From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: MrHua269 <mrhua269@gmail.com>
Date: Thu, 9 Jul 2026 11:54:24 +0800
Subject: [PATCH] Leaves Vanilla Hopper

A part from leaves

Origin patch link: https://github.com/LeavesMC/Leaves/blob/master/leaves-server/minecraft-patches/features/0092-Vanilla-hopper.patch
Origin license: https://github.com/LeavesMC/Leaves/blob/master/LICENSE.md

diff --git a/net/minecraft/world/level/block/entity/HopperBlockEntity.java b/net/minecraft/world/level/block/entity/HopperBlockEntity.java
index a858cb658af70f07614fa1f4d9e8a3435d5c161f..95f0b3276137cb9d1fc296e97cc25a08a5200c95 100644
--- a/net/minecraft/world/level/block/entity/HopperBlockEntity.java
+++ b/net/minecraft/world/level/block/entity/HopperBlockEntity.java
@@ -281,36 +281,67 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
         ItemStack movedItem = origItemStack;
         final int originalItemCount = origItemStack.getCount();
         final int movedItemCount = Math.min(level.spigotConfig.hopperAmount, originalItemCount);
-        container.setChanged(); // original logic always marks source inv as changed even if no move happens.
-        movedItem.setCount(movedItemCount);
-
-        if (!worldData.skipPullModeEventFire) { // Folia - region threading
-            movedItem = callPullMoveEvent(hopper, container, movedItem);
-            if (movedItem == null) { // cancelled
-                origItemStack.setCount(originalItemCount);
-                // Drastically improve performance by returning true.
-                // No plugin could have relied on the behavior of false as the other call
-                // site for IMIE did not exhibit the same behavior
+        // Leaves start - fix vanilla hopper
+        if (movedItem.getCount() <= movedItemCount) {
+            if (!worldData.skipPullModeEventFire) {
+                movedItem = callPullMoveEvent(hopper, container, movedItem);
+                if (movedItem == null) { // cancelled
+                    origItemStack.setCount(originalItemCount);
+                    container.setChanged(); // keep parity with vanilla: source inv always marked changed
+                    return true;
+                }
+            }
+            final int toRemove = Math.min(movedItem.getCount(), container.getItem(i).getCount());
+            final ItemStack remainingItem = addItem(container, hopper, container.removeItem(i, toRemove), null);
+            final int remainingItemCount = remainingItem.getCount();
+            if (remainingItem.isEmpty()) {
+                container.setChanged();
                 return true;
             }
-        }
-
-        final ItemStack remainingItem = addItem(container, hopper, movedItem, null);
-        final int remainingItemCount = remainingItem.getCount();
-        if (remainingItemCount != movedItemCount) {
-            origItemStack = origItemStack.copy(true);
-            origItemStack.setCount(originalItemCount);
-            if (!origItemStack.isEmpty()) {
-                origItemStack.setCount(originalItemCount - movedItemCount + remainingItemCount);
+            if (remainingItemCount != toRemove) {
+                IGNORE_TILE_UPDATES.set(true); // Folia - region threading
+                container.setItem(i, remainingItem);
+                IGNORE_TILE_UPDATES.set(false); // Folia - region threading
+                container.setChanged();
+                return true;
             }
-
             IGNORE_TILE_UPDATES.set(true); // Folia - region threading
-            container.setItem(i, origItemStack);
+            container.setItem(i, remainingItem);
             IGNORE_TILE_UPDATES.set(false); // Folia - region threading
             container.setChanged();
-            return true;
+        } else {
+            container.setChanged(); // original logic always marks source inv as changed even if no move happens.
+            movedItem.setCount(movedItemCount);
+
+            if (!worldData.skipPullModeEventFire) {
+                movedItem = callPullMoveEvent(hopper, container, movedItem);
+                if (movedItem == null) { // cancelled
+                    origItemStack.setCount(originalItemCount);
+                    // Drastically improve performance by returning true.
+                    // No plugin could have relied on the behavior of false as the other call
+                    // site for IMIE did not exhibit the same behavior
+                    return true;
+                }
+            }
+
+            final ItemStack remainingItem = addItem(container, hopper, movedItem, null);
+            final int remainingItemCount = remainingItem.getCount();
+            if (remainingItemCount != movedItemCount) {
+                origItemStack = origItemStack.copy(true);
+                origItemStack.setCount(originalItemCount);
+                if (!origItemStack.isEmpty()) {
+                    origItemStack.setCount(originalItemCount - movedItemCount + remainingItemCount);
+                }
+
+                IGNORE_TILE_UPDATES.set(true);
+                container.setItem(i, origItemStack);
+                IGNORE_TILE_UPDATES.set(false);
+                container.setChanged();
+                return true;
+            }
+            origItemStack.setCount(originalItemCount);
         }
-        origItemStack.setCount(originalItemCount);
+        // Leaves end - fix vanilla hopper
 
         if (level.paperConfig().hopper.cooldownWhenFull) {
             applyCooldown(hopper);