neoforge-1.21.1: runtime fixes and build improvements

- Fix ServerTickEvent: register listener for ServerTickEvent.Post instead of
  abstract ServerTickEvent base class (NeoForge 21.x requirement)
- Fix null BlockGetter: replace null with EmptyBlockGetter.INSTANCE in
  isSolidRender() and propagatesSkylightDown() calls (1.21+ actually uses param)
- Fix chunk iteration: replace direct visibleChunkMap field access with
  getChunks() iteration and getChunkToSend() with getLatestChunk() (1.21.1 API)
- Build: fix shadowJar config to properly bundle DynmapCore into fat jar
  (was producing 80KB hollow jar missing all core classes)
- Build: cap Gradle daemon and forked javac heap to prevent OOM on large hosts
- Tested: server starts cleanly, Dynmap web UI accessible, maps rendered

build.gradle

@@ -30,10 +30,15 @@ minecraft {
     }
 }
 
+configurations {
+    shadow
+    implementation.extendsFrom shadow
+}
+
 dependencies {
     implementation 'net.neoforged:neoforge:21.1.219'
-    // DynmapCore and DynmapCoreAPI as local jars (build these separately)
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    // DynmapCore bundled into the fat jar via shadow config
+    shadow fileTree(dir: 'libs', include: ['*.jar'])
 }
 
 processResources {
@@ -50,7 +55,13 @@ shadowJar {
     mergeServiceFiles()
 
     archiveBaseName = 'Dynmap'
+    archiveVersion = project.version
     archiveClassifier = 'neoforge-1.21.1'
+
+    // Exclude signature files that cause security exceptions
+    exclude 'META-INF/*.RSA'
+    exclude 'META-INF/*.SF'
+    exclude 'META-INF/*.DSA'
 }
 
 tasks.jar {
@@ -66,4 +77,11 @@ tasks.jar {
     }
 }
 
-build.dependsOn(jar)
+// Build the fat jar, not the thin one
+build.dependsOn(shadowJar)
+
+// Cap memory on forked javac process (prevents OOM on large NeoForge compile)
+tasks.withType(JavaCompile).configureEach {
+    options.fork = true
+    options.forkOptions.memoryMaximumSize = '3g'
+}

gradle.properties

@@ -1,4 +1,4 @@
-org.gradle.jvmargs=-Xmx4G
+org.gradle.jvmargs=-Xmx2G
 org.gradle.daemon=false
 org.gradle.parallel=false
 # GitHub user and password (workaround for OSSRH beeing sunset - https://central.sonatype.org/pages/ossrh-eol/

src/main/java/org/dynmap/neoforge_1_21_1/DynmapPlugin.java

@@ -245,7 +245,7 @@ public class DynmapPlugin
                 }
                 int lightAtten = 15;
                 try {	// Workaround for mods with broken block state logic...
-                    lightAtten = bs.isSolidRender(null, BlockPos.ZERO) ? 15 : (bs.propagatesSkylightDown(null, BlockPos.ZERO) ? 0 : 1);
+                    lightAtten = bs.isSolidRender(net.minecraft.world.level.EmptyBlockGetter.INSTANCE, BlockPos.ZERO) ? 15 : (bs.propagatesSkylightDown(net.minecraft.world.level.EmptyBlockGetter.INSTANCE, BlockPos.ZERO) ? 0 : 1);
                 } catch (Exception x) {
                 	Log.warning(String.format("Exception while checking lighting data for block state: %s[%s]", bn, statename));
                 	Log.verboseinfo("Exception: " + x.toString());
@@ -913,7 +913,7 @@ public class DynmapPlugin
         }
 
         @SubscribeEvent
-		public void tickEvent(ServerTickEvent event)  {
+		public void tickEvent(ServerTickEvent.Post event)  {
             cur_tick_starttime = System.nanoTime();
             long elapsed = cur_tick_starttime - lasttick;
             lasttick = cur_tick_starttime;
@@ -1850,13 +1850,10 @@ public class DynmapPlugin
             for (ServerLevel world : server.getAllLevels()) {
             	ForgeWorld fw = getWorld(world);
             	if (fw == null) continue;
-            	Long2ObjectLinkedOpenHashMap<ChunkHolder> chunks = world.getChunkSource().chunkMap.visibleChunkMap;
-            	for (Entry<Long, ChunkHolder> k : chunks.long2ObjectEntrySet()) {
-            		long key = k.getKey().longValue();
-            		ChunkHolder ch = k.getValue();
+            	for (ChunkHolder ch : world.getChunkSource().chunkMap.visibleChunkMap.values()) {
             		ChunkAccess c = null;
             		try {
-            			c = ch.getChunkToSend();
+            			c = ch.getLatestChunk();
             		} catch (Exception x) { }
             		if (c == null) continue;
             		ChunkStatus cs = c.getPersistedStatus();