Tracked generated content ownership

- Generated furniture keeps ownership tokens for targeted removal
- Native writes invalidate pending custom content and tile records
- Regeneration and chunk updates remove invalidated content on owning threads
- Provider callbacks return ownership tokens across server platforms
- Regression fixtures cover terrain replacement and restart cleanup

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

@@ -57,6 +57,8 @@ import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeModdedChunkGenera
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeGeneratorContext;
 
 import art.arcane.volmlib.nativelib.terrain.NativeWorld;
+import art.arcane.volmlib.util.mantle.runtime.Mantle;
+import art.arcane.volmlib.util.matter.Matter;
 
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeModdedStructureStage;
 import art.arcane.iris.world.safeguard.GenerationRefusalNotice;
@@ -829,12 +831,12 @@ public final class IrisModdedChunkGenerator implements NativeGeneratorOwner, Nat
         importedFeatures.invalidate();
     }
 
-    public void updateRegeneratedChunk(int chunkX, int chunkZ) {
+    public void updateRegeneratedChunk(Mantle<Matter> mantle, int chunkX, int chunkZ) {
         ModdedChunkUpdateService service = ModdedEngineBootstrap.services().service(ModdedChunkUpdateService.class);
         if (service == null) {
             throw new IllegalStateException("Iris chunk update service is unavailable during regeneration");
         }
-        service.updateRegeneratedChunk(engine(), boundLevel(), chunkX, chunkZ);
+        service.updateRegeneratedChunk(engine(), boundLevel(), mantle, chunkX, chunkZ);
     }
 
     public NativeBiomeResolver regenBiomeResolver() {

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

@@ -19,6 +19,8 @@
 package art.arcane.iris.modded.api;
 
 import art.arcane.iris.generation.runtime.Engine;
+import art.arcane.iris.generation.mantle.CustomBlockOwnership;
+import art.arcane.iris.integration.Identifier;
 import art.arcane.iris.modded.ModdedIrisLog;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.ModdedBlockState;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeBlockPlacement;
@@ -297,11 +299,11 @@ public final class ModdedCustomContentRegistry {
      * consulted for that position. An unparseable key or no matching provider is logged and skipped. Called on the
      * server thread with the chunk loaded.
      */
-    public static void processBlockPlacement(Engine engine, String key, Supplier<NativeBlockPlacement> placement) {
+    public static CustomBlockOwnership.Entry processBlockPlacement(Engine engine, String key, Supplier<NativeBlockPlacement> placement) {
         String base = parseIdentifier(key);
         if (base == null) {
             ModdedIrisLog.warn("Iris deferred custom block placement rejected invalid id {}", key);
-            return;
+            return null;
         }
         Map<String, String> state = parseState(key);
         for (ModdedDataProvider provider : PROVIDERS) {
@@ -309,14 +311,33 @@ public final class ModdedCustomContentRegistry {
                 continue;
             }
             try {
-                provider.processBlockPlacement(new ModdedBlockPlacementContext(
+                String token = provider.processBlockPlacement(new ModdedBlockPlacementContext(
                         engine, placement.get(), base, state));
+                int properties = key.indexOf('[');
+                String qualifiedKey = base.replace(':', '/') + (properties < 0 ? "" : key.substring(properties));
+                return token == null ? null : new CustomBlockOwnership.Entry(
+                        new Identifier(provider.modId(), qualifiedKey), token, false);
             } catch (Throwable error) {
                 ModdedIrisLog.error("Iris custom content provider '{}' failed post-placement for {}", provider.modId(), key, error);
             }
-            return;
+            return null;
         }
         ModdedIrisLog.warn("Iris deferred custom block placement has no provider for {}", key);
+        return null;
+    }
+
+    public static boolean removeGenerated(Engine engine, CustomBlockOwnership.Entry entry,
+                                          Supplier<NativeBlockPlacement> placement) {
+        for (ModdedDataProvider provider : PROVIDERS) {
+            if (provider.modId().equals(entry.identifier().namespace()) && provider.isReady()) {
+                String storedKey = entry.identifier().key();
+                int separator = storedKey.indexOf('/');
+                String key = storedKey.substring(0, separator) + ":" + storedKey.substring(separator + 1);
+                return provider.removeGenerated(new ModdedBlockPlacementContext(
+                        engine, placement.get(), parseIdentifier(key), parseState(key)), entry.token());
+            }
+        }
+        return false;
     }
 
     /**

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

@@ -95,7 +95,12 @@ public interface ModdedDataProvider {
      * Called on the server thread, once per deferred position, by the first provider that claims the identifier -
      * later providers are not consulted for that position. Only fires for states returned as deferred.
      */
-    default void processBlockPlacement(ModdedBlockPlacementContext context) {
+    default String processBlockPlacement(ModdedBlockPlacementContext context) {
+        return null;
+    }
+
+    default boolean removeGenerated(ModdedBlockPlacementContext context, String token) {
+        return false;
     }
 
     /**

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

@@ -22,6 +22,7 @@ import art.arcane.iris.modded.ModdedIrisLog;
 import art.arcane.iris.world.WorldMaintenance;
 import art.arcane.iris.generation.runtime.Engine;
 import art.arcane.iris.generation.mantle.EngineMantle;
+import art.arcane.iris.generation.mantle.DeferredPlacementRecords;
 import art.arcane.iris.modded.IrisModdedChunkGenerator;
 import art.arcane.iris.modded.ModdedBlockBuffer;
 import art.arcane.iris.spi.IrisPlatforms;
@@ -36,6 +37,9 @@ import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeCommandSource;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeChunkRegeneration;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeProtocolPlayer;
 import art.arcane.volmlib.nativelib.terrain.NativeWorld;
+import art.arcane.volmlib.util.mantle.runtime.Mantle;
+import art.arcane.volmlib.util.mantle.runtime.MantleChunk;
+import art.arcane.volmlib.util.matter.Matter;
 
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
@@ -110,10 +114,12 @@ public final class ModdedRegen {
 
     private void resetMantleMargin() {
         EngineMantle engineMantle = engine.getMantle();
+        Mantle<Matter> mantle = engineMantle.getMantle();
         int margin = radius + Math.max(engineMantle.getRadius(), engineMantle.getRealRadius()) + 1;
         for (int dx = -margin; dx <= margin; dx++) {
             for (int dz = -margin; dz <= margin; dz++) {
-                engineMantle.getMantle().deleteChunk(centerX + dx, centerZ + dz);
+                DeferredPlacementRecords.resetMantleChunk(mantle, centerX + dx, centerZ + dz,
+                        Math.abs(dx) <= radius && Math.abs(dz) <= radius);
             }
         }
     }
@@ -199,10 +205,21 @@ public final class ModdedRegen {
     }
 
     private void apply(int chunkX, int chunkZ, ModdedBlockBuffer blocks, Hunk<NativeBiome> biomes) {
+        Mantle<Matter> mantle = engine.getMantle().getMantle();
         regeneration.apply(new NativeChunkRegeneration.Replacement(chunkX, chunkZ,
                         engine.getMinHeight(), engine.getMaxHeight() - engine.getMinHeight(),
                         blocks::rawOrNull, generator.regenBiomeResolver()),
-                () -> generator.updateRegeneratedChunk(chunkX, chunkZ));
+                () -> completeReplacement(mantle, chunkX, chunkZ));
+    }
+
+    private void completeReplacement(Mantle<Matter> mantle, int chunkX, int chunkZ) {
+        MantleChunk<Matter> records = mantle.useChunk(chunkX, chunkZ);
+        try {
+            DeferredPlacementRecords.invalidateCustomBlockOwnership(records);
+        } finally {
+            records.release();
+        }
+        generator.updateRegeneratedChunk(mantle, chunkX, chunkZ);
     }
 
     private void ok(String message) {

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

@@ -28,6 +28,8 @@ import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeBlockProperties;
 import art.arcane.iris.configuration.IrisSettings;
 import art.arcane.iris.studio.view.PregeneratorJob;
 import art.arcane.iris.integration.Identifier;
+import art.arcane.iris.generation.mantle.CustomBlockOwnership;
+import art.arcane.iris.generation.mantle.DeferredPlacementRecords;
 import art.arcane.iris.generation.cache.Cache;
 import art.arcane.iris.generation.runtime.Engine;
 import art.arcane.iris.generation.block.TileData;
@@ -166,8 +168,8 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
                 updatePassChunk(engine, level, (int) chunkKey, (int) (chunkKey >> 32)));
     }
 
-    public void updateRegeneratedChunk(Engine engine, NativeWorld level, int chunkX, int chunkZ) {
-        updateChunk(engine, level, chunkX, chunkZ, false);
+    public void updateRegeneratedChunk(Engine engine, NativeWorld level, Mantle<Matter> mantle, int chunkX, int chunkZ) {
+        updateChunk(engine, level, mantle, chunkX, chunkZ, false);
     }
 
     /**
@@ -176,7 +178,7 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
      */
     private void updatePassChunk(Engine engine, NativeWorld level, int chunkX, int chunkZ) {
         try {
-            updateChunk(engine, level, chunkX, chunkZ, true);
+            updateChunk(engine, level, engine.getMantle().getMantle(), chunkX, chunkZ, true);
         } catch (Throwable failure) {
             if (engine.isClosed() || engine.getMantle().getMantle().isClosed()) {
                 throw failure;
@@ -188,7 +190,8 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
         }
     }
 
-    private void updateChunk(Engine engine, NativeWorld level, int chunkX, int chunkZ, boolean requireNeighbors) {
+    private void updateChunk(Engine engine, NativeWorld level, Mantle<Matter> mantle,
+                             int chunkX, int chunkZ, boolean requireNeighbors) {
         if (requireNeighbors) {
             for (int x = -1; x <= 1; x++) {
                 for (int z = -1; z <= 1; z++) {
@@ -199,11 +202,11 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
             }
         }
 
-        Mantle<Matter> mantle = engine.getMantle().getMantle();
         if (!mantle.isChunkLoaded(chunkX, chunkZ)) {
             warmupMantleChunk(mantle, chunkX, chunkZ);
             return;
         }
+        DeferredPlacementRecords.removeInvalidated(engine, mantle, chunkX, chunkZ);
         if (mantle.hasFlag(chunkX, chunkZ, MantleFlag.ETCHED)) {
             return;
         }
@@ -229,14 +232,19 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
         int baseX = chunkX << 4;
         int baseZ = chunkZ << 4;
         int minHeight = engine.getWorld().minHeight();
-        materializeDeferredSlice(chunk, TileWrapper.class, () ->
-                chunk.iterate(TileWrapper.class, (Integer x, Integer yf, Integer z, TileWrapper v) -> {
-                    int y = yf + minHeight;
-                    if (y < level.minHeight() || y >= level.maxHeight() - 1) {
-                        return;
-                    }
-                    applyTile(level, baseX + (x & 15), y, baseZ + (z & 15), v.getData());
-                }));
+        materializeDeferredSlice(chunk, TileWrapper.class, () -> {
+            for (DeferredPlacementRecords.Pending<TileWrapper> record : DeferredPlacementRecords.snapshot(chunk, TileWrapper.class)) {
+                if (!DeferredPlacementRecords.isPending(chunk, TileWrapper.class, record)) {
+                    continue;
+                }
+                NativeBlockPoint position = record.position();
+                int y = position.y() + minHeight;
+                if (y < level.minHeight() || y >= level.maxHeight() - 1) {
+                    continue;
+                }
+                applyTile(level, baseX + (position.x() & 15), y, baseZ + (position.z() & 15), record.value().getData());
+            }
+        });
     }
 
     private void runCustomPass(Engine engine, NativeWorld level, int chunkX, int chunkZ, MantleChunk<Matter> chunk) {
@@ -244,22 +252,30 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
         int baseZ = chunkZ << 4;
         int minHeight = engine.getWorld().minHeight();
         StaleCarriers stale = new StaleCarriers();
-        materializeDeferredSlice(chunk, Identifier.class, () ->
-                chunk.iterate(Identifier.class, (Integer x, Integer yf, Integer z, Identifier identifier) -> {
-                    int y = yf + minHeight;
-                    if (y < level.minHeight() || y >= level.maxHeight() - 1) {
-                        return;
-                    }
-                    int blockX = baseX + (x & 15);
-                    int blockZ = baseZ + (z & 15);
-                    String key = identifier.toString();
-                    if (stale.carrierReplaced(key, level.getBlock(blockX, y, blockZ))) {
-                        return;
-                    }
-                    NativeBlockPoint position = new NativeBlockPoint(blockX, y, blockZ);
-                    ModdedCustomContentRegistry.processBlockPlacement(engine, key,
-                            () -> NativeWorldMaintenance.placement(level, position));
-                }));
+        materializeDeferredSlice(chunk, Identifier.class, () -> {
+            for (DeferredPlacementRecords.Pending<Identifier> record : DeferredPlacementRecords.snapshot(chunk, Identifier.class)) {
+                if (!DeferredPlacementRecords.isPending(chunk, Identifier.class, record)) {
+                    continue;
+                }
+                NativeBlockPoint local = record.position();
+                int y = local.y() + minHeight;
+                if (y < level.minHeight() || y >= level.maxHeight() - 1) {
+                    continue;
+                }
+                int blockX = baseX + (local.x() & 15);
+                int blockZ = baseZ + (local.z() & 15);
+                String key = record.value().toString();
+                if (stale.carrierReplaced(key, level.getBlock(blockX, y, blockZ))) {
+                    continue;
+                }
+                NativeBlockPoint position = new NativeBlockPoint(blockX, y, blockZ);
+                CustomBlockOwnership.Entry ownership = ModdedCustomContentRegistry.processBlockPlacement(engine, key,
+                        () -> NativeWorldMaintenance.placement(level, position));
+                if (ownership != null) {
+                    DeferredPlacementRecords.remember(engine, chunk, local, ownership);
+                }
+            }
+        });
         stale.report(level.name(), chunkX, chunkZ);
     }
 
@@ -411,7 +427,8 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
                 carrier = carrierKey(key);
                 carriers.put(key, carrier);
             }
-            if (carrier.equals(UNCHECKED) || carrier.equals(IrisProceduralBlocks.materialKey(live))) {
+            if (carrier.equals(UNCHECKED) || carrier.equals(IrisProceduralBlocks.materialKey(live))
+                    || ((carrier.equals("minecraft:fire") || carrier.equals("minecraft:soul_fire")) && live.isAir())) {
                 return false;
             }
             skipped++;

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

@@ -28,6 +28,10 @@ import art.arcane.iris.modded.ModdedSavedTerrainCapture;
 
 import java.util.concurrent.CompletableFuture;
 import art.arcane.iris.generation.runtime.EnginePlatformHooks;
+import art.arcane.iris.generation.mantle.CustomBlockOwnership;
+import art.arcane.iris.modded.api.ModdedCustomContentRegistry;
+import art.arcane.volmlib.nativelib.terrain.NativeBlockPoint;
+import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeWorldMaintenance;
 import art.arcane.volmlib.nativelib.terrain.structure.NativeStructureVolume;
 import art.arcane.iris.generation.terrain.IrisDimension;
 import art.arcane.iris.generation.terrain.IrisDimensionRuntimeContract;
@@ -72,6 +76,12 @@ public final class ModdedStudioHotloadService implements ModdedTickableService,
     private volatile ExecutorService executor;
     private long lastPollAt;
 
+    @Override
+    public boolean removeCustomBlock(Engine engine, NativeBlockPoint position, CustomBlockOwnership.Entry entry) {
+        return ModdedCustomContentRegistry.removeGenerated(engine, entry,
+                () -> NativeWorldMaintenance.placement(engine.getWorld().platformWorld(), position));
+    }
+
     @Override
     public CompletableFuture<Void> flushSavedTerrainCapture(Engine engine) {
         return ModdedSavedTerrainCapture.flush(engine);

adapters/modded-common/src/test/java/art/arcane/iris/modded/ModdedNativeStructureWorldgenAccessTest.java

@@ -231,7 +231,7 @@ public class ModdedNativeStructureWorldgenAccessTest {
                 recording.world(), generationCenter,
                 (x, z) -> SURFACE_FIRST_FREE_Y,
                 (x, z) -> FLOOR_FIRST_FREE_Y,
-                true,
+                true, true,
                 position -> false,
                 NativeBlockChangeSet.disabled());
         int x = generationCenter.getMiddleBlockX();
@@ -250,7 +250,7 @@ public class ModdedNativeStructureWorldgenAccessTest {
                 recording.world(), generationCenter(),
                 (x, z) -> SURFACE_FIRST_FREE_Y,
                 (x, z) -> FLOOR_FIRST_FREE_Y,
-                false,
+                false, true,
                 position::equals,
                 NativeBlockChangeSet.disabled());
 
@@ -284,7 +284,7 @@ public class ModdedNativeStructureWorldgenAccessTest {
                 delegate, generationCenter(),
                 (x, z) -> SURFACE_FIRST_FREE_Y,
                 (x, z) -> FLOOR_FIRST_FREE_Y,
-                false,
+                false, true,
                 protectedCell::equals,
                 changes);
         BlockPos written = protectedCell.above();
@@ -353,7 +353,7 @@ public class ModdedNativeStructureWorldgenAccessTest {
                 recording.world(), generationCenter(),
                 (x, z) -> SURFACE_FIRST_FREE_Y,
                 (x, z) -> FLOOR_FIRST_FREE_Y,
-                false,
+                false, true,
                 position -> false,
                 NativeBlockChangeSet.disabled());
     }

adapters/modded-common/src/test/java/art/arcane/iris/modded/api/ModdedCustomContentRegistryTest.java

@@ -1,5 +1,9 @@
 package art.arcane.iris.modded.api;
 
+import art.arcane.iris.generation.mantle.CustomBlockOwnership;
+import art.arcane.iris.generation.runtime.Engine;
+import art.arcane.iris.integration.Identifier;
+import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeBlockPlacement;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeEntityRuntime;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeSpawnedEntity;
 import net.minecraft.SharedConstants;
@@ -9,6 +13,7 @@ import org.junit.Test;
 
 import java.util.Collection;
 import java.util.List;
+import java.util.Map;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -20,6 +25,33 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 public class ModdedCustomContentRegistryTest {
+    @Test
+    public void removalReturnsToOriginalProviderWithTokenAndPlacementState() {
+        ModdedDataProvider provider = mock(ModdedDataProvider.class);
+        Engine engine = mock(Engine.class);
+        NativeBlockPlacement placement = mock(NativeBlockPlacement.class);
+        ModdedBlockPlacementContext context = new ModdedBlockPlacementContext(
+                engine, placement, "provider_test:furniture/chair", Map.of("variant", "oak"));
+        when(provider.modId()).thenReturn("ownership_test");
+        when(provider.isReady()).thenReturn(true);
+        when(provider.isValidProvider("provider_test:furniture/chair", ModdedDataType.BLOCK)).thenReturn(true);
+        when(provider.processBlockPlacement(context)).thenReturn("entity-token");
+        when(provider.removeGenerated(context, "entity-token")).thenReturn(true);
+        ModdedCustomContentRegistry.Discovery discovery = ModdedCustomContentRegistry.discover(List.of(provider));
+        try {
+            CustomBlockOwnership.Entry ownership = ModdedCustomContentRegistry.processBlockPlacement(engine,
+                    "provider_test:furniture/chair[variant=oak]", () -> placement);
+
+            assertEquals(new CustomBlockOwnership.Entry(
+                    Identifier.fromString("ownership_test:provider_test/furniture/chair[variant=oak]"),
+                    "entity-token", false), ownership);
+            assertTrue(ModdedCustomContentRegistry.removeGenerated(engine, ownership, () -> placement));
+            verify(provider).removeGenerated(context, "entity-token");
+        } finally {
+            discovery.rollback();
+        }
+    }
+
     @BeforeClass
     public static void bootstrapRegistries() {
         SharedConstants.tryDetectVersion();

adapters/modded-common/src/test/java/art/arcane/iris/modded/service/ModdedChunkUpdateServiceCarrierTest.java

@@ -53,6 +53,8 @@ public class ModdedChunkUpdateServiceCarrierTest {
     private static final String MOD_ID = "iris_carrier_guard_test";
     private static final String LAMP = MOD_ID + ":lamp";
     private static final String CHAIR = MOD_ID + ":chair";
+    private static final String FIRE = MOD_ID + ":fire";
+    private static final String SOUL_FIRE = MOD_ID + ":soul_fire";
     private static final List<BlockPos> PLACED = new CopyOnWriteArrayList<>();
 
     @BeforeClass
@@ -80,6 +82,7 @@ public class ModdedChunkUpdateServiceCarrierTest {
                 3, Blocks.COBBLESTONE.defaultBlockState(),
                 4, Blocks.COBBLESTONE.defaultBlockState()));
         List<String> debug = new ArrayList<>();
+        Engine engine = engine(chunk);
 
         try (MockedStatic<IrisLogging> logging = mockStatic(IrisLogging.class)) {
             logging.when(() -> IrisLogging.debug(anyString(), any(Object[].class))).thenAnswer((InvocationOnMock invocation) -> {
@@ -88,7 +91,7 @@ public class ModdedChunkUpdateServiceCarrierTest {
                 return null;
             });
 
-            new ModdedChunkUpdateService().updateRegeneratedChunk(engine(chunk), level, 0, 0);
+            new ModdedChunkUpdateService().updateRegeneratedChunk(engine, level, engine.getMantle().getMantle(), 0, 0);
         }
 
         assertEquals(List.of(new BlockPos(1, 6, 1), new BlockPos(4, 6, 4)), PLACED);
@@ -98,6 +101,24 @@ public class ModdedChunkUpdateServiceCarrierTest {
         assertTrue(debug.getFirst(), debug.getFirst().contains("2 stale"));
     }
 
+    @Test
+    public void extinguishedFireCarriersArePlacedWhileCoveredCarriersAreSkipped() {
+        RecordMantleChunk chunk = new RecordMantleChunk(List.of(
+                new Placed(1, FIRE), new Placed(2, SOUL_FIRE),
+                new Placed(3, FIRE), new Placed(4, SOUL_FIRE)));
+        NativeWorld level = level(Map.of(
+                1, Blocks.AIR.defaultBlockState(),
+                2, Blocks.CAVE_AIR.defaultBlockState(),
+                3, Blocks.COBBLESTONE.defaultBlockState(),
+                4, Blocks.COBBLESTONE.defaultBlockState()));
+        Engine engine = engine(chunk);
+
+        new ModdedChunkUpdateService().updateRegeneratedChunk(engine, level, engine.getMantle().getMantle(), 0, 0);
+
+        assertEquals(List.of(new BlockPos(1, 6, 1), new BlockPos(2, 6, 2)), PLACED);
+        assertTrue(chunk.customDeleted());
+    }
+
     private static NativeWorld level(Map<Integer, BlockState> live) {
         ServerLevel serverLevel = mock(ServerLevel.class);
         when(serverLevel.getBlockState(any(BlockPos.class))).thenReturn(Blocks.STONE.defaultBlockState());
@@ -163,6 +184,18 @@ public class ModdedChunkUpdateServiceCarrierTest {
             }
         }
 
+        @Override
+        public <T> T get(int x, int y, int z, Class<T> type) {
+            if (type == Identifier.class && y == 70 && x == z) {
+                for (Placed record : records) {
+                    if (record.offset() == x) {
+                        return type.cast(Identifier.fromString(record.key()));
+                    }
+                }
+            }
+            return null;
+        }
+
         @Override
         public void deleteSlices(Class<?> type) {
             if (type == Identifier.class) {
@@ -183,23 +216,29 @@ public class ModdedChunkUpdateServiceCarrierTest {
 
         @Override
         public Collection<String> getTypes(ModdedDataType type) {
-            return type == ModdedDataType.BLOCK ? List.of(LAMP, CHAIR) : List.of();
+            return type == ModdedDataType.BLOCK ? List.of(LAMP, CHAIR, FIRE, SOUL_FIRE) : List.of();
         }
 
         @Override
         public boolean isValidProvider(String id, ModdedDataType type) {
-            return type == ModdedDataType.BLOCK && (LAMP.equals(id) || CHAIR.equals(id));
+            return type == ModdedDataType.BLOCK && getTypes(type).contains(id);
         }
 
         @Override
         public ModdedBlockData getBlockData(String blockId, Map<String, String> state) {
-            BlockState carrier = CHAIR.equals(blockId) ? Blocks.AIR.defaultBlockState() : Blocks.NOTE_BLOCK.defaultBlockState();
+            BlockState carrier = switch (blockId) {
+                case CHAIR -> Blocks.AIR.defaultBlockState();
+                case FIRE -> Blocks.FIRE.defaultBlockState();
+                case SOUL_FIRE -> Blocks.SOUL_FIRE.defaultBlockState();
+                default -> Blocks.NOTE_BLOCK.defaultBlockState();
+            };
             return ModdedBlockData.deferred(ModdedBlockState.of(carrier, null));
         }
 
         @Override
-        public void processBlockPlacement(ModdedBlockPlacementContext context) {
+        public String processBlockPlacement(ModdedBlockPlacementContext context) {
             PLACED.add(context.placement().position());
+            return null;
         }
     }
 }

adapters/modded-common/src/test/java/art/arcane/iris/modded/service/ModdedChunkUpdateServiceTest.java

@@ -68,6 +68,29 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 public class ModdedChunkUpdateServiceTest {
+    @Test
+    @SuppressWarnings("unchecked")
+    public void regeneratedCleanupUsesSuppliedMantleAfterCurrentRuntimeChanges() {
+        Mantle<Matter> selected = mock(Mantle.class);
+        Mantle<Matter> replacement = mock(Mantle.class);
+        MantleDataAdapter<Matter> adapter = mock(MantleDataAdapter.class);
+        MantleChunk<Matter> chunk = new MantleChunk<>(1, 0, 0, adapter, MantleHooks.NONE);
+        when(selected.isChunkLoaded(0, 0)).thenReturn(true);
+        when(selected.useChunk(0, 0)).thenAnswer(invocation -> chunk.use());
+        when(selected.hasFlag(0, 0, MantleFlag.ETCHED)).thenReturn(true);
+        NativeWorld level = mock(NativeWorld.class);
+        when(level.isChunkLoaded(0, 0)).thenReturn(true);
+        Engine engine = engineWith(replacement);
+        when(engine.getWorld().platformWorld()).thenReturn(level);
+
+        new ModdedChunkUpdateService().updateRegeneratedChunk(engine, level, selected, 0, 0);
+
+        verify(selected).useChunk(0, 0);
+        verify(replacement, never()).isChunkLoaded(anyInt(), anyInt());
+        verify(replacement, never()).useChunk(anyInt(), anyInt());
+        assertFalse(chunk.inUse());
+    }
+
     @Test
     public void fallingFluidUpdateRetainsLevelEightStateAndRequestsPhysics() {
         SharedConstants.tryDetectVersion();
@@ -154,7 +177,7 @@ public class ModdedChunkUpdateServiceTest {
                 return null;
             });
 
-            service.updateRegeneratedChunk(engine, level, 0, 0);
+            service.updateRegeneratedChunk(engine, level, engine.getMantle().getMantle(), 0, 0);
 
             assertFalse(chunk.isFlagged(MantleFlag.ETCHED));
             assertFalse(chunk.isFlagged(MantleFlag.UPDATE));
@@ -162,7 +185,7 @@ public class ModdedChunkUpdateServiceTest {
             logging.verify(() -> IrisLogging.reportError(any(Throwable.class)), never());
             logging.verify(() -> IrisLogging.reportError(anyString(), any(Throwable.class)), never());
 
-            service.updateRegeneratedChunk(engine, level, 0, 0);
+            service.updateRegeneratedChunk(engine, level, engine.getMantle().getMantle(), 0, 0);
 
             assertTrue(chunk.isFlagged(MantleFlag.ETCHED));
             assertTrue(chunk.deleted());
@@ -187,7 +210,7 @@ public class ModdedChunkUpdateServiceTest {
             });
 
             assertThrows(SavedBiomeUnavailableException.class,
-                    () -> new ModdedChunkUpdateService().updateRegeneratedChunk(engine, level, 0, 0));
+                    () -> new ModdedChunkUpdateService().updateRegeneratedChunk(engine, level, engine.getMantle().getMantle(), 0, 0));
 
             assertFalse(chunk.isFlagged(MantleFlag.ETCHED));
             assertFalse(chunk.isFlagged(MantleFlag.UPDATE));
@@ -215,13 +238,13 @@ public class ModdedChunkUpdateServiceTest {
             });
 
             assertSame(failure, assertThrows(IllegalStateException.class,
-                    () -> service.updateRegeneratedChunk(engine, level, 0, 0)));
+                    () -> service.updateRegeneratedChunk(engine, level, engine.getMantle().getMantle(), 0, 0)));
             assertFalse(chunk.isFlagged(MantleFlag.UPDATE));
             assertFalse(chunk.isFlagged(MantleFlag.ETCHED));
             assertFalse(chunk.deleted());
             verify(chunk.slice, never()).set(2, 5, 2, null);
 
-            service.updateRegeneratedChunk(engine, level, 0, 0);
+            service.updateRegeneratedChunk(engine, level, engine.getMantle().getMantle(), 0, 0);
 
             assertTrue(chunk.isFlagged(MantleFlag.ETCHED));
             assertTrue(chunk.deleted());

adapters/modded-common/src/versions/1.21.1/test/source-replacements.json

@@ -136,6 +136,12 @@
         "replacement": "when(level.getMaxBuildHeight()).thenReturn(320);"
       }
     ],
+    "art/arcane/iris/modded/api/ModdedCustomContentRegistryTest.java": [
+      {
+        "pattern": "\\bResourceLocation\\b",
+        "replacement": "Identifier"
+      }
+    ],
     "art/arcane/iris/modded/service/ModdedChunkUpdateServiceCarrierTest.java": [
       {
         "pattern": "\\bResourceLocation\\b",