d

2026-08-29 05:20:40 +00:00 · 2026-08-15 21:32:00 -04:00
parent ef2e1b8f58
commit fc0fdf4ce4
81 changed files with 5109 additions and 511 deletions
@@ -0,0 +1,130 @@
+package art.arcane.iris.core.nms.v26_2_R1;
+
+import art.arcane.iris.core.lifecycle.WorldReplacementSeed;
+import art.arcane.iris.util.common.scheduling.J;
+import io.papermc.paper.world.saveddata.PaperLevelOverrides;
+import io.papermc.paper.world.saveddata.PaperWorldMetadata;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.world.level.storage.PrimaryLevelData;
+import net.minecraft.world.level.storage.SavedDataStorage;
+import org.bukkit.Bukkit;
+import org.bukkit.craftbukkit.CraftServer;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.LinkOption;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+final class CurrentPaperWorldDataWriter {
+    private static final long SNAPSHOT_TIMEOUT_SECONDS = 30L;
+
+    private CurrentPaperWorldDataWriter() {
+    }
+
+    static void write(
+            Path sourceWorldDirectory,
+            Path targetWorldDirectory,
+            long seed
+    ) throws IOException {
+        CraftServer craftServer = (CraftServer) Bukkit.getServer();
+        MinecraftServer server = craftServer.getHandle().getServer();
+        PaperLevelOverrides levelOverrides = captureLevelOverrides(craftServer, server);
+
+        Path targetWorld = targetWorldDirectory.toAbsolutePath().normalize();
+        UUID metadataUuid = UUID.randomUUID();
+        WorldReplacementSeed.copyWithAuthoritativeSeed(sourceWorldDirectory, targetWorld, seed);
+        try (SavedDataStorage savedDataStorage = new SavedDataStorage(
+                targetWorld.resolve("data"),
+                server.getFixerUpper(),
+                server.registryAccess()
+        )) {
+            savedDataStorage.set(PaperWorldMetadata.TYPE, new PaperWorldMetadata(metadataUuid));
+            savedDataStorage.set(PaperLevelOverrides.TYPE, levelOverrides);
+        }
+
+        List<Path> requiredDataFiles = List.of(
+                targetWorld.resolve("data/minecraft/world_gen_settings.dat"),
+                targetWorld.resolve("data/paper/metadata.dat"),
+                targetWorld.resolve("data/paper/level_overrides.dat")
+        );
+        for (Path requiredDataFile : requiredDataFiles) {
+            if (!Files.isRegularFile(requiredDataFile, LinkOption.NOFOLLOW_LINKS)) {
+                throw new IOException("Current Paper world data was not written: " + requiredDataFile);
+            }
+        }
+
+        long writtenSeed = WorldReplacementSeed.readAuthoritativeSeed(targetWorld);
+        if (writtenSeed != seed) {
+            throw new IOException("Current Paper world data did not retain the requested seed.");
+        }
+
+        try (SavedDataStorage verificationStorage = new SavedDataStorage(
+                targetWorld.resolve("data"),
+                server.getFixerUpper(),
+                server.registryAccess()
+        )) {
+            PaperWorldMetadata metadata = verificationStorage.get(PaperWorldMetadata.TYPE);
+            if (metadata == null || !metadataUuid.equals(metadata.uuid())) {
+                throw new IOException("Current Paper world metadata could not be verified.");
+            }
+            PaperLevelOverrides overrides = verificationStorage.get(PaperLevelOverrides.TYPE);
+            if (overrides == null || overrides.isInitialized()) {
+                throw new IOException("Current Paper level overrides could not be verified.");
+            }
+        }
+    }
+
+    private static PaperLevelOverrides captureLevelOverrides(
+            CraftServer craftServer,
+            MinecraftServer server
+    ) throws IOException {
+        if (craftServer.isGlobalTickThread()) {
+            return createLevelOverrides(craftServer, server);
+        }
+        if (J.isFolia() && J.isPrimaryThread()) {
+            throw new IOException("Current Paper world data cannot be staged from a Folia region tick thread.");
+        }
+
+        CompletableFuture<PaperLevelOverrides> captured = new CompletableFuture<>();
+        boolean scheduled = J.runGlobal(() -> {
+            try {
+                captured.complete(createLevelOverrides(craftServer, server));
+            } catch (Throwable failure) {
+                captured.completeExceptionally(failure);
+            }
+        });
+        if (!scheduled) {
+            throw new IOException("Could not schedule the current Paper level-data snapshot on the global thread.");
+        }
+
+        try {
+            return captured.get(SNAPSHOT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+        } catch (InterruptedException failure) {
+            Thread.currentThread().interrupt();
+            throw new IOException("Interrupted while capturing current Paper level data.", failure);
+        } catch (ExecutionException failure) {
+            throw new IOException("Could not capture current Paper level data.", failure.getCause());
+        } catch (TimeoutException failure) {
+            throw new IOException("Timed out while capturing current Paper level data.", failure);
+        }
+    }
+
+    private static PaperLevelOverrides createLevelOverrides(
+            CraftServer craftServer,
+            MinecraftServer server
+    ) throws IOException {
+        if (!craftServer.isGlobalTickThread()) {
+            throw new IOException("Current Paper level data must be captured on the global tick thread.");
+        }
+        if (!(server.getWorldData().overworldData() instanceof PrimaryLevelData primaryLevelData)) {
+            throw new IOException("Paper primary level data is unavailable for current world data staging.");
+        }
+        return PaperLevelOverrides.createFromLiveLevelData(primaryLevelData);
+    }
+}
@@ -7,7 +7,6 @@ import net.minecraft.core.Holder;
 import net.minecraft.core.HolderOwner;
 import net.minecraft.core.Vec3i;
 import net.minecraft.resources.ResourceKey;
-import net.minecraft.world.level.chunk.ChunkGeneratorStructureState;
 import net.minecraft.world.level.levelgen.structure.StructureSet;
 import net.minecraft.world.level.levelgen.structure.placement.ConcentricRingsStructurePlacement;
 import net.minecraft.world.level.levelgen.structure.placement.RandomSpreadStructurePlacement;
@@ -41,16 +40,31 @@ final class DatapackStructureStateFilter {
            DatapackStructureScopeIndex scopeIndex,
            Set<String> declaredSources,
            IrisImportedStructureControl importedStructures
+    ) {
+        return filter(
+                structureSets,
+                scopeIndex,
+                declaredSources,
+                importedStructures,
+                keyIndex(structureSets));
+    }
+
+    static Selection filter(
+            List<Holder<StructureSet>> structureSets,
+            DatapackStructureScopeIndex scopeIndex,
+            Set<String> declaredSources,
+            IrisImportedStructureControl importedStructures,
+            StructureSetKeyIndex keyIndex
    ) {
        if (scopeIndex.isEmpty()) {
            return new Selection(
-                    scaleFrequencyOverrides(structureSets, importedStructures),
+                    scaleFrequencyOverrides(structureSets, importedStructures, keyIndex),
                    0,
                    0);
        }
        Map<String, Holder<StructureSet>> holdersByKey = new HashMap<>();
        for (Holder<StructureSet> holder : structureSets) {
-            String key = structureSetKey(holder);
+            String key = structureSetKey(holder, keyIndex);
            if (key != null) {
                holdersByKey.putIfAbsent(key, holder);
            }
@@ -61,7 +75,7 @@ final class DatapackStructureStateFilter {
        int retainedManagedSets = 0;
        int excludedManagedSets = 0;
        for (Holder<StructureSet> holder : structureSets) {
-            String setKey = structureSetKey(holder);
+            String setKey = structureSetKey(holder, keyIndex);
            boolean managedSet = setKey != null && scopeIndex.isManagedStructureSet(setKey);
            Holder<StructureSet> scopedHolder = scopeHolder(
                    holder,
@@ -69,7 +83,8 @@ final class DatapackStructureStateFilter {
                    declaredSources,
                    holdersByKey,
                    scopedByIdentity,
-                    visiting);
+                    visiting,
+                    keyIndex);
            if (scopedHolder == null) {
                if (managedSet) {
                    excludedManagedSets++;
@@ -82,21 +97,29 @@ final class DatapackStructureStateFilter {
            filteredSets.add(scopedHolder);
        }
        return new Selection(
-                scaleFrequencyOverrides(List.copyOf(filteredSets), importedStructures),
+                scaleFrequencyOverrides(
+                        List.copyOf(filteredSets), importedStructures, keyIndex),
                retainedManagedSets,
                excludedManagedSets);
    }

    static String structureSetKey(Holder<StructureSet> holder) {
-        Optional<ResourceKey<StructureSet>> key = holder.unwrapKey();
-        if (key.isPresent()) {
-            return key.get().identifier().toString();
-        }
-        if (holder.value().placement()
-                instanceof ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement keyedPlacement) {
-            return keyedPlacement.key.identifier().toString();
-        }
-        return null;
+        return structureSetKey(holder, keyIndex(List.of(holder)));
+    }
+
+    static StructureSetKeyIndex keyIndex(
+            Iterable<? extends Holder<StructureSet>> registeredStructureSets
+    ) {
+        return StructureSetKeyIndex.create(registeredStructureSets);
+    }
+
+    private static String structureSetKey(
+            Holder<StructureSet> holder,
+            StructureSetKeyIndex keyIndex
+    ) {
+        return keyIndex.resolve(holder)
+                .map(key -> key.identifier().toString())
+                .orElse(null);
    }

    private static List<StructureSet.StructureSelectionEntry> filterEntries(
@@ -122,7 +145,8 @@ final class DatapackStructureStateFilter {
            Set<String> declaredSources,
            Map<String, Holder<StructureSet>> holdersByKey,
            Map<Holder<StructureSet>, Holder<StructureSet>> scopedByIdentity,
-            Set<Holder<StructureSet>> visiting
+            Set<Holder<StructureSet>> visiting,
+            StructureSetKeyIndex keyIndex
    ) {
        if (scopedByIdentity.containsKey(holder)) {
            return scopedByIdentity.get(holder);
@@ -131,7 +155,7 @@ final class DatapackStructureStateFilter {
            return null;
        }
        try {
-            String setKey = structureSetKey(holder);
+            String setKey = structureSetKey(holder, keyIndex);
            if (setKey != null && scopeIndex.isManagedStructureSet(setKey)
                    && !scopeIndex.allowsStructureSet(setKey, declaredSources)) {
                scopedByIdentity.put(holder, null);
@@ -150,14 +174,15 @@ final class DatapackStructureStateFilter {
                    declaredSources,
                    holdersByKey,
                    scopedByIdentity,
-                    visiting);
+                    visiting,
+                    keyIndex);
            if (entries.size() == originalSet.structures().size()
                    && placement == originalSet.placement()) {
                scopedByIdentity.put(holder, holder);
                return holder;
            }
            Holder<StructureSet> scoped = replacementHolder(
-                    holder, new StructureSet(entries, placement));
+                    holder, new StructureSet(entries, placement), keyIndex);
            scopedByIdentity.put(holder, scoped);
            return scoped;
        } finally {
@@ -184,7 +209,8 @@ final class DatapackStructureStateFilter {
            Set<String> declaredSources,
            Map<String, Holder<StructureSet>> holdersByKey,
            Map<Holder<StructureSet>, Holder<StructureSet>> scopedByIdentity,
-            Set<Holder<StructureSet>> visiting
+            Set<Holder<StructureSet>> visiting,
+            StructureSetKeyIndex keyIndex
    ) {
        Optional<StructurePlacement.ExclusionZone> currentZone = exclusionZone(placement);
        if (currentZone.isEmpty()) {
@@ -192,7 +218,7 @@ final class DatapackStructureStateFilter {
        }

        Holder<StructureSet> target = currentZone.get().otherSet();
-        String targetKey = structureSetKey(target);
+        String targetKey = structureSetKey(target, keyIndex);
        if (targetKey != null) {
            target = holdersByKey.getOrDefault(targetKey, target);
        }
@@ -202,7 +228,8 @@ final class DatapackStructureStateFilter {
                declaredSources,
                holdersByKey,
                scopedByIdentity,
-                visiting);
+                visiting,
+                keyIndex);
        Optional<StructurePlacement.ExclusionZone> scopedZone = Optional.empty();
        if (scopedTarget != null) {
            scopedZone = Optional.of(new StructurePlacement.ExclusionZone(
@@ -217,14 +244,15 @@ final class DatapackStructureStateFilter {

    private static List<Holder<StructureSet>> scaleFrequencyOverrides(
            List<Holder<StructureSet>> structureSets,
-            IrisImportedStructureControl importedStructures
+            IrisImportedStructureControl importedStructures,
+            StructureSetKeyIndex keyIndex
    ) {
        if (!importedStructures.hasFrequencyOverrides()) {
            return structureSets;
        }
        Map<String, Holder<StructureSet>> holdersByKey = new HashMap<>();
        for (Holder<StructureSet> holder : structureSets) {
-            String key = structureSetKey(holder);
+            String key = structureSetKey(holder, keyIndex);
            if (key != null) {
                holdersByKey.putIfAbsent(key, holder);
            }
@@ -234,7 +262,11 @@ final class DatapackStructureStateFilter {
        boolean changed = false;
        for (Holder<StructureSet> holder : structureSets) {
            Holder<StructureSet> scaled = scaleFrequencyHolder(
-                    holder, importedStructures, holdersByKey, scaledByIdentity);
+                    holder,
+                    importedStructures,
+                    holdersByKey,
+                    scaledByIdentity,
+                    keyIndex);
            scaledSets.add(scaled);
            changed |= scaled != holder;
        }
@@ -245,17 +277,19 @@ final class DatapackStructureStateFilter {
            Holder<StructureSet> holder,
            IrisImportedStructureControl importedStructures,
            Map<String, Holder<StructureSet>> holdersByKey,
-            Map<Holder<StructureSet>, Holder<StructureSet>> scaledByIdentity
+            Map<Holder<StructureSet>, Holder<StructureSet>> scaledByIdentity,
+            StructureSetKeyIndex keyIndex
    ) {
        if (scaledByIdentity.containsKey(holder)) {
            return scaledByIdentity.get(holder);
        }
-        if (!dependsOnFrequencyOverride(holder, importedStructures, holdersByKey)) {
+        if (!dependsOnFrequencyOverride(
+                holder, importedStructures, holdersByKey, keyIndex)) {
            scaledByIdentity.put(holder, holder);
            return holder;
        }

-        ResourceKey<StructureSet> holderKey = structureSetResourceKey(holder).orElseThrow(() ->
+        ResourceKey<StructureSet> holderKey = keyIndex.resolve(holder).orElseThrow(() ->
                new IllegalStateException(
                        "An affected native structure-set exclusion graph has an unkeyed holder"));
        ReboundStructureSetHolder scaledHolder = new ReboundStructureSetHolder(holderKey);
@@ -267,16 +301,21 @@ final class DatapackStructureStateFilter {
        Optional<StructurePlacement.ExclusionZone> scaledZone = originalZone;
        if (originalZone.isPresent()) {
            Holder<StructureSet> target = canonicalHolder(
-                    originalZone.get().otherSet(), holdersByKey);
+                    originalZone.get().otherSet(), holdersByKey, keyIndex);
            Holder<StructureSet> scaledTarget = scaleFrequencyHolder(
-                    target, importedStructures, holdersByKey, scaledByIdentity);
+                    target,
+                    importedStructures,
+                    holdersByKey,
+                    scaledByIdentity,
+                    keyIndex);
            if (scaledTarget != originalZone.get().otherSet()) {
                scaledZone = Optional.of(new StructurePlacement.ExclusionZone(
                        scaledTarget, originalZone.get().chunkCount()));
            }
        }

-        double multiplier = importedStructures.frequencyMultiplier(structureSetKey(holder));
+        double multiplier = importedStructures.frequencyMultiplier(
+                structureSetKey(holder, keyIndex));
        StructurePlacement scaledPlacement = multiplier == 1D && scaledZone.equals(originalZone)
                ? originalPlacement
                : copyPlacement(originalPlacement, scaledZone, multiplier);
@@ -287,12 +326,14 @@ final class DatapackStructureStateFilter {
    private static boolean dependsOnFrequencyOverride(
            Holder<StructureSet> holder,
            IrisImportedStructureControl importedStructures,
-            Map<String, Holder<StructureSet>> holdersByKey
+            Map<String, Holder<StructureSet>> holdersByKey,
+            StructureSetKeyIndex keyIndex
    ) {
        Set<Holder<StructureSet>> visited = Collections.newSetFromMap(new IdentityHashMap<>());
        Holder<StructureSet> current = holder;
        while (visited.add(current)) {
-            if (importedStructures.frequencyMultiplier(structureSetKey(current)) != 1D) {
+            if (importedStructures.frequencyMultiplier(
+                    structureSetKey(current, keyIndex)) != 1D) {
                return true;
            }
            Optional<StructurePlacement.ExclusionZone> zone =
@@ -300,24 +341,26 @@ final class DatapackStructureStateFilter {
            if (zone.isEmpty()) {
                return false;
            }
-            current = canonicalHolder(zone.get().otherSet(), holdersByKey);
+            current = canonicalHolder(zone.get().otherSet(), holdersByKey, keyIndex);
        }
        return false;
    }

    private static Holder<StructureSet> canonicalHolder(
            Holder<StructureSet> holder,
-            Map<String, Holder<StructureSet>> holdersByKey
+            Map<String, Holder<StructureSet>> holdersByKey,
+            StructureSetKeyIndex keyIndex
    ) {
-        String key = structureSetKey(holder);
+        String key = structureSetKey(holder, keyIndex);
        return key == null ? holder : holdersByKey.getOrDefault(key, holder);
    }

    private static Holder<StructureSet> replacementHolder(
            Holder<StructureSet> original,
-            StructureSet replacement
+            StructureSet replacement,
+            StructureSetKeyIndex keyIndex
    ) {
-        Optional<ResourceKey<StructureSet>> key = structureSetResourceKey(original);
+        Optional<ResourceKey<StructureSet>> key = keyIndex.resolve(original);
        if (key.isEmpty()) {
            return Holder.direct(replacement);
        }
@@ -326,20 +369,6 @@ final class DatapackStructureStateFilter {
        return holder;
    }

-    private static Optional<ResourceKey<StructureSet>> structureSetResourceKey(
-            Holder<StructureSet> holder
-    ) {
-        Optional<ResourceKey<StructureSet>> key = holder.unwrapKey();
-        if (key.isPresent()) {
-            return key;
-        }
-        if (holder.value().placement()
-                instanceof ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement keyedPlacement) {
-            return Optional.of(keyedPlacement.key);
-        }
-        return Optional.empty();
-    }
-
    private static StructurePlacement copyPlacement(
            StructurePlacement placement,
            Optional<StructurePlacement.ExclusionZone> exclusionZone,
@@ -357,26 +386,7 @@ final class DatapackStructureStateFilter {
        int salt = (int) declaredFieldValue(
                StructurePlacement.class, placement, int.class);

-        if (placement.getClass()
-                == ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement.class) {
-            ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement keyedPlacement =
-                    (ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement) placement;
-            NativeStructureFrequencyScale scale = NativeStructureFrequencyScale.randomSpread(
-                    frequency, keyedPlacement.spacing(), keyedPlacement.separation(), frequencyMultiplier);
-            return new ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement(
-                    keyedPlacement.key,
-                    locateOffset,
-                    frequencyReductionMethod,
-                    scale.frequency(),
-                    salt,
-                    exclusionZone,
-                    scale.spacing(),
-                    keyedPlacement.separation(),
-                    keyedPlacement.spreadType());
-        }
-        if (placement.getClass() == RandomSpreadStructurePlacement.class) {
-            RandomSpreadStructurePlacement randomSpread =
-                    (RandomSpreadStructurePlacement) placement;
+        if (placement instanceof RandomSpreadStructurePlacement randomSpread) {
            NativeStructureFrequencyScale scale = NativeStructureFrequencyScale.randomSpread(
                    frequency, randomSpread.spacing(), randomSpread.separation(), frequencyMultiplier);
            return new RandomSpreadStructurePlacement(
@@ -439,6 +449,46 @@ final class DatapackStructureStateFilter {
        }
    }

+    static final class StructureSetKeyIndex {
+        private final Map<List<StructureSet.StructureSelectionEntry>, ResourceKey<StructureSet>>
+                keysByEntries;
+
+        private StructureSetKeyIndex(
+                Map<List<StructureSet.StructureSelectionEntry>, ResourceKey<StructureSet>>
+                        keysByEntries
+        ) {
+            this.keysByEntries = keysByEntries;
+        }
+
+        private static StructureSetKeyIndex create(
+                Iterable<? extends Holder<StructureSet>> registeredStructureSets
+        ) {
+            Map<List<StructureSet.StructureSelectionEntry>, ResourceKey<StructureSet>> keys =
+                    new IdentityHashMap<>();
+            for (Holder<StructureSet> holder : registeredStructureSets) {
+                Optional<ResourceKey<StructureSet>> key = holder.unwrapKey();
+                if (key.isEmpty()) {
+                    continue;
+                }
+                List<StructureSet.StructureSelectionEntry> entries = holder.value().structures();
+                ResourceKey<StructureSet> previous = keys.put(entries, key.get());
+                if (previous != null && !previous.equals(key.get())) {
+                    throw new IllegalStateException(
+                            "Multiple registered structure sets share the same entry list");
+                }
+            }
+            return new StructureSetKeyIndex(keys);
+        }
+
+        private Optional<ResourceKey<StructureSet>> resolve(Holder<StructureSet> holder) {
+            Optional<ResourceKey<StructureSet>> key = holder.unwrapKey();
+            if (key.isPresent()) {
+                return key;
+            }
+            return Optional.ofNullable(keysByEntries.get(holder.value().structures()));
+        }
+    }
+
    record Selection(
            List<Holder<StructureSet>> structureSets,
            int retainedManagedSets,
@@ -15,7 +15,6 @@ import art.arcane.iris.core.nms.container.BiomeColor;
 import art.arcane.iris.core.nms.container.Pair;
 import art.arcane.iris.core.nms.container.BlockProperty;
 import art.arcane.iris.core.nms.datapack.DataVersion;
-import art.arcane.iris.core.lifecycle.WorldReplacementSeed;
 import art.arcane.iris.engine.data.cache.AtomicCache;
 import art.arcane.iris.engine.data.chunk.TerrainChunk;
 import art.arcane.iris.engine.framework.Engine;
@@ -55,8 +54,6 @@ import art.arcane.volmlib.util.nbt.tag.CompoundTag;
 import art.arcane.iris.util.common.scheduling.J;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
 import it.unimi.dsi.fastutil.shorts.ShortList;
-import io.papermc.paper.world.saveddata.PaperLevelOverrides;
-import io.papermc.paper.world.saveddata.PaperWorldMetadata;
 import net.bytebuddy.ByteBuddy;
 import net.bytebuddy.agent.builder.AgentBuilder;
 import net.bytebuddy.agent.builder.ResettableClassFileTransformer;
@@ -119,14 +116,14 @@ import net.minecraft.world.level.levelgen.XoroshiroRandomSource;
 import net.minecraft.world.level.levelgen.structure.StructureCheck;
 import net.minecraft.world.level.levelgen.structure.BoundingBox;
 import net.minecraft.world.level.levelgen.structure.Structure;
+import net.minecraft.world.level.levelgen.structure.StructureSet;
 import net.minecraft.world.level.levelgen.structure.structures.JigsawStructure;
-import net.minecraft.world.level.storage.PrimaryLevelData;
-import net.minecraft.world.level.storage.SavedDataStorage;
 import net.minecraft.world.level.levelgen.feature.AbstractHugeMushroomFeature;
 import net.minecraft.world.level.levelgen.feature.ConfiguredFeature;
 import net.minecraft.world.level.levelgen.feature.FallenTreeFeature;
 import net.minecraft.world.level.levelgen.feature.Feature;
 import net.minecraft.world.level.levelgen.feature.TreeFeature;
+import net.minecraft.world.level.storage.LevelStorageSource;
 import net.minecraft.world.level.levelgen.flat.FlatLayerInfo;
 import net.minecraft.world.level.levelgen.flat.FlatLevelGeneratorSettings;
 import org.bukkit.Bukkit;
@@ -162,8 +159,6 @@ import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.nio.file.Files;
-import java.nio.file.LinkOption;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -173,23 +168,18 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.List;
 import java.util.Set;
-import java.util.UUID;
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;

 public class NMSBinding implements INMSBinding {
-    private static final long CURRENT_WORLD_DATA_SNAPSHOT_TIMEOUT_SECONDS = 30L;
-
    private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
    private volatile DataVersion dataVersion;
    private final BlockData AIR = Material.AIR.createBlockData();
    private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
    private final AtomicBoolean injected = new AtomicBoolean();
+    private volatile ResettableClassFileTransformer levelStorageAccessTransformer;
    private volatile ResettableClassFileTransformer serverLevelTransformer;
    private final AtomicCache<MCAIdMapper<BlockState>> registryCache = new AtomicCache<>();
    private final AtomicCache<MCAPalette<BlockState>> globalCache = new AtomicCache<>();
@@ -1249,8 +1239,15 @@ public class NMSBinding implements INMSBinding {
        ChunkGeneratorStructureState currentState = level.getChunkSource().getGeneratorState();
        net.minecraft.world.level.chunk.ChunkGenerator generator = level.getChunkSource().getGenerator();
        ChunkGeneratorStructureState scopedState = createStructureState(level, generator, currentState);
+        Registry<StructureSet> structureSetRegistry =
+                level.registryAccess().lookupOrThrow(Registries.STRUCTURE_SET);
        DatapackStructureStateFilter.Selection selection = DatapackStructureStateFilter.filter(
-                scopedState.possibleStructureSets(), scopeIndex, declaredSources, importedStructures);
+                scopedState.possibleStructureSets(),
+                scopeIndex,
+                declaredSources,
+                importedStructures,
+                DatapackStructureStateFilter.keyIndex(
+                        structureSetRegistry.listElements().toList()));

        Field possibleSetsField = getField(scopedState.getClass(), List.class);
        possibleSetsField.setAccessible(true);
@@ -1328,7 +1325,7 @@ public class NMSBinding implements INMSBinding {
                level.registryAccess().lookupOrThrow(Registries.STRUCTURE_SET),
                currentState.randomState(),
                currentState.getLevelSeed(),
-                currentState.conf);
+                level.spigotConfig);
    }

    private void initializeAndPublishStructureState(
@@ -1542,6 +1539,18 @@ public class NMSBinding implements INMSBinding {
            }
            try {
                IrisLogging.info("Injecting Bukkit");
+                levelStorageAccessTransformer = new AgentBuilder.Default()
+                        .disableClassFormatChanges()
+                        .with(AgentBuilder.RedefinitionStrategy.RETRANSFORMATION)
+                        .type(ElementMatchers.is(LevelStorageSource.LevelStorageAccess.class))
+                        .transform((builder, typeDescription, classLoader, module, protectionDomain) ->
+                                builder.visit(Advice.to(LevelStorageAccessAdvice.class).on(ElementMatchers.isConstructor()
+                                        .and(ElementMatchers.takesArguments(4))
+                                        .and(ElementMatchers.takesArgument(0, LevelStorageSource.class))
+                                        .and(ElementMatchers.takesArgument(1, String.class))
+                                        .and(ElementMatchers.takesArgument(2, Path.class))
+                                        .and(ElementMatchers.takesArgument(3, ResourceKey.class)))))
+                        .installOn(Agent.getInstrumentation());
                serverLevelTransformer = new AgentBuilder.Default()
                        .disableClassFormatChanges()
                        .with(AgentBuilder.RedefinitionStrategy.RETRANSFORMATION)
@@ -1549,8 +1558,7 @@ public class NMSBinding implements INMSBinding {
                        .transform((builder, typeDescription, classLoader, module, protectionDomain) ->
                                builder.visit(Advice.to(ServerLevelAdvice.class).on(ElementMatchers.isConstructor()
                                        .and(ElementMatchers.takesArgument(0, MinecraftServer.class))
-                                        .and(ElementMatchers.takesArgument(5, LevelStem.class))
-                                        .and(ElementMatchers.takesArgument(12, ChunkGenerator.class)))))
+                                        .and(ElementMatchers.takesArgument(5, LevelStem.class)))))
                        .installOn(Agent.getInstrumentation());
                ByteBuddy buddy = new ByteBuddy();
                for (Class<?> clazz : List.of(ChunkAccess.class, ProtoChunk.class)) {
@@ -1565,12 +1573,17 @@ public class NMSBinding implements INMSBinding {
            } catch (Throwable e) {
                IrisLogging.error(C.RED + "Failed to inject Bukkit");
                e.printStackTrace();
-                // The ServerLevel transformer may already be installed when the ChunkAccess
-                // redefine throws; remove it or a retry would stack a second one and orphan
-                // this one permanently.
-                ResettableClassFileTransformer partial = serverLevelTransformer;
+                ResettableClassFileTransformer partialServerLevel = serverLevelTransformer;
+                ResettableClassFileTransformer partialStorageAccess = levelStorageAccessTransformer;
                serverLevelTransformer = null;
-                if (partial != null) {
+                levelStorageAccessTransformer = null;
+                for (ResettableClassFileTransformer partial : new ResettableClassFileTransformer[]{
+                        partialServerLevel,
+                        partialStorageAccess
+                }) {
+                    if (partial == null) {
+                        continue;
+                    }
                    try {
                        partial.reset(Agent.getInstrumentation(), AgentBuilder.RedefinitionStrategy.RETRANSFORMATION);
                    } catch (Throwable ignored) {
@@ -1586,26 +1599,36 @@ public class NMSBinding implements INMSBinding {
        if (!injected.get())
            return;
        try {
-            Agent.getInstrumentation().retransformClasses(ServerLevel.class);
+            Agent.getInstrumentation().retransformClasses(
+                    LevelStorageSource.LevelStorageAccess.class,
+                    ServerLevel.class
+            );
        } catch (Throwable e) {
-            IrisLogging.error(C.RED + "Failed to re-apply ServerLevel injection");
+            IrisLogging.error(C.RED + "Failed to re-apply Bukkit world lifecycle injection");
        }
    }

    @Override
    public void uninjectBukkit() {
        synchronized (injected) {
-            ResettableClassFileTransformer transformer = serverLevelTransformer;
+            ResettableClassFileTransformer activeServerLevel = serverLevelTransformer;
+            ResettableClassFileTransformer activeStorageAccess = levelStorageAccessTransformer;
            serverLevelTransformer = null;
+            levelStorageAccessTransformer = null;
            injected.set(false);
-            if (transformer == null) {
-                return;
-            }
-            try {
-                transformer.reset(Agent.getInstrumentation(), AgentBuilder.RedefinitionStrategy.RETRANSFORMATION);
-            } catch (Throwable e) {
-                IrisLogging.error(C.RED + "Failed to remove ServerLevel injection");
-                e.printStackTrace();
+            for (ResettableClassFileTransformer transformer : new ResettableClassFileTransformer[]{
+                    activeServerLevel,
+                    activeStorageAccess
+            }) {
+                if (transformer == null) {
+                    continue;
+                }
+                try {
+                    transformer.reset(Agent.getInstrumentation(), AgentBuilder.RedefinitionStrategy.RETRANSFORMATION);
+                } catch (Throwable e) {
+                    IrisLogging.error(C.RED + "Failed to remove Bukkit world lifecycle injection");
+                    e.printStackTrace();
+                }
            }
        }
    }
@@ -1616,103 +1639,7 @@ public class NMSBinding implements INMSBinding {
            Path targetWorldDirectory,
            long seed
    ) throws IOException {
-        CraftServer craftServer = (CraftServer) Bukkit.getServer();
-        MinecraftServer server = craftServer.getHandle().getServer();
-        PaperLevelOverrides levelOverrides = captureCurrentPaperLevelOverrides(craftServer, server);
-
-        Path targetWorld = targetWorldDirectory.toAbsolutePath().normalize();
-        UUID metadataUuid = UUID.randomUUID();
-        WorldReplacementSeed.copyWithAuthoritativeSeed(sourceWorldDirectory, targetWorld, seed);
-        try (SavedDataStorage savedDataStorage = new SavedDataStorage(
-                targetWorld.resolve("data"),
-                server.getFixerUpper(),
-                server.registryAccess()
-        )) {
-            savedDataStorage.set(PaperWorldMetadata.TYPE, new PaperWorldMetadata(metadataUuid));
-            savedDataStorage.set(
-                    PaperLevelOverrides.TYPE,
-                    levelOverrides
-            );
-        }
-
-        List<Path> requiredDataFiles = List.of(
-                targetWorld.resolve("data/minecraft/world_gen_settings.dat"),
-                targetWorld.resolve("data/paper/metadata.dat"),
-                targetWorld.resolve("data/paper/level_overrides.dat")
-        );
-        for (Path requiredDataFile : requiredDataFiles) {
-            if (!Files.isRegularFile(requiredDataFile, LinkOption.NOFOLLOW_LINKS)) {
-                throw new IOException("Current Paper world data was not written: " + requiredDataFile);
-            }
-        }
-
-        long writtenSeed = WorldReplacementSeed.readAuthoritativeSeed(targetWorld);
-        if (writtenSeed != seed) {
-            throw new IOException("Current Paper world data did not retain the requested seed.");
-        }
-
-        try (SavedDataStorage verificationStorage = new SavedDataStorage(
-                targetWorld.resolve("data"),
-                server.getFixerUpper(),
-                server.registryAccess()
-        )) {
-            PaperWorldMetadata metadata = verificationStorage.get(PaperWorldMetadata.TYPE);
-            if (metadata == null || !metadataUuid.equals(metadata.uuid())) {
-                throw new IOException("Current Paper world metadata could not be verified.");
-            }
-            PaperLevelOverrides overrides = verificationStorage.get(PaperLevelOverrides.TYPE);
-            if (overrides == null || overrides.isInitialized()) {
-                throw new IOException("Current Paper level overrides could not be verified.");
-            }
-        }
-    }
-
-    private PaperLevelOverrides captureCurrentPaperLevelOverrides(
-            CraftServer craftServer,
-            MinecraftServer server
-    ) throws IOException {
-        if (craftServer.isGlobalTickThread()) {
-            return createCurrentPaperLevelOverrides(craftServer, server);
-        }
-        if (J.isFolia() && J.isPrimaryThread()) {
-            throw new IOException("Current Paper world data cannot be staged from a Folia region tick thread.");
-        }
-
-        CompletableFuture<PaperLevelOverrides> captured = new CompletableFuture<>();
-        boolean scheduled = J.runGlobal(() -> {
-            try {
-                captured.complete(createCurrentPaperLevelOverrides(craftServer, server));
-            } catch (Throwable failure) {
-                captured.completeExceptionally(failure);
-            }
-        });
-        if (!scheduled) {
-            throw new IOException("Could not schedule the current Paper level-data snapshot on the global thread.");
-        }
-
-        try {
-            return captured.get(CURRENT_WORLD_DATA_SNAPSHOT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
-        } catch (InterruptedException failure) {
-            Thread.currentThread().interrupt();
-            throw new IOException("Interrupted while capturing current Paper level data.", failure);
-        } catch (ExecutionException failure) {
-            throw new IOException("Could not capture current Paper level data.", failure.getCause());
-        } catch (TimeoutException failure) {
-            throw new IOException("Timed out while capturing current Paper level data.", failure);
-        }
-    }
-
-    private PaperLevelOverrides createCurrentPaperLevelOverrides(
-            CraftServer craftServer,
-            MinecraftServer server
-    ) throws IOException {
-        if (!craftServer.isGlobalTickThread()) {
-            throw new IOException("Current Paper level data must be captured on the global tick thread.");
-        }
-        if (!(server.getWorldData().overworldData() instanceof PrimaryLevelData primaryLevelData)) {
-            throw new IOException("Paper primary level data is unavailable for current world data staging.");
-        }
-        return PaperLevelOverrides.createFromLiveLevelData(primaryLevelData);
+        CurrentPaperWorldDataWriter.write(sourceWorldDirectory, targetWorldDirectory, seed);
    }

    @Override
@@ -1777,13 +1704,76 @@ public class NMSBinding implements INMSBinding {
        }
    }

+    private static class LevelStorageAccessAdvice {
+        @Advice.OnMethodEnter
+        static void enter(
+                @Advice.Argument(1) String levelId,
+                @Advice.Argument(value = 3, readOnly = false) ResourceKey<LevelStem> dimensionType
+        ) {
+            if (levelId == null || levelId.isBlank()) {
+                return;
+            }
+
+            ClassLoader pluginClassLoader;
+            Class<?> generatorType;
+            Class<?> stagingType;
+            try {
+                org.bukkit.plugin.Plugin irisPlugin = Bukkit.getPluginManager().getPlugin("Iris");
+                if (irisPlugin == null) {
+                    return;
+                }
+                pluginClassLoader = irisPlugin.getClass().getClassLoader();
+                generatorType = Class.forName("art.arcane.iris.engine.platform.PlatformChunkGenerator", true, pluginClassLoader);
+                stagingType = Class.forName("art.arcane.iris.core.lifecycle.WorldLifecycleStaging", true, pluginClassLoader);
+            } catch (Throwable ignored) {
+                return;
+            }
+
+            Object generator;
+            try {
+                generator = stagingType
+                        .getDeclaredMethod("peekStemGenerator", String.class)
+                        .invoke(null, levelId);
+            } catch (Throwable e) {
+                throw new RuntimeException("Iris failed to inspect the staged world generator",
+                        e instanceof InvocationTargetException ex ? ex.getCause() : e);
+            }
+            if (generator == null || !generatorType.isInstance(generator)) {
+                return;
+            }
+
+            try {
+                Object target = generatorType.getMethod("getTarget").invoke(generator);
+                if (target == null) {
+                    throw new IllegalStateException("Iris generator has no engine target.");
+                }
+                Object world = target.getClass().getMethod("getWorld").invoke(target);
+                if (world == null) {
+                    throw new IllegalStateException("Iris generator target has no world identity.");
+                }
+                Object rawIdentity = world.getClass().getMethod("identity").invoke(world);
+                String worldIdentity = rawIdentity == null ? "" : rawIdentity.toString().trim();
+                Identifier worldIdentifier = Identifier.parse(worldIdentity);
+                if (!"iris".equals(worldIdentifier.getNamespace())
+                        && !"minecraft".equals(worldIdentifier.getNamespace())) {
+                    throw new IllegalStateException(
+                            "Iris generator has an unmanaged world identity: " + worldIdentity);
+                }
+                dimensionType = ResourceKey.create(Registries.LEVEL_STEM, worldIdentifier);
+            } catch (Throwable e) {
+                throw new RuntimeException("Iris failed to bind the staged world storage identity",
+                        e instanceof InvocationTargetException ex ? ex.getCause() : e);
+            }
+        }
+    }
+
    private static class ServerLevelAdvice {
        @Advice.OnMethodEnter
        static void enter(
                @Advice.Argument(0) MinecraftServer server,
-                @Advice.Argument(4) ResourceKey<Level> dimensionKey,
+                @Advice.Argument(value = 4, readOnly = false) ResourceKey<Level> dimensionKey,
                @Advice.Argument(value = 5, readOnly = false) LevelStem levelStem,
-                @Advice.Argument(12) ChunkGenerator constructorGenerator
+                @Advice.AllArguments Object[] constructorArguments
        ) {
            if (dimensionKey == null)
                return;
@@ -1818,6 +1808,13 @@ public class NMSBinding implements INMSBinding {
            // the vanilla stem corrupts generation.
            ChunkGenerator gen = null;
            try {
+                ChunkGenerator constructorGenerator = null;
+                for (Object argument : constructorArguments) {
+                    if (argument instanceof ChunkGenerator candidate) {
+                        constructorGenerator = candidate;
+                        break;
+                    }
+                }
                Object generator = generatorType.isInstance(constructorGenerator) ? constructorGenerator : null;
                if (generator == null) {
                    generator = stagingType
@@ -1855,10 +1852,27 @@ public class NMSBinding implements INMSBinding {
                if (stemMethod == null) {
                    throw new IllegalStateException("Iris binding is missing createRuntimeLevelStem.");
                }
+                Object target = generatorType.getMethod("getTarget").invoke(gen);
+                if (target == null) {
+                    throw new IllegalStateException("Iris generator has no engine target.");
+                }
+                Object world = target.getClass().getMethod("getWorld").invoke(target);
+                if (world == null) {
+                    throw new IllegalStateException("Iris generator target has no world identity.");
+                }
+                Object rawIdentity = world.getClass().getMethod("identity").invoke(world);
+                String worldIdentity = rawIdentity == null ? "" : rawIdentity.toString().trim();
+                Identifier worldIdentifier = Identifier.parse(worldIdentity);
+                if (!"iris".equals(worldIdentifier.getNamespace())
+                        && !"minecraft".equals(worldIdentifier.getNamespace())) {
+                    throw new IllegalStateException(
+                            "Iris generator has an unmanaged world identity: " + worldIdentity);
+                }
                Object resolvedStem = stemMethod.invoke(bindings, server.registryAccess(), gen);
                if (!(resolvedStem instanceof LevelStem runtimeStem)) {
                    throw new IllegalStateException("Iris runtime LevelStem binding returned " + (resolvedStem == null ? "null" : resolvedStem.getClass().getName()) + ".");
                }
+                dimensionKey = ResourceKey.create(Registries.DIMENSION, worldIdentifier);
                levelStem = runtimeStem;
            } catch (Throwable e) {
                throw new RuntimeException("Iris failed to replace the levelStem", e instanceof InvocationTargetException ex ? ex.getCause() : e);
@@ -215,6 +215,14 @@ final class NativeStructureWorldgenAccess implements WorldGenLevel {
        }
    }

+    @Override
+    public ChunkAccess getChunk(int chunkX, int chunkZ) {
+        if (isInsideGenerationRegion(chunkX, chunkZ)) {
+            return delegate.getChunk(chunkX, chunkZ);
+        }
+        return outsideChunk(chunkX, chunkZ);
+    }
+
    @Override
    public ChunkAccess getChunk(int chunkX, int chunkZ, ChunkStatus status, boolean create) {
        if (isInsideGenerationRegion(chunkX, chunkZ)) {
@@ -3,29 +3,54 @@ package art.arcane.iris.core.nms.v26_2_R1;
 import art.arcane.iris.core.nms.INMSBinding;
 import org.junit.Test;

+import java.io.InputStream;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Proxy;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;

 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;

 public class NMSBindingCurrentPaperWorldDataContractTest {
    @Test
-    public void stagesAllCurrentPaperWorldDataFromLiveServerState() throws Exception {
-        String source = Files.readString(Path.of(System.getProperty("iris.nmsBindingSource")));
+    public void bindingDelegatesWithoutLinkingPaperSavedDataClasses() throws Exception {
+        String bindingSource = Files.readString(bindingSourcePath());
        String writer = section(
-                source,
+                bindingSource,
                "public void writeCurrentPaperWorldData(",
-                "public KMap<Material, List<BlockProperty>> getBlockProperties()"
+                "public boolean awaitServerShutdownBoundary("
        );

+        assertTrue(writer.contains("CurrentPaperWorldDataWriter.write("));
+        assertFalse(bindingSource.contains("PaperWorldMetadata"));
+        assertFalse(bindingSource.contains("PaperLevelOverrides"));
+        assertFalse(bindingSource.contains("io.papermc.paper.world.saveddata"));
+
+        InputStream classResource = NMSBindingCurrentPaperWorldDataContractTest.class
+                .getResourceAsStream("NMSBinding.class");
+        assertNotNull(classResource);
+        try (InputStream input = classResource) {
+            String classFile = new String(input.readAllBytes(), StandardCharsets.ISO_8859_1);
+            assertFalse(classFile.contains("PaperWorldMetadata"));
+            assertFalse(classFile.contains("PaperLevelOverrides"));
+            assertFalse(classFile.contains("io/papermc/paper/world/saveddata"));
+        }
+    }
+
+    @Test
+    public void stagesAllCurrentPaperWorldDataFromLiveServerState() throws Exception {
+        String writer = Files.readString(writerSourcePath());
+
        assertTrue(writer.contains("WorldReplacementSeed.copyWithAuthoritativeSeed("));
        assertTrue(writer.contains("UUID metadataUuid = UUID.randomUUID()"));
        assertTrue(writer.contains("new PaperWorldMetadata(metadataUuid)"));
-        assertTrue(writer.contains("captureCurrentPaperLevelOverrides(craftServer, server)"));
+        assertTrue(writer.contains("captureLevelOverrides(craftServer, server)"));
+        assertTrue(writer.indexOf("captureLevelOverrides(craftServer, server)")
+                < writer.indexOf("WorldReplacementSeed.copyWithAuthoritativeSeed("));
        assertTrue(writer.contains("new SavedDataStorage("));
        assertTrue(writer.contains("server.getFixerUpper()"));
        assertTrue(writer.contains("server.registryAccess()"));
@@ -44,23 +69,23 @@ public class NMSBindingCurrentPaperWorldDataContractTest {

    @Test
    public void capturesOnlyLiveLevelOverridesOnTheGlobalThread() throws Exception {
-        String source = Files.readString(Path.of(System.getProperty("iris.nmsBindingSource")));
+        String source = Files.readString(writerSourcePath());
        String capture = section(
                source,
-                "private PaperLevelOverrides captureCurrentPaperLevelOverrides(",
-                "private PaperLevelOverrides createCurrentPaperLevelOverrides("
+                "private static PaperLevelOverrides captureLevelOverrides(",
+                "private static PaperLevelOverrides createLevelOverrides("
        );
        String create = section(
                source,
-                "private PaperLevelOverrides createCurrentPaperLevelOverrides(",
-                "public KMap<Material, List<BlockProperty>> getBlockProperties()"
+                "private static PaperLevelOverrides createLevelOverrides(",
+                "\n    }\n}"
        );

        assertTrue(capture.contains("craftServer.isGlobalTickThread()"));
        assertTrue(capture.contains("J.isFolia() && J.isPrimaryThread()"));
        assertTrue(capture.contains("J.runGlobal("));
-        assertTrue(capture.contains("createCurrentPaperLevelOverrides(craftServer, server)"));
-        assertTrue(capture.contains("captured.get(CURRENT_WORLD_DATA_SNAPSHOT_TIMEOUT_SECONDS"));
+        assertTrue(capture.contains("createLevelOverrides(craftServer, server)"));
+        assertTrue(capture.contains("captured.get(SNAPSHOT_TIMEOUT_SECONDS"));
        assertTrue(capture.contains("Thread.currentThread().interrupt()"));
        assertTrue(create.contains("if (!craftServer.isGlobalTickThread())"));
        assertTrue(create.indexOf("if (!craftServer.isGlobalTickThread())")
@@ -89,6 +114,14 @@ public class NMSBindingCurrentPaperWorldDataContractTest {
        assertTrue(error.getMessage().contains("does not support current Paper world data staging"));
    }

+    private static Path bindingSourcePath() {
+        return Path.of(System.getProperty("iris.nmsBindingSource"));
+    }
+
+    private static Path writerSourcePath() {
+        return bindingSourcePath().resolveSibling("CurrentPaperWorldDataWriter.java");
+    }
+
    private static String section(String source, String startMarker, String endMarker) {
        int start = source.indexOf(startMarker);
        int end = source.indexOf(endMarker, start);
@@ -27,6 +27,8 @@ import org.junit.Test;
 import org.junit.BeforeClass;

 import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
@@ -38,8 +40,8 @@ import java.util.stream.Stream;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotSame;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;

 public class NMSBindingDatapackStructureScopeTest {
@@ -108,28 +110,56 @@ public class NMSBindingDatapackStructureScopeTest {
    }

    @Test
-    public void spigotDirectHolderRetainsItsStructureSetKey() {
+    public void spigotDirectHolderRecoversItsRegistryKeyFromSharedEntries() {
        ResourceKey<StructureSet> key = ResourceKey.create(
                Registries.STRUCTURE_SET,
-                Identifier.parse("minecraft:villages"));
-        ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement placement =
-                new ChunkGeneratorStructureState.KeyedRandomSpreadStructurePlacement(
-                        key,
-                        Vec3i.ZERO,
-                        StructurePlacement.FrequencyReductionMethod.DEFAULT,
-                        1.0F,
-                        10387312,
-                        Optional.empty(),
-                        34,
-                        8,
-                        RandomSpreadType.LINEAR);
-        StructureSet structureSet = new StructureSet(
-                List.of(new StructureSet.StructureSelectionEntry(
-                        structureHolder("minecraft:village_plains"), 1)),
-                placement);
+                Identifier.parse("managed:illager_barracks"));
+        List<StructureSet.StructureSelectionEntry> entries = List.of(
+                new StructureSet.StructureSelectionEntry(
+                        structureHolder("minecraft:pillager_outpost"), 1));
+        Holder<StructureSet> registered = new KeyedHolder<>(key, new StructureSet(
+                entries,
+                new RandomSpreadStructurePlacement(
+                        34, 8, RandomSpreadType.LINEAR, 10387312)));
+        Holder<StructureSet> spigotDirect = Holder.direct(new StructureSet(
+                entries,
+                new RandomSpreadStructurePlacement(
+                        34, 8, RandomSpreadType.LINEAR, 14357620)));
+        DatapackStructureScopeIndex scopeIndex = index(
+                List.of(), List.of("managed:illager_barracks"));
+        DatapackStructureStateFilter.StructureSetKeyIndex keyIndex =
+                DatapackStructureStateFilter.keyIndex(List.of(registered));

-        assertEquals("minecraft:villages",
-                DatapackStructureStateFilter.structureSetKey(Holder.direct(structureSet)));
+        DatapackStructureStateFilter.Selection excluded =
+                DatapackStructureStateFilter.filter(
+                        List.of(spigotDirect),
+                        scopeIndex,
+                        Set.of(),
+                        new IrisImportedStructureControl(),
+                        keyIndex);
+        DatapackStructureStateFilter.Selection retained =
+                DatapackStructureStateFilter.filter(
+                        List.of(spigotDirect),
+                        scopeIndex,
+                        scopeIndex.declaredSources(List.of(SOURCE)),
+                        new IrisImportedStructureControl(),
+                        keyIndex);
+
+        assertEquals(0, excluded.structureSets().size());
+        assertEquals(1, excluded.excludedManagedSets());
+        assertSame(spigotDirect, retained.structureSets().getFirst());
+        assertEquals(1, retained.retainedManagedSets());
+    }
+
+    @Test
+    public void structureScopeDoesNotLinkPaperOnlyPlacementClasses() throws IOException {
+        InputStream classResource = NMSBindingDatapackStructureScopeTest.class
+                .getResourceAsStream("DatapackStructureStateFilter.class");
+        assertNotNull(classResource);
+        try (InputStream input = classResource) {
+            String classFile = new String(input.readAllBytes(), StandardCharsets.ISO_8859_1);
+            assertFalse(classFile.contains("KeyedRandomSpreadStructurePlacement"));
+        }
    }

    @Test
@@ -271,7 +301,7 @@ public class NMSBindingDatapackStructureScopeTest {
    }

    @Test
-    public void affectedRandomSpreadSubclassFailsInsteadOfLosingSubtypeBehavior() {
+    public void randomSpreadSubtypeUsesTheCanonicalPlacementContract() {
        Holder<StructureSet> custom = structureSetHolder(
                "example:custom",
                new CustomRandomSpreadPlacement(),
@@ -283,8 +313,12 @@ public class NMSBindingDatapackStructureScopeTest {
        IrisImportedStructureControl control = new IrisImportedStructureControl()
                .setFrequencyOverrides(overrides);

-        assertThrows(IllegalStateException.class, () -> DatapackStructureStateFilter.filter(
-                List.of(custom), index(List.of(), List.of()), Set.of(), control));
+        DatapackStructureStateFilter.Selection selection = DatapackStructureStateFilter.filter(
+                List.of(custom), index(List.of(), List.of()), Set.of(), control);
+        StructurePlacement placement = selection.structureSets().getFirst().value().placement();
+
+        assertEquals(RandomSpreadStructurePlacement.class, placement.getClass());
+        assertEquals(26, ((RandomSpreadStructurePlacement) placement).spacing());
    }

    @Test
@@ -395,6 +429,21 @@ public class NMSBindingDatapackStructureScopeTest {
        assertTrue(structureRetarget > identityGate);
    }

+    @Test
+    public void structureStateRecreationUsesTheWorldOwnedSpigotConfiguration() throws IOException {
+        Path chunkGeneratorSource = Path.of(System.getProperty("iris.nmsChunkGeneratorSource"));
+        String source = Files.readString(chunkGeneratorSource.resolveSibling("NMSBinding.java"));
+        int methodStart = source.indexOf("private ChunkGeneratorStructureState createStructureState(");
+        int methodEnd = source.indexOf(
+                "\n    private void initializeAndPublishStructureState(", methodStart);
+
+        assertTrue(methodStart >= 0);
+        assertTrue(methodEnd > methodStart);
+        String method = source.substring(methodStart, methodEnd);
+        assertTrue(method.contains("level.spigotConfig"));
+        assertFalse(method.contains("currentState.conf"));
+    }
+
    private static DatapackStructureScopeIndex index(
            List<String> structureKeys,
            List<String> structureSetKeys
@@ -0,0 +1,103 @@
+package art.arcane.iris.core.nms.v26_2_R1;
+
+import org.junit.Test;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class NMSBindingServerLevelAdviceContractTest {
+    @Test
+    public void serverLevelAdviceSupportsCurrentSpigotAndPaperConstructorLayouts() throws Exception {
+        String source = Files.readString(
+                Path.of(System.getProperty("iris.nmsBindingSource")));
+        String transformer = section(
+                source,
+                "public boolean injectBukkit()",
+                "public void ensureServerLevelInjection()");
+        String advice = section(
+                source,
+                "private static class ServerLevelAdvice",
+                "\n    }\n}");
+
+        assertTrue(transformer.contains("takesArgument(0, MinecraftServer.class)"));
+        assertTrue(transformer.contains("takesArgument(5, LevelStem.class)"));
+        assertFalse(transformer.contains("takesArgument(12, ChunkGenerator.class)"));
+        assertFalse(transformer.contains("takesArgument(13, ChunkGenerator.class)"));
+        assertTrue(advice.contains("@Advice.AllArguments Object[] constructorArguments"));
+        assertTrue(advice.contains("argument instanceof ChunkGenerator candidate"));
+        assertFalse(advice.contains("@Advice.Argument(12)"));
+        assertFalse(advice.contains("@Advice.Argument(13)"));
+    }
+
+    @Test
+    public void currentSpigotStorageAccessReceivesManagedIdentityBeforeConstruction() throws Exception {
+        String source = Files.readString(
+                Path.of(System.getProperty("iris.nmsBindingSource")));
+        String transformer = section(
+                source,
+                "public boolean injectBukkit()",
+                "public void ensureServerLevelInjection()");
+        String advice = section(
+                source,
+                "private static class LevelStorageAccessAdvice",
+                "private static class ServerLevelAdvice");
+
+        assertTrue(transformer.contains(
+                ".type(ElementMatchers.is(LevelStorageSource.LevelStorageAccess.class))"));
+        assertTrue(transformer.contains("Advice.to(LevelStorageAccessAdvice.class)"));
+        assertTrue(transformer.contains("ElementMatchers.takesArguments(4)"));
+        assertTrue(transformer.contains(
+                "ElementMatchers.takesArgument(0, LevelStorageSource.class)"));
+        assertTrue(transformer.contains("ElementMatchers.takesArgument(1, String.class)"));
+        assertTrue(transformer.contains("ElementMatchers.takesArgument(2, Path.class)"));
+        assertTrue(transformer.contains("ElementMatchers.takesArgument(3, ResourceKey.class)"));
+        assertTrue(advice.contains("@Advice.Argument(1) String levelId"));
+        assertTrue(advice.contains(
+                "@Advice.Argument(value = 3, readOnly = false) ResourceKey<LevelStem> dimensionType"));
+        assertTrue(advice.contains("getDeclaredMethod(\"peekStemGenerator\", String.class)"));
+        assertTrue(advice.contains(".invoke(null, levelId)"));
+        assertTrue(advice.contains(
+                "dimensionType = ResourceKey.create(Registries.LEVEL_STEM, worldIdentifier);"));
+        assertFalse(advice.contains("dimensionRoot("));
+        assertFalse(advice.contains("Files.copy"));
+    }
+
+    @Test
+    public void ownedWorldPublishesItsManagedIdentityAndRuntimeStemTogether() throws Exception {
+        String source = Files.readString(
+                Path.of(System.getProperty("iris.nmsBindingSource")));
+        String advice = section(
+                source,
+                "private static class ServerLevelAdvice",
+                "\n    }\n}");
+
+        assertTrue(advice.contains(
+                "@Advice.Argument(value = 4, readOnly = false) ResourceKey<Level> dimensionKey"));
+        assertTrue(advice.contains("getMethod(\"getTarget\")"));
+        assertTrue(advice.contains("getMethod(\"getWorld\")"));
+        assertTrue(advice.contains("getMethod(\"identity\")"));
+        assertTrue(advice.contains("\"iris\".equals(worldIdentifier.getNamespace())"));
+        assertTrue(advice.contains("\"minecraft\".equals(worldIdentifier.getNamespace())"));
+
+        int resolvedStem = advice.indexOf("Object resolvedStem = stemMethod.invoke(");
+        int validatedStem = advice.indexOf("resolvedStem instanceof LevelStem runtimeStem");
+        int identityPublication = advice.indexOf(
+                "dimensionKey = ResourceKey.create(Registries.DIMENSION, worldIdentifier);");
+        int stemPublication = advice.indexOf("levelStem = runtimeStem;");
+        assertTrue(resolvedStem >= 0);
+        assertTrue(validatedStem > resolvedStem);
+        assertTrue(identityPublication > validatedStem);
+        assertTrue(stemPublication > identityPublication);
+    }
+
+    private static String section(String source, String startMarker, String endMarker) {
+        int start = source.indexOf(startMarker);
+        int end = source.indexOf(endMarker, start);
+        assertTrue("Missing source section starting with " + startMarker, start >= 0);
+        assertTrue("Missing source section ending with " + endMarker, end > start);
+        return source.substring(start, end);
+    }
+}
@@ -135,6 +135,18 @@ public class NativeStructureWorldgenAccessTest {
        assertEquals(1, recording.blockTicks.count());
    }

+    @Test
+    public void statuslessChunkReadsPreserveWorldgenDelegateSemantics() {
+        RecordingDelegate recording = new RecordingDelegate();
+        NativeStructureWorldgenAccess access = access(recording);
+        ChunkPos generationCenter = generationCenter();
+
+        assertNull(access.getChunk(generationCenter.getWorldPosition()));
+
+        assertEquals(1, recording.statuslessChunkReads);
+        assertEquals(0, recording.statusChunkReads);
+    }
+
    @Test
    public void entityQueriesRejectDisjointAreasAndClampOverlaps() {
        RecordingDelegate recording = new RecordingDelegate();
@@ -187,6 +199,8 @@ public class NativeStructureWorldgenAccessTest {
        private int terrainReads;
        private int heightReads;
        private int chunkReads;
+        private int statuslessChunkReads;
+        private int statusChunkReads;
        private int mutations;
        private int events;

@@ -240,7 +254,16 @@ public class NativeStructureWorldgenAccessTest {
                terrainReads++;
                return Blocks.WATER.defaultBlockState().getFluidState();
            }
-            if (name.equals("getChunk") || name.equals("getChunkIfLoadedImmediately")) {
+            if (name.equals("getChunk")) {
+                chunkReads++;
+                if (arguments.length == 2) {
+                    statuslessChunkReads++;
+                } else {
+                    statusChunkReads++;
+                }
+                return null;
+            }
+            if (name.equals("getChunkIfLoadedImmediately")) {
                chunkReads++;
                return null;
            }