From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: chickeneer <emcchickeneer@gmail.com>
Date: Tue, 16 Feb 2021 21:37:51 -0600
Subject: [PATCH] Prevent grindstones from overstacking items


diff --git a/src/main/java/net/minecraft/server/ContainerGrindstone.java b/src/main/java/net/minecraft/server/ContainerGrindstone.java
index 39f809a37b58e008e7ef32c0759eeecbde26bc94..34e98efa04e545047e7b844c098c18b89442bd40 100644
--- a/src/main/java/net/minecraft/server/ContainerGrindstone.java
+++ b/src/main/java/net/minecraft/server/ContainerGrindstone.java
@@ -183,13 +183,13 @@ public class ContainerGrindstone extends Container {
                 i = Math.max(item.getMaxDurability() - l, 0);
                 itemstack2 = this.b(itemstack, itemstack1);
                 if (!itemstack2.e()) {
-                    if (!ItemStack.matches(itemstack, itemstack1)) {
+                    if (!ItemStack.matches(itemstack, itemstack1) || itemstack2.getMaxStackSize() == 1) { // Paper - add max stack size check
                         this.resultInventory.setItem(0, ItemStack.b);
                         this.c();
                         return;
                     }
 
-                    b0 = 2;
+                    b0 = 2; // Paper - the problem line for above change, causing over-stacking
                 }
             } else {
                 boolean flag3 = !itemstack.isEmpty();