[1.21.3] Add remove count context to ItemSmeltedEvent and fix firing multiple times with shift-click

patches/net/minecraft/world/inventory/FurnaceResultSlot.java.patch

@@ -1,9 +1,12 @@
 --- a/net/minecraft/world/inventory/FurnaceResultSlot.java
 +++ b/net/minecraft/world/inventory/FurnaceResultSlot.java
-@@ -49,5 +_,6 @@
+@@ -48,6 +_,9 @@
+             abstractfurnaceblockentity.awardUsedRecipesAndPopExperience(serverplayer);
          }
 
++        if (this.removeCount != 0) {
++            net.neoforged.neoforge.event.EventHooks.firePlayerSmeltedEvent(this.player, p_39558_, this.removeCount);
++        }
          this.removeCount = 0;
-+        net.neoforged.neoforge.event.EventHooks.firePlayerSmeltedEvent(this.player, p_39558_);
      }
  }

src/main/java/net/neoforged/neoforge/event/EventHooks.java

@@ -908,8 +908,8 @@ public static void firePlayerCraftingEvent(Player player, ItemStack crafted, Con
         NeoForge.EVENT_BUS.post(new PlayerEvent.ItemCraftedEvent(player, crafted, craftMatrix));
     }
 
-    public static void firePlayerSmeltedEvent(Player player, ItemStack smelted) {
-        NeoForge.EVENT_BUS.post(new PlayerEvent.ItemSmeltedEvent(player, smelted));
+    public static void firePlayerSmeltedEvent(Player player, ItemStack smelted, int amountRemoved) {
+        NeoForge.EVENT_BUS.post(new PlayerEvent.ItemSmeltedEvent(player, smelted, amountRemoved));
     }
 
     /**

src/main/java/net/neoforged/neoforge/event/entity/player/PlayerEvent.java

@@ -408,15 +408,21 @@ public Container getInventory() {
 
     public static class ItemSmeltedEvent extends PlayerEvent {
         private final ItemStack smelting;
+        private final int amountRemoved;
 
-        public ItemSmeltedEvent(Player player, ItemStack crafting) {
+        public ItemSmeltedEvent(Player player, ItemStack crafting, int amountRemoved) {
             super(player);
             this.smelting = crafting;
+            this.amountRemoved = amountRemoved;
         }
 
         public ItemStack getSmelting() {
             return this.smelting;
         }
+
+        public int getAmountRemoved() {
+            return this.amountRemoved;
+        }
     }
 
     public static class PlayerLoggedInEvent extends PlayerEvent {

tests/src/main/java/net/neoforged/neoforge/debug/crafting/CraftingEventTests.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.debug.crafting;
+
+import com.mojang.blaze3d.platform.InputConstants;
+import java.util.concurrent.atomic.AtomicInteger;
+import net.minecraft.core.BlockPos;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.level.GameType;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.level.block.entity.FurnaceBlockEntity;
+import net.neoforged.neoforge.event.entity.player.PlayerEvent;
+import net.neoforged.testframework.DynamicTest;
+import net.neoforged.testframework.annotation.ForEachTest;
+import net.neoforged.testframework.annotation.TestHolder;
+import net.neoforged.testframework.gametest.EmptyTemplate;
+
+@ForEachTest(groups = "crafting.event")
+public class CraftingEventTests {
+    @GameTest
+    @EmptyTemplate
+    @TestHolder(description = "Tests that ItemSmeltedEvent is fired correctly")
+    static void itemSmeltedEventTest(final DynamicTest test) {
+        AtomicInteger timesFired = new AtomicInteger(0);
+        test.whenEnabled(listeners -> {
+            listeners.forge().addListener((final PlayerEvent.ItemSmeltedEvent event) -> {
+                timesFired.incrementAndGet();
+                var removed = event.getAmountRemoved();
+                if (removed != 32) {
+                    test.fail("Test should be removing half of a stack, yet extracted a different amount");
+                }
+            });
+        });
+        test.onGameTest(helper -> {
+            helper.setBlock(BlockPos.ZERO, Blocks.FURNACE);
+            var be = helper.getBlockEntity(BlockPos.ZERO, FurnaceBlockEntity.class);
+            helper.assertFalse(be == null, "FurnaceBlockEntity was not found for furnace position");
+            // Slot 2 is the result slot
+            be.setItem(2, new ItemStack(Items.IRON_INGOT, 64));
+            var player = helper.makeTickingMockServerPlayerInLevel(GameType.CREATIVE);
+            player.openMenu(be);
+            // Test that right-clicking half of the stack out of the FurnaceResultSlot functions as expected
+            player.containerMenu.clicked(2, InputConstants.MOUSE_BUTTON_RIGHT, ClickType.PICKUP, player);
+            helper.assertTrue(timesFired.getPlain() == 1, "Event was not fired the expected number of times for right-click pickup. Fired: " + timesFired.getPlain());
+            player.containerMenu.setCarried(ItemStack.EMPTY);
+            // Test that shift-left-clicking the rest of the stack out works (should only fire once, not twice)
+            player.containerMenu.clicked(2, InputConstants.MOUSE_BUTTON_LEFT, ClickType.QUICK_MOVE, player);
+            helper.assertTrue(timesFired.getPlain() == 2, "Event was not fired the expected number of times for shift-left-click quick-move. Fired: " + timesFired.getPlain());
+            // The slot is now empty, this should not fire the event
+            player.containerMenu.clicked(2, InputConstants.MOUSE_BUTTON_LEFT, ClickType.QUICK_MOVE, player);
+            helper.assertTrue(timesFired.getPlain() == 2, "Event fired for an empty slot, which should not happen.");
+            helper.succeed();
+        });
+    }
+}