Fix WearBlackAllDay#72. Time ticking is not thread-safe and cause piston problems on worlds that does not tick the time

Author: CaveNightingale

src/main/java/wearblackallday/dimthread/mixin/EntityMixin.java

@@ -115,7 +115,7 @@ public void onMoveToWorld(ServerWorld destination, CallbackInfoReturnable<Entity
 							this.uncompletedTeleportTargetForMoveToWorld = null;
 							this.nbtCachedForMoveToWorld = null;
 							this.world.spawnEntity((Entity) (Object) this);// if the teleporting failed, we need to add it back to the world
-							LOGGER.debug("Failed to teleport {}, return it to it's previous world", this);
+							LOGGER.debug("Failed to teleport {}, return it to its previous world", this);
 						}
 					}
 			);

src/main/java/wearblackallday/dimthread/mixin/MinecraftServerMixin.java

@@ -13,6 +13,7 @@
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 import wearblackallday.dimthread.DimThread;
 import wearblackallday.dimthread.util.CrashInfo;
+import wearblackallday.dimthread.util.ServerWorldAccessor;
 import wearblackallday.dimthread.util.ThreadPool;
 
 import java.util.Collections;
@@ -72,6 +73,7 @@ public void tickWorlds(BooleanSupplier shouldKeepTicking, CallbackInfo ci) {
 		});
 
 		pool.awaitCompletion();
+		getWorlds().forEach(world -> ((ServerWorldAccessor) world).dimthread_tickTime()); // Time ticking is not thread-safe, fix https://github.com/WearBlackAllDay/DimensionalThreading/issues/72
 
 		if(crash.get() != null) {
 			crash.get().crash("Exception ticking world");

src/main/java/wearblackallday/dimthread/mixin/ServerWorldMixin.java

@@ -0,0 +1,51 @@
+package wearblackallday.dimthread.mixin;
+
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.profiler.Profiler;
+import net.minecraft.util.registry.RegistryEntry;
+import net.minecraft.util.registry.RegistryKey;
+import net.minecraft.world.MutableWorldProperties;
+import net.minecraft.world.World;
+import net.minecraft.world.dimension.DimensionType;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import wearblackallday.dimthread.DimThread;
+import wearblackallday.dimthread.util.ServerWorldAccessor;
+
+import java.util.function.Supplier;
+
+@Mixin(ServerWorld.class)
+public abstract class ServerWorldMixin extends World implements ServerWorldAccessor {
+	protected ServerWorldMixin(MutableWorldProperties properties, RegistryKey<World> registryRef, RegistryEntry<DimensionType> registryEntry, Supplier<Profiler> profiler, boolean isClient, boolean debugWorld, long seed) {
+		super(properties, registryRef, registryEntry, profiler, isClient, debugWorld, seed);
+	}
+
+	@Shadow protected abstract void tickTime();
+
+	boolean onMainThread = false;
+	boolean timeTickedOnWorldThread = false;
+
+	/**
+	 * Time ticking is not thread-safe. We cancel time ticking from the world thread. However, DimThread will tick time on the main thread
+	 */
+	@Inject(method = "tickTime", at = @At("HEAD"), cancellable = true)
+	private void preventTimeTicking(CallbackInfo ci) {
+		if (DimThread.MANAGER.isActive(getServer()) && !onMainThread) {
+			timeTickedOnWorldThread = true;
+			ci.cancel();
+		}
+	}
+
+	@Override
+	public void dimthread_tickTime() {
+		if (timeTickedOnWorldThread) {
+			onMainThread = true;
+			tickTime();
+			onMainThread = false;
+			timeTickedOnWorldThread = false;
+		}
+	}
+}

src/main/java/wearblackallday/dimthread/util/ServerWorldAccessor.java

@@ -0,0 +1,8 @@
+package wearblackallday.dimthread.util;
+
+/**
+ * Create this calass wo that we can call tickTime from ServerWorldMixin
+ */
+public interface ServerWorldAccessor {
+	void dimthread_tickTime();
+}

src/main/resources/dimthread.mixins.json

@@ -8,6 +8,7 @@
     "MinecraftServerMixin",
     "RedstoneWireBlockMixin",
     "ServerChunkManagerMixin",
+    "ServerWorldMixin",
     "WorldMixin"
   ],
   "client": [