Add getDescription() to IStructureElement (#57)

Fixing the issue where the ofBlock method does not show a hint about
which block cannot be placed.
<img width="942" height="261" alt="image"
src="https://github.com/user-attachments/assets/2162c68e-e7ef-4fa4-ab86-61321884bfe7"
/>

.github/workflows/optimize-images.yml

@@ -0,0 +1,17 @@
+name: Optimize images
+
+on:
+  pull_request:
+    branches: [ master, main, release/** ]
+    paths:
+      - "**/*.png"
+
+  push:
+    branches: [ master, main, release/** ]
+    paths:
+      - "**/*.png"
+
+jobs:
+  optimize-images:
+    uses: GTNewHorizons/GTNH-Actions-Workflows/.github/workflows/optimize-images.yml@master
+    secrets: inherit

dependencies.gradle

@@ -1,9 +1,10 @@
 // Add your dependencies here
 
 dependencies {
-    api("com.github.GTNewHorizons:GTNHLib:0.6.39:dev")
-    implementation("com.github.GTNewHorizons:NotEnoughItems:2.7.85-GTNH:dev")
+    api("com.github.GTNewHorizons:GTNHLib:0.9.47:dev")
+    implementation("com.github.GTNewHorizons:NotEnoughItems:2.8.84-GTNH:dev")
 
     testImplementation(platform('org.junit:junit-bom:5.9.2'))
     testImplementation('org.junit.jupiter:junit-jupiter')
+	testRuntimeOnly ('org.junit.platform:junit-platform-launcher')
 }

gradle.properties

@@ -39,9 +39,33 @@ remoteMappings = https\://raw.githubusercontent.com/MinecraftForge/FML/1.7.10/co
 # `./gradlew runClient --username=AnotherPlayer`, or configuring this command in your IDE.
 developmentEnvironmentUserName = Developer
 
-# Enables using modern Java syntax (up to version 17) via Jabel, while still targeting JVM 8.
-# See https://github.com/bsideup/jabel for details on how this works.
-enableModernJavaSyntax = true
+# Enables modern Java syntax support. Valid values:
+# - false: No modern syntax, Java 8 only
+# - jabel: Jabel syntax-only support, compiles to J8 bytecode
+# - jvmDowngrader: Full modern Java via JVM Downgrader (syntax + stdlib APIs)
+# - modern: Native modern Java bytecode, no downgrading
+enableModernJavaSyntax = jabel
+
+# If set, ignores the above setting and compiles with the given toolchain. This may cause unexpected issues,
+# and should *not* be used in most situations. -1 disables this.
+# forceToolchainVersion = -1
+
+# Target JVM version for JVM Downgrader bytecode downgrading.
+# Only used when enableModernJavaSyntax = jvmDowngrader
+# downgradeTargetVersion = 8
+
+# Comma-separated list of Java versions for multi-release jar support (JVM Downgrader only).
+# Classes will be available in META-INF/versions/N/ for each version N in this list.
+# Default: "21,25" (J25+ gets native classes, J21-24 gets partial downgrade, J8-20 gets full downgrade).
+# jvmDowngraderMultiReleaseVersions = 21,25
+
+# Specifies how JVM Downgrader API stubs are provided. Options:
+# - shade: Shade minimized stubs into the jar
+# - gtnhlib: GTNHLib provides stubs at runtime (adds version constraint)
+# - external: Another dependency provides stubs (no constraint, no warning)
+# - (empty): Warning reminding you to configure stubs
+# Note: 'shade' option requires you to verify license compliance, see: https://github.com/unimined/JvmDowngrader/blob/main/LICENSE.md
+# jvmDowngraderStubsProvider =
 
 # Enables injecting missing generics into the decompiled source code for a better coding experience.
 # Turns most publicly visible List, Map, etc. into proper List<E>, Map<K, V> types.
@@ -96,7 +120,9 @@ usesMixinDebug = false
 # Specify the location of your implementation of IMixinConfigPlugin. Leave it empty otherwise.
 mixinPlugin =
 
-# Specify the package that contains all of your Mixins. You may only place Mixins in this package or the build will fail!
+# Specify the package that contains all of your Mixins. The package must exist or
+# the build will fail. If you have a package property defined in your mixins.<modid>.json,
+# it must match with this or the build will fail.
 mixinsPackage = mixins
 
 # Specify the core mod entry class if you use a core mod. This class must implement IFMLLoadingPlugin!
@@ -172,6 +198,12 @@ curseForgeRelations =
 # projects. New projects should not use this parameter.
 # customArchiveBaseName =
 
+# Optional parameter to customize the default working directory used by the runClient* tasks. Relative to the project directory.
+# runClientWorkingDirectory = run/client
+
+# Optional parameter to customize the default working directory used by the runServer* tasks. Relative to the project directory.
+# runServerWorkingDirectory = run/server
+
 # Optional parameter to have the build automatically fail if an illegal version is used.
 # This can be useful if you e.g. only want to allow versions in the form of '1.1.xxx'.
 # The check is ONLY performed if the version is a git tag.
@@ -201,3 +233,6 @@ curseForgeRelations =
 # This is meant to be set in $HOME/.gradle/gradle.properties.
 # ideaCheckSpotlessOnBuild = true
 
+# Non-GTNH properties
+org.gradle.configuration-cache = true
+org.gradle.parallel = true

gradle/gradle-daemon-jvm.properties

@@ -0,0 +1,12 @@
+#This file is generated by updateDaemonJvm
+toolchainUrl.FREE_BSD.AARCH64=https\://api.foojay.io/disco/v3.0/ids/1630f7ebef05444cb27a2709ea0249b3/redirect
+toolchainUrl.FREE_BSD.X86_64=https\://api.foojay.io/disco/v3.0/ids/cd495626d2ee49a75447e3fdc6afb287/redirect
+toolchainUrl.LINUX.AARCH64=https\://api.foojay.io/disco/v3.0/ids/1630f7ebef05444cb27a2709ea0249b3/redirect
+toolchainUrl.LINUX.X86_64=https\://api.foojay.io/disco/v3.0/ids/cd495626d2ee49a75447e3fdc6afb287/redirect
+toolchainUrl.MAC_OS.AARCH64=https\://api.foojay.io/disco/v3.0/ids/d4fd992c9557644e637ebe98263e0ae7/redirect
+toolchainUrl.MAC_OS.X86_64=https\://api.foojay.io/disco/v3.0/ids/faa12903720d410b387cc69ccafb1a74/redirect
+toolchainUrl.UNIX.AARCH64=https\://api.foojay.io/disco/v3.0/ids/1630f7ebef05444cb27a2709ea0249b3/redirect
+toolchainUrl.UNIX.X86_64=https\://api.foojay.io/disco/v3.0/ids/cd495626d2ee49a75447e3fdc6afb287/redirect
+toolchainUrl.WINDOWS.AARCH64=https\://api.foojay.io/disco/v3.0/ids/a4c09dd2e2d7079373d30e524bbc2829/redirect
+toolchainUrl.WINDOWS.X86_64=https\://api.foojay.io/disco/v3.0/ids/8e1d9ee5d0f13e442218f6884a306da1/redirect
+toolchainVersion=25

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.13-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.0-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

gradlew

@@ -1,7 +1,7 @@
 #!/bin/sh
 
 #
-# Copyright © 2015-2021 the original authors.
+# Copyright © 2015 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -57,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/b631911858264c0b6e4d6603d677ff5218766cee/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -114,7 +114,6 @@ case "$( uname )" in                #(
   NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 
 # Determine the Java command to use to start the JVM.
@@ -172,7 +171,6 @@ fi
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
     APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
     JAVACMD=$( cygpath --unix "$JAVACMD" )
 
@@ -212,8 +210,7 @@ DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 set -- \
         "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
         "$@"
 
 # Stop when "xargs" is not available.

gradlew.bat

@@ -70,11 +70,10 @@ goto fail
 :execute
 @rem Setup the command line
 
-set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
 
 :end
 @rem End local scope for the variables with windows NT shell

settings.gradle

@@ -17,7 +17,7 @@ pluginManagement {
 }
 
 plugins {
-    id 'com.gtnewhorizons.gtnhsettingsconvention' version '1.0.42'
+    id 'com.gtnewhorizons.gtnhsettingsconvention' version '2.0.24'
 }
 
 

src/main/java/com/gtnewhorizon/structurelib/block/BlockHint.java

@@ -50,6 +50,10 @@ public class BlockHint extends Block {
 
     @Override
     public IIcon getIcon(int aSide, int aMeta) {
+        // For numbered hints, top and bottom are blank
+        if (aSide <= 1 && aMeta <= 11) {
+            return hint[13];
+        }
         return hint[aMeta];
     }
 

src/main/java/com/gtnewhorizon/structurelib/gui/GuiScreenConfigureChannels.java

@@ -218,8 +218,7 @@ public class GuiScreenConfigureChannels extends GuiContainer implements IGuiScre
         actionPerformed(but);
     }
 
-    @SuppressWarnings("unchecked")
-    private List<GuiButton> getButtonList() {
+    public List<GuiButton> getButtonList() {
         return buttonList;
     }
 
@@ -262,6 +261,11 @@ public class GuiScreenConfigureChannels extends GuiContainer implements IGuiScre
         switch (aKey) {
             case Keyboard.KEY_TAB:
                 if (key.isFocused()) {
+                    if (autoCompleteList.getSelectedElement() != null) {
+                        key.setText(autoCompleteList.getSelectedElement());
+                        return;
+                    }
+
                     key.setFocused(false);
                     value.setFocused(true);
                 } else {
@@ -299,11 +303,10 @@ public class GuiScreenConfigureChannels extends GuiContainer implements IGuiScre
                 }
                 break;
         }
-        if (key.textboxKeyTyped(aChar, aKey)) {
+        if (key.textboxKeyTyped(aChar, aKey) || value.textboxKeyTyped(aChar, aKey)) {
             updateButtons();
             return;
         }
-        if (value.textboxKeyTyped(aChar, aKey)) return;
         super.keyTyped(aChar, aKey);
     }
 
@@ -314,7 +317,8 @@ public class GuiScreenConfigureChannels extends GuiContainer implements IGuiScre
         boolean existing = !StringUtils.isEmpty(keyText) && ChannelDataAccessor.hasSubChannel(trigger, keyText);
         getButtonList().get(ADD_BTN).displayString = existing ? I18n.format(I18N_PREFIX + "set")
                 : I18n.format(I18N_PREFIX + "add");
-        getButtonList().get(ADD_BTN).enabled = !StringUtils.isBlank(value.getText())
+        getButtonList().get(ADD_BTN).enabled = !StringUtils.isBlank(key.getText())
+                && !StringUtils.isBlank(value.getText())
                 && Integer.parseInt(value.getText()) > 0;
         getButtonList().get(UNSET_BTN).enabled = existing && !StringUtils.isBlank(value.getText());
 

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureDefinition.java

@@ -319,6 +319,22 @@ public interface IStructureDefinition<T> {
         return walker.getBuilt();
     }
 
+    default void iterate(String piece, World world, ExtendedFacing extendedFacing, int basePositionX, int basePositionY,
+            int basePositionZ, int basePositionA, int basePositionB, int basePositionC, IStructureWalker<T> predicate) {
+        StructureUtility.iterateV2(
+                getStructureFor(piece),
+                world,
+                extendedFacing,
+                basePositionX,
+                basePositionY,
+                basePositionZ,
+                basePositionA,
+                basePositionB,
+                basePositionC,
+                predicate,
+                "customIterate");
+    }
+
     /**
      * Low level utility.
      *

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElement.java

@@ -5,6 +5,7 @@ import static com.gtnewhorizon.structurelib.StructureLib.PANIC_MODE;
 
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.List;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
 
@@ -42,6 +43,28 @@ public interface IStructureElement<T> {
         return true;
     }
 
+    /**
+     * Returns a human-readable description of what block(s) this element accepts. Used for diagnostic messages when
+     * structure checks fail (e.g. "expected Input Bus at (1, 2, 3)").
+     * <p>
+     * Unlike {@link #getBlocksToPlace}, which returns the full set of concrete block variants for autoplacing (e.g.
+     * every tier of Input Bus), this method returns <b>category-level</b> descriptions suitable for display to the
+     * player (e.g. just "Input Bus"). It also requires no parameters, no world, trigger item, or environment, making it
+     * usable in contexts where those are unavailable.
+     * <p>
+     * Implementations should return <b>lang keys</b> (e.g. {@code "tile.blockGlass.name"}) rather than pre-translated
+     * display names. The caller is responsible for translating these keys on the client side via
+     * {@code StatCollector.translateToLocal()}. If a key has no matching translation, {@code translateToLocal} returns
+     * the input string unchanged, so pre-translated fallback strings also work.
+     *
+     * @return a list of accepted block descriptions as lang keys (or display names as fallback), or null if no
+     *         description is available
+     */
+    @Nullable
+    default List<String> getDescription() {
+        return null;
+    }
+
     boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger);
 
     boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger);
@@ -204,6 +227,12 @@ public interface IStructureElement<T> {
             public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
                 return IStructureElement.this.spawnHint(t, world, x, y, z, trigger);
             }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return IStructureElement.this.getDescription();
+            }
         };
     }
 

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureElementChain.java

@@ -1,7 +1,9 @@
 package com.gtnewhorizon.structurelib.structure;
 
 import java.util.ArrayList;
+import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
 
@@ -61,6 +63,19 @@ public interface IStructureElementChain<T> extends IStructureElement<T> {
         return false;
     }
 
+    @Nullable
+    @Override
+    default List<String> getDescription() {
+        Set<String> descriptions = new LinkedHashSet<>();
+        for (IStructureElement<T> fallback : fallbacks()) {
+            List<String> desc = fallback.getDescription();
+            if (desc != null) {
+                descriptions.addAll(desc);
+            }
+        }
+        return descriptions.isEmpty() ? null : new ArrayList<>(descriptions);
+    }
+
     @Nullable
     @Override
     default BlocksToPlace getBlocksToPlace(T t, World world, int x, int y, int z, ItemStack trigger,

src/main/java/com/gtnewhorizon/structurelib/structure/IStructureWalker.java

@@ -2,8 +2,25 @@ package com.gtnewhorizon.structurelib.structure;
 
 import net.minecraft.world.World;
 
-interface IStructureWalker<T> {
+/**
+ * A functional interface that is used to iterate over an arbitrary structure.
+ */
+@FunctionalInterface
+public interface IStructureWalker<T> {
 
+    /**
+     * Called once per structure element.
+     *
+     * @param element The current element
+     * @param world   The current world
+     * @param x       The absolute X position of the element in world coordinates
+     * @param y       The absolute Y position of the element in world coordinates
+     * @param z       The absolute Z position of the element in world coordinates
+     * @param a       The relative A position of the element in structure-local coordinates (pre transform)
+     * @param b       The relative B position of the element in structure-local coordinates (pre transform)
+     * @param c       The relative C position of the element in structure-local coordinates (pre transform)
+     * @return False to stop iterating, true to continue.
+     */
     boolean visit(IStructureElement<T> element, World world, int x, int y, int z, int a, int b, int c);
 
     default boolean blockNotLoaded(IStructureElement<T> element, World world, int x, int y, int z, int a, int b,

src/main/java/com/gtnewhorizon/structurelib/structure/LazyStructureElement.java

@@ -1,5 +1,6 @@
 package com.gtnewhorizon.structurelib.structure;
 
+import java.util.List;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -65,4 +66,10 @@ class LazyStructureElement<T> implements IStructureElementDeferred<T> {
             AutoPlaceEnvironment env) {
         return get(t).survivalPlaceBlock(t, world, x, y, z, trigger, env);
     }
+
+    @Nullable
+    @Override
+    public List<String> getDescription() {
+        return elem != null ? elem.getDescription() : null;
+    }
 }

src/main/java/com/gtnewhorizon/structurelib/structure/StructureDefinition.java

@@ -148,15 +148,32 @@ public class StructureDefinition<T> implements IStructureDefinition<T> {
 
             occupiedSpaces.put(name, occupiedSpace);
 
-            String built = builder.toString().replaceAll("[\\uA000\\uB000\\uC000]", "");
+            boolean hasPlus = false;
+            boolean hasMinus = false;
 
-            if (built.contains("+")) {
+            int write = 0;
+            for (int read = 0; read < builder.length(); read++) {
+                char ch = builder.charAt(read);
+                if (ch == A || ch == B || ch == C) {
+                    continue;
+                }
+                if (ch == '+') {
+                    hasPlus = true;
+                } else if (ch == '-') {
+                    hasMinus = true;
+                }
+                if (read != write) builder.setCharAt(write, ch);
+                write++;
+            }
+            builder.setLength(write);
+
+            if (hasPlus) {
                 addElement('+', notAir());
             }
-            if (built.contains("-")) {
+            if (hasMinus) {
                 addElement('-', isAir());
             }
-            shapes.put(name, built);
+            shapes.put(name, builder.toString());
             return this;
         }
 

src/main/java/com/gtnewhorizon/structurelib/structure/StructureUtility.java

@@ -36,7 +36,10 @@ import net.minecraft.item.ItemBlock;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.tileentity.TileEntity;
+import net.minecraft.util.ChatComponentText;
 import net.minecraft.util.ChatComponentTranslation;
+import net.minecraft.util.ChatStyle;
+import net.minecraft.util.EnumChatFormatting;
 import net.minecraft.util.IChatComponent;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.World;
@@ -338,9 +341,7 @@ public class StructureUtility {
         ItemStack stack = new ItemStack(itemBlock, 1, itemMeta);
         if (!s.takeOne(stack, true)) {
             if (chatter != null) chatter.accept(
-                    new ChatComponentTranslation(
-                            "structurelib.autoplace.error.no_simple_block",
-                            stack.func_151000_E()));
+                    new ChatComponentTranslation("structurelib.autoplace.missing_block", stack.func_151000_E()));
             return PlaceResult.REJECT;
         }
         if (block instanceof ICustomBlockSetting) {
@@ -447,7 +448,7 @@ public class StructureUtility {
         if (!StructureLibAPI.isBlockTriviallyReplaceable(world, x, y, z, actor)) return PlaceResult.REJECT;
         if (!assumeStackPresent && !s.takeOne(stack, true)) {
             if (chatter != null) chatter.accept(
-                    new ChatComponentTranslation("structurelib.autoplace.error.no_item_stack", stack.func_151000_E()));
+                    new ChatComponentTranslation("structurelib.autoplace.missing_block", stack.func_151000_E()));
             return PlaceResult.REJECT;
         }
         if (!stack.copy().tryPlaceItemIntoWorld(actor, world, x, y, z, ForgeDirection.UP.ordinal(), 0.5f, 0.5f, 0.5f))
@@ -706,6 +707,19 @@ public class StructureUtility {
     public static <T, TIER> IStructureElement<T> ofBlocksTiered(ITierConverter<TIER> tierExtractor,
             @Nullable List<Pair<Block, Integer>> allKnownTiers, @Nullable TIER notSet, BiConsumer<T, TIER> setter,
             Function<T, TIER> getter) {
+        return ofBlocksTiered(tierExtractor, allKnownTiers, notSet, setter, getter, null);
+    }
+
+    /**
+     * Like {@link #ofBlocksTiered(ITierConverter, List, Object, BiConsumer, Function)}, but with an explicit
+     * description that will be returned by {@link IStructureElement#getDescription()}.
+     *
+     * @param description the description lang keys to attach to this element, or null for no description
+     * @see #ofBlocksTiered(ITierConverter, List, Object, BiConsumer, Function)
+     */
+    public static <T, TIER> IStructureElement<T> ofBlocksTiered(ITierConverter<TIER> tierExtractor,
+            @Nullable List<Pair<Block, Integer>> allKnownTiers, @Nullable TIER notSet, BiConsumer<T, TIER> setter,
+            Function<T, TIER> getter, @Nullable List<String> description) {
         List<Pair<Block, Integer>> hints = allKnownTiers == null ? Collections.emptyList() : allKnownTiers;
         if (hints.stream().anyMatch(Objects::isNull)) throw new IllegalArgumentException();
         IStructureElementCheckOnly<T> check = ofBlocksTiered(tierExtractor, notSet, setter, getter);
@@ -784,6 +798,13 @@ public class StructureUtility {
                         env.getActor(),
                         env.getChatter());
             }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return description;
+            }
+
         };
     }
 
@@ -1407,10 +1428,65 @@ public class StructureUtility {
                         AutoPlaceEnvironment env) {
                     return BlocksToPlace.create(block, meta);
                 }
+
+                @Nullable
+                @Override
+                public List<String> getDescription() {
+                    Item item = Item.getItemFromBlock(block);
+                    if (item == null) return null;
+                    return Collections.singletonList(new ItemStack(item, 1, meta).getUnlocalizedName() + ".name");
+                }
             };
         } else {
             return new IStructureElement<T>() {
 
+                @Override
+                public PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+                        AutoPlaceEnvironment env) {
+                    BlocksToPlace e = getBlocksToPlace(t, world, x, y, z, trigger, env);
+                    IItemSource source = env.getSource();
+                    EntityPlayer actor = env.getActor();
+                    Consumer<IChatComponent> chatter = env.getChatter();
+                    if (check(t, world, x, y, z)) return PlaceResult.SKIP;
+                    if (e.getStacks() == null) {
+                        ItemStack taken = source.takeOne(e.getPredicate(), true);
+                        return StructureUtility.survivalPlaceBlock(
+                                taken,
+                                NBTMode.EXACT,
+                                taken.stackTagCompound,
+                                false,
+                                world,
+                                x,
+                                y,
+                                z,
+                                source,
+                                actor,
+                                chatter);
+                    }
+                    for (ItemStack stack : e.getStacks()) {
+                        if (!source.takeOne(stack, true)) {
+                            IChatComponent name = new ChatComponentText(stack.getDisplayName());
+                            name.setChatStyle(new ChatStyle().setColor(EnumChatFormatting.YELLOW));
+                            env.getChatter()
+                                    .accept(new ChatComponentTranslation("structurelib.autoplace.missing_block", name));
+                            continue;
+                        }
+                        return StructureUtility.survivalPlaceBlock(
+                                stack,
+                                NBTMode.EXACT,
+                                stack.stackTagCompound,
+                                false,
+                                world,
+                                x,
+                                y,
+                                z,
+                                source,
+                                actor,
+                                chatter);
+                    }
+                    return PlaceResult.REJECT;
+                }
+
                 @Override
                 public boolean check(T t, World world, int x, int y, int z) {
                     Block worldBlock = world.getBlock(x, y, z);
@@ -1439,6 +1515,14 @@ public class StructureUtility {
                         AutoPlaceEnvironment env) {
                     return BlocksToPlace.create(block, meta);
                 }
+
+                @Nullable
+                @Override
+                public List<String> getDescription() {
+                    Item item = Item.getItemFromBlock(block);
+                    if (item == null) return null;
+                    return Collections.singletonList(new ItemStack(item, 1, meta).getUnlocalizedName() + ".name");
+                }
             };
         }
     }
@@ -1481,6 +1565,14 @@ public class StructureUtility {
                     // there is getSubItems on ItemBlock, but it's client only
                     return BlocksToPlace.create(defaultBlock, defaultMeta);
                 }
+
+                @Nullable
+                @Override
+                public List<String> getDescription() {
+                    Item item = Item.getItemFromBlock(block);
+                    if (item == null) return null;
+                    return Collections.singletonList(new ItemStack(item, 1, 0).getUnlocalizedName() + ".name");
+                }
             };
         } else {
             return new IStructureElement<T>() {
@@ -1513,6 +1605,14 @@ public class StructureUtility {
                     // there is getSubItems on ItemBlock, but it's client only
                     return BlocksToPlace.create(defaultBlock, defaultMeta);
                 }
+
+                @Nullable
+                @Override
+                public List<String> getDescription() {
+                    Item item = Item.getItemFromBlock(block);
+                    if (item == null) return null;
+                    return Collections.singletonList(new ItemStack(item, 1, 0).getUnlocalizedName() + ".name");
+                }
             };
         }
     }
@@ -1776,6 +1876,71 @@ public class StructureUtility {
                     AutoPlaceEnvironment env) {
                 return element.survivalPlaceBlock(t, world, x, y, z, trigger, env);
             }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return element.getDescription();
+            }
+        };
+    }
+
+    /**
+     * Wraps an element and overrides its description. Useful for providing human-readable names to elements whose
+     * underlying implementation doesn't provide a description (e.g. tiered block elements).
+     *
+     * @param description the description to use, or null to clear any existing description
+     * @param element     the element to wrap
+     */
+    public static <B extends IStructureElement<T>, T> IStructureElement<T> withDescription(
+            @Nullable List<String> description, B element) {
+        return new IStructureElement<T>() {
+
+            @Override
+            public boolean check(T t, World world, int x, int y, int z) {
+                return element.check(t, world, x, y, z);
+            }
+
+            @Override
+            public boolean couldBeValid(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return element.couldBeValid(t, world, x, y, z, trigger);
+            }
+
+            @Override
+            public boolean placeBlock(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return element.placeBlock(t, world, x, y, z, trigger);
+            }
+
+            @Override
+            public boolean spawnHint(T t, World world, int x, int y, int z, ItemStack trigger) {
+                return element.spawnHint(t, world, x, y, z, trigger);
+            }
+
+            @Nullable
+            @Override
+            public BlocksToPlace getBlocksToPlace(T t, World world, int x, int y, int z, ItemStack trigger,
+                    AutoPlaceEnvironment env) {
+                return element.getBlocksToPlace(t, world, x, y, z, trigger, env);
+            }
+
+            @Override
+            @Deprecated
+            public PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+                    IItemSource s, EntityPlayerMP actor, Consumer<IChatComponent> chatter) {
+                return element.survivalPlaceBlock(t, world, x, y, z, trigger, s, actor, chatter);
+            }
+
+            @Override
+            public PlaceResult survivalPlaceBlock(T t, World world, int x, int y, int z, ItemStack trigger,
+                    AutoPlaceEnvironment env) {
+                return element.survivalPlaceBlock(t, world, x, y, z, trigger, env);
+            }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return description;
+            }
         };
     }
 
@@ -1832,6 +1997,12 @@ public class StructureUtility {
                     AutoPlaceEnvironment env) {
                 return element.survivalPlaceBlock(t, world, x, y, z, trigger, env);
             }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return element.getDescription();
+            }
         };
     }
 
@@ -1901,6 +2072,12 @@ public class StructureUtility {
                 if (predicate.test(t)) return downstream.survivalPlaceBlock(t, world, x, y, z, trigger, env);
                 return placeResultWhenDisabled;
             }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return downstream.getDescription();
+            }
         };
     }
 
@@ -1998,6 +2175,12 @@ public class StructureUtility {
                     AutoPlaceEnvironment env) {
                 return elem.survivalPlaceBlock(t.getCurrentContext(), world, x, y, z, trigger, env);
             }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return elem.getDescription();
+            }
         };
     }
     // endregion
@@ -2835,6 +3018,12 @@ public class StructureUtility {
                     warnNoExplicitSubChannel(env.getActor());
                 return backing.survivalPlaceBlock(t, world, x, y, z, newTrigger, env);
             }
+
+            @Nullable
+            @Override
+            public List<String> getDescription() {
+                return backing.getDescription();
+            }
         };
     }
     // endregion

src/main/resources/assets/structurelib/lang/en_US.lang

@@ -51,6 +51,7 @@ structurelib.autoplace.error.not_enabled=§cThis multiblock does not support aut
 structurelib.autoplace.error.no_simple_block=§cSuggested to place §r%s§c but none was found
 structurelib.autoplace.error.no_item_stack=§cSuggested to place block by using §r%s§c but none was found
 structurelib.autoplace.warning.no_explicit_channel=§6This structure depends on nonexistent sub channel §r%s§6. Using master channel instead.
+structurelib.autoplace.missing_block=§cMissing block: %s
 
 structurelib.blockhint.desc.0=Helps while building
 structurelib.blockhint.0.name=Hint 1 dot