Don't pre-generate the pattern on wandering trader scrolls

CHANGELOG.md

@@ -28,6 +28,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - Fixed an error when trying to cast a Great Spell that no longer exists, such as when an addon has been removed ([#1335](https://github.com/FallingColors/HexMod/pull/1335)) @Robotgiggle
 - Fixed a broken translation key when referring to a jump iota in a mishap message ([#1350](https://github.com/FallingColors/HexMod/pull/1350)) @hauveli
 - Fixed Thoth's Gambit counting one extra pattern towards the pattern limit every iteration ([#1352](https://github.com/FallingColors/HexMod/pull/1352)) @Robotgiggle
+- Fixed an exploit that let you read the pattern from a for-sale Ancient Scroll without buying it ([#1363](https://github.com/FallingColors/HexMod/pull/1363)) @Robotgiggle
+- Fixed Erase Item not working properly on Ancient Scrolls ([#1363](https://github.com/FallingColors/HexMod/pull/1363)) @Robotgiggle
 
 ## `0.11.4` - 2026-08-26
 

Common/src/main/java/at/petrak/hexcasting/common/casting/actions/spells/OpErase.kt

@@ -6,6 +6,9 @@ import at.petrak.hexcasting.api.casting.eval.CastingEnvironment
 import at.petrak.hexcasting.api.casting.iota.Iota
 import at.petrak.hexcasting.api.casting.mishaps.MishapBadOffhandItem
 import at.petrak.hexcasting.api.misc.MediaConstants
+import at.petrak.hexcasting.api.utils.hasString
+import at.petrak.hexcasting.api.utils.remove
+import at.petrak.hexcasting.common.items.storage.ItemScroll
 import at.petrak.hexcasting.xplat.IXplatAbstractions
 import net.minecraft.world.item.ItemStack
 
@@ -50,6 +53,9 @@ object OpErase : SpellAction {
 
             if (datumHolder != null && datumHolder.writeIota(null, true))
                 datumHolder.writeIota(null, false)
+
+            if (stack.hasString(ItemScroll.TAG_OP_ID))
+                stack.remove(ItemScroll.TAG_OP_ID)
         }
     }
 }

Common/src/main/java/at/petrak/hexcasting/common/items/storage/ItemScroll.java

@@ -166,8 +166,8 @@ public Component getName(ItemStack pStack) {
 
     @Override
     public void inventoryTick(ItemStack pStack, Level pLevel, Entity pEntity, int pSlotId, boolean pIsSelected) {
-        // the needs_purchase tag is used so you can't see the pattern on scrolls sold by a wandering trader
-        // once you put the scroll into your inventory, this removes the tag to reveal the pattern
+        // this tag applies the "purchase to show pattern" tooltip line to scrolls sold by wandering traders
+        // once you buy the scroll and put it in your inventory, the tag (and thus the tooltip) gets removed
         if (NBTHelper.getBoolean(pStack, TAG_NEEDS_PURCHASE)) {
             NBTHelper.remove(pStack, TAG_NEEDS_PURCHASE);
         }
@@ -212,7 +212,7 @@ public void appendHoverText(ItemStack pStack, @Nullable Level pLevel, List<Compo
     @Override
     public Optional<TooltipComponent> getTooltipImage(ItemStack stack) {
         var compound = NBTHelper.getCompound(stack, TAG_PATTERN);
-        if (compound != null && !NBTHelper.getBoolean(stack, TAG_NEEDS_PURCHASE)) {
+        if (compound != null) {
             var pattern = HexPattern.fromNBT(compound);
             return Optional.of(new PatternTooltip(
                 pattern,

Common/src/main/java/at/petrak/hexcasting/common/lib/HexItems.java

@@ -1,8 +1,6 @@
 package at.petrak.hexcasting.common.lib;
 
 import at.petrak.hexcasting.api.misc.MediaConstants;
-import at.petrak.hexcasting.api.utils.HexUtils;
-import at.petrak.hexcasting.api.casting.ActionRegistryEntry;
 import at.petrak.hexcasting.api.mod.HexTags;
 import at.petrak.hexcasting.common.items.ItemJewelerHammer;
 import at.petrak.hexcasting.common.items.ItemLens;
@@ -14,8 +12,6 @@
 import at.petrak.hexcasting.xplat.IXplatAbstractions;
 import com.google.common.base.Suppliers;
 import net.minecraft.Util;
-import net.minecraft.core.Registry;
-import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.food.FoodProperties;
@@ -161,16 +157,12 @@ public static Item.Properties unstackable() {
     }
 
     private static void generateScrollEntries() {
-        var keyList = new ArrayList<ResourceKey<ActionRegistryEntry>>();
-        Registry<ActionRegistryEntry> regi = IXplatAbstractions.INSTANCE.getActionRegistry();
-        for (var key : regi.registryKeySet())
-            if (HexUtils.isOfTag(regi, key, HexTags.Actions.PER_WORLD_PATTERN))
-                keyList.add(key);
-        keyList.sort( (a, b) -> a.location().compareTo(b.location()) );
-        for (var key : keyList) {
+        var actionIDs = IXplatAbstractions.INSTANCE.getActionRegistry().getTag(HexTags.Actions.PER_WORLD_PATTERN)
+                .orElseThrow().stream().map(holder -> holder.unwrapKey().orElseThrow().location().toString())
+                .sorted().toList();
+        for (var id : actionIDs) {
             addToTab(() -> ItemScroll.withPerWorldPattern(
-                new ItemStack(HexItems.SCROLL_LARGE),
-                key.location().toString()
+                new ItemStack(HexItems.SCROLL_LARGE), id
             ),HexCreativeTabs.SCROLLS);
         }
     }

Common/src/main/java/at/petrak/hexcasting/common/loot/AddPerWorldPatternToScrollFunc.java

@@ -1,9 +1,7 @@
 package at.petrak.hexcasting.common.loot;
 
 import at.petrak.hexcasting.api.HexAPI;
-import at.petrak.hexcasting.api.casting.ActionRegistryEntry;
 import at.petrak.hexcasting.api.mod.HexTags;
-import at.petrak.hexcasting.api.utils.HexUtils;
 import at.petrak.hexcasting.api.utils.NBTHelper;
 import at.petrak.hexcasting.common.casting.PatternRegistryManifest;
 import at.petrak.hexcasting.common.items.storage.ItemScroll;
@@ -12,20 +10,15 @@
 import com.google.gson.JsonDeserializationContext;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonSerializationContext;
+import net.minecraft.core.Holder;
 import net.minecraft.util.RandomSource;
-import net.minecraft.core.Registry;
-import net.minecraft.nbt.CompoundTag;
-import net.minecraft.resources.ResourceKey;
-import net.minecraft.resources.ResourceLocation;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.storage.loot.LootContext;
 import net.minecraft.world.level.storage.loot.functions.LootItemConditionalFunction;
 import net.minecraft.world.level.storage.loot.functions.LootItemFunctionType;
 import net.minecraft.world.level.storage.loot.predicates.LootItemCondition;
 
-import java.util.ArrayList;
-
 /**
  * Slap a random per-world pattern on the scroll.
  * <p>
@@ -41,23 +34,17 @@ public AddPerWorldPatternToScrollFunc(LootItemCondition[] lootItemConditions) {
      * This doesn't actually have any params so extract behaviour out for the benefit of forge
      */
     public static ItemStack doStatic(ItemStack stack, RandomSource rand, ServerLevel overworld) {
-        var perWorldKeys = new ArrayList<ResourceKey<ActionRegistryEntry>>();
-        Registry<ActionRegistryEntry> regi = IXplatAbstractions.INSTANCE.getActionRegistry();
-        for (var key : regi.registryKeySet()) {
-            if (HexUtils.isOfTag(regi, key, HexTags.Actions.PER_WORLD_PATTERN)) {
-                perWorldKeys.add(key);
-            }
-        }
-        var patternKey = perWorldKeys.get(rand.nextInt(perWorldKeys.size()));
-        var patternID = patternKey.location().toString();
-        var pat = PatternRegistryManifest.getCanonicalStrokesPerWorld(patternKey, overworld);
+        var actionKey = IXplatAbstractions.INSTANCE.getActionRegistry().getTag(HexTags.Actions.PER_WORLD_PATTERN)
+                .flatMap(set -> set.getRandomElement(rand)).flatMap(Holder::unwrapKey).orElseThrow();
+        var actionID = actionKey.location().toString();
+        var pat = PatternRegistryManifest.getCanonicalStrokesPerWorld(actionKey, overworld);
         if (pat == null) {
-            HexAPI.LOGGER.error("No per-world pattern found for action " + patternID + " while generating loot scroll! " +
+            HexAPI.LOGGER.error("No per-world pattern found for action " + actionID + " while generating loot scroll! " +
                                 "Try running '/hexcasting recalcPatterns' to generate the patterns for this world.");
-            NBTHelper.putString(stack, ItemScroll.TAG_RECALC_WARNING, patternID);
+            NBTHelper.putString(stack, ItemScroll.TAG_RECALC_WARNING, actionID);
             return stack;
         }
-        NBTHelper.putString(stack, ItemScroll.TAG_OP_ID, patternID);
+        NBTHelper.putString(stack, ItemScroll.TAG_OP_ID, actionID);
         NBTHelper.put(stack, ItemScroll.TAG_PATTERN, pat.serializeToNBT());
         return stack;
     }

Common/src/main/java/at/petrak/hexcasting/mixin/MixinWanderingTrader.java

@@ -1,16 +1,17 @@
 package at.petrak.hexcasting.mixin;
 
+import at.petrak.hexcasting.api.mod.HexTags;
+import at.petrak.hexcasting.xplat.IXplatAbstractions;
+import net.minecraft.core.Holder;
 import net.minecraft.world.entity.npc.WanderingTrader;
 import net.minecraft.world.item.trading.MerchantOffers;
 import net.minecraft.world.item.trading.MerchantOffer;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.Items;
 import net.minecraft.util.RandomSource;
-import net.minecraft.server.MinecraftServer;
 import at.petrak.hexcasting.api.mod.HexConfig;
 import at.petrak.hexcasting.api.utils.NBTHelper;
 import at.petrak.hexcasting.common.lib.HexItems;
-import at.petrak.hexcasting.common.loot.AddPerWorldPatternToScrollFunc;
 import at.petrak.hexcasting.common.items.storage.ItemScroll;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
@@ -28,8 +29,10 @@ private void addNewTrades(CallbackInfo ci) {
             return;
         RandomSource rand = self.getRandom();
         if (rand.nextFloat() < HexConfig.server().traderScrollChance() && self.getServer() != null) {
-            ItemStack scroll = new ItemStack(HexItems.SCROLL_LARGE);
-            AddPerWorldPatternToScrollFunc.doStatic(scroll, rand, self.getServer().overworld());
+            var actionID = IXplatAbstractions.INSTANCE.getActionRegistry().getTag(HexTags.Actions.PER_WORLD_PATTERN)
+                    .flatMap(set -> set.getRandomElement(rand)).flatMap(Holder::unwrapKey)
+                    .map(key -> key.location().toString()).orElseThrow();
+            ItemStack scroll = ItemScroll.withPerWorldPattern(new ItemStack(HexItems.SCROLL_LARGE), actionID);
             NBTHelper.putBoolean(scroll, ItemScroll.TAG_NEEDS_PURCHASE, true);
             offerList.set(5, new MerchantOffer(new ItemStack(Items.EMERALD, 12), scroll, 1, 1, 1));
         }

Common/src/main/resources/assets/hexcasting/lang/en_us.flatten.json5

@@ -26,13 +26,13 @@
 
     scroll_small: {
       "": "Small Scroll",
-      of: "How did you get this item of %s",
+      of: "Ancient Scroll of %s",
       empty: "Empty Small Scroll",
     },
 
     scroll_medium: {
       "": "Medium Scroll",
-      of: "How did you get this item of %s",
+      of: "Ancient Scroll of %s",
       empty: "Empty Medium Scroll",
     },