Switch to Fabric Mixin

gradle.properties

@@ -6,7 +6,7 @@ modlauncher_version=10.0.9
 securejarhandler_version=2.1.23
 bootstraplauncher_version=1.1.2
 asm_version=9.5
-mixin_version=0.8.5
+mixin_version=0.12.5+mixin.0.8.5
 terminalconsoleappender_version=1.2.0
 nightconfig_version=3.6.4
 jetbrains_annotations_version=24.0.1

loader/build.gradle

@@ -27,7 +27,7 @@ dependencies {
     implementation("net.neoforged.accesstransformers:at-modlauncher:${accesstransformers_version}") {
         exclude module: 'modlauncher'
     }
-    implementation("org.spongepowered:mixin:${mixin_version}")
+    implementation("net.fabricmc:sponge-mixin:${mixin_version}")
     implementation("net.minecrell:terminalconsoleappender:${terminalconsoleappender_version}")
     implementation("commons-io:commons-io:${commons_io_version}")
 

loader/src/main/java/net/neoforged/fml/loading/LoadingModList.java

@@ -82,9 +82,10 @@ public void addCoreMods()
     public void addMixinConfigs() {
         modFiles.stream()
                 .map(ModFileInfo::getFile)
-                .map(ModFile::getMixinConfigs)
-                .flatMap(List::stream)
-                .forEach(DeferredMixinConfigRegistration::addMixinConfig);
+                .forEach(file -> {
+                    final String modId = file.getModInfos().get(0).getModId();
+                    file.getMixinConfigs().forEach(cfg -> DeferredMixinConfigRegistration.addMixinConfig(cfg, modId));
+                });
     }
 
     public void addAccessTransformers()

loader/src/main/java/net/neoforged/fml/loading/MixinSyntheticPackageProvider.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.fml.loading;
+
+import cpw.mods.jarhandling.VirtualJar;
+import cpw.mods.modlauncher.api.IEnvironment;
+import cpw.mods.modlauncher.api.IModuleLayerManager;
+import cpw.mods.modlauncher.api.ITransformationService;
+import cpw.mods.modlauncher.api.ITransformer;
+import cpw.mods.modlauncher.api.IncompatibleEnvironmentException;
+import org.jetbrains.annotations.NotNull;
+import org.spongepowered.asm.util.Constants;
+
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Set;
+
+public class MixinSyntheticPackageProvider implements ITransformationService {
+    @Override
+    public @NotNull String name() {
+        return "mixin-synthetic-package";
+    }
+
+    @Override
+    public void initialize(IEnvironment environment) {
+
+    }
+
+    @Override
+    public void onLoad(IEnvironment env, Set<String> otherServices) throws IncompatibleEnvironmentException {
+
+    }
+
+    @Override
+    public List<Resource> beginScanning(IEnvironment environment) {
+        try {
+            return List.of(
+                    new Resource(IModuleLayerManager.Layer.GAME, List.of(
+                            new VirtualJar("mixinsynthetic", Path.of(this.getClass().getProtectionDomain().getCodeSource().getLocation().toURI()),
+                                    Constants.SYNTHETIC_PACKAGE, Constants.SYNTHETIC_PACKAGE + ".args")
+                    ))
+            );
+        } catch (Exception exception) {
+            throw new RuntimeException("Failed to intialise synthetic Mixin virtual jar", exception);
+        }
+    }
+
+    @Override
+    public @NotNull List<ITransformer> transformers() {
+        return List.of();
+    }
+}

loader/src/main/java/net/neoforged/fml/loading/mixin/DeferredMixinConfigRegistration.java

@@ -5,16 +5,27 @@
 
 package net.neoforged.fml.loading.mixin;
 
+import net.neoforged.fml.loading.FMLLoader;
+import org.apache.logging.log4j.LogManager;
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.spongepowered.asm.launch.GlobalProperties;
 import org.spongepowered.asm.launch.MixinBootstrap;
+import org.spongepowered.asm.mixin.FabricUtil;
 import org.spongepowered.asm.mixin.Mixins;
+import org.spongepowered.asm.mixin.transformer.Config;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 public class DeferredMixinConfigRegistration {
+    private static final Logger LOG = LoggerFactory.getLogger("fml-mixin-setup");
+
     private static boolean added = false;
-    private static final List<String> mixinConfigs = new ArrayList<>();
+    record ConfigInfo(String fileName, @Nullable String modId) {}
+    private static final List<ConfigInfo> mixinConfigs = new ArrayList<>();
 
     static {
         // Register our platform agent first
@@ -25,16 +36,33 @@ public class DeferredMixinConfigRegistration {
     }
 
     public static void addMixinConfig(String config) {
+        addMixinConfig(config, null);
+    }
+
+    public static void addMixinConfig(String config, @Nullable String modId) {
         if (added) {
             throw new IllegalStateException("Too late to add mixin configs!");
         }
 
-        mixinConfigs.add(config);
+        mixinConfigs.add(new ConfigInfo(config, modId));
     }
 
     static void registerConfigs() {
         added = true;
-        mixinConfigs.forEach(Mixins::addConfiguration);
+        mixinConfigs.forEach(cfg -> Mixins.addConfiguration(cfg.fileName()));
+        final var configMap = Mixins.getConfigs().stream().collect(
+                Collectors.toMap(Config::getName, Config::getConfig)
+        );
+        mixinConfigs.forEach(cfg -> {
+            if (cfg.modId() == null) return;
+
+            final var config = configMap.get(cfg.fileName());
+            if (config == null) {
+                LOG.warn("Config file {} was not registered!", cfg.fileName());
+            } else {
+                config.decorate(FabricUtil.KEY_MOD_ID, cfg.modId());
+            }
+        });
         mixinConfigs.clear();
     }
 }

loader/src/main/resources/META-INF/services/cpw.mods.modlauncher.api.ITransformationService

@@ -1 +1,2 @@
-net.neoforged.fml.loading.FMLServiceProvider
+net.neoforged.fml.loading.FMLServiceProvider
+net.neoforged.fml.loading.MixinSyntheticPackageProvider