From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Legitimoose <legitimoose@gmail.com>
Date: Wed, 28 Sep 2022 22:45:49 -0700
Subject: [PATCH] fix Jigsaw block kicking user


diff --git a/src/main/java/net/minecraft/world/level/block/entity/JigsawBlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/JigsawBlockEntity.java
index fee4aef1bdae1b1ca57ff0b6c3fd2ec31439c37b..b56e4be3228489b5b910c23bde1717d5d3e2ad9a 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/JigsawBlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/JigsawBlockEntity.java
@@ -108,7 +108,12 @@ public class JigsawBlockEntity extends BlockEntity {
     public void generate(ServerLevel world, int maxDepth, boolean keepJigsaws) {
         BlockPos blockPos = this.getBlockPos().relative(this.getBlockState().getValue(JigsawBlock.ORIENTATION).front());
         Registry<StructureTemplatePool> registry = world.registryAccess().registryOrThrow(Registry.TEMPLATE_POOL_REGISTRY);
-        Holder<StructureTemplatePool> holder = registry.getHolderOrThrow(this.pool);
+        // Paper start - Replace getHolderOrThrow with a null check
+        Holder<StructureTemplatePool> holder = registry.getHolder(this.pool).orElse(null);
+        if (holder == null) {
+            return;
+        }
+        // Paper end
         JigsawPlacement.generateJigsaw(world, holder, this.target, maxDepth, blockPos, keepJigsaws);
     }
 
diff --git a/src/main/java/net/minecraft/world/level/levelgen/structure/pools/StructureTemplatePool.java b/src/main/java/net/minecraft/world/level/levelgen/structure/pools/StructureTemplatePool.java
index de7435f6596e200c8511224a0479c2ad499b2a97..bcf9eb1096b09748bcabba05bc9ffac494d3c611 100644
--- a/src/main/java/net/minecraft/world/level/levelgen/structure/pools/StructureTemplatePool.java
+++ b/src/main/java/net/minecraft/world/level/levelgen/structure/pools/StructureTemplatePool.java
@@ -89,7 +89,13 @@ public class StructureTemplatePool {
     }
 
     public StructurePoolElement getRandomTemplate(RandomSource random) {
+        //Paper start - Prevent random.nextInt throwing an IllegalArgumentException
+        if (this.templates.size() == 0) {
+            return EmptyPoolElement.INSTANCE;
+        } else {
         return this.templates.get(random.nextInt(this.templates.size()));
+        }
+        // Paper end
     }
 
     public List<StructurePoolElement> getShuffledTemplates(RandomSource random) {