Fix game not exiting after using the multithreaded crafting planner

src/main/java/org/cyclops/integratedterminals/IntegratedTerminals.java

@@ -35,6 +35,7 @@
 import org.cyclops.integratedterminals.gametest.GameTestAdvancementsIntegratedTerminals;
 import org.cyclops.integratedterminals.gametest.GameTestCraftingJobIndication;
 import org.cyclops.integratedterminals.gametest.GameTestCraftingJobNotify;
+import org.cyclops.integratedterminals.gametest.GameTestCraftingPlanWorkerPool;
 import org.cyclops.integratedterminals.gametest.GameTestIngredientQueryMatchers;
 import org.cyclops.integratedterminals.gametest.GameTestPendingCraftingJobOutputs;
 import org.cyclops.integratedterminals.gametest.GameTestTerminalCraftingJobFinishedEvent;
@@ -158,6 +159,7 @@ public Class<?>[] getGameTestClasses() {
                 GameTestAdvancementsIntegratedTerminals.class,
                 GameTestCraftingJobIndication.class,
                 GameTestCraftingJobNotify.class,
+                GameTestCraftingPlanWorkerPool.class,
                 GameTestIngredientQueryMatchers.class,
                 GameTestPendingCraftingJobOutputs.class,
                 GameTestTerminalCraftingJobFinishedEvent.class,

src/main/java/org/cyclops/integratedterminals/gametest/GameTestCraftingPlanWorkerPool.java

@@ -0,0 +1,23 @@
+package org.cyclops.integratedterminals.gametest;
+
+import net.minecraft.gametest.framework.GameTestHelper;
+import org.cyclops.cyclopscore.gametest.GameTest;
+import org.cyclops.integratedterminals.inventory.container.ContainerTerminalStorageCraftingPlanBase;
+
+import java.util.concurrent.ExecutionException;
+
+/**
+ * Game tests for the crafting planner worker pool.
+ * @author rubensworks
+ */
+public class GameTestCraftingPlanWorkerPool {
+
+    @GameTest(template = "cyclopscore:empty")
+    public void testWorkerThreadsAreDaemon(GameTestHelper helper) throws ExecutionException, InterruptedException {
+        // Non-daemon worker threads would keep the client JVM alive after quitting the game.
+        boolean daemon = ContainerTerminalStorageCraftingPlanBase.getWorkerPool().submit(() -> Thread.currentThread().isDaemon()).get();
+        helper.assertTrue(daemon, "Crafting planner worker threads must be daemon threads");
+        helper.succeed();
+    }
+
+}

src/main/java/org/cyclops/integratedterminals/inventory/container/ContainerTerminalStorageCraftingPlanBase.java

@@ -1,5 +1,7 @@
 package org.cyclops.integratedterminals.inventory.container;
 
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import net.minecraft.core.RegistryAccess;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.SimpleContainer;
@@ -29,7 +31,19 @@
 public abstract class ContainerTerminalStorageCraftingPlanBase<L> extends InventoryContainer {
 
     public static final String BUTTON_START = "start";
-    private static final ExecutorService WORKER_POOL = Executors.newFixedThreadPool(GeneralConfig.craftingPlannerThreads);
+    // Daemon threads, so they don't prevent the client JVM from exiting.
+    private static final ExecutorService WORKER_POOL = Executors.newFixedThreadPool(
+            GeneralConfig.craftingPlannerThreads,
+            new ThreadFactoryBuilder()
+                    .setNameFormat("IntegratedTerminals Crafting Planner #%d")
+                    .setDaemon(true)
+                    .build()
+    );
+
+    @VisibleForTesting
+    public static ExecutorService getWorkerPool() {
+        return WORKER_POOL;
+    }
 
     private final CraftingOptionGuiData craftingOptionGuiData;
     private final int craftingPlanNotifierId;