Paper/patches/server/0936-Fix-possible-StackOverflowError-and-NPE-for-some-dis.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sat, 29 Oct 2022 17:02:42 -0700
Subject: [PATCH] Fix possible StackOverflowError and NPE for some dispenses

For saddles, carpets, horse armor, and chests for horse-likes
a BlockDispenseEvent handler that always mutated the item without
changing the type would result in a SO error because when it went
to find the replacement dispense behavior (since the item "changed")
it didn't properly handle if the replacement was the same instance
of dispense behavior.

Additionally equippable mob heads, wither skulls, and carved pumpkins
are subject to the same possible error.

Furthermore since 1.21.2, the DISPENSER_REGISTRY map doesn't have a default
return value anymore and some dispense behaviors like equippable and
regular items will not have a defined behavior in that map and might throw
a NPE in that case.

diff --git a/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java
index 36180e80dbd681e68c60e097015dad890a48b574..dff30954e4c588ee4cc79d3f6dab6fb456934d65 100644
--- a/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java
@@ -67,7 +67,7 @@ public class BoatDispenseItemBehavior extends DefaultDispenseItemBehavior {
             stack.grow(1);
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-            DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+            DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
             if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                 idispensebehavior.dispense(pointer, eventStack);
                 return stack;
diff --git a/src/main/java/net/minecraft/core/dispenser/DefaultDispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/DefaultDispenseItemBehavior.java
index 39c96f5db6e90a470404c6387fa0c1d5531822e5..8aae1d113e84dfad9f2b6f0bcd203ca6c68bc5ce 100644
--- a/src/main/java/net/minecraft/core/dispenser/DefaultDispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/DefaultDispenseItemBehavior.java
@@ -101,7 +101,7 @@ public class DefaultDispenseItemBehavior implements DispenseItemBehavior {
         if (!dropper && !event.getItem().getType().equals(craftItem.getType())) {
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-            DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+            DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(sourceblock, eventStack); // Paper - Fix NPE with equippable and items without behavior
             if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior.getClass() != DefaultDispenseItemBehavior.class) {
                 idispensebehavior.dispense(sourceblock, eventStack);
             } else {
diff --git a/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
index 18304349c9ab24657c4152aff800dba969174665..681c38f4457fc10806c10518b16159580c0f2619 100644
--- a/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
@@ -124,7 +124,7 @@ public interface DispenseItemBehavior {
                     stack.grow(1);
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -178,7 +178,7 @@ public interface DispenseItemBehavior {
                     stack.grow(1);
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -231,8 +231,8 @@ public interface DispenseItemBehavior {
                         stack.grow(1);
                         // Chain to handler for new item
                         ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                        DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
-                        if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != EquipmentDispenseItemBehavior.INSTANCE) {
+                        DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
+                        if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) { // Paper - fix possible StackOverflowError
                             idispensebehavior.dispense(pointer, eventStack);
                             return stack;
                         }
@@ -282,8 +282,8 @@ public interface DispenseItemBehavior {
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
-                    if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != EquipmentDispenseItemBehavior.INSTANCE) {
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
+                    if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) { // Paper - fix possible StackOverflowError
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
                     }
@@ -352,7 +352,7 @@ public interface DispenseItemBehavior {
                     if (!event.getItem().equals(craftItem)) {
                         // Chain to handler for new item
                         ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                        DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                        DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                         if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                             idispensebehavior.dispense(pointer, eventStack);
                             return stack;
@@ -414,7 +414,7 @@ public interface DispenseItemBehavior {
                         if (!event.getItem().equals(craftItem)) {
                             // Chain to handler for new item
                             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                            DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                            DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                             if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                                 idispensebehavior.dispense(pointer, eventStack);
                                 return stack;
@@ -452,7 +452,7 @@ public interface DispenseItemBehavior {
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -514,7 +514,7 @@ public interface DispenseItemBehavior {
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -585,7 +585,7 @@ public interface DispenseItemBehavior {
                     stack.grow(1);
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -625,7 +625,7 @@ public interface DispenseItemBehavior {
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -645,7 +645,7 @@ public interface DispenseItemBehavior {
                     stack.shrink(1);
                     this.setSuccess(true);
                 } else {
-                    this.setSuccess(EquipmentDispenseItemBehavior.dispenseEquipment(pointer, stack));
+                    this.setSuccess(EquipmentDispenseItemBehavior.dispenseEquipment(pointer, stack, this)); // Paper - fix possible StackOverflowError
                 }
 
                 return stack;
@@ -674,7 +674,7 @@ public interface DispenseItemBehavior {
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -691,7 +691,7 @@ public interface DispenseItemBehavior {
                     stack.shrink(1);
                     this.setSuccess(true);
                 } else {
-                    this.setSuccess(EquipmentDispenseItemBehavior.dispenseEquipment(pointer, stack));
+                    this.setSuccess(EquipmentDispenseItemBehavior.dispenseEquipment(pointer, stack, this)); // Paper - fix possible StackOverflowError
                 }
 
                 return stack;
@@ -736,7 +736,7 @@ public interface DispenseItemBehavior {
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                    DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                    DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                     if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
@@ -818,8 +818,8 @@ public interface DispenseItemBehavior {
                     if (!event.getItem().equals(craftItem)) {
                         // Chain to handler for new item
                         ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                        DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
-                        if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != EquipmentDispenseItemBehavior.INSTANCE) {
+                        DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
+                        if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) { // Paper - fix possible StackOverflowError
                             idispensebehavior.dispense(pointer, eventStack);
                             return stack;
                         }
diff --git a/src/main/java/net/minecraft/core/dispenser/EquipmentDispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/EquipmentDispenseItemBehavior.java
index a03cc350973fda213251cad273a2db86f438904b..a43ea83dbbd5946096cdde31af766674bda6c3be 100644
--- a/src/main/java/net/minecraft/core/dispenser/EquipmentDispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/EquipmentDispenseItemBehavior.java
@@ -23,10 +23,15 @@ public class EquipmentDispenseItemBehavior extends DefaultDispenseItemBehavior {
 
     @Override
     protected ItemStack execute(BlockSource pointer, ItemStack stack) {
-        return EquipmentDispenseItemBehavior.dispenseEquipment(pointer, stack) ? stack : super.execute(pointer, stack);
+        return EquipmentDispenseItemBehavior.dispenseEquipment(pointer, stack, this) ? stack : super.execute(pointer, stack); // Paper - fix possible StackOverflowError
     }
 
-    public static boolean dispenseEquipment(BlockSource pointer, ItemStack stack) {
+    @Deprecated @io.papermc.paper.annotation.DoNotUse // Paper
+    public static boolean dispenseEquipment(BlockSource pointer, ItemStack armor) {
+        // Paper start
+        return dispenseEquipment(pointer, armor, null);
+    }
+    public static boolean dispenseEquipment(BlockSource pointer, ItemStack stack, @javax.annotation.Nullable DispenseItemBehavior currentBehavior) {
         BlockPos blockposition = pointer.pos().relative((Direction) pointer.state().getValue(DispenserBlock.FACING));
         List<LivingEntity> list = pointer.level().getEntitiesOfClass(LivingEntity.class, new AABB(blockposition), (entityliving) -> {
             return entityliving.canEquipWithDispenser(stack);
@@ -58,8 +63,8 @@ public class EquipmentDispenseItemBehavior extends DefaultDispenseItemBehavior {
                 stack.grow(1);
                 // Chain to handler for new item
                 ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
-                if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != EquipmentDispenseItemBehavior.INSTANCE) {
+                DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
+                if (idispensebehavior != DispenseItemBehavior.NOOP && (currentBehavior == null || idispensebehavior != currentBehavior)) { // Paper - fix possible StackOverflowError
                     idispensebehavior.dispense(pointer, eventStack);
                     return true;
                 }
diff --git a/src/main/java/net/minecraft/core/dispenser/MinecartDispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/MinecartDispenseItemBehavior.java
index f2e19218cf0d3b44a617c7d74f782c3e15e3f07f..aae9ec8f3bd39685b37251bef3f9ac846d65c192 100644
--- a/src/main/java/net/minecraft/core/dispenser/MinecartDispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/MinecartDispenseItemBehavior.java
@@ -87,7 +87,7 @@ public class MinecartDispenseItemBehavior extends DefaultDispenseItemBehavior {
             stack.grow(1);
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-            DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+            DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
             if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                 idispensebehavior.dispense(pointer, eventStack);
                 return stack;
diff --git a/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java b/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java
index 6b343afe473624082e13bee935638eb140271184..baf3feee740c816cf9f0470a8e56a36d02c9a29c 100644
--- a/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java
@@ -56,7 +56,7 @@ public class ProjectileDispenseBehavior extends DefaultDispenseItemBehavior {
             stack.grow(1);
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-            DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+            DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
             if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                 idispensebehavior.dispense(pointer, eventStack);
                 return stack;
diff --git a/src/main/java/net/minecraft/core/dispenser/ShearsDispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/ShearsDispenseItemBehavior.java
index f5206e4176f58cff4cfe70c94f014afebc98c589..afad4fa3ca1a3186c4569ea073f776dac16817e1 100644
--- a/src/main/java/net/minecraft/core/dispenser/ShearsDispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/ShearsDispenseItemBehavior.java
@@ -52,7 +52,7 @@ public class ShearsDispenseItemBehavior extends OptionalDispenseItemBehavior {
         if (!event.getItem().equals(craftItem)) {
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-            DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+            DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
             if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                 idispensebehavior.dispense(pointer, eventStack);
                 return stack;
diff --git a/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java b/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
index f84987c36a16df19286d6f1badfb1ffb9cc7e770..cc85e96035f7cb2e6493b1cc4748031171d7dbee 100644
--- a/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
@@ -48,7 +48,7 @@ public class ShulkerBoxDispenseBehavior extends OptionalDispenseItemBehavior {
             if (!event.getItem().equals(craftItem)) {
                 // Chain to handler for new item
                 ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-                DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+                DispenseItemBehavior idispensebehavior = DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
                 if (idispensebehavior != DispenseItemBehavior.NOOP && idispensebehavior != this) {
                     idispensebehavior.dispense(pointer, eventStack);
                     return stack;
diff --git a/src/main/java/net/minecraft/world/level/block/DispenserBlock.java b/src/main/java/net/minecraft/world/level/block/DispenserBlock.java
index a02f24448b002824b068278fa427003008c0d0f1..500c56c4ef0878434582a50d6dba2ccca9773275 100644
--- a/src/main/java/net/minecraft/world/level/block/DispenserBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/DispenserBlock.java
@@ -116,6 +116,12 @@ public class DispenserBlock extends BaseEntityBlock {
         }
     }
 
+    // Paper start - Fix NPE with equippable and items without behavior
+    public static DispenseItemBehavior getDispenseBehavior(BlockSource pointer, ItemStack stack) {
+        return ((DispenserBlock) pointer.state().getBlock()).getDispenseMethod(pointer.level(), stack);
+    }
+    // Paper end - Fix NPE with equippable and items without behavior
+
     protected DispenseItemBehavior getDispenseMethod(Level world, ItemStack stack) {
         if (!stack.isItemEnabled(world.enabledFeatures())) {
             return DispenserBlock.DEFAULT_BEHAVIOR;
diff --git a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
index 937ed4e77739ff02ff1e4405047f15eac40906fe..41a0650bfd6e72b83364441dd76df3d561d3163e 100644
--- a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
+++ b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
@@ -2232,7 +2232,7 @@ public class CraftEventFactory {
         if (!event.getItem().equals(craftItem)) {
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
-            net.minecraft.core.dispenser.DispenseItemBehavior itemBehavior = net.minecraft.world.level.block.DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
+            net.minecraft.core.dispenser.DispenseItemBehavior itemBehavior = net.minecraft.world.level.block.DispenserBlock.getDispenseBehavior(pointer, eventStack); // Paper - Fix NPE with equippable and items without behavior
             if (itemBehavior != net.minecraft.core.dispenser.DispenseItemBehavior.NOOP && itemBehavior != instance) {
                 itemBehavior.dispense(pointer, eventStack);
                 return itemStack;