Fix #694: for some values of "fix".

This might actually be problematic but I can't think of any other way to
do this. Funnily enough this was actually an issue (always) in 1.21, I
guess?

Author: noobanidus

common/src/main/java/noobanidus/mods/lootr/common/block/entity/BlockEntityTicker.java

@@ -80,7 +80,7 @@ private void addEntity(Level level, BlockEntity entity, ChunkPos chunkPos) {
   }
 
   private static boolean isValidEntity(BlockEntity entity) {
-    if (LootrAPI.resolveBlockEntity(entity) instanceof ILootrBlockEntity) {
+    if (entity instanceof ILootrBlockEntity || LootrAPI.resolveBlockEntity(entity) instanceof ILootrBlockEntity) {
       return false;
     }
     ILootrDataAdapter<BlockEntity> adapter = LootrAPI.getAdapter(entity);

common/src/main/java/noobanidus/mods/lootr/common/mixins/MixinRandomizableContainer.java

@@ -0,0 +1,23 @@
+package noobanidus.mods.lootr.common.mixins;
+
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+import net.minecraft.world.RandomizableContainer;
+import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import noobanidus.mods.lootr.common.block.entity.BlockEntityTicker;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+
+@Mixin(RandomizableContainer.class)
+public interface MixinRandomizableContainer {
+  @WrapOperation(method = "tryLoadLootTable", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/RandomizableContainer;setLootTableSeed(J)V"))
+  default void lootr$tryLoadLootTable(RandomizableContainer instance, long l, Operation<Void> original) {
+    original.call(instance, l);
+    if (instance instanceof BlockEntity blockEntity && blockEntity.getLevel() != null) {
+      BlockEntityTicker.addEntity(blockEntity, blockEntity.getLevel(), new ChunkPos(blockEntity.getBlockPos()));
+    }
+  }
+
+  // TODO: Maybe a hook in `unpackLootTable`? That would need to ensure that the block is convertible as we'd want to cancel unpacking in the event that the block is converting, but otherwise continue as normal.
+}

common/src/main/resources/lootr-common.mixins.json

@@ -14,6 +14,7 @@
     "MixinLootTable",
     "MixinPoiType",
     "MixinPoiTypes",
+    "MixinRandomizableContainer",
     "MixinServerGamePacketListenerImpl",
     "MixinStructureTemplate"
   ],