PaperMC/paper-server/nms-patches/net/minecraft/world/item/ItemMinecart.patch

--- a/net/minecraft/world/item/ItemMinecart.java
+++ b/net/minecraft/world/item/ItemMinecart.java
@@ -18,6 +18,12 @@
 import net.minecraft.world.level.gameevent.GameEvent;
 import net.minecraft.world.phys.Vec3D;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.block.CraftBlock;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.block.BlockDispenseEvent;
+// CraftBukkit end
+
 public class ItemMinecart extends Item {
 
     private static final IDispenseBehavior DISPENSE_ITEM_BEHAVIOR = new DispenseBehaviorItem() {
@@ -57,14 +63,43 @@
                 }
             }
 
-            EntityMinecartAbstract entityminecartabstract = EntityMinecartAbstract.createMinecart(worldserver, d0, d1 + d3, d2, ((ItemMinecart) itemstack.getItem()).type);
+            // CraftBukkit start
+            // EntityMinecartAbstract entityminecartabstract = EntityMinecartAbstract.createMinecart(worldserver, d0, d1 + d3, d2, ((ItemMinecart) itemstack.getItem()).type);
+            ItemStack itemstack1 = itemstack.split(1);
+            org.bukkit.block.Block block2 = CraftBlock.at(worldserver, sourceblock.pos());
+            CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
+
+            BlockDispenseEvent event = new BlockDispenseEvent(block2, craftItem.clone(), new org.bukkit.util.Vector(d0, d1 + d3, d2));
+            if (!BlockDispenser.eventFired) {
+                worldserver.getCraftServer().getPluginManager().callEvent(event);
+            }
+
+            if (event.isCancelled()) {
+                itemstack.grow(1);
+                return itemstack;
+            }
+
+            if (!event.getItem().equals(craftItem)) {
+                itemstack.grow(1);
+                // Chain to handler for new item
+                ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
+                IDispenseBehavior idispensebehavior = (IDispenseBehavior) BlockDispenser.DISPENSER_REGISTRY.get(eventStack.getItem());
+                if (idispensebehavior != IDispenseBehavior.NOOP && idispensebehavior != this) {
+                    idispensebehavior.dispense(sourceblock, eventStack);
+                    return itemstack;
+                }
+            }
+
+            itemstack1 = CraftItemStack.asNMSCopy(event.getItem());
+            EntityMinecartAbstract entityminecartabstract = EntityMinecartAbstract.createMinecart(worldserver, event.getVelocity().getX(), event.getVelocity().getY(), event.getVelocity().getZ(), ((ItemMinecart) itemstack1.getItem()).type);
 
             if (itemstack.hasCustomHoverName()) {
                 entityminecartabstract.setCustomName(itemstack.getHoverName());
             }
 
-            worldserver.addFreshEntity(entityminecartabstract);
-            itemstack.shrink(1);
+            if (!worldserver.addFreshEntity(entityminecartabstract)) itemstack.grow(1);
+            // itemstack.shrink(1); // CraftBukkit - handled during event processing
+            // CraftBukkit end
             return itemstack;
         }
 
@@ -106,7 +141,12 @@
                     entityminecartabstract.setCustomName(itemstack.getHoverName());
                 }
 
-                world.addFreshEntity(entityminecartabstract);
+                // CraftBukkit start
+                if (org.bukkit.craftbukkit.event.CraftEventFactory.callEntityPlaceEvent(itemactioncontext, entityminecartabstract).isCancelled()) {
+                    return EnumInteractionResult.FAIL;
+                }
+                // CraftBukkit end
+                if (!world.addFreshEntity(entityminecartabstract)) return EnumInteractionResult.PASS; // CraftBukkit
                 world.gameEvent(GameEvent.ENTITY_PLACE, blockposition, GameEvent.a.of(itemactioncontext.getPlayer(), world.getBlockState(blockposition.below())));
             }