Add ChunkEvent.LightingCalculated, fixes #8354 (#10533)

patches/minecraft/net/minecraft/server/level/ThreadedLevelLightEngine.java.patch

@@ -0,0 +1,10 @@
+--- a/net/minecraft/server/level/ThreadedLevelLightEngine.java
++++ b/net/minecraft/server/level/ThreadedLevelLightEngine.java
+@@ -171,6 +_,7 @@
+         }, () -> "lightChunk " + chunkpos + " " + p_9355_));
+         return CompletableFuture.supplyAsync(() -> {
+             p_9354_.setLightCorrect(true);
++            net.minecraftforge.common.ForgeHooks.fireLightingCalculatedEvent(p_9354_);
+             return p_9354_;
+         }, p_280982_ -> this.addTask(chunkpos.x, chunkpos.z, ThreadedLevelLightEngine.TaskType.POST_UPDATE, p_280982_));
+     }

src/main/java/net/minecraftforge/common/ForgeHooks.java

@@ -153,6 +153,7 @@ import net.minecraftforge.event.entity.player.PlayerEvent;
 import net.minecraftforge.event.entity.living.LivingGetProjectileEvent;
 import net.minecraftforge.event.level.BlockEvent;
 import net.minecraftforge.event.level.NoteBlockEvent;
+import net.minecraftforge.event.level.ChunkEvent;
 import net.minecraftforge.event.network.CustomPayloadEvent;
 import net.minecraftforge.eventbus.api.Event;
 import net.minecraftforge.fluids.FluidType;
@@ -188,6 +189,7 @@ import net.minecraft.world.level.GameType;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.state.pattern.BlockInWorld;
 import net.minecraft.world.level.material.Fluid;
+import net.minecraft.world.level.chunk.ChunkAccess;
 import org.apache.maven.artifact.versioning.ArtifactVersion;
 import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
 import org.jetbrains.annotations.ApiStatus;
@@ -204,6 +206,10 @@ public final class ForgeHooks {
 
     private ForgeHooks() {}
 
+    public static void fireLightingCalculatedEvent(ChunkAccess chunk) {
+        MinecraftForge.EVENT_BUS.post(new ChunkEvent.LightingCalculated(chunk));
+    }
+    
     public static boolean canContinueUsing(@NotNull ItemStack from, @NotNull ItemStack to) {
         if (!from.isEmpty() && !to.isEmpty()) {
             return from.getItem().canContinueUsing(from, to);

src/main/java/net/minecraftforge/event/level/ChunkEvent.java

@@ -22,24 +22,20 @@ import org.jetbrains.annotations.ApiStatus;
  * <br>
  * All children of this event are fired on the {@link MinecraftForge#EVENT_BUS}.<br>
  **/
-public class ChunkEvent extends LevelEvent
-{
+public class ChunkEvent extends LevelEvent {
     private final ChunkAccess chunk;
 
-    public ChunkEvent(ChunkAccess chunk)
-    {
+    public ChunkEvent(ChunkAccess chunk) {
         super(chunk.getWorldForge());
         this.chunk = chunk;
     }
 
-    public ChunkEvent(ChunkAccess chunk, LevelAccessor level)
-    {
+    public ChunkEvent(ChunkAccess chunk, LevelAccessor level) {
         super(level);
         this.chunk = chunk;
     }
 
-    public ChunkAccess getChunk()
-    {
+    public ChunkAccess getChunk() {
         return chunk;
     }
 
@@ -56,13 +52,11 @@ public class ChunkEvent extends LevelEvent
      * <br>
      * This event is fired on the {@link MinecraftForge#EVENT_BUS}.<br>
      **/
-    public static final class Load extends ChunkEvent
-    {
+    public static final class Load extends ChunkEvent {
         private final boolean newChunk;
 
         @ApiStatus.Internal
-        public Load(ChunkAccess chunk, boolean newChunk)
-        {
+        public Load(ChunkAccess chunk, boolean newChunk) {
             super(chunk);
             this.newChunk = newChunk;
         }
@@ -74,8 +68,7 @@ public class ChunkEvent extends LevelEvent
          *
          * @return whether the Chunk is newly generated
          */
-        public boolean isNewChunk()
-        {
+        public boolean isNewChunk() {
             return newChunk;
         }
     }
@@ -91,10 +84,27 @@ public class ChunkEvent extends LevelEvent
      * <br>
      * This event is fired on the {@link MinecraftForge#EVENT_BUS}.<br>
      **/
-    public static final class Unload extends ChunkEvent
-    {
-        public Unload(ChunkAccess chunk)
-        {
+    public static final class Unload extends ChunkEvent {
+        public Unload(ChunkAccess chunk) {
+            super(chunk);
+        }
+    }
+    
+    /**
+     * ChunkEvent.LightingCalculated is fired when MinecraftForge flags that lighting is correct in a chunk.<br>
+     * This event is fired during light propagation in ThreadedLevelLightEngine.CompletableFuture(), specifically upon setting 
+     * the ChunkAccess isLightCorrect to true.<br>
+     * <br>
+     * The game test for this event is lighting_event_test in net.minecraftforge.debug.chunk<br>
+     * <br>
+     * This event is not {@link Cancelable}.<br>
+     * <br>
+     * This event does not have a result. {@link HasResult} <br>
+     * <br>
+     * This event is fired on the {@link MinecraftForge#EVENT_BUS}.<br>
+     **/
+    public static final class LightingCalculated extends ChunkEvent {
+        public LightingCalculated(ChunkAccess chunk) {
             super(chunk);
         }
     }

src/main/resources/META-INF/mods.toml

@@ -5,13 +5,13 @@ logoFile="forge_logo.png"
 license="LGPL v2.1"
 
 [[mods]]
-    modId="forge"
-    version="${global.forgeVersion}"
-    updateJSONURL="https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json"
-    displayURL="https://minecraftforge.net/"
-    displayName="Forge"
-    credits="Anyone who has contributed on Github and supports our development"
-    authors="LexManos,cpw"
-    description='''
-    Forge, a broad compatibility API.
-    '''
+modId="forge"
+version="${global.forgeVersion}"
+updateJSONURL="https://files.minecraftforge.net/net/minecraftforge/forge/promotions_slim.json"
+displayURL="https://minecraftforge.net/"
+displayName="Forge"
+credits="Anyone who has contributed on Github and supports our development"
+authors="LexManos,cpw"
+description='''
+Forge, a broad compatibility API.
+'''

src/test/generated/lighting_event_test/data/forge/test_instance/lighting_event_test/test_lighting_event_fires.json

@@ -0,0 +1,7 @@
+{
+  "type": "minecraft:function",
+  "environment": "minecraft:default",
+  "function": "forge:lighting_event_test/test_lighting_event_fires",
+  "max_ticks": 100,
+  "structure": "forge:empty3x3x3"
+}

src/test/java/net/minecraftforge/debug/chunk/LightingEventTest.java

@@ -0,0 +1,67 @@
+package net.minecraftforge.debug.chunk;
+
+import net.minecraft.ChatFormatting;
+import net.minecraft.core.BlockPos;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.network.chat.Component;
+import net.minecraft.util.RandomSource;
+import net.minecraft.world.level.chunk.ChunkAccess;
+import net.minecraftforge.event.level.ChunkEvent;
+import net.minecraftforge.fml.common.Mod;
+import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
+import net.minecraftforge.gametest.GameTest;
+import net.minecraftforge.gametest.GameTestNamespace;
+import net.minecraftforge.test.BaseTestMod;
+
+/**
+ * This is a test for the ChunkEvent.LightingCalculated event.
+ */
+@GameTestNamespace("forge")
+@Mod(LightingEventTest.MODID)
+public class LightingEventTest extends BaseTestMod {
+    public static final String MODID = "lighting_event_test";
+
+    private static final int MAX_CHUNK_LOCATION_ATTEMPTS = 5;
+
+    public LightingEventTest(FMLJavaModLoadingContext context) {
+        super(context);
+    }
+
+    @GameTest
+    public static void testLightingEventFires(GameTestHelper helper) {
+        var eventFired = helper.boolFlag("eventFired");
+        helper.<ChunkEvent.LightingCalculated>addEventListener(event -> eventFired.set(true));
+
+        var random = RandomSource.create();
+        var level = helper.getLevel();
+        var chunkSource = level.getChunkSource();
+
+        // try to find a far away chunk that is not already ticking
+        int attempts;
+        var origin = helper.absolutePos(BlockPos.ZERO);
+        ChunkAccess chunk = null;
+        for (attempts = 0; attempts < MAX_CHUNK_LOCATION_ATTEMPTS && chunk == null; attempts++) {
+            int x = random.nextInt(1, 10) * 10000;
+            int z = random.nextInt(1, 10) * 10000;
+            chunk = level.getChunk(origin.offset(x, 0, z));
+
+            // If the chunk is already ticking, we can't force it
+            chunk = chunkSource.isPositionTicking(chunk.getPos().toLong()) ? null : chunk;
+        }
+
+        if (chunk == null) {
+            helper.fail(Component.literal("Failed to find a far away chunk that is not already ticking after " + MAX_CHUNK_LOCATION_ATTEMPTS + " attempts"));
+            return;
+        } else if (attempts > 1) {
+            helper.say("WARNING: Finding a far away chunk took " + attempts + " attempts.", ChatFormatting.YELLOW);
+        }
+
+        helper.runAfterDelay(20, () -> {
+            if (!eventFired.getBool()) {
+                helper.fail("LightingCalculated event was not fired!");
+            }
+
+            helper.succeed();
+        });
+    }
+}

src/test/java/net/minecraftforge/debug/gameplay/level/ForcedChunkLoadingTest.java

@@ -22,12 +22,12 @@ import net.minecraftforge.test.BaseTestMod;
 public class ForcedChunkLoadingTest extends BaseTestMod {
     static final String MOD_ID = "forced_chunk_loading";
 
+    private static final int MAX_CHUNK_LOCATION_ATTEMPTS = 5;
+
     public ForcedChunkLoadingTest(FMLJavaModLoadingContext context) {
         super(context);
     }
 
-    private static final int MAX_CHUNK_LOCATION_ATTEMPTS = 5;
-
     @GameTest
     public static void force_far_away_chunk(GameTestHelper helper) {
         var random = RandomSource.create();