PaperMC/nms-patches/ItemArmor.patch

--- a/net/minecraft/server/ItemArmor.java
+++ b/net/minecraft/server/ItemArmor.java
@@ -4,6 +4,11 @@
 import java.util.List;
 import java.util.UUID;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.block.BlockDispenseArmorEvent;
+// CraftBukkit end
+
 public class ItemArmor extends Item {
 
     private static final UUID[] k = new UUID[] { UUID.fromString("845DB27C-C624-495F-8C9F-6020A9A58B6B"), UUID.fromString("D8499B04-0E66-4726-AB29-64469D734E0D"), UUID.fromString("9F3D476D-C118-4544-8365-64846904B48E"), UUID.fromString("2AD3F246-FEE1-4E67-B886-69FD380BB150")};
@@ -29,6 +34,32 @@
             EntityLiving entityliving = (EntityLiving) list.get(0);
             EnumItemSlot enumitemslot = EntityInsentient.e(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);
+
+            BlockDispenseArmorEvent event = new BlockDispenseArmorEvent(block, craftItem.clone(), (org.bukkit.craftbukkit.entity.CraftLivingEntity) entityliving.bukkitEntity);
+            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.a) {
+                    idispensebehavior.dispense(isourceblock, eventStack);
+                    return itemstack;
+                }
+            }
+            // CraftBukkit end
 
             entityliving.setSlot(enumitemslot, itemstack1);
             if (entityliving instanceof EntityInsentient) {