From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Fri, 17 Jun 2016 20:50:11 -0400
Subject: [PATCH] Fix Old Sign Conversion

1) Sign loading code was trying to parse the JSON before the check for oldSign.
   That code could then skip the old sign converting code if it triggers a JSON parse exception.
2) New Mojang Schematic system has Tile Entities in the new converted format, but missing the Bukkit.isConverted flag
   This causes Igloos and such to render broken signs. We fix this by ignoring sign conversion for Defined Structures

diff --git a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
index 14ac3c7b47525b7fd0345d817c9020b5a59d2ebc..1e416b23a38458f16add472cea09b0ac5ac91869 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
@@ -33,6 +33,7 @@ public abstract class BlockEntity implements io.papermc.paper.util.KeyedObject {
     public CraftPersistentDataContainer persistentDataContainer;
     // CraftBukkit end
     private static final Logger LOGGER = LogManager.getLogger();
+    public boolean isLoadingStructure = false; // Paper
     private final BlockEntityType<?> type;
     @Nullable
     protected Level level;
diff --git a/src/main/java/net/minecraft/world/level/block/entity/SignBlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/SignBlockEntity.java
index e390cfea5bed64284a97c88a717503f07f073a30..3a2e2adeefe73981b443216724270023408c1feb 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/SignBlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/SignBlockEntity.java
@@ -93,7 +93,7 @@ public class SignBlockEntity extends BlockEntity implements CommandSource { // C
                 s = "\"\"";
             }
 
-            if (oldSign) {
+            if (oldSign && !this.isLoadingStructure) { // Paper - saved structures will be in the new format, but will not have isConverted
                 this.messages[i] = org.bukkit.craftbukkit.util.CraftChatMessage.fromString(s)[0];
                 continue;
             }
diff --git a/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java b/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java
index 2aaa7bb03ab200a5df1ae1aab7b81ac8ce85d64c..ef8dd3fa4f7ac8f85ae508999264850659bf9606 100644
--- a/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java
+++ b/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java
@@ -284,7 +284,9 @@ public class StructureTemplate {
                                         definedstructure_blockinfo.nbt.putLong("LootTableSeed", random.nextLong());
                                     }
 
+                                    tileentity.isLoadingStructure = true; // Paper
                                     tileentity.load(definedstructure_blockinfo.nbt);
+                                    tileentity.isLoadingStructure = false; // Paper
                                 }
                             }
 
