Potentially better handling for #313.

Error messages when attempting to save including the block position and
dimension instead of just straight up crashing.

Properly check for a null `tileId` when loading and generate a new
`tileId` if it's null, instead of if it's just not loaded properly. I'm
not sure if it's ever possible for this to take place, but it's worth
it.

Finally, if a player opens a container which doesn't have a generated
`tileId` for whatever reason, inform them of that fact.

src/main/java/noobanidus/mods/lootr/block/entities/LootrBarrelBlockEntity.java

@@ -211,7 +211,8 @@ public void load(CompoundTag compound) {
     }
     if (compound.hasUUID("tileId")) {
       this.tileId = compound.getUUID("tileId");
-    } else if (this.tileId == null) {
+    }
+    if (this.tileId == null) {
       getTileId();
     }
     if (compound.contains("LootrOpeners")) {

src/main/java/noobanidus/mods/lootr/block/entities/LootrChestBlockEntity.java

@@ -117,7 +117,8 @@ public void load(CompoundTag compound) {
     }
     if (compound.hasUUID("tileId")) {
       this.tileId = compound.getUUID("tileId");
-    } else if (this.tileId == null) {
+    }
+    if (this.tileId == null) {
       getTileId();
     }
     if (compound.contains("LootrOpeners")) {

src/main/java/noobanidus/mods/lootr/block/entities/LootrShulkerBlockEntity.java

@@ -232,7 +232,8 @@ public void load(CompoundTag compound) {
     }
     if (compound.hasUUID("tileId")) {
       this.tileId = compound.getUUID("tileId");
-    } else if (this.tileId == null) {
+    }
+    if (this.tileId == null) {
       getTileId();
     }
     if (compound.contains("LootrOpeners")) {

src/main/java/noobanidus/mods/lootr/data/ChestData.java

@@ -78,6 +78,9 @@ public static String ID(UUID id) {
   }
 
   public static Supplier<ChestData> ref_id(ResourceKey<Level> dimension, BlockPos pos, UUID id, NonNullList<ItemStack> base) {
+    if (id == null) {
+      throw new IllegalArgumentException("Can't create ChestData for custom container in dimension '" + dimension + "' at '" + pos + "' with a null id.");
+    }
     return () -> {
       ChestData data = new ChestData(ID(id));
       data.pos = pos;
@@ -94,6 +97,9 @@ public static Supplier<ChestData> ref_id(ResourceKey<Level> dimension, BlockPos
   }
 
   public static Supplier<ChestData> id(ResourceKey<Level> dimension, BlockPos pos, UUID id) {
+    if (id == null) {
+      throw new IllegalArgumentException("Can't create ChestData for container in dimension '" + dimension + "' at '" + pos + "' with a null id.");
+    }
     return () -> {
       ChestData data = new ChestData(ID(id));
       data.pos = pos;
@@ -107,6 +113,9 @@ public static Supplier<ChestData> id(ResourceKey<Level> dimension, BlockPos pos,
   }
 
   public static Supplier<ChestData> entity(ResourceKey<Level> dimension, BlockPos pos, UUID entityId) {
+    if (entityId == null) {
+      throw new IllegalArgumentException("Can't create ChestData for minecart in dimension '" + dimension + "' at '" + pos + "' with a null entityId.");
+    }
     return () -> {
       ChestData data = new ChestData(ID(entityId));
       data.pos = pos;
@@ -199,15 +208,7 @@ public SpecialChestInventory createInventory(ServerPlayer player, LootFiller fil
       result = new SpecialChestInventory(this, items, cart.getDisplayName());
       lootTable = cart.lootTable;
     } else {
-/*      if (world.dimension() != dimension) {
-        MinecraftServer server = ServerLifecycleHooks.getCurrentServer();
-        if (server == null) {
-          return null;
-        }
-        world = server.getLevel(dimension);
-      }*/
-
-      if (/*world == null || */tile == null) {
+      if (tile == null) {
         return null;
       }
 
@@ -327,7 +328,11 @@ public CompoundTag save(CompoundTag compound) {
     } else {
       LootrAPI.LOG.error("Attempted to save a data file with no `dimension`: '" + key + "'");
     }
-    compound.putUUID("uuid", uuid);
+    if (uuid != null) {
+      compound.putUUID("uuid", uuid);
+    } else {
+      throw new IllegalStateException("Attempted to save a data file with no `uuid`: '" + key + "'. Located in dimension '" + dimension + "' at '" + pos + "'. This is an unrecoverable error.");
+    }
     compound.putBoolean("custom", custom);
     compound.putBoolean("entity", entity);
     if (reference != null) {

src/main/java/noobanidus/mods/lootr/util/ChestUtil.java

@@ -78,6 +78,10 @@ public static void handleLootChest(Block block, Level level, BlockPos pos, Playe
     BlockEntity te = level.getBlockEntity(pos);
     if (te instanceof ILootBlockEntity tile) {
       UUID tileId = tile.getTileId();
+      if (tileId == null) {
+        player.displayClientMessage(Component.translatable("lootr.message.invalid_block").setStyle(Style.EMPTY.withColor(TextColor.fromLegacyFormat(ChatFormatting.RED)).withBold(true)), true);
+        return;
+      }
       if (DataStorage.isDecayed(tileId)) {
         level.destroyBlock(pos, true);
         notifyDecay(player, tileId);

src/main/resources/assets/lootr/lang/en_us.json

@@ -13,6 +13,7 @@
   "lootr.message.refresh_in": "This container will refresh its contents in %s seconds.",
   "lootr.message.refresh_start": "The container will refresh with new contents in %s seconds!",
   "lootr.message.invalid_table": "The loot table for this container [%s] resolved to empty and loot could not be generated. Check your `latest.log` for errors.",
+  "lootr.message.invalid_block": "The container that you have tried to open is invalid as it has not generated its identifier.",
   "block.lootr.lootr_chest": "Loot Chest",
   "block.lootr.lootr_trapped_chest": "Loot Chest",
   "block.lootr.lootr_barrel": "Loot Barrel",