Prevent mod mixins from applying if there is a Forge loading error

Author: embeddedt

forge/src/main/java/org/embeddedt/modernfix/forge/classloading/ATInjector.java

@@ -1,15 +1,26 @@
 package org.embeddedt.modernfix.forge.classloading;
 
+import cpw.mods.jarhandling.SecureJar;
+import cpw.mods.modlauncher.LaunchPluginHandler;
+import cpw.mods.modlauncher.Launcher;
+import cpw.mods.modlauncher.api.NamedPath;
+import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
 import net.minecraftforge.fml.loading.FMLLoader;
 import net.minecraftforge.fml.loading.moddiscovery.ModFile;
 import net.minecraftforge.fml.loading.moddiscovery.ModValidator;
 import net.minecraftforge.fml.util.ObfuscationReflectionHelper;
 import org.apache.commons.lang3.tuple.Pair;
 import org.embeddedt.modernfix.core.ModernFixMixinPlugin;
 import org.embeddedt.modernfix.util.CommonModUtil;
+import org.objectweb.asm.Type;
 
+import java.lang.reflect.Field;
 import java.nio.file.Path;
+import java.util.EnumSet;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
 public class ATInjector {
@@ -31,6 +42,80 @@ public static void injectModATs() {
                     }
                 }
             }
+
+            // inject into Launcher.INSTANCE.launchPlugins and wrap the mixin plugin, so that mixin transformations
+            // are not applied
+            try {
+                Launcher launcher = Launcher.INSTANCE;
+                Field launchPlugins = Launcher.class.getDeclaredField("launchPlugins");
+                launchPlugins.setAccessible(true);
+
+                LaunchPluginHandler handler = (LaunchPluginHandler) launchPlugins.get(launcher);
+                Field plugins = LaunchPluginHandler.class.getDeclaredField("plugins");
+                plugins.setAccessible(true);
+
+                //noinspection unchecked
+                Map<String, ILaunchPluginService> map = (Map<String, ILaunchPluginService>) plugins.get(handler);
+                Map<String, ILaunchPluginService> newMap = new HashMap<>(map);
+                NonTransformingLaunchPluginService.class.getName(); // trigger classloading, just to be safe
+                newMap.replaceAll((name, plugin) -> {
+                    if(plugin.getClass().getName().startsWith("org.spongepowered.asm.launch.MixinLaunchPlugin")) {
+                        ModernFixMixinPlugin.instance.logger.warn("Disabling plugin '{}': {}", name, plugin.getClass().getName());
+                        return new NonTransformingLaunchPluginService(plugin);
+                    } else {
+                        return plugin;
+                    }
+                });
+                plugins.set(handler, newMap);
+            } catch (ReflectiveOperationException e) {
+                e.printStackTrace();
+            }
         }, "applying mod ATs in errored state");
     }
+
+    static class NonTransformingLaunchPluginService implements ILaunchPluginService {
+
+        private final ILaunchPluginService delegate;
+
+        NonTransformingLaunchPluginService(ILaunchPluginService delegate) {
+            this.delegate = delegate;
+        }
+
+        @Override
+        public String name() {
+            return delegate.name();
+        }
+
+        private static final EnumSet<Phase> NEVER = EnumSet.noneOf(Phase.class);
+
+        @Override
+        public EnumSet<Phase> handlesClass(Type classType, boolean isEmpty) {
+            return NEVER;
+        }
+
+        @Override
+        public void offerResource(Path resource, String name) {
+            delegate.offerResource(resource, name);
+        }
+
+        @Override
+        public void addResources(List<SecureJar> resources) {
+            delegate.addResources(resources);
+        }
+
+        @Override
+        public void initializeLaunch(ITransformerLoader transformerLoader, NamedPath[] specialPaths) {
+            delegate.initializeLaunch(transformerLoader, specialPaths);
+        }
+
+        @Override
+        public <T> T getExtension() {
+            return delegate.getExtension();
+        }
+
+        @Override
+        public void customAuditConsumer(String className, Consumer<String[]> auditDataAcceptor) {
+            delegate.customAuditConsumer(className, auditDataAcceptor);
+        }
+    }
 }