiece.setMode(ObjectPlaceMode.STRUCTURE_PIECE);
+
+        assertTrue(tree().place(0, SURFACE_Y, 0, exempt, structurePiece, new RNG(1234L), data) >= 0);
+        assertFalse(exempt.written().isEmpty());
+    }
+
+    @Test
+    public void forcePlaceStillObeysTheVeto() {
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes(volume(-64, -64, -64, 64, 320, 64));
+        IrisObjectPlacement placement = placement();
+        placement.setForcePlace(true);
+
+        assertEquals(-1, tree().place(0, -1, 0, placer, placement, new RNG(1234L), data));
+        assertTrue(placer.written().isEmpty());
+    }
+
+    @Test
+    public void structurePiecePlacementsBypassTheVeto() {
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes(volume(-64, -64, -64, 64, 320, 64));
+        IrisObjectPlacement placement = placement();
+        placement.setMode(ObjectPlaceMode.STRUCTURE_PIECE);
+
+        assertTrue(tree().place(0, 100, 0, placer, placement, new RNG(1234L), data) >= 0);
+        assertFalse(placer.written().isEmpty());
+    }
+
+    private int plantedTopY() {
+        int top = Integer.MIN_VALUE;
+        for (int[] position : plantedPositions()) {
+            top = Math.max(top, position[1]);
+        }
+        return top;
+    }
+
+    private int plantedBottomY() {
+        int bottom = Integer.MAX_VALUE;
+        for (int[] position : plantedPositions()) {
+            bottom = Math.min(bottom, position[1]);
+        }
+        return bottom;
+    }
+
+    private List<int[]> plantedPositions() {
+        RecordingPlacer placer = new RecordingPlacer(engine);
+        volumes();
+        assertTrue(place(placer) >= 0);
+        assertFalse(placer.written().isEmpty());
+        return placer.written();
+    }
+
+    private int place(RecordingPlacer placer) {
+        return tree().place(0, -1, 0, placer, placement(), new RNG(1234L), data);
+    }
+
+    private IrisObjectPlacement placement() {
+        IrisObjectPlacement placement = new IrisObjectPlacement();
+        placement.setMode(ObjectPlaceMode.CENTER_HEIGHT);
+        return placement;
+    }
+
+    private IrisObject tree() {
+        IrisObject object = new IrisObject(3, 7, 3);
+        for (int y = 0; y < 7; y++) {
+            object.setUnsigned(1, y, 1, log);
+        }
+        return object;
+    }
+
+    private void volumes(NativeStructureVolume... volumes) {
+        KList<NativeStructureVolume> list = new KList<>();
+        for (NativeStructureVolume volume : volumes) {
+            list.add(volume);
+        }
+        when(engine.getNativeStructureVolumes(anyInt(), anyInt(), anyInt(), anyInt())).thenReturn(list);
+    }
+
+    private NativeStructureVolume volume(int minX, int minY, int minZ, int maxX, int maxY, int maxZ) {
+        return new NativeStructureVolume("minecraft:village_plains", minX, minY, minZ, maxX, maxY, maxZ);
+    }
+
+    private static PlatformBlockState state(String key, boolean solid) {
+        PlatformBlockState state = mock(PlatformBlockState.class);
+        when(state.isSolid()).thenReturn(solid);
+        when(state.key()).thenReturn(key);
+        when(state.materialKey()).thenReturn(key);
+        return state;
+    }
+
+    private static final class RecordingPlacer implements IObjectPlacer {
+        private final List<int[]> written = new ArrayList<>();
+        private final PlatformBlockState air = state("minecraft:air", false);
+        private final Engine engine;
+        private int tiles;
+        private int markers;
+
+        private RecordingPlacer(Engine engine) {
+            this.engine = engine;
+        }
+
+        private List<int[]> written() {
+            return written;
+        }
+
+        private int tiles() {
+            return tiles;
+        }
+
+        private int markers() {
+            return markers;
+        }
+
+        @Override
+        public int getHighest(int x, int z, IrisData data) {
+            return SURFACE_Y;
+        }
+
+        @Override
+        public int getHighest(int x, int z, IrisData data, boolean ignoreFluid) {
+            return SURFACE_Y;
+        }
+
+        @Override
+        public void set(int x, int y, int z, PlatformBlockState state) {
+            written.add(new int[]{x, y, z});
+        }
+
+        @Override
+        public PlatformBlockState get(int x, int y, int z) {
+            return air;
+        }
+
+        @Override
+        public boolean isPreventingDecay() {
+            return false;
+        }
+
+        @Override
+        public boolean isCarved(int x, int y, int z) {
+            return false;
+        }
+
+        @Override
+        public boolean isSolid(int x, int y, int z) {
+            return false;
+        }
+
+        @Override
+        public boolean isUnderwater(int x, int z) {
+            return false;
+        }
+
+        @Override
+        public int getFluidHeight() {
+            return 0;
+        }
+
+        @Override
+        public boolean isDebugSmartBore() {
+            return false;
+        }
+
+        @Override
+        public void setTile(int x, int y, int z, TileData tile) {
+            tiles++;
+        }
+
+        @Override
+        public <T> void setData(int x, int y, int z, T data) {
+            markers++;
+        }
+
+        @Override
+        public <T> T getData(int x, int y, int z, Class<T> type) {
+            return null;
+        }
+
+        @Override
+        public Engine getEngine() {
+            return engine;
+        }
+    }
+}

core/src/test/java/art/arcane/iris/platform/bukkit/BukkitSpiConformanceTest.java

@@ -62,7 +62,10 @@ public class BukkitSpiConformanceTest {
             doReturn("1.0").when(server).getVersion();
             doReturn("1.0").when(server).getBukkitVersion();
             doAnswer((InvocationOnMock invocation) -> blockData("minecraft:" + invocation.getArgument(0, Material.class).name().toLowerCase(Locale.ROOT))).when(server).createBlockData(any(Material.class));
+            try {
                 Bukkit.setServer(server);
+            } catch (Throwable ignored) {
+            }
         }
         doAnswer((InvocationOnMock invocation) -> blockData(invocation.getArgument(0))).when(server).createBlockData(anyString());
     }

core/src/test/java/art/arcane/iris/util/project/noise/CNGInjectorParityTest.java

@@ -36,7 +36,10 @@ public class CNGInjectorParityTest {
         doReturn("1.0").when(server).getBukkitVersion();
         doAnswer((InvocationOnMock invocation) -> namedBlockData(invocation.getArgument(0, Material.class).name().toLowerCase(Locale.ROOT))).when(server).createBlockData(any(Material.class));
         doAnswer((InvocationOnMock invocation) -> namedBlockData(invocation.getArgument(0, String.class))).when(server).createBlockData(anyString());
+        try {
             Bukkit.setServer(server);
+        } catch (Throwable ignored) {
+        }
     }
 
     private static BlockData namedBlockData(String key) {