Drain world chunk task queue on unload

Author: aromaa

src/main/resources/common.accesswidener

@@ -20,3 +20,4 @@ accessible class net/minecraft/network/protocol/game/ServerboundInteractPacket$A
 accessible class net/minecraft/network/protocol/game/ServerboundInteractPacket$ActionType
 accessible class net/minecraft/world/entity/monster/SpellcasterIllager$IllagerSpell
 accessible class net/minecraft/world/level/biome/Biome$ClimateSettings
+accessible class net/minecraft/server/level/ServerChunkCache$MainThreadExecutor

src/mixins/java/org/spongepowered/common/mixin/core/server/level/ServerChunkCacheMixin.java

@@ -33,14 +33,17 @@
 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.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 import org.spongepowered.common.accessor.server.level.ChunkMapAccessor;
 
 @Mixin(ServerChunkCache.class)
 public abstract class ServerChunkCacheMixin {
 
     // @formatter:off
     @Shadow @Final private ServerLevel level;
+    @Shadow @Final private ServerChunkCache.MainThreadExecutor mainThreadProcessor;
     // @formatter:on
 
     @Redirect(method = "save", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/level/ChunkMap;saveAllChunks(Z)V"))
@@ -51,4 +54,9 @@ public abstract class ServerChunkCacheMixin {
             ((ChunkMapAccessor) chunkManager).invoker$saveAllChunks(flush);
         }
     }
+
+    @Inject(method = "close", at = @At("TAIL"))
+    private void impl$onClose(final CallbackInfo ci) {
+        this.mainThreadProcessor.close();
+    }
 }

src/mixins/java/org/spongepowered/common/mixin/core/server/level/ServerChunkCache_MainThreadExecutorMixin.java

@@ -0,0 +1,61 @@
+/*
+ * This file is part of Sponge, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) SpongePowered <https://www.spongepowered.org>
+ * Copyright (c) contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package org.spongepowered.common.mixin.core.server.level;
+
+import net.minecraft.server.level.ServerChunkCache;
+import net.minecraft.util.thread.BlockableEventLoop;
+import org.spongepowered.asm.mixin.Mixin;
+
+@Mixin(ServerChunkCache.MainThreadExecutor.class)
+public abstract class ServerChunkCache_MainThreadExecutorMixin extends BlockableEventLoop<Runnable> {
+
+    private volatile boolean impl$closed;
+
+    protected ServerChunkCache_MainThreadExecutorMixin(final String $$0) {
+        super($$0);
+    }
+
+    @Override
+    public void tell(final Runnable $$0) {
+        if (this.impl$closed) {
+            $$0.run();
+            return;
+        }
+
+        super.tell($$0);
+
+        if (this.impl$closed) {
+            this.runAllTasks();
+        }
+    }
+
+    @Override
+    public void close() {
+        super.close();
+
+        this.impl$closed = true;
+        this.runAllTasks();
+    }
+}

src/mixins/java/org/spongepowered/common/mixin/core/server/level/ServerLevelMixin.java

@@ -153,6 +153,7 @@ public abstract class ServerLevelMixin extends LevelMixin implements ServerLevel
     private Weather impl$prevWeather;
     private boolean impl$isManualSave = false;
     private long impl$preTickTime = 0L;
+    private boolean impl$closed = false;
 
     @Inject(method = "<init>", at = @At("TAIL"))
     private void impl$onInit(
@@ -206,7 +207,7 @@ public abstract class ServerLevelMixin extends LevelMixin implements ServerLevel
 
     @Override
     public boolean bridge$isLoaded() {
-        if (((LevelBridge) this).bridge$isFake()) {
+        if (((LevelBridge) this).bridge$isFake() || this.impl$closed) {
             return false;
         }
 
@@ -553,4 +554,9 @@ public String toString() {
         //Weather, game rules and spawns are per world in Sponge.
         instance.broadcastAll($$0, this.shadow$dimension());
     }
+
+    @Inject(method = "close", at = @At("HEAD"))
+    private void impl$onClose(final CallbackInfo ci) {
+        this.impl$closed = true;
+    }
 }

src/mixins/resources/mixins.sponge.core.json

@@ -77,6 +77,7 @@
     "server.level.DistanceManagerMixin",
     "server.level.GenerationChunkHolderMixin",
     "server.level.ServerBossEventMixin",
+    "server.level.ServerChunkCache_MainThreadExecutorMixin",
     "server.level.ServerChunkCacheMixin",
     "server.level.ServerEntityMixin",
     "server.level.ServerLevelMixin",