Fix thread leak and graceful shutdown issue in NightConfigWatchThrottler

Fix thread leak and graceful shutdown issue in NightConfigWatchThrottler

src/main/java/org/embeddedt/modernfix/common/mixin/perf/optimize_surface_rules/SurfaceSystemMixin.java

@@ -37,11 +37,18 @@ public class SurfaceSystemMixin {
                                                               @Local(ordinal = 0, argsOnly = true) BiomeManager manager,
                                                               @Local(ordinal = 0, argsOnly = true) ChunkAccess chunk,
                                                               @Share("chunkBiomeLookup") LocalRef<ChunkBiomeLookup> lookupRef) {
-        var lookup = MFIX_LOOKUP_CACHE.get();
-        BiomeManagerAccessor accessor = (BiomeManagerAccessor)manager;
-        lookup.prepare(accessor.mfix$getBiomeSource(), accessor.mfix$getZoomSeed(), chunk, manager);
-        lookupRef.set(lookup);
-        return lookup;
+        // If mods use their own BiomeManager subclass, we cannot trust them to use the same blurring as vanilla,
+        // so we cannot apply our optimized path
+        if (manager.getClass() == BiomeManager.class) {
+            var lookup = MFIX_LOOKUP_CACHE.get();
+            BiomeManagerAccessor accessor = (BiomeManagerAccessor)manager;
+            lookup.prepare(accessor.mfix$getBiomeSource(), accessor.mfix$getZoomSeed(), chunk, manager);
+            lookupRef.set(lookup);
+            return lookup;
+        } else {
+            lookupRef.set(null);
+            return biomeGetter;
+        }
     }
 
     @Inject(method = "buildSurface", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/levelgen/SurfaceRules$RuleSource;apply(Ljava/lang/Object;)Ljava/lang/Object;", ordinal = 0))
@@ -60,7 +67,12 @@ public class SurfaceSystemMixin {
 
     @Redirect(method = "buildSurface", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/biome/BiomeManager;getBiome(Lnet/minecraft/core/BlockPos;)Lnet/minecraft/core/Holder;"))
     private Holder<Biome> useFasterLookup(BiomeManager instance, BlockPos pos, @Share("chunkBiomeLookup") LocalRef<ChunkBiomeLookup> lookupRef) {
-        return lookupRef.get().apply(pos);
+        var lookup = lookupRef.get();
+        if (lookup != null) {
+            return lookup.apply(pos);
+        } else {
+            return instance.getBiome(pos);
+        }
     }
 
     @Inject(method = "buildSurface", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/levelgen/SurfaceRules$Context;<init>(Lnet/minecraft/world/level/levelgen/SurfaceSystem;Lnet/minecraft/world/level/levelgen/RandomState;Lnet/minecraft/world/level/chunk/ChunkAccess;Lnet/minecraft/world/level/levelgen/NoiseChunk;Ljava/util/function/Function;Lnet/minecraft/core/Registry;Lnet/minecraft/world/level/levelgen/WorldGenerationContext;)V"))

src/main/java/org/embeddedt/modernfix/forge/config/NightConfigWatchThrottler.java

@@ -18,9 +18,18 @@ import java.util.concurrent.locks.LockSupport;
  */
 public class NightConfigWatchThrottler {
     private static final long DELAY = TimeUnit.MILLISECONDS.toNanos(1000);
-
+    
+    // FIXED: Add shutdown hook to clean up watcher threads
+    private static void addShutdownHook() {
+        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+            isShuttingDown.set(true);
+        }, "ModernFix-ShutdownHook"));
+    }
+    
     @SuppressWarnings("rawtypes")
     public static void throttle() {
+        // FIXED: Register shutdown hook for clean cleanup
+        addShutdownHook();
         Map watchedDirs = ObfuscationReflectionHelper.getPrivateValue(FileWatcher.class, FileWatcher.defaultInstance(), "watchedDirs");
         Thread launchThread = Thread.currentThread();
         Map watchedDirsWrapper = new ForwardingMap() {
@@ -46,7 +55,15 @@ public class NightConfigWatchThrottler {
                             // iterator() is called at the beginning of each iteration of the watch loop,
                             // so it is a good spot to inject the delay.
                             if (Thread.currentThread() != launchThread) {
+                                // FIXED: Check for shutdown state to prevent new watches from being created
+                                if (isShuttingDown.get()) {
+                                    return java.util.Collections.emptyIterator();
+                                }
                                 LockSupport.parkNanos(DELAY);
+                                // FIXED: Properly handle thread interruption to allow graceful container shutdown
+                                if (Thread.currentThread().isInterrupted()) {
+                                    return java.util.Collections.emptyIterator();
+                                }
                             }
                             return super.iterator();
                         }

src/main/java/org/embeddedt/modernfix/world/gen/ChunkBiomeLookup.java

@@ -97,6 +97,9 @@ public class ChunkBiomeLookup implements Function<BlockPos, Holder<Biome>> {
     }
 
     public void dispose() {
+        if (this.fallbackManager == null) {
+            return;
+        }
         // Make sure we do not retain strong references to the biome holders
         Arrays.fill(biomes, null);
         this.fallbackManager = null;