Merge branch 'client-fixes' into review

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

@@ -79,6 +79,8 @@ import art.arcane.iris.spi.IrisServices;
 import art.arcane.iris.generation.concurrent.MultiBurst;
 
 import java.util.ArrayDeque;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 public final class ModdedEngineBootstrap {
     private static final String[] CORE_SELF_TEST_CLASSES = {
@@ -87,12 +89,17 @@ public final class ModdedEngineBootstrap {
         "art.arcane.iris.pack.loading.IrisData"
     };
     private static final Object LOCK = new Object();
+    private static final Object STOP_LOCK = new Object();
+    private static final AtomicBoolean EXIT_FLUSH_REGISTERED = new AtomicBoolean();
+    private static final long EXIT_FLUSH_SERVER_WAIT_SECONDS = 30L;
     private static final ModdedServiceManager UNBOUND_SERVICE_MANAGER = new ModdedServiceManager();
     private static volatile NativeModdedLoader loader;
     private static volatile BoundRuntime runtime;
     private static volatile NativeModdedServer currentServer;
     private static volatile NativeModdedServer spawnCaptureServer;
     private static volatile boolean initialSpawnWasDefault;
+    private static volatile boolean stoppedPending;
+    private static volatile Thread stoppingThread;
 
     private ModdedEngineBootstrap() {
     }
@@ -119,10 +126,12 @@ public final class ModdedEngineBootstrap {
     }
 
     public static void start(NativeModdedServer server) {
+        finishPreviousServer("server start");
+        registerExitFlush();
         captureInitialSpawn(server);
         currentServer = server;
         bind();
-        // Pair of the stop() burst-pools stage. Load-bearing on integrated servers: once
+        // Pair of the stopped() burst-pools stage. Load-bearing on integrated servers: once
         // closed, MultiBurst falls back to a same-thread executor, so a second world load
         // without reopen() would silently run every burst inline.
         MultiBurst.burst.reopen();
@@ -150,6 +159,7 @@ public final class ModdedEngineBootstrap {
     }
 
     public static void serverAboutToStart(NativeModdedServer server) {
+        finishPreviousServer("server start");
         captureInitialSpawn(server);
         ModdedStartup.prepareForStartup();
     }
@@ -180,20 +190,16 @@ public final class ModdedEngineBootstrap {
         try {
             generator.unbindEngine(world);
         } catch (Throwable exception) {
+            // Never propagate into the loader's unload loop: a throw there skips closing every later level. A
+            // runtime dimension removal retries the eviction itself and fails with the retained mapping.
             ModdedIrisLog.error("Iris engine unload failed for {}", world.name(), exception);
-            if (exception instanceof RuntimeException runtimeException) {
-                throw runtimeException;
-            }
-            if (exception instanceof Error fatalError) {
-                throw fatalError;
-            }
-            throw new IllegalStateException("Iris engine unload failed for "
-                    + world.name(), exception);
         }
     }
 
     public static void stop() {
         NativeModdedServer stoppingServer = currentServer;
+        stoppingThread = Thread.currentThread();
+        stoppedPending = true;
         Throwable failure = null;
         failure = runStopStage(failure, "pack downloads", IrisModdedCommands::shutdownDownloads);
         failure = runStopStage(failure, "world check", () -> ModdedWorldCheck.serverStopped(stoppingServer));
@@ -205,6 +211,62 @@ public final class ModdedEngineBootstrap {
         failure = runStopStage(failure, "studio commands", ModdedStudioCommands::clear);
         failure = runStopStage(failure, "gui host", ModdedGuiHost::clear);
         failure = runStopStage(failure, "services", () -> services().disableAll());
+        reportStopFailure("stopping", failure);
+    }
+
+    /**
+     * The loaders still drain queued chunk generation after server stopping and only close levels afterwards, so
+     * engines, their mantle and generation history, and the generation pools stay open until the server stopped.
+     * Engines of unloaded levels are already closed by {@link #levelUnloaded}; this closes whatever remains.
+     * Fabric fires it at the tail of stopServer, so a throw there skips it: the next server start or the JVM
+     * exit runs it instead.
+     */
+    public static void stopped() {
+        synchronized (STOP_LOCK) {
+            stoppedPending = false;
+            stoppingThread = null;
+            closeStoppedServer();
+        }
+    }
+
+    private static void finishPreviousServer(String trigger) {
+        synchronized (STOP_LOCK) {
+            if (!stoppedPending) {
+                return;
+            }
+            ModdedIrisLog.warn("Iris closing the engines the previous server left open ({})", trigger);
+            stopped();
+        }
+    }
+
+    private static void registerExitFlush() {
+        if (EXIT_FLUSH_REGISTERED.compareAndSet(false, true)) {
+            Runtime.getRuntime().addShutdownHook(new Thread(ModdedEngineBootstrap::flushAtExit, "Iris Exit Flush"));
+        }
+    }
+
+    private static void flushAtExit() {
+        if (!stoppedPending) {
+            return;
+        }
+        Thread serverThread = stoppingThread;
+        if (serverThread != null && serverThread != Thread.currentThread()) {
+            try {
+                serverThread.join(TimeUnit.SECONDS.toMillis(EXIT_FLUSH_SERVER_WAIT_SECONDS));
+            } catch (InterruptedException interrupted) {
+                Thread.currentThread().interrupt();
+                return;
+            }
+            if (serverThread.isAlive()) {
+                ModdedIrisLog.warn("Iris skipped its exit flush: the server thread is still stopping");
+                return;
+            }
+        }
+        finishPreviousServer("JVM exit");
+    }
+
+    private static void closeStoppedServer() {
+        Throwable failure = null;
         failure = runStopStage(failure, "world engines", ModdedWorldEngines::shutdown);
         failure = runStopStage(failure, "primary world router", ModdedPrimaryWorldRouter::clear);
         failure = runStopStage(failure, "dimension manager", ModdedDimensionManager::clear);
@@ -226,10 +288,14 @@ public final class ModdedEngineBootstrap {
             spawnCaptureServer = null;
             initialSpawnWasDefault = false;
         });
+        reportStopFailure("stopped", failure);
+    }
+
+    private static void reportStopFailure(String phase, Throwable failure) {
         if (failure != null) {
             // The shutdown path must not propagate: propagating aborts the remaining loader stop handlers and
             // can leave the level unsaved. Every stage already logged its own failure.
-            ModdedIrisLog.error("Iris modded shutdown completed with failures", failure);
+            ModdedIrisLog.error("Iris modded shutdown ({}) completed with failures", phase, failure);
         }
     }
 

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

@@ -25,6 +25,7 @@ import art.arcane.volmlib.nativelib.terrain.feature.NativeFeatureTable;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeModdedImportedFeatures;
 
 import art.arcane.iris.generation.runtime.Engine;
+import art.arcane.iris.generation.runtime.GenerationFailures;
 import art.arcane.iris.generation.runtime.GenerationSessionLease;
 import art.arcane.iris.structure.nativegen.NativeFeatureGenerationPolicy;
 import art.arcane.iris.structure.nativegen.IrisImportedFeatureControl;
@@ -163,6 +164,7 @@ final class ModdedImportedFeatureStage implements NativeModdedGeneratorPolicy.Fe
         try {
             control = NativeFeatureGenerationPolicy.control(engine);
         } catch (RuntimeException error) {
+            GenerationFailures.rethrowEngineFailure(error);
             ModdedIrisLog.error("Iris could not read importedFeatures for this dimension; features off: {}",
                     error.toString(), error);
             markInert(runtimeIdentity, generation);
@@ -177,6 +179,7 @@ final class ModdedImportedFeatureStage implements NativeModdedGeneratorPolicy.Fe
              IrisContext.Scope ignored = IrisContext.open(engine, lease.sessionId(), null)) {
             built = nativeFeatures.buildTable(new ModdedImportedFeaturePolicy(engine), control, generation);
         } catch (Throwable error) {
+            GenerationFailures.rethrowEngineFailure(error);
             ModdedIrisLog.error("Iris importedFeatures is off for {}: feature table construction failed: {}",
                     dimensionKey(engine), error.toString(), error);
             markInert(runtimeIdentity, generation);

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

@@ -16,6 +16,7 @@ public final class ModdedLifecycleCallbacks {
                 ModdedEngineBootstrap::start,
                 ModdedEngineBootstrap::serverStarted,
                 ModdedEngineBootstrap::stop,
+                ModdedEngineBootstrap::stopped,
                 ModdedEngineBootstrap::levelLoaded,
                 ModdedEngineBootstrap::levelUnloaded,
                 ModdedProtocolHandler::onPlayerJoin,

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

@@ -40,29 +40,31 @@ import java.util.function.BooleanSupplier;
  * references and is safe on a dedicated server.
  */
 public final class ModdedMixinAudit {
+    private static final String ENTITY_CONFIG = "volmlib.entity.mixins.json";
+    private static final String CLIENT_CONFIG = "volmlib.client.mixins.json";
     private static final AtomicBoolean AUDITED = new AtomicBoolean(false);
 
-    private static final List<ExpectedMixin> EXPECTED = List.of(
-            new ExpectedMixin("EntityPersistenceMixin", "entity",
+    static final List<ExpectedMixin> EXPECTED = List.of(
+            new ExpectedMixin(ENTITY_CONFIG, "EntityPersistenceMixin",
                     NativeMixinTarget.ENTITY, "iris$applyGeneratedPersistence",
                     false, NativeMixinFlags::entityPersistenceRan),
-            new ExpectedMixin("LivingEntityLootMixin", "entity",
+            new ExpectedMixin(ENTITY_CONFIG, "LivingEntityLootMixin",
                     NativeMixinTarget.LIVING_ENTITY, "iris$replaceBaseLoot",
                     false, NativeMixinFlags::livingEntityLootRan),
-            new ExpectedMixin("MobAwarenessMixin", "entity",
+            new ExpectedMixin(ENTITY_CONFIG, "MobAwarenessMixin",
                     NativeMixinTarget.MOB, "iris$tickUnawareMob",
                     false, NativeMixinFlags::mobAwarenessRan),
-            new ExpectedMixin("StructureTemplatePaletteConcurrencyMixin", "common",
+            new ExpectedMixin(ENTITY_CONFIG, "StructureTemplatePaletteConcurrencyMixin",
                     NativeMixinTarget.STRUCTURE_PALETTE,
                     "iris$installConcurrentBlockCache",
                     false, NativeMixinFlags::structureTemplatePaletteRan),
-            new ExpectedMixin("NativeWorldOpenFlowsMixin", "client",
+            new ExpectedMixin(CLIENT_CONFIG, "NativeWorldOpenFlowsMixin",
                     NativeMixinTarget.WORLD_OPEN_FLOWS,
-                    "iris$openWorldCheckWorldStemCompatibility",
+                    "volmlib$openWorldCheckWorldStemCompatibility",
                     true, NativeMixinFlags::worldOpenFlowsRan),
-            new ExpectedMixin("NativeWorldTypeEntryMixin", "client",
+            new ExpectedMixin(CLIENT_CONFIG, "NativeWorldTypeEntryMixin",
                     NativeMixinTarget.WORLD_TYPE_ENTRY,
-                    "iris$describePreset",
+                    "volmlib$describePreset",
                     true, NativeMixinFlags::worldTypeEntryRan));
 
     private ModdedMixinAudit() {
@@ -90,7 +92,7 @@ public final class ModdedMixinAudit {
             if (isApplied(expected)) {
                 applied.add(expected.mixinName() + (expected.ran().getAsBoolean() ? "" : " (not yet exercised)"));
             } else {
-                missing.add(expected.config() + '/' + expected.mixinName() + " -> " + expected.targetClass());
+                missing.add(expected.config() + '/' + expected.mixinName() + " -> " + expected.targetClass().className());
             }
         }
         if (missing.isEmpty()) {
@@ -119,7 +121,7 @@ public final class ModdedMixinAudit {
         }
     }
 
-    private record ExpectedMixin(String mixinName, String config, NativeMixinTarget targetClass, String handlerMethod,
-                                 boolean clientOnly, BooleanSupplier ran) {
+    record ExpectedMixin(String config, String mixinName, NativeMixinTarget targetClass, String handlerMethod,
+                         boolean clientOnly, BooleanSupplier ran) {
     }
 }

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

@@ -195,7 +195,8 @@ public final class ModdedScheduler implements PlatformScheduler {
         mainQueue.clear();
         delayedQueue.clear();
         mainThread = null;
-        // Shutdown stage that always runs (ModdedEngineBootstrap.stop): release the level snapshot with it.
+        // Runs from ModdedEngineBootstrap.stopped, or its fallback at the next server start or JVM exit when the
+        // loader skipped it: release the level snapshot with it.
         ModdedServerLevels.forget();
     }
 

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

@@ -426,9 +426,9 @@ public final class ModdedWorldEngines {
             Engine engine = entry.getValue();
             try {
                 // Latch the generator's unloading flag BEFORE closing (unbindEngine sets it,
-                // then evicts): chunk-system drain work running after this stage would
-                // otherwise see a closed engine and silently rebuild a fresh engine + Mantle
-                // that no teardown stage ever closes, writing plates after the final save.
+                // then evicts): late chunk work would otherwise see a closed engine and
+                // silently rebuild a fresh engine + Mantle that no teardown stage ever
+                // closes, writing plates after the final save.
                 IrisModdedChunkGenerator generator = NativeWorldGenerators.find(level, IrisModdedChunkGenerator.class);
                 if (generator != null) {
                     generator.unbindEngine(level);

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

@@ -60,12 +60,16 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.TreeMap;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
 import java.util.concurrent.TimeUnit;
 
 import art.arcane.volmlib.util.localization.MessageArgument;
 
 public final class IrisModdedCommands {
     private static final long DOWNLOAD_SHUTDOWN_POLL_SECONDS = 15L;
+    // The first chunk of a cold dimension also loads the pack and binds the engine; the deadline only bounds a
+    // destination whose chunk never completes (a refusing generator or a removed dimension).
+    private static final long TELEPORT_DEADLINE_SECONDS = 120L;
     private static final Object DOWNLOAD_MONITOR = new Object();
 
     static final SuggestionProvider<NativeCommandSource> PACK_NAMES = ModdedCommandSuggestions.PACK_NAMES;
@@ -133,7 +137,7 @@ public final class IrisModdedCommands {
         NativeModdedServer server = source.server();
         CompletableFuture<Boolean> teleport = NativeWorldTeleport.teleport(player, new NativeWorldTeleport.Destination(
                 server, ModdedDimensionManager.level(server, dimensionId), 8.5D, Double.MIN_VALUE, 8.5D,
-                System.nanoTime() + TimeUnit.SECONDS.toNanos(10L)));
+                System.nanoTime() + TimeUnit.SECONDS.toNanos(TELEPORT_DEADLINE_SECONDS)));
         teleport.whenComplete((success, failure) -> {
             if (Boolean.TRUE.equals(success) && failure == null) {
                 return;
@@ -142,14 +146,42 @@ public final class IrisModdedCommands {
                 ModdedIrisLog.error("Iris teleport into '{}' failed for {}",
                         dimensionId, player.id(), failure);
             }
-            server.execute(() -> fail(source, IrisLanguage.plain(
-                    ModdedCommandMessages.IRIS_MODDED_COMMANDS_TELEPORT_FAILED_DIMENSION_IS_NOT_LOADED,
-                    MessageArgument.untrusted("dimensionId", dimensionId))));
+            server.execute(() -> fail(source, teleportFailure(dimensionId, player.name(), failure,
+                    ModdedDimensionManager.level(server, dimensionId) != null, server.player(player.id()) != null)));
         });
         ok(source, IrisLanguage.plain(ModdedCommandMessages.IRIS_MODDED_COMMANDS_TELEPORTING, MessageArgument.untrusted("value", player.name()), MessageArgument.untrusted("dimensionId", dimensionId)));
         return 1;
     }
 
+    static String teleportFailure(String dimensionId, String playerName, Throwable failure,
+                                  boolean dimensionLoaded, boolean playerOnline) {
+        if (failure != null) {
+            return IrisLanguage.plain(ModdedCommandMessages.IRIS_MODDED_COMMANDS_TELEPORT_FAILED_REASON,
+                    MessageArgument.untrusted("dimensionId", dimensionId),
+                    MessageArgument.untrusted("reason", failureReason(failure)));
+        }
+        if (!dimensionLoaded) {
+            return IrisLanguage.plain(ModdedCommandMessages.IRIS_MODDED_COMMANDS_TELEPORT_FAILED_DIMENSION_IS_NOT_LOADED,
+                    MessageArgument.untrusted("dimensionId", dimensionId));
+        }
+        if (!playerOnline) {
+            return IrisLanguage.plain(ModdedCommandMessages.IRIS_MODDED_COMMANDS_TELEPORT_CANCELLED_PLAYER_OFFLINE,
+                    MessageArgument.untrusted("dimensionId", dimensionId),
+                    MessageArgument.untrusted("value", playerName));
+        }
+        return IrisLanguage.plain(ModdedCommandMessages.IRIS_MODDED_COMMANDS_TELEPORT_REFUSED,
+                MessageArgument.untrusted("dimensionId", dimensionId));
+    }
+
+    private static String failureReason(Throwable failure) {
+        Throwable cause = failure;
+        while (cause instanceof CompletionException && cause.getCause() != null) {
+            cause = cause.getCause();
+        }
+        String message = cause.getMessage();
+        return message == null || message.isBlank() ? cause.getClass().getSimpleName() : message;
+    }
+
     static int evacuate(NativeCommandSource source, NativeWorld target) {
         NativeModdedServer server = source.server();
         NativeWorld level = target != null ? target : source.world();

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

@@ -71,6 +71,18 @@ public final class ModdedCommandMessages {
             "iris.modded.irismoddedcommands.teleport_failed_dimension_is_not_loaded",
             "Teleport failed: dimension " + "{dimensionId}" + " is not loaded."
     );
+    public static final TextKey IRIS_MODDED_COMMANDS_TELEPORT_FAILED_REASON = TextKey.of(
+            "iris.modded.irismoddedcommands.teleport_failed_reason",
+            "Teleport into " + "{dimensionId}" + " failed: " + "{reason}"
+    );
+    public static final TextKey IRIS_MODDED_COMMANDS_TELEPORT_CANCELLED_PLAYER_OFFLINE = TextKey.of(
+            "iris.modded.irismoddedcommands.teleport_cancelled_player_offline",
+            "Teleport into " + "{dimensionId}" + " cancelled: " + "{value}" + " is no longer online."
+    );
+    public static final TextKey IRIS_MODDED_COMMANDS_TELEPORT_REFUSED = TextKey.of(
+            "iris.modded.irismoddedcommands.teleport_refused",
+            "Teleport into " + "{dimensionId}" + " was refused by the server."
+    );
     public static final TextKey IRIS_MODDED_COMMANDS_TELEPORTING = TextKey.of(
             "iris.modded.irismoddedcommands.teleporting",
             "Teleporting " + "{value}" + " to " + "{dimensionId}" + "..."
@@ -1266,6 +1278,9 @@ public final class ModdedCommandMessages {
             IRIS_MODDED_COMMANDS_CONSOLE_MUST_NAME_PLAYER_IRIS_TP_DIMENSION_PLAYER,
             IRIS_MODDED_COMMANDS_IS_NOT_GENERATED_BY_IRIS,
             IRIS_MODDED_COMMANDS_TELEPORT_FAILED_DIMENSION_IS_NOT_LOADED,
+            IRIS_MODDED_COMMANDS_TELEPORT_FAILED_REASON,
+            IRIS_MODDED_COMMANDS_TELEPORT_CANCELLED_PLAYER_OFFLINE,
+            IRIS_MODDED_COMMANDS_TELEPORT_REFUSED,
             IRIS_MODDED_COMMANDS_TELEPORTING,
             IRIS_MODDED_COMMANDS_IS_NOT_GENERATED_BY_IRIS_2,
             IRIS_MODDED_COMMANDS_CANNOT_EVACUATE_PRIMARY_WORLD_THERE_IS_NOWHERE_SEND_PLAYERS,

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

@@ -30,6 +30,7 @@ import art.arcane.iris.studio.view.PregeneratorJob;
 import art.arcane.iris.integration.Identifier;
 import art.arcane.iris.generation.cache.Cache;
 import art.arcane.iris.generation.runtime.Engine;
+import art.arcane.iris.generation.runtime.GenerationFailures;
 import art.arcane.iris.generation.block.TileData;
 import art.arcane.iris.modded.IrisModdedChunkGenerator;
 import art.arcane.iris.modded.ModdedBlockResolution;
@@ -38,6 +39,7 @@ import art.arcane.iris.modded.ModdedTileData;
 import art.arcane.iris.modded.api.ModdedCustomContentRegistry;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeBlockPlacement;
 import art.arcane.iris.spi.IrisLogging;
+import art.arcane.iris.world.history.SavedBiomeUnavailableException;
 import art.arcane.iris.world.storage.matter.TileWrapper;
 import art.arcane.volmlib.util.mantle.flag.MantleFlag;
 import art.arcane.volmlib.util.mantle.runtime.Mantle;
@@ -47,6 +49,7 @@ import art.arcane.volmlib.util.matter.MatterCavern;
 import art.arcane.volmlib.util.matter.MatterUpdate;
 import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
 import art.arcane.volmlib.nativelib.minecraft26_2.modded.NativeModdedServer;
+import it.unimi.dsi.fastutil.ints.IntArrayList;
 
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -149,7 +152,7 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
             int centerZ = player.z() >> 4;
             for (int dx = -PLAYER_CHUNK_RADIUS; dx <= PLAYER_CHUNK_RADIUS; dx++) {
                 for (int dz = -PLAYER_CHUNK_RADIUS; dz <= PLAYER_CHUNK_RADIUS; dz++) {
-                    updateChunk(engine, level, centerX + dx, centerZ + dz);
+                    updatePassChunk(engine, level, centerX + dx, centerZ + dz);
                 }
             }
         });
@@ -157,15 +160,29 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
 
     private void updateForcedChunks(Engine engine, NativeWorld level) {
         new NativeWorldMaintenance(level).forEachForcedChunk(chunkKey ->
-                updateChunk(engine, level, (int) chunkKey, (int) (chunkKey >> 32)));
+                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);
     }
 
-    private void updateChunk(Engine engine, NativeWorld level, int chunkX, int chunkZ) {
-        updateChunk(engine, level, chunkX, chunkZ, true);
+    /**
+     * One chunk of a level pass. A failed chunk keeps its flags and retries on a later pass without stopping the
+     * chunks after it; only a closed engine ends the level's pass.
+     */
+    private void updatePassChunk(Engine engine, NativeWorld level, int chunkX, int chunkZ) {
+        try {
+            updateChunk(engine, level, chunkX, chunkZ, true);
+        } catch (Throwable failure) {
+            if (engine.isClosed() || engine.getMantle().getMantle().isClosed()) {
+                throw failure;
+            }
+            if (IrisLogging.errorOnce("chunk-update:" + level.name() + ":" + chunkX + "," + chunkZ + ":" + failure,
+                    "Iris chunk update failed at " + chunkX + "," + chunkZ + " in " + level.name() + ", retrying each pass: " + failure)) {
+                IrisLogging.reportError(failure);
+            }
+        }
     }
 
     private void updateChunk(Engine engine, NativeWorld level, int chunkX, int chunkZ, boolean requireNeighbors) {
@@ -195,6 +212,11 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
                 chunk.raiseFlagUnchecked(MantleFlag.CUSTOM, () -> runCustomPass(engine, level, chunkX, chunkZ, chunk));
                 chunk.raiseFlagUnchecked(MantleFlag.UPDATE, () -> runUpdatePass(engine, level, chunkX, chunkZ, chunk));
             });
+        } catch (SavedBiomeUnavailableException unavailable) {
+            if (!unavailable.isLoading() || unavailable.getSuppressed().length != 0) {
+                throw unavailable;
+            }
+            IrisLogging.debug("Iris chunk update deferred at " + chunkX + "," + chunkZ + ": saved biomes loading");
         } finally {
             chunk.release();
         }
@@ -315,15 +337,40 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
             }
         }
 
-        chunk.iterate(MatterUpdate.class, (Integer x, Integer yf, Integer z, MatterUpdate v) -> {
-            if (v != null && v.isUpdate()) {
-                update(engine, level, x, yf + minHeight, z, baseX, baseZ, chunk);
-            }
-        });
+        IntArrayList completed = new IntArrayList();
+        try {
+            chunk.iterate(MatterUpdate.class, (Integer x, Integer yf, Integer z, MatterUpdate v) -> {
+                if (v != null && v.isUpdate()) {
+                    update(engine, level, x, yf + minHeight, z, baseX, baseZ, chunk);
+                    completed.add((yf << 8) | ((x & 15) << 4) | (z & 15));
+                }
+            });
+        } catch (RuntimeException | Error failure) {
+            forgetCompletedUpdates(chunk, completed, failure);
+            throw failure;
+        }
         chunk.deleteSlices(MatterUpdate.class);
         engine.getMetrics().getUpdates().put(stopwatch.getMilliseconds());
     }
 
+    private static void forgetCompletedUpdates(MantleChunk<Matter> chunk, IntArrayList completed, Throwable failure) {
+        try {
+            for (int index = 0; index < completed.size(); index++) {
+                int position = completed.getInt(index);
+                int y = position >>> 8;
+                Matter section = chunk.get(y >> 4);
+                if (section != null && section.hasSlice(MatterUpdate.class)) {
+                    section.<MatterUpdate>getSlice(MatterUpdate.class)
+                            .set((position >> 4) & 15, y & 15, position & 15, null);
+                }
+            }
+        } catch (RuntimeException | Error cleanupFailure) {
+            if (cleanupFailure != failure) {
+                failure.addSuppressed(cleanupFailure);
+            }
+        }
+    }
+
     private void update(Engine engine, NativeWorld level, int x, int y, int z, int baseX, int baseZ, MantleChunk<Matter> chunk) {
         if (y < level.minHeight() || y >= level.maxHeight() - 1) {
             return;
@@ -337,7 +384,12 @@ public final class ModdedChunkUpdateService implements ModdedTickableService {
             }
             try {
                 ModdedLootApplier.apply(engine, level, pos, state, chunk);
+            } catch (SavedBiomeUnavailableException unavailable) {
+                GenerationFailures.rethrowEngineFailure(unavailable);
+                IrisLogging.warnOnce("chunk-update-loot:" + level.name() + ":" + unavailable.getMessage(),
+                        "Iris left the container at " + pos + " in " + level.name() + " without loot: " + unavailable.getMessage());
             } catch (Throwable e) {
+                GenerationFailures.rethrowEngineFailure(e);
                 IrisLogging.reportError(e);
             }
         } else {