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 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 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
@@ -0,0 +0,0 @@ public abstract class BlockEntity implements net.minecraft.server.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 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 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
@@ -0,0 +0,0 @@ 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 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 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
@@ -0,0 +0,0 @@ public class StructureTemplate {
                                         definedstructure_blockinfo.nbt.putLong("LootTableSeed", random.nextLong());
                                     }
 
+                                    tileentity.isLoadingStructure = true; // Paper
                                     tileentity.load(definedstructure_blockinfo.nbt);
+                                    tileentity.isLoadingStructure = false; // Paper
                                 }
                             }
 
