Make it all work.

src/main/java/net/theopalgames/descript/coremods/CoreModLoader.java

@@ -52,6 +52,9 @@ private void swapClassFinder() {
 		Function<String, URL> oldFinder = ReflectUtil.readField(TransformingClassLoader.class, "classBytesFinder", CoremodClassLoader.gameLoader);
 		Function<String, URL> newFinder = oldFinder.andThen(url -> (isDescript(url) ? null : url));
 
+		ClassLoader oldParent = ReflectUtil.readField(ClassLoader.class,  "parent", CoremodClassLoader.gameLoader);
+		ReflectUtil.writeField(ClassLoader.class, "parent", CoremodClassLoader.gameLoader, new DescriptClassLoader(oldParent));
+
 		ReflectUtil.writeField(TransformingClassLoader.class, "classBytesFinder", CoremodClassLoader.gameLoader, newFinder);
 	}
 

src/main/java/net/theopalgames/descript/coremods/DescriptClassLoader.java

@@ -0,0 +1,12 @@
+package net.theopalgames.descript.coremods;
+
+public final class DescriptClassLoader extends ClassLoader {
+	public DescriptClassLoader(ClassLoader parent) {
+		super(parent);
+	}
+
+	@Override
+	protected Class<?> findClass(String name) throws ClassNotFoundException {
+		return getClass().getClassLoader().loadClass(name);
+	}
+}

src/main/java/net/theopalgames/descript/init/DescriptInit.java

@@ -6,6 +6,8 @@
 import java.lang.reflect.Method;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.nio.file.FileSystem;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
@@ -25,7 +27,7 @@
 import net.minecraftforge.fml.loading.FMLLoader;
 import net.minecraftforge.fml.loading.moddiscovery.CoreModFile;
 
-// WARNING: If you make any changes to this file, you need to recompile it and put the bytes into src/main/js/core-plugin.js
+// WARNING: No warning anymore lol
 
 @UtilityClass
 public class DescriptInit {
@@ -46,14 +48,22 @@ private File findDescriptJar() throws Exception {
 
 		List<CoreMod> coreMods = readField(CoreModEngine.class, "coreMods", engine);
 		CoreModFile fileWrapper;
+		Path path;
+		FileSystem fs;
 		File file = null;
 		JarEntry entry;
 		byte[] bytes;
 		ClassNode clazz;
 
 		for (CoreMod coreMod : coreMods) {
 			fileWrapper = readField(CoreMod.class, "file", coreMod);
-			file = fileWrapper.getPath().toFile();
+			path = fileWrapper.getPath();
+			fs = path.getFileSystem();
+
+			if (fs.getClass().getName().endsWith(".ZipFileSystem"))
+				path = readField(fs.getClass(), "zfpath", fs);
+
+			file = path.toFile();
 
 			if (file.isFile()) {
 				if (file.getName().endsWith(".jar"))

src/main/java/net/theopalgames/descript/init/UclClassLoader.java

@@ -8,15 +8,21 @@
 
 import org.apache.commons.lang3.tuple.Pair;
 
+import lombok.SneakyThrows;
 import net.theopalgames.descript.reflect.ReflectUtil;
 import net.theopalgames.descript.transformers.UclTransformer;
 
 public final class UclClassLoader extends SecureClassLoader {
 	private final Map<String, Pair<byte[], ProtectionDomain>> loadedClasses = new HashMap<>();
 
+	@SneakyThrows
 	public IClassLoaderDelegate getDelegate() {
+//		System.out.println("Defining ClassLoaderDelegate...");
+
 		byte[] uclBytes = UclTransformer.getUclLoader(this);
-		Class<?> clazz = defineClass("net.theopalgames.descript.ucl.ClassLoaderDelegate", uclBytes, 0, uclBytes.length);
+		createClass("net.theopalgames.descript.ucl.ClassLoaderDelegate", uclBytes, null);
+
+		Class<?> clazz = Class.forName("net.theopalgames.descript.ucl.ClassLoaderDelegate", true, this);
 		Class<? extends IClassLoaderDelegate> cast = clazz.asSubclass(IClassLoaderDelegate.class);
 		return ReflectUtil.findConstructor(cast, URL[].class, ClassLoader.class).newInstance((Object) new URL[0], getClass().getClassLoader());
 	}
@@ -27,10 +33,21 @@ public void createClass(String name, byte[] bytes, ProtectionDomain domain) {
 	}
 
 	@Override
-	public Class<?> findClass(String name) {
+	public Class<?> findClass(String name) throws ClassNotFoundException {
+		if (name.equals("net.theopalgames.descript.init.IClassLoaderDelegate") || name.equals("net.theopalgames.descript.transformers.UclTransformer"))
+			return getClass().getClassLoader().loadClass(name);
+
 //		System.out.println("Loading UCL class " + name);
 
 		Pair<byte[], ProtectionDomain> pair = loadedClasses.get(name);
-		return defineClass(name, pair.getLeft(), 0, pair.getLeft().length, pair.getRight());
+
+//		if (pair == null)
+//			throw new ClassNotFoundException(name, new NullPointerException("pair"));
+
+		try {
+			return defineClass(name, pair.getLeft(), 0, pair.getLeft().length, pair.getRight());
+		} catch (NullPointerException e) {
+			throw new ClassNotFoundException(name, e);
+		}
 	}
 }

src/main/java/net/theopalgames/descript/transformers/InnerUclTransformer.java

@@ -7,7 +7,6 @@
 
 import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.ClassWriter;
-import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
 import org.objectweb.asm.tree.AbstractInsnNode;
 import org.objectweb.asm.tree.ClassNode;
@@ -23,7 +22,7 @@
 @UtilityClass
 public class InnerUclTransformer {
 	@SuppressWarnings("unchecked")
-	public void loadBytes(String name, UclClassLoader classLoader, String clPackage) throws Exception {
+	public void loadBytes(String name, UclClassLoader classLoader, String clPackage, String descAccess100) throws Exception {
 //		System.out.println("Transforming inner class: " + name);
 
 		if (!name.startsWith("java/net/"))
@@ -50,6 +49,7 @@ public void loadBytes(String name, UclClassLoader classLoader, String clPackage)
 		for (MethodNode method : clazz.methods) {
 			Type type = Type.getMethodType(method.desc);
 			Type[] args = type.getArgumentTypes();
+			boolean descChanged = false;
 
 			for (int i = 0; i < args.length; i++) {
 				if (args[i].getDescriptor().equals("Ljava/net/URLClassLoader;"))
@@ -58,6 +58,11 @@ public void loadBytes(String name, UclClassLoader classLoader, String clPackage)
 
 //			System.out.println("\n" + clazz.name + "" + method.name + method.desc);
 
+			if (clazz.name.equals("net/theopalgames/descript/ucl/ClassLoaderDelegate$1") && method.name.equals("run") && method.desc.equals("()Ljava/lang/Class;")) {
+				method.desc = "()Lorg/apache/commons/lang3/tuple/Pair;";
+				descChanged = true;
+			}
+
 			for (AbstractInsnNode insn : (Iterable<AbstractInsnNode>) () -> method.instructions.iterator()) {
 //				System.out.println(insn.getOpcode());
 
@@ -69,6 +74,10 @@ public void loadBytes(String name, UclClassLoader classLoader, String clPackage)
 
 						if (cast.name.equals("defineClass"))
 							cast.desc = "(Ljava/lang/String;L" + clPackage + "/Resource;)Lorg/apache/commons/lang3/tuple/Pair;";
+						else if (cast.name.equals("access$100"))
+							cast.desc = descAccess100;
+						else if (cast.name.equals("run"))
+							cast.desc = "()Lorg/apache/commons/lang3/tuple/Pair;";
 					}
 
 					Type calleeType = Type.getMethodType(cast.desc);
@@ -81,8 +90,8 @@ public void loadBytes(String name, UclClassLoader classLoader, String clPackage)
 
 					cast.desc = Type.getMethodType(calleeType.getReturnType(), calleeargs).getDescriptor();
 
-					if (cast.getOpcode() == Opcodes.INVOKEVIRTUAL)
-						System.out.println(clazz.name + "/" + method.name + method.desc + " -> " + cast.owner + "/" + cast.name + cast.desc);
+//					if (cast.getOpcode() == Opcodes.INVOKEVIRTUAL)
+//						System.out.println(clazz.name + "/" + method.name + method.desc + " -> " + cast.owner + "/" + cast.name + cast.desc);
 				} else if (insn instanceof FieldInsnNode) {
 					FieldInsnNode cast = (FieldInsnNode) insn;
 
@@ -106,8 +115,10 @@ public void loadBytes(String name, UclClassLoader classLoader, String clPackage)
 				}
 			}
 
-			Type newType = Type.getMethodType(type.getReturnType(), args);
-			method.desc = newType.getDescriptor();
+			if (!descChanged) {
+				Type newType = Type.getMethodType(type.getReturnType(), args);
+				method.desc = newType.getDescriptor();
+			}
 		}
 
 		ClassWriter cw = new ClassWriter(0);

src/main/java/net/theopalgames/descript/transformers/UclTransformer.java

@@ -68,9 +68,12 @@ public byte[] getUclLoader(UclClassLoader classLoader) {
 		List<MethodNode> toRemove = new ArrayList<>();
 		boolean descChanged;
 
+		String descAccess100 = null;
+
 		for (MethodNode method : clazz.methods) {
 			Type type = Type.getMethodType(method.desc);
 			Type[] args = type.getArgumentTypes();
+			Type ret = type.getReturnType();
 			descChanged = false;
 
 			for (int i = 0; i < args.length; i++) {
@@ -151,6 +154,16 @@ public byte[] getUclLoader(UclClassLoader classLoader) {
 			} else if (method.name.equals("addURL")) {
 				method.access &= ~Opcodes.ACC_PROTECTED;
 				method.access |= Opcodes.ACC_PUBLIC;
+			} else if (method.name.equals("access$100")) {
+				ret = Type.getType("Lorg/apache/commons/lang3/tuple/Pair;");
+
+				for (AbstractInsnNode insn : (Iterable<AbstractInsnNode>) () -> method.instructions.iterator())
+					if (insn instanceof MethodInsnNode) {
+						MethodInsnNode cast = (MethodInsnNode) insn;
+
+						if (cast.name.equals("defineClass"))
+							cast.desc = "(Ljava/lang/String;L" + clPackage + "/Resource;)Lorg/apache/commons/lang3/tuple/Pair;";
+					}
 			}
 
 			for (AbstractInsnNode insn : (Iterable<AbstractInsnNode>) () -> method.instructions.iterator())
@@ -183,20 +196,22 @@ public byte[] getUclLoader(UclClassLoader classLoader) {
 				}
 
 			if (!descChanged) {
-				Type ret = type.getReturnType();
 				if (ret.getDescriptor().equals("Ljava/lang/ClassLoader;"))
 					ret = Type.getType("Lnet/theopalgames/descript/ucl/ClassLoaderDelegate;");
 
 				Type newType = Type.getMethodType(ret, args);
 				method.desc = newType.getDescriptor();
 			}
+
+			if (method.name.equals("access$100"))
+				descAccess100 = method.desc;
 		}
 
 //		toRemove.stream().map(method -> method.name + method.desc).forEach(System.out::println);
 		clazz.methods.removeAll(toRemove);
 
 		for (InnerClassNode inner : clazz.innerClasses) {
-			InnerUclTransformer.loadBytes(inner.name, classLoader, clPackage);
+			InnerUclTransformer.loadBytes(inner.name, classLoader, clPackage, descAccess100);
 			inner.name = inner.name.replace("java/net/URLClassLoader", "net/theopalgames/descript/ucl/ClassLoaderDelegate");
 		}