Fill in values for the item tags

src/main/java/com/minelittlepony/unicopia/UTags.java

@@ -6,8 +6,8 @@ import net.minecraft.tag.Tag;
 import net.minecraft.util.Identifier;
 
 public interface UTags {
-    // TODO: includes unicopia:alicorn_amulet
     Tag<Item> CURSED_ARTEFACTS = TagRegistry.item(new Identifier(UnicopiaCore.MODID, "cursed_artefacts"));
+    Tag<Item> HAMMERPACE_IMMUNE = TagRegistry.item(new Identifier(UnicopiaCore.MODID, "hammerspace_immune"));
 
-    static void bootstrap() {}
+    static void bootstrap() { }
 }

src/main/java/com/minelittlepony/unicopia/container/BagOfHoldingInventory.java

@@ -5,8 +5,8 @@ import java.util.List;
 import java.util.Optional;
 import java.util.function.BiFunction;
 
+import com.minelittlepony.unicopia.UTags;
 import com.minelittlepony.unicopia.advancement.BOHDeathCriterion;
-import com.minelittlepony.unicopia.magic.MagicalItem;
 import com.minelittlepony.unicopia.util.HeavyInventoryUtils;
 import com.minelittlepony.unicopia.util.NbtSerialisable;
 import com.minelittlepony.unicopia.util.MagicalDamageSource;
@@ -15,13 +15,11 @@ import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.Blocks;
 import net.minecraft.block.EnderChestBlock;
-import net.minecraft.block.ShulkerBoxBlock;
 import net.minecraft.block.entity.BlockEntity;
 import net.minecraft.entity.ItemEntity;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.inventory.BasicInventory;
 import net.minecraft.inventory.Inventory;
-import net.minecraft.item.BlockItem;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.ListTag;
@@ -156,10 +154,8 @@ public class BagOfHoldingInventory extends BasicInventory implements NbtSerialis
         CompoundTag compound = stack.getSubTag("inventory");
 
         return isIllegalBlock(Block.getBlockFromItem(stack.getItem()))
-                // TODO: tag for items that are invalid for the inventory of holding
+                || stack.getItem().isIn(UTags.HAMMERPACE_IMMUNE)
-                || stack.getItem() instanceof BlockItem && (((BlockItem)stack.getItem()).getBlock() instanceof ShulkerBoxBlock)
+                || (compound != null && compound.containsKey("invalid"));
-                || (compound != null && compound.containsKey("invalid"))
-                || (stack.getItem() instanceof MagicalItem && ((MagicalItem) stack.getItem()).hasInnerSpace());
     }
 
     protected boolean isIllegalBlock(Block block) {

src/main/java/com/minelittlepony/unicopia/item/BagOfHoldingItem.java

@@ -122,11 +122,6 @@ public class BagOfHoldingItem extends Item implements MagicalItem {
         return Affinity.NEUTRAL;
     }
 
-    @Override
-    public boolean hasInnerSpace() {
-        return true;
-    }
-
     public static class ContainerProvider implements NameableContainerProvider {
 
         private Text customname = null;

src/main/java/com/minelittlepony/unicopia/magic/MagicalItem.java

@@ -3,14 +3,6 @@ package com.minelittlepony.unicopia.magic;
 import net.minecraft.item.ItemStack;
 
 public interface MagicalItem extends Affine {
-    /**
-     * If true this item serves as host to its own inner dimensional space.
-     * Bag of Holding will explode if you try to store items of this kind inside of it.
-     */
-    default boolean hasInnerSpace() {
-        return false;
-    }
-
     /**
      * Gets the affinity of this magical artifact. Either good, bad, or unaligned.
      * What this returns may have effects on the behaviour of certain spells and effects.

src/main/resources/data/unicopia/tags/items/cursed_artefacts.json

@@ -0,0 +1,6 @@
+{
+  "replace": false,
+  "values": [
+    "unicopia:alicorn_amulet"
+  ]
+}

src/main/resources/data/unicopia/tags/items/hammerspace_immune.json

@@ -0,0 +1,23 @@
+{
+  "replace": false,
+  "values": [
+    "minecraft:shulker_box",
+    "minecraft:white_shulker_box",
+    "minecraft:orange_shulker_box",
+    "minecraft:magenta_shulker_box",
+    "minecraft:light_blue_shulker_box",
+    "minecraft:yellow_shulker_box",
+    "minecraft:lime_shulker_box",
+    "minecraft:pink_shulker_box",
+    "minecraft:gray_shulker_box",
+    "minecraft:light_gray_shulker_box",
+    "minecraft:cyan_shulker_box",
+    "minecraft:purple_shulker_box",
+    "minecraft:blue_shulker_box",
+    "minecraft:brown_shulker_box",
+    "minecraft:green_shulker_box",
+    "minecraft:red_shulker_box",
+    "minecraft:black_shulker_box",
+    "unicopia:bag_of_holding"
+  ]
+}