First Test MV

README.md

@@ -18,9 +18,9 @@ Canonical English is defined in the typed Java catalogs under `core/src/main/jav
 
 | Platform | Artifact | Minecraft | Notes |
 |---|---|---|---|
-| Paper / Purpur / Leaf / Canvas | plugin jar | 26.2 | Full feature set |
+| Paper / Purpur / Leaf / Canvas | plugin jar | 26.1.2 - 26.2 | Full feature set |
-| Folia | plugin jar | 26.2 | Region-safe scheduling throughout |
+| Folia | plugin jar | 26.1.2 - 26.2 | Region-safe scheduling throughout |
-| Spigot / CraftBukkit | plugin jar | 26.2 | Full feature set |
+| Spigot / CraftBukkit | plugin jar | 26.1.2 - 26.2 | Full feature set |
 | Fabric | mod jar | 26.2 | Server worldgen + client HUD; requires Fabric Loader 0.19.3+ |
 | Forge | mod jar | 26.2 | Server worldgen + client HUD; requires Forge 65.0.4+ |
 | NeoForge | mod jar | 26.2 | Server worldgen + client HUD; requires NeoForge 26.2.0.12-beta+ |

adapters/bukkit/nms/v26_2_R1/src/main/java/art/arcane/iris/core/nms/v26_2_R1/NMSBinding.java

@@ -6,6 +6,7 @@ import ca.spottedleaf.moonrise.patches.chunk_system.scheduling.NewChunkHolder;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import art.arcane.iris.spi.IrisLogging;
 import art.arcane.iris.core.nms.INMSBinding;
+import art.arcane.iris.core.nms.MinecraftVersion;
 import art.arcane.iris.core.nms.container.BiomeColor;
 import art.arcane.iris.core.nms.container.Pair;
 import art.arcane.iris.core.nms.container.BlockProperty;
@@ -161,6 +162,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 
 public class NMSBinding implements INMSBinding {
     private final KMap<Biome, Object> baseBiomeCache = new KMap<>();
+    private volatile DataVersion dataVersion;
     private final BlockData AIR = Material.AIR.createBlockData();
     private final AtomicCache<MCAIdMap<net.minecraft.world.level.biome.Biome>> biomeMapCache = new AtomicCache<>();
     private final AtomicBoolean injected = new AtomicBoolean();
@@ -1238,23 +1240,19 @@ public class NMSBinding implements INMSBinding {
         }
 
         try {
-            String descriptionId = "entity.minecraft." + entity.name().toLowerCase(Locale.ROOT);
+            // Registry lookup instead of an EntityType static-field scan: 26.2 moved the constants
-            Field[] fields = EntityType.class.getDeclaredFields();
+            // to a separate EntityTypes holder class that 26.1.2 does not have, while the registry
-            for (Field field : fields) {
+            // resolves identically on both. ENTITY_TYPE is a DefaultedRegistry, so guard containsKey
-                if (!Modifier.isStatic(field.getModifiers()) || !field.getType().equals(EntityType.class)) {
+            // to avoid silently resolving unknown keys to the default entry.
-                    continue;
+            Identifier key = Identifier.fromNamespaceAndPath(entity.getKey().getNamespace(), entity.getKey().getKey());
-                }
+            if (!BuiltInRegistries.ENTITY_TYPE.containsKey(key)) {
-
-                EntityType entityType = (EntityType) field.get(null);
-                if (entityType == null) {
-                    continue;
-                }
-
-                if (descriptionId.equals(entityType.getDescriptionId())) {
-                    return new Vector3d(entityType.getWidth(), entityType.getHeight(), entityType.getWidth());
-                }
-            }
                 return null;
+            }
+            EntityType<?> entityType = BuiltInRegistries.ENTITY_TYPE.getValue(key);
+            if (entityType == null) {
+                return null;
+            }
+            return new Vector3d(entityType.getWidth(), entityType.getHeight(), entityType.getWidth());
         } catch (Throwable e) {
             IrisLogging.error("Unable to get entity dimensions for " + entity + "!");
             IrisLogging.reportError(e);
@@ -1362,7 +1360,13 @@ public class NMSBinding implements INMSBinding {
 
     @Override
     public DataVersion getDataVersion() {
-        return DataVersion.V26_2;
+        DataVersion cached = dataVersion;
+        if (cached == null) {
+            MinecraftVersion detected = MinecraftVersion.detect(Bukkit.getServer());
+            cached = detected != null && detected.isSameRelease(26, 1, 2) ? DataVersion.V26_1_2 : DataVersion.V26_2;
+            dataVersion = cached;
+        }
+        return cached;
     }
 
     @Override

adapters/bukkit/nms/v26_2_R1/src/test/java/art/arcane/iris/nativegen/NativeStructurePostProcessorSurfaceTerrainTest.java

@@ -6,7 +6,6 @@ import art.arcane.iris.engine.object.IrisStructureTerrain;
 import art.arcane.iris.engine.object.IrisStructureTerrainMode;
 import com.mojang.datafixers.util.Either;
 import com.mojang.serialization.Codec;
-import com.mojang.serialization.MapCodec;
 import net.minecraft.SharedConstants;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Holder;
@@ -17,7 +16,6 @@ import net.minecraft.nbt.CompoundTag;
 import net.minecraft.server.Bootstrap;
 import net.minecraft.util.RandomSource;
 import net.minecraft.world.level.ChunkPos;
-import net.minecraft.world.level.LevelReader;
 import net.minecraft.world.level.LevelHeightAccessor;
 import net.minecraft.world.level.WorldGenLevel;
 import net.minecraft.world.level.biome.Biome;
@@ -46,8 +44,11 @@ import net.minecraft.world.level.levelgen.structure.pools.ListPoolElement;
 import net.minecraft.world.level.levelgen.structure.pools.SinglePoolElement;
 import net.minecraft.world.level.levelgen.structure.pools.StructurePoolElement;
 import net.minecraft.world.level.levelgen.structure.pools.StructureTemplatePool;
+import net.minecraft.world.level.levelgen.structure.templatesystem.AlwaysTrueTest;
+import net.minecraft.world.level.levelgen.structure.templatesystem.BlockStateMatchTest;
 import net.minecraft.world.level.levelgen.structure.templatesystem.LiquidSettings;
-import net.minecraft.world.level.levelgen.structure.templatesystem.BlockIgnoreProcessor;
+import net.minecraft.world.level.levelgen.structure.templatesystem.ProcessorRule;
+import net.minecraft.world.level.levelgen.structure.templatesystem.RuleProcessor;
 import net.minecraft.world.level.levelgen.structure.structures.DesertPyramidPiece;
 import net.minecraft.world.level.levelgen.structure.structures.DesertPyramidStructure;
 import net.minecraft.world.level.levelgen.structure.templatesystem.StructurePlaceSettings;
@@ -267,7 +268,7 @@ public class NativeStructurePostProcessorSurfaceTerrainTest {
                 block(0, 0, 0, Blocks.COBBLESTONE.defaultBlockState()),
                 block(15, 0, 0, Blocks.STONE.defaultBlockState())));
         InlineSinglePoolElement element = new InlineSinglePoolElement(
-                sparseTemplate, List.of(new ReplaceBlockProcessor(
+                sparseTemplate, List.of(replaceBlockProcessor(
                         Blocks.STONE.defaultBlockState(), Blocks.AIR.defaultBlockState())));
         PoolElementStructurePiece piece = rigidTemplatePiece(
                 element, new BoundingBox(0, 64, 0, 15, 70, 3), 1, Rotation.NONE);
@@ -369,7 +370,7 @@ public class NativeStructurePostProcessorSurfaceTerrainTest {
                 block(2, 0, 0, Blocks.AIR.defaultBlockState()),
                 block(2, 2, 0, Blocks.COBBLESTONE.defaultBlockState())));
         InlineSinglePoolElement element = new InlineSinglePoolElement(
-                template, List.of(new ReplaceBlockProcessor(
+                template, List.of(replaceBlockProcessor(
                         Blocks.STONE.defaultBlockState(), Blocks.AIR.defaultBlockState())));
         PoolElementStructurePiece piece = rigidTemplatePiece(
                 element, new BoundingBox(0, 65, 0, 2, 72, 0), 1, Rotation.NONE);
@@ -551,7 +552,7 @@ public class NativeStructurePostProcessorSurfaceTerrainTest {
                 block(0, 0, 0, Blocks.STONE.defaultBlockState()),
                 block(0, 2, 0, Blocks.COBBLESTONE.defaultBlockState())));
         PoolElementStructurePiece piece = rigidTemplatePiece(
-                new InlineSinglePoolElement(template, List.of(new ReplaceBlockProcessor(
+                new InlineSinglePoolElement(template, List.of(replaceBlockProcessor(
                         Blocks.STONE.defaultBlockState(), Blocks.AIR.defaultBlockState()))),
                 new BoundingBox(0, 66, 0, 7, 72, 7), 1, Rotation.NONE);
         StructureStart start = rigidSurfaceStart(List.of(piece), TerrainAdjustment.NONE);
@@ -1081,10 +1082,10 @@ public class NativeStructurePostProcessorSurfaceTerrainTest {
                 block(1, 0, 0, Blocks.STONE.defaultBlockState())));
         InlineSinglePoolElement upperElement = new InlineSinglePoolElement(
                 upperTemplate, List.of(
-                new ReplaceBlockProcessor(
+                replaceBlockProcessor(
                         Blocks.COBBLESTONE.defaultBlockState(),
                         Blocks.AIR.defaultBlockState()),
-                new ReplaceBlockProcessor(
+                replaceBlockProcessor(
                         Blocks.STONE.defaultBlockState(),
                         Blocks.WATER.defaultBlockState())));
         PoolElementStructurePiece lower = rigidTemplatePiece(
@@ -2131,32 +2132,13 @@ public class NativeStructurePostProcessorSurfaceTerrainTest {
         }
     }
 
-    private static final class ReplaceBlockProcessor implements StructureProcessor {
+    private static StructureProcessor replaceBlockProcessor(BlockState source, BlockState replacement) {
-        private final BlockState source;
+        // Vanilla RuleProcessor instead of a custom StructureProcessor subtype: StructureProcessor
-        private final BlockState replacement;
+        // is an abstract class on 26.1.2 and an interface on 26.2, so a direct subtype cannot
-
+        // compile against both dev bundles. BlockStateMatchTest matches the exact source state,
-        private ReplaceBlockProcessor(BlockState source, BlockState replacement) {
+        // matching the previous custom processor's identity-equality semantics.
-            this.source = source;
+        return new RuleProcessor(List.of(new ProcessorRule(
-            this.replacement = replacement;
+                new BlockStateMatchTest(source), AlwaysTrueTest.INSTANCE, replacement)));
-        }
-
-        @Override
-        public StructureTemplate.StructureBlockInfo processBlock(
-                LevelReader level, BlockPos targetPosition, BlockPos referencePos,
-                BlockPos templateRelativePos,
-                StructureTemplate.StructureBlockInfo processedBlockInfo,
-                StructurePlaceSettings settings) {
-            if (!processedBlockInfo.state().equals(source)) {
-                return processedBlockInfo;
-            }
-            return new StructureTemplate.StructureBlockInfo(
-                    processedBlockInfo.pos(), replacement, processedBlockInfo.nbt());
-        }
-
-        @Override
-        public MapCodec<? extends StructureProcessor> codec() {
-            return BlockIgnoreProcessor.STRUCTURE_BLOCK.codec();
-        }
     }
 
     private static StructureStart desertStart() {

adapters/bukkit/nms/v26_2_R1/src/test/java/art/arcane/iris/nativegen/NativeStructureTemplateOccupancyTest.java

@@ -1,15 +1,16 @@
 package art.arcane.iris.nativegen;
 
 import com.mojang.datafixers.util.Either;
-import com.mojang.serialization.MapCodec;
 import net.minecraft.SharedConstants;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Holder;
 import net.minecraft.core.HolderSet;
 import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.resources.Identifier;
 import net.minecraft.server.Bootstrap;
+import net.minecraft.tags.TagKey;
 import net.minecraft.util.valueproviders.ConstantInt;
-import net.minecraft.world.level.LevelReader;
 import net.minecraft.world.level.WorldGenLevel;
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.Rotation;
@@ -34,11 +35,13 @@ import net.minecraft.world.level.levelgen.structure.templatesystem.StructureProc
 import net.minecraft.world.level.levelgen.structure.templatesystem.StructureProcessorList;
 import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplate;
 import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplateManager;
+import org.junit.Assume;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.ArrayList;
 import java.util.List;
@@ -62,38 +65,33 @@ public class NativeStructureTemplateOccupancyTest {
     }
 
     @Test
-    public void straddlingGravityPieceReadsHeightsOnlyInsideTheProcessingArea() throws Exception {
+    public void straddlingGravityPieceHeightReadsHonorTheVanillaClipContract() throws Exception {
         ColumnRecorder recorder = new ColumnRecorder();
 
         resolve(straddlingPiece(
                 List.of(new GravityProcessor(Heightmap.Types.WORLD_SURFACE_WG, 0))), recorder);
 
-        assertEquals(columns(0, 15), recorder.heightColumns);
+        // 26.2 vanilla clips processor evaluation to the placement bounding box; 26.1.2 vanilla
-    }
+        // runs processors across the whole piece. Iris mirrors the pinned version's semantics.
-
+        assertEquals(expectedClippedColumns(), recorder.heightColumns);
-    @Test
-    public void straddlingPieceRunsProcessorsOnlyInsideTheProcessingArea() throws Exception {
-        CountingProcessor counter = new CountingProcessor();
-
-        resolve(straddlingPiece(List.of(counter)), new ColumnRecorder());
-
-        assertEquals(columns(0, 15), counter.columns);
-        assertTrue(counter.columns.size() < TEMPLATE_WIDTH);
     }
 
     @Test
     public void cappedStraddlingPieceRunsProcessorsAcrossTheWholePiece() throws Exception {
-        CountingProcessor counter = new CountingProcessor();
+        ColumnRecorder recorder = new ColumnRecorder();
 
-        resolve(straddlingPiece(List.of(counter,
+        resolve(straddlingPiece(List.of(
-                new CappedProcessor(NopProcessor.INSTANCE, ConstantInt.of(0)))),
+                new GravityProcessor(Heightmap.Types.WORLD_SURFACE_WG, 0),
-                new ColumnRecorder());
+                new CappedProcessor(NopProcessor.INSTANCE, ConstantInt.of(0)))), recorder);
 
-        assertEquals(columns(0, TEMPLATE_WIDTH - 1), counter.columns);
+        assertEquals(columns(0, TEMPLATE_WIDTH - 1), recorder.heightColumns);
     }
 
     @Test
-    public void cappedProcessorIsTheOnlyProcessorThatDisablesTheProcessingAreaClip() {
+    public void cappedProcessorIsTheOnlyProcessorThatDisablesTheProcessingAreaClip() throws Exception {
+        Method contract = clipContractMethod();
+        Assume.assumeTrue("evaluatesEntirePieceState only exists on 26.2+", contract != null);
+
         for (StructureProcessor processor : List.of(
                 BlockIgnoreProcessor.STRUCTURE_BLOCK,
                 JigsawReplacementProcessor.INSTANCE,
@@ -103,12 +101,12 @@ public class NativeStructureTemplateOccupancyTest {
                 new GravityProcessor(Heightmap.Types.WORLD_SURFACE_WG, 0),
                 new RuleProcessor(List.of()),
                 new BlockAgeProcessor(0.5F),
-                new ProtectedBlockProcessor(HolderSet.empty()))) {
+                protectedBlockProcessor())) {
             assertFalse(processor.getClass().getName(),
-                    processor.evaluatesEntirePieceState());
+                    (Boolean) contract.invoke(processor));
         }
-        assertTrue(new CappedProcessor(NopProcessor.INSTANCE, ConstantInt.of(4))
+        assertTrue((Boolean) contract.invoke(
-                .evaluatesEntirePieceState());
+                new CappedProcessor(NopProcessor.INSTANCE, ConstantInt.of(4))));
     }
 
     @Test
@@ -146,6 +144,30 @@ public class NativeStructureTemplateOccupancyTest {
         return columns;
     }
 
+    private static Method clipContractMethod() {
+        try {
+            return StructureProcessor.class.getMethod("evaluatesEntirePieceState");
+        } catch (NoSuchMethodException absent) {
+            return null;
+        }
+    }
+
+    private static Set<Integer> expectedClippedColumns() {
+        return clipContractMethod() != null
+                ? columns(PROCESSING_AREA.minX(), PROCESSING_AREA.maxX())
+                : columns(0, TEMPLATE_WIDTH - 1);
+    }
+
+    private static StructureProcessor protectedBlockProcessor() throws Exception {
+        // Constructed reflectively: the constructor takes HolderSet on 26.2 and TagKey on 26.1.2.
+        Constructor<?> constructor = ProtectedBlockProcessor.class.getConstructors()[0];
+        Class<?> parameter = constructor.getParameterTypes()[0];
+        Object argument = parameter == HolderSet.class
+                ? HolderSet.empty()
+                : TagKey.create(Registries.BLOCK, Identifier.fromNamespaceAndPath("minecraft", "air"));
+        return (StructureProcessor) constructor.newInstance(argument);
+    }
+
     private static StructureTemplateManager forbiddenTemplateManager() {
         throw new AssertionError("Inline templates must not resolve a template manager");
     }
@@ -202,25 +224,6 @@ public class NativeStructureTemplateOccupancyTest {
         private final Set<Integer> stateColumns = new TreeSet<>();
     }
 
-    private static final class CountingProcessor implements StructureProcessor {
-        private final Set<Integer> columns = new TreeSet<>();
-
-        @Override
-        public StructureTemplate.StructureBlockInfo processBlock(
-                LevelReader level, BlockPos targetPosition, BlockPos referencePos,
-                BlockPos templateRelativePos,
-                StructureTemplate.StructureBlockInfo processedBlockInfo,
-                StructurePlaceSettings settings) {
-            columns.add(processedBlockInfo.pos().getX());
-            return processedBlockInfo;
-        }
-
-        @Override
-        public MapCodec<? extends StructureProcessor> codec() {
-            return BlockIgnoreProcessor.STRUCTURE_BLOCK.codec();
-        }
-    }
-
     private static final class InlineSinglePoolElement extends SinglePoolElement {
         private InlineSinglePoolElement(
                 StructureTemplate template, List<StructureProcessor> processors) {

adapters/bukkit/plugin/build.gradle

@@ -1,4 +1,4 @@
-String apiVersion = providers.gradleProperty('minecraftVersion').get()
+String apiVersion = providers.gradleProperty('apiVersion').get()
 def mainClass = 'art.arcane.iris.Iris'
 def bootstrapperClass = 'art.arcane.iris.IrisBootstrap'
 

build.gradle

@@ -87,7 +87,7 @@ String forgeConsumerPath = "${consumerLocation}/forge-mod-consumers/dropins/mods
 String neoForgeConsumerPath = "${consumerLocation}/neoforge-mod-consumers/dropins/mods"
 
 def nmsBindings = [
-    v26_2_R1: '26.2.build.60-beta',
+    v26_2_R1: '26.1.2.build.74-stable',
 ]
 Class nmsTypeClass = Class.forName('NMSBinding$Type')
 nmsBindings.each { key, value ->

core/src/main/java/art/arcane/iris/core/IrisDatapackCompiler.java

@@ -46,7 +46,6 @@ public final class IrisDatapackCompiler {
             List<File> packRoots,
             KList<File> datapackRoots,
             IDataFixer fixer,
-            int packFormat,
             boolean adjustVanillaHeight
     ) throws IOException {
         Objects.requireNonNull(packRoots, "packRoots");
@@ -98,7 +97,7 @@ public final class IrisDatapackCompiler {
             }
         }
 
-        IrisDimension.writeShared(datapackRoots, height, packFormat, adjustVanillaHeight);
+        IrisDimension.writeShared(datapackRoots, height, adjustVanillaHeight);
         validateOutputs(datapackRoots, dimensionCount);
         return new CompilationResult(packCount, dimensionCount, countBiomes(biomes));
     }

core/src/main/java/art/arcane/iris/core/ServerConfigurator.java

@@ -200,7 +200,6 @@ public class ServerConfigurator {
                     packRoots,
                     stagedRoots,
                     fixer,
-                    BukkitPlatform.dataPackFormat(),
                     IrisSettings.get().getGeneral().adjustVanillaHeight
             );
             for (int i = 0; i < liveRoots.size(); i++) {

core/src/main/java/art/arcane/iris/core/nms/INMSBinding.java

@@ -257,7 +257,7 @@ public interface INMSBinding {
         if (!supportsIrisWorldGeneration()) {
             throw new IllegalStateException("Iris world '" + c.name() + "' cannot be created with limited NMS binding "
                     + getClass().getSimpleName()
-                    + "; set general.disableNMS=false and use the supported Minecraft 26.2 server runtime");
+                    + "; set general.disableNMS=false and use a supported Minecraft server runtime (26.1.2 or 26.2)");
         }
         if (missingDimensionTypes(generator.getTarget().getDimension().getDimensionTypeKey())) {
             throw new IllegalStateException("Missing dimension types to create world");

core/src/main/java/art/arcane/iris/core/nms/NmsBindingSelector.java

@@ -1,7 +1,7 @@
 package art.arcane.iris.core.nms;
 
 final class NmsBindingSelector {
-    private static final String SUPPORTED_VERSION = "26.2";
+    private static final String SUPPORTED_VERSIONS = "26.1.2 or 26.2";
     private static final String SUPPORTED_TAG = "v26_2_R1";
 
     private NmsBindingSelector() {
@@ -11,8 +11,8 @@ final class NmsBindingSelector {
         if (version == null) {
             throw new IllegalStateException("Iris requires an exact Minecraft version before selecting NMS");
         }
-        if (!version.isSameRelease(26, 2, 0)) {
+        if (!version.isSameRelease(26, 2, 0) && !version.isSameRelease(26, 1, 2)) {
-            throw new IllegalStateException("Iris requires Minecraft " + SUPPORTED_VERSION
+            throw new IllegalStateException("Iris requires Minecraft " + SUPPORTED_VERSIONS
                     + ". Detected server version: " + version.value());
         }
         return SUPPORTED_TAG;

core/src/main/java/art/arcane/iris/core/nms/datapack/DataVersion.java

@@ -13,6 +13,7 @@ import java.util.function.Supplier;
 @Getter
 public enum DataVersion {
     UNSUPPORTED("0.0.0", 0, () -> null),
+    V26_1_2("26.1.2", 101, DataFixerV1217::new),
     V26_2("26.2", 107, DataFixerV1217::new);
     private static final KMap<DataVersion, IDataFixer> cache = new KMap<>();
     @Getter(AccessLevel.NONE)
@@ -51,4 +52,15 @@ public enum DataVersion {
     public static DataVersion getLatest() {
         return values()[values().length - 1];
     }
+
+    public static int minSupportedPackFormat() {
+        int minimum = Integer.MAX_VALUE;
+        for (DataVersion version : values()) {
+            if (version == UNSUPPORTED) {
+                continue;
+            }
+            minimum = Math.min(minimum, version.packFormat);
+        }
+        return minimum;
+    }
 }

core/src/main/java/art/arcane/iris/core/nms/v1X/NMSBinding1X.java

@@ -293,6 +293,6 @@ public class NMSBinding1X implements INMSBinding {
     private IllegalStateException unsupportedStructureHook(String operation) {
         return new IllegalStateException("Iris cannot " + operation + " with limited NMS binding "
                 + getClass().getSimpleName()
-                + "; set general.disableNMS=false and use the supported Minecraft 26.2 server runtime");
+                + "; set general.disableNMS=false and use a supported Minecraft server runtime (26.1.2 or 26.2)");
     }
 }

core/src/main/java/art/arcane/iris/core/pack/DefaultPackBootstrapProvisioner.java

@@ -41,7 +41,6 @@ import java.util.zip.ZipInputStream;
 public final class DefaultPackBootstrapProvisioner {
     private static final URI DEFAULT_SOURCE = URI.create("https://github.com/IrisDimensions/overworld/releases/download/beta/overworld.zip");
     private static final String WORLD_DATAPACK_DIRECTORY = "iris";
-    private static final int PACK_FORMAT = 107;
     private static final int MARKER_SCHEMA = 2;
     private static final int MAX_ARCHIVE_ENTRIES = 100_000;
     private static final long MAX_ARCHIVE_BYTES = 512L * 1024L * 1024L;
@@ -189,7 +188,7 @@ public final class DefaultPackBootstrapProvisioner {
                 if (fixer == null) {
                     throw new IOException("Latest Iris datapack fixer is unavailable during bootstrap");
                 }
-                IrisDatapackCompiler.compile(packRoots, outputFolders, fixer, PACK_FORMAT, false);
+                IrisDatapackCompiler.compile(packRoots, outputFolders, fixer, false);
                 if (!isDatapackRoot(compileContainer)) {
                     throw new IOException("Canonical Iris datapack compiler produced incomplete output at " + compileContainer);
                 }

core/src/main/java/art/arcane/iris/engine/object/IrisDimension.java

@@ -23,6 +23,7 @@ import art.arcane.iris.core.loader.IrisData;
 import art.arcane.iris.spi.IrisLogging;
 import art.arcane.iris.spi.PlatformBlockState;
 import art.arcane.iris.core.loader.IrisRegistrant;
+import art.arcane.iris.core.nms.datapack.DataVersion;
 import art.arcane.iris.core.nms.datapack.IDataFixer;
 import art.arcane.iris.core.nms.datapack.IDataFixer.Dimension;
 import art.arcane.iris.engine.data.cache.AtomicCache;
@@ -763,7 +764,6 @@ public class IrisDimension extends IrisRegistrant {
     public static void writeShared(
             KList<File> datapackRoots,
             DimensionHeight height,
-            int packFormat,
             boolean adjustVanillaHeight
     ) throws IOException {
         IrisLogging.debug("    Installing Data Pack Vanilla Dimension Types");
@@ -774,16 +774,22 @@ public class IrisDimension extends IrisRegistrant {
             write(datapackRoot, "the_end", jsonStrings[2], adjustVanillaHeight);
         }
 
+        // Ranged formats spanning every supported runtime (26.1.2 = 101, 26.2 = 107). The bootstrap
+        // provisioner stages this datapack before the server (and INMS) exists, so the runtime
+        // version cannot be resolved there; a range keeps the emitted bytes identical on both
+        // install paths and both Paper versions parse ranged min_format/max_format.
+        int minFormat = DataVersion.minSupportedPackFormat();
+        int maxFormat = DataVersion.getLatest().getPackFormat();
         String raw = """
                         {
                             "pack": {
                                 "description": "Iris Data Pack. This pack contains all installed Iris Packs' resources.",
-                                "pack_format": {},
+                                "pack_format": %d,
-                                "min_format": {},
+                                "min_format": %d,
-                                "max_format": {}
+                                "max_format": %d
                             }
                         }
-                        """.replace("{}", Integer.toString(packFormat));
+                        """.formatted(maxFormat, minFormat, maxFormat);
 
         for (File datapackRoot : datapackRoots) {
             File mcm = new File(datapackRoot, "pack.mcmeta");

core/src/main/java/art/arcane/iris/platform/bukkit/BukkitPlatform.java

@@ -242,10 +242,6 @@ public final class BukkitPlatform implements IrisPlatform {
         return INMS.get().applyCustomNbt(itemStack, customNbt);
     }
 
-    public static int dataPackFormat() {
-        return INMS.get().getDataVersion().getPackFormat();
-    }
-
     public static java.util.concurrent.CompletableFuture<Boolean> teleportAsync(Entity entity, Location destination) {
         return io.papermc.lib.PaperLib.teleportAsync(entity, destination);
     }

core/src/main/java/art/arcane/iris/util/common/director/DirectorExecutor.java

@@ -36,6 +36,11 @@ public interface DirectorExecutor extends DirectorExecutorBase {
         return sender == null ? null : sender.player();
     }
 
+    default boolean playerWorldGeneratesStructures() {
+        Player activePlayer = player();
+        return activePlayer != null && activePlayer.getWorld().canGenerateStructures();
+    }
+
     default IrisData data() {
         var access = access();
         if (access != null) {

core/src/main/java/art/arcane/iris/util/common/director/specialhandlers/StructureHandler.java

@@ -29,7 +29,6 @@ import art.arcane.iris.spi.PlatformStructureHooks;
 import art.arcane.iris.util.common.director.DirectorParameterHandler;
 import art.arcane.volmlib.util.collection.KList;
 import art.arcane.volmlib.util.director.exceptions.DirectorParsingException;
-import org.bukkit.entity.Player;
 
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -100,8 +99,7 @@ public class StructureHandler implements DirectorParameterHandler<String> {
     }
 
     protected boolean nativeStructureGenerationEnabled() {
-        Player activePlayer = player();
+        return playerWorldGeneratesStructures();
-        return activePlayer != null && activePlayer.getWorld().canGenerateStructures();
     }
 
     private static Map<String, String> distinctKeys(List<String> keys) {

core/src/test/java/art/arcane/iris/core/IrisDatapackCompilerTest.java

@@ -1,7 +1,9 @@
 package art.arcane.iris.core;
 
+import art.arcane.iris.core.nms.datapack.DataVersion;
 import art.arcane.iris.core.nms.datapack.v1217.DataFixerV1217;
 import art.arcane.volmlib.util.collection.KList;
+import art.arcane.volmlib.util.json.JSONObject;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.Assume;
@@ -41,7 +43,6 @@ public class IrisDatapackCompilerTest {
                 packRoots,
                 new KList<File>().qadd(datapackRoot.toFile()),
                 new DataFixerV1217(),
-                107,
                 false
         );
 
@@ -72,7 +73,6 @@ public class IrisDatapackCompilerTest {
                 List.of(packRoot.toFile()),
                 new KList<File>().qadd(datapackRoot.toFile()),
                 new DataFixerV1217(),
-                107,
                 false
         );
 
@@ -99,6 +99,33 @@ public class IrisDatapackCompilerTest {
                 IrisDatapackCompiler.collectPackRoots(dataDirectory, serverRoot));
     }
 
+    @Test
+    public void packMcmetaSpansEverySupportedRuntimeFormat() throws Exception {
+        Path datapackRoot = temporaryFolder.newFolder("mcmeta-datapack").toPath();
+
+        IrisDatapackCompiler.compile(
+                List.of(),
+                new KList<File>().qadd(datapackRoot.toFile()),
+                new DataFixerV1217(),
+                false
+        );
+
+        JSONObject pack = new JSONObject(Files.readString(datapackRoot.resolve("pack.mcmeta"), StandardCharsets.UTF_8))
+                .getJSONObject("pack");
+        int minFormat = pack.getInt("min_format");
+        int maxFormat = pack.getInt("max_format");
+
+        assertEquals(101, minFormat);
+        assertEquals(107, maxFormat);
+        assertEquals(maxFormat, pack.getInt("pack_format"));
+
+        // One artifact serves both runtimes: each supported DataVersion's format must be in range.
+        assertTrue(minFormat <= DataVersion.V26_1_2.getPackFormat()
+                && DataVersion.V26_1_2.getPackFormat() <= maxFormat);
+        assertTrue(minFormat <= DataVersion.V26_2.getPackFormat()
+                && DataVersion.V26_2.getPackFormat() <= maxFormat);
+    }
+
     @Test
     public void compilingNoPacksPublishesCleanEmptyDatapack() throws Exception {
         Path datapackRoot = temporaryFolder.newFolder("empty-datapack").toPath();
@@ -110,7 +137,6 @@ public class IrisDatapackCompilerTest {
                 List.of(),
                 new KList<File>().qadd(datapackRoot.toFile()),
                 new DataFixerV1217(),
-                107,
                 false
         );
 

core/src/test/java/art/arcane/iris/core/nms/MinecraftVersionTest.java

@@ -57,6 +57,30 @@ public class MinecraftVersionTest {
         assertEquals(0, version.patch());
     }
 
+    @Test
+    public void parsesThreePartNewSchemeVersion() {
+        MinecraftVersion version = MinecraftVersion.fromBukkitVersion("26.1.2-R0.1-SNAPSHOT");
+        assertEquals("26.1.2", version.value());
+        assertEquals(26, version.major());
+        assertEquals(1, version.minor());
+        assertEquals(2, version.patch());
+        assertTrue(version.isSameRelease(26, 1, 2));
+        assertFalse(version.isSameRelease(26, 2, 0));
+    }
+
+    @Test
+    public void detectsThreePartVersionFromDecoratedVersion() {
+        Server server = mock(Server.class);
+        doReturn("git-Paper-74 (MC: 26.1.2)").when(server).getVersion();
+        doReturn("26.1.2-R0.1-SNAPSHOT").when(server).getBukkitVersion();
+
+        MinecraftVersion version = MinecraftVersion.detect(server);
+        assertEquals("26.1.2", version.value());
+        assertEquals(26, version.major());
+        assertEquals(1, version.minor());
+        assertEquals(2, version.patch());
+    }
+
     @Test
     public void comparesMajorBeforeMinor() {
         MinecraftVersion version = MinecraftVersion.fromBukkitVersion("26.2-R0.1-SNAPSHOT");

core/src/test/java/art/arcane/iris/core/nms/NmsBindingSelectorTest.java

@@ -14,6 +14,13 @@ public class NmsBindingSelectorTest {
         assertEquals("v26_2_R1", NmsBindingSelector.select(version));
     }
 
+    @Test
+    public void selectsSharedRevisionFor2612() {
+        MinecraftVersion version = MinecraftVersion.fromBukkitVersion("26.1.2-R0.1-SNAPSHOT");
+
+        assertEquals("v26_2_R1", NmsBindingSelector.select(version));
+    }
+
     @Test
     public void rejectsUnsupportedVersionsWithoutProbingAnotherRevision() {
         MinecraftVersion version = MinecraftVersion.fromBukkitVersion("26.3-R0.1-SNAPSHOT");
@@ -24,6 +31,16 @@ public class NmsBindingSelectorTest {
         assertTrue(failure.getMessage().contains("26.3"));
     }
 
+    @Test
+    public void rejectsBasePatchOfSupportedMinorLine() {
+        MinecraftVersion version = MinecraftVersion.fromBukkitVersion("26.1-R0.1-SNAPSHOT");
+
+        IllegalStateException failure = assertThrows(IllegalStateException.class,
+                () -> NmsBindingSelector.select(version));
+
+        assertTrue(failure.getMessage().contains("26.1"));
+    }
+
     @Test
     public void rejectsMissingVersionDetection() {
         assertThrows(IllegalStateException.class, () -> NmsBindingSelector.select(null));

core/src/test/java/art/arcane/iris/core/nms/datapack/DataVersionTest.java

@@ -0,0 +1,32 @@
+package art.arcane.iris.core.nms.datapack;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
+
+public class DataVersionTest {
+    @Test
+    public void latestRemainsNewestSupportedRelease() {
+        assertSame(DataVersion.V26_2, DataVersion.getLatest());
+    }
+
+    @Test
+    public void packFormatsMatchServerVersionJson() {
+        assertEquals(101, DataVersion.V26_1_2.getPackFormat());
+        assertEquals(107, DataVersion.V26_2.getPackFormat());
+    }
+
+    @Test
+    public void minSupportedPackFormatIsTheOldestSupportedRuntime() {
+        assertEquals(101, DataVersion.minSupportedPackFormat());
+    }
+
+    @Test
+    public void bothSupportedReleasesShareAFixer() {
+        assertNotNull(DataVersion.V26_1_2.get());
+        assertNotNull(DataVersion.V26_2.get());
+        assertSame(DataVersion.V26_1_2.get().getClass(), DataVersion.V26_2.get().getClass());
+    }
+}

docs/mc-version-bump.md

@@ -8,9 +8,13 @@ to a new Minecraft version, in order.
 
 `gradle.properties`:
 
-- `minecraftVersion` — target MC version (e.g. `26.2`). Drives the Bukkit plugin `api-version`,
+- `minecraftVersion` — target MC version (e.g. `26.2`). Drives
   `BuildConstants.MINECRAFT_VERSION`, the `com.mojang:minecraft` coordinate, all mod-metadata
   minecraft ranges, and every dist/jar artifact name.
+- `apiVersion` — Bukkit plugin `api-version` (e.g. `26.1`). Deliberately decoupled from
+  `minecraftVersion`: it is the lowest Minecraft release line the single plugin artifact loads on
+  (currently `26.1` so one jar serves 26.1.2 and 26.2). Bump it only when dropping support for the
+  older line.
 - `fabricLoaderVersion` — Fabric Loader version.
 - `forgeVersion` — Forge version (`<mc>-<forge>`).
 - `neoForgeVersion` — NeoForge version.
@@ -19,7 +23,8 @@ to a new Minecraft version, in order.
 ## Ordered steps
 
 1. Edit `gradle.properties`: update `minecraftVersion`, `fabricLoaderVersion`, `forgeVersion`,
-   `neoForgeVersion`, and the `irisVersion` suffix.
+   `neoForgeVersion`, and the `irisVersion` suffix. Revisit `apiVersion` only if the bump drops
+   support for the oldest Minecraft line the plugin artifact still loads on.
 
 2. Edit `gradle/libs.versions.toml`:
    - `spigot` — the Spigot/Paper API pin used to compile against (`<mc>-R0.1-SNAPSHOT`).
@@ -148,7 +153,7 @@ to a new Minecraft version, in order.
 
 ## Derived automatically (do not hand-edit on a version bump)
 
-- Bukkit plugin `api-version` — `adapters/bukkit/plugin/build.gradle` reads `minecraftVersion`.
+- Bukkit plugin `api-version` — `adapters/bukkit/plugin/build.gradle` reads `apiVersion`.
 - `BuildConstants.MINECRAFT_VERSION` — stamped by the `generateTemplates` task in
   `core/build.gradle` from `minecraftVersion`; consumed by `Tasks.supportedVersions`.
 - Mod-metadata `minecraft` version ranges — templated from `minecraftVersion` at `processResources`.

gradle.properties

@@ -25,6 +25,8 @@ nmsTools.repo-url=https://repo.codemc.org/repository/nms/
 nmsTools.specialSourceVersion=1.11.4
 irisVersion=4.0.0-26.2
 minecraftVersion=26.2
+# Bukkit plugin api-version: lowest supported Minecraft release line so one artifact loads on 26.1.2 and 26.2
+apiVersion=26.1
 fabricLoaderVersion=0.19.3
 forgeVersion=26.2-65.0.4
 neoForgeVersion=26.2.0.12-beta

gradle/libs.versions.toml

@@ -12,7 +12,7 @@ sentryPlugin = "6.14.0" # https://github.com/getsentry/sentry-android-gradle-plu
 # Core Libraries
 lombok = "1.18.46"
 spigot = "26.2-R0.1-SNAPSHOT" # https://hub.spigotmc.org/nexus/repository/snapshots/org/spigotmc/spigot-api/maven-metadata.xml
-paper-api = "26.2.build.60-beta"
+paper-api = "26.1.2.build.74-stable"
 log4j = "2.26.1" # https://central.sonatype.com/artifact/org.apache.logging.log4j/log4j-api
 adventure-api = "4.26.1" # https://github.com/KyoriPowered/adventure
 adventure-platform = "4.4.1" # https://github.com/KyoriPowered/adventure-platform