PaperMC/nms-patches/ItemArmor.patch

--- a/net/minecraft/server/ItemArmor.java
+++ b/net/minecraft/server/ItemArmor.java
@@ -5,6 +5,11 @@
 import java.util.List;
 import java.util.UUID;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.block.BlockDispenseEvent;
+// CraftBukkit end
+
 public class ItemArmor extends Item {
 
     private static final int[] n = new int[] { 13, 15, 16, 11};
@@ -33,6 +38,32 @@
             EntityLiving entityliving = (EntityLiving) list.get(0);
             EnumItemSlot enumitemslot = EntityInsentient.d(itemstack);
             ItemStack itemstack1 = itemstack.cloneAndSubtract(1);
+            // CraftBukkit start
+            World world = isourceblock.getWorld();
+            org.bukkit.block.Block block = world.getWorld().getBlockAt(isourceblock.getBlockPosition().getX(), isourceblock.getBlockPosition().getY(), isourceblock.getBlockPosition().getZ());
+            CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
+
+            BlockDispenseEvent event = new BlockDispenseEvent(block, craftItem.clone(), new org.bukkit.util.Vector(0, 0, 0));
+            if (!BlockDispenser.eventFired) {
+                world.getServer().getPluginManager().callEvent(event);
+            }
+
+            if (event.isCancelled()) {
+                itemstack.add(1);
+                return itemstack;
+            }
+
+            if (!event.getItem().equals(craftItem)) {
+                itemstack.add(1);
+                // Chain to handler for new item
+                ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
+                IDispenseBehavior idispensebehavior = (IDispenseBehavior) BlockDispenser.REGISTRY.get(eventStack.getItem());
+                if (idispensebehavior != IDispenseBehavior.NONE && idispensebehavior != ItemArmor.b) {
+                    idispensebehavior.a(isourceblock, eventStack);
+                    return itemstack;
+                }
+            }
+            // CraftBukkit end
 
             entityliving.setSlot(enumitemslot, itemstack1);
             if (entityliving instanceof EntityInsentient) {