Only assign blockstate data if super ctor did not (#10841)

The CraftBlockStateMeta constructor CraftBlockStateMeta(Map) invokes its
parent constructor, which itself invokes deserializeInternal, which is
implemented on CraftBlockStateMeta to read the components and block
entity tag from the passed map.

Field initialization happens after the call to the super constructor,
meaning the current code overwrites the parsed internal data with the
EMPTY defaults.

This is prevented by moving the initialization into its own code block
that can null check the fields prior to defaulting their value to EMPTY.

1 files changed, 24 insertions, 17 deletions

diff --git a/patches/server/1037-General-ItemMeta-fixes.patch b/patches/server/1037-General-ItemMeta-fixes.patch
index 052b5dc3ba..3e6d33f33e 100644
--- a/patches/server/1037-General-ItemMeta-fixes.patch
+++ b/patches/server/1037-General-ItemMeta-fixes.patch
@@ -35,7 +35,7 @@ index 8e2b3dd109dca3089cbce82cd3788874613a3230..893efb2c4a07c33d41e934279dd914a9
      // CraftBukkit end
  
 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 65170cbb50d8d5030fc5e33b6389c554aec6ae31..6349f2e0a5ba30d250f5ffe43771f325c0999a76 100644
+index 139cc0123921bf981d10334d9bd7378d19ec5f3b..c0563260277f9f4bd9ff08993b2efb4bca9a0c60 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
 @@ -140,6 +140,11 @@ public abstract class BlockEntity {
@@ -155,10 +155,10 @@ index 1ac3bec02fce28d5ce698305a7482a9eccbb1867..b494568f833dc21d4e2447ac3e5c5002
  
          for (Pattern p : this.patterns) {
 diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBlockState.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBlockState.java
-index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553afedecdf7 100644
+index 12911233c01d0ac1af9adbd157d56d28361fc76f..3faef745d9b5d3baaea8c20c6f8e06f7bb529665 100644
 --- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBlockState.java
 +++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBlockState.java
-@@ -142,9 +142,17 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -142,9 +142,24 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
  
      @ItemMetaKey.Specific(ItemMetaKey.Specific.To.NBT)
      static final ItemMetaKeyType<CustomData> BLOCK_ENTITY_TAG = new ItemMetaKeyType<>(DataComponents.BLOCK_ENTITY_DATA, "BlockEntityTag");
@@ -168,8 +168,15 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
      final Material material;
 -    private CraftBlockEntityState<?> blockEntityTag;
 +    // Paper start - store data separately
-+    DataComponentMap components = DataComponentMap.EMPTY;
-+    CustomData blockEntityTag = CustomData.EMPTY;
++    DataComponentMap components;
++    CustomData blockEntityTag;
++    {
++        // this is because the fields are possibly assigned in the super constructor (via deserializeInternal)
++        // and a direct field initialization happens **after** the super constructor. So we only want to
++        // set them to empty if they weren't assigned by the super constructor (via deserializeInternal)
++        this.components = this.components != null ? this.components : DataComponentMap.EMPTY;
++        this.blockEntityTag = this.blockEntityTag != null ? this.blockEntityTag : CustomData.EMPTY;
++    }
 +    private Material materialForBlockEntityType() {
 +        return (this.material != Material.SHIELD) ? this.material : CraftMetaBlockState.shieldToBannerHack();
 +    }
@@ -177,7 +184,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
      private CompoundTag internalTag;
  
      CraftMetaBlockState(CraftMetaItem meta, Material material) {
-@@ -153,41 +161,61 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -153,41 +168,61 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
  
          if (!(meta instanceof CraftMetaBlockState)
                  || ((CraftMetaBlockState) meta).material != material) {
@@ -252,7 +259,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
          }
      }
  
-@@ -200,7 +228,10 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -200,7 +235,10 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
          } else {
              this.material = Material.AIR;
          }
@@ -264,7 +271,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
          this.internalTag = null;
      }
  
-@@ -208,13 +239,21 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -208,13 +246,21 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
      void applyToItem(CraftMetaItem.Applicator tag) {
          super.applyToItem(tag);
  
@@ -291,7 +298,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
      }
  
      @Override
-@@ -223,14 +262,29 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -223,14 +269,29 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
  
          if (tag.contains(CraftMetaBlockState.BLOCK_ENTITY_TAG.NBT, CraftMagicNumbers.NBT.TAG_COMPOUND)) {
              this.internalTag = tag.getCompound(CraftMetaBlockState.BLOCK_ENTITY_TAG.NBT);
@@ -300,10 +307,10 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
 +        // Paper start - new serialization format
 +        if (tag.contains(CraftMetaBlockState.BLOCK_ENTITY_TAG_CUSTOM_DATA.NBT, CraftMagicNumbers.NBT.TAG_COMPOUND)) {
 +            this.blockEntityTag = CustomData.of(tag.getCompound(CraftMetaBlockState.BLOCK_ENTITY_TAG_CUSTOM_DATA.NBT));
-+        }
+         }
 +        if (tag.contains(CraftMetaBlockState.BLOCK_ENTITY_COMPONENTS.NBT, CraftMagicNumbers.NBT.TAG_COMPOUND)) {
 +            this.components = DataComponentMap.CODEC.parse(org.bukkit.craftbukkit.CraftRegistry.getMinecraftRegistry().createSerializationContext(net.minecraft.nbt.NbtOps.INSTANCE), tag.getCompound(CraftMetaBlockState.BLOCK_ENTITY_COMPONENTS.NBT)).getOrThrow();
-         }
++        }
 +        // Paper end - new serialization format
      }
  
@@ -314,16 +321,16 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
 +        // Paper start - new serialization format
 +        if (!this.blockEntityTag.isEmpty()) {
 +            internalTags.put(CraftMetaBlockState.BLOCK_ENTITY_TAG_CUSTOM_DATA.NBT, this.blockEntityTag.getUnsafe()); // unsafe because it's serialized right away
-         }
++        }
 +        if (!this.components.isEmpty()) {
 +            final Tag componentsTag = DataComponentMap.CODEC.encodeStart(org.bukkit.craftbukkit.CraftRegistry.getMinecraftRegistry().createSerializationContext(net.minecraft.nbt.NbtOps.INSTANCE), this.components).getOrThrow();
 +            internalTags.put(CraftMetaBlockState.BLOCK_ENTITY_COMPONENTS.NBT, componentsTag);
-+        }
+         }
 +        // Paper end - new serialization format
      }
  
      @Override
-@@ -244,9 +298,10 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -244,9 +305,10 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
      int applyHash() {
          final int original;
          int hash = original = super.applyHash();
@@ -337,7 +344,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
          return original != hash ? CraftMetaBlockState.class.hashCode() ^ hash : hash;
      }
  
-@@ -258,19 +313,19 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -258,19 +320,19 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
          if (meta instanceof CraftMetaBlockState) {
              CraftMetaBlockState that = (CraftMetaBlockState) meta;
  
@@ -360,7 +367,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
      }
  
      @Override
-@@ -281,27 +336,53 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -281,27 +343,53 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
      @Override
      public CraftMetaBlockState clone() {
          CraftMetaBlockState meta = (CraftMetaBlockState) super.clone();
@@ -421,7 +428,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..f7b3ce6056b2d2c3b1c4d08ddce4553a
      }
  
      private static CraftBlockEntityState<?> getBlockState(Material material, CompoundTag blockEntityTag) {
-@@ -331,7 +412,23 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
+@@ -331,7 +419,23 @@ public class CraftMetaBlockState extends CraftMetaItem implements BlockStateMeta
          Class<?> blockStateType = CraftBlockStates.getBlockStateType(stateMaterial);
          Preconditions.checkArgument(blockStateType == blockState.getClass() && blockState instanceof CraftBlockEntityState, "Invalid blockState for " + this.material);