Added a coremod, shush, don't tell Lex.

Seriously, this is how to do targeted changes to specific classes.

In this case, adding a fieldtomethod redirect for EffectInstance.potion
to allow substitution.

Signed-off-by: cpw <cpw+github@weeksfamily.ca>

build.gradle

@@ -372,7 +372,7 @@ project(':forge') {
         installer 'net.minecraftforge:accesstransformers:0.16.+:shadowed'
         installer 'net.minecraftforge:eventbus:0.10.+:service'
         installer 'net.minecraftforge:forgespi:0.13.+'
-        installer 'net.minecraftforge:coremods:0.6.+'
+        installer 'net.minecraftforge:coremods:0.7.+'
         installer 'net.minecraftforge:unsafe:0.2.+'
         installer 'com.electronwill.night-config:core:3.6.0'
         installer 'com.electronwill.night-config:toml:3.6.0'

src/fmllauncher/java/net/minecraftforge/common/asm/FieldRedirectTransformer.java

@@ -1,126 +0,0 @@
-/*
- * Minecraft Forge
- * Copyright (c) 2016-2019.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-package net.minecraftforge.common.asm;
-
-import java.util.EnumSet;
-import java.util.ListIterator;
-
-import org.objectweb.asm.Opcodes;
-import org.objectweb.asm.Type;
-import org.objectweb.asm.tree.AbstractInsnNode;
-import org.objectweb.asm.tree.ClassNode;
-import org.objectweb.asm.tree.FieldInsnNode;
-import org.objectweb.asm.tree.FieldNode;
-import org.objectweb.asm.tree.MethodInsnNode;
-import org.objectweb.asm.tree.MethodNode;
-
-import cpw.mods.modlauncher.serviceapi.ILaunchPluginService;
-
-@Deprecated // TODO as this only targets a single class, it can be moved to a JS coremod
-public abstract class FieldRedirectTransformer implements ILaunchPluginService
-{
-    private final String clsName;
-    private final String TYPE;
-    private final String DESC;
-    private final String bypass;
-
-    protected FieldRedirectTransformer(String cls, String type, String bypass)
-    {
-        this.clsName = cls;
-        this.TYPE = type;
-        this.DESC = "()" + type;
-        this.bypass = bypass;
-    }
-    
-    private static final EnumSet<Phase> YAY = EnumSet.of(Phase.AFTER);
-    private static final EnumSet<Phase> NAY = EnumSet.noneOf(Phase.class);
-    
-    @Override
-    public EnumSet<Phase> handlesClass(Type classType, boolean isEmpty)
-    {
-        return classType.getClassName().equals(clsName) && !isEmpty ? YAY : NAY;
-    }
-    
-    @Override
-    public boolean processClass(Phase phase, ClassNode classNode, Type classType)
-    {
-        FieldNode fieldRef = null;
-        for (FieldNode f : classNode.fields)
-        {
-            if (this.TYPE.equals(f.desc) && fieldRef == null)
-            {
-                fieldRef = f;
-            }
-            else if (this.TYPE.equals(f.desc))
-            {
-                throw new RuntimeException("Error processing " + clsName + " - found a duplicate holder field");
-            }
-        }
-        if (fieldRef == null)
-        {
-            throw new RuntimeException("Error processing " + clsName + " - no holder field declared (is the code somehow obfuscated?)");
-        }
-
-        MethodNode getMethod = null;
-        for (MethodNode m: classNode.methods)
-        {
-            if (m.name.equals(this.bypass)) continue;
-            if (this.DESC.equals(m.desc) && getMethod == null)
-            {
-                getMethod = m;
-            }
-            else if (this.DESC.equals(m.desc))
-            {
-                throw new RuntimeException("Error processing " + clsName + " - duplicate get method found");
-            }
-        }
-        if (getMethod == null)
-        {
-            throw new RuntimeException("Error processing " + clsName + " - no get method found (is the code somehow obfuscated?)");
-        }
-
-        for (MethodNode m: classNode.methods)
-        {
-            if (m.name.equals(this.bypass)) continue;
-            for (ListIterator<AbstractInsnNode> it = m.instructions.iterator(); it.hasNext(); )
-            {
-                AbstractInsnNode insnNode = it.next();
-                if (insnNode.getType() == AbstractInsnNode.FIELD_INSN)
-                {
-                    FieldInsnNode fi = (FieldInsnNode)insnNode;
-                    if (fieldRef.name.equals(fi.name) && fi.getOpcode() == Opcodes.GETFIELD)
-                    {
-                        it.remove();
-                        MethodInsnNode replace = new MethodInsnNode(Opcodes.INVOKEVIRTUAL, classNode.name, getMethod.name, getMethod.desc, false);
-                        it.add(replace);
-                    }
-                }
-            }
-        }
-        
-        return true;
-    }
-
-    @Override
-    public String name()
-    {
-        return "field_redirect_" + clsName + "/" + TYPE;
-    }
-}

src/fmllauncher/java/net/minecraftforge/common/asm/PotionEffectTransformer.java

@@ -1,29 +0,0 @@
-/*
- * Minecraft Forge
- * Copyright (c) 2016-2019.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation version 2.1
- * of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-package net.minecraftforge.common.asm;
-
-@Deprecated
-public class PotionEffectTransformer extends FieldRedirectTransformer
-{
-    public PotionEffectTransformer()
-    {
-        super("net.minecraft.potion.PotionEffect", "Lnet/minecraft/potion/Potion;", "getPotionRaw");
-    }
-}

src/fmllauncher/resources/META-INF/services/cpw.mods.modlauncher.serviceapi.ILaunchPluginService

@@ -2,4 +2,3 @@ net.minecraftforge.fml.loading.RuntimeDistCleaner
 net.minecraftforge.common.asm.RuntimeEnumExtender
 net.minecraftforge.common.asm.ObjectHolderDefinalize
 net.minecraftforge.common.asm.CapabilityInjectDefinalize
-net.minecraftforge.common.asm.PotionEffectTransformer

src/main/resources/META-INF/coremods.json

@@ -0,0 +1,3 @@
+{
+  "fieldtomethodtransformers": "META-INF/fieldtomethodtransformers.js"
+}

src/main/resources/META-INF/fieldtomethodtransformers.js

@@ -0,0 +1,15 @@
+function initializeCoreMod() {
+    return {
+        'potion': {
+            'target': {
+                'type': 'CLASS',
+                'name': 'net.minecraft.potion.EffectInstance'
+            },
+            'transformer': function(classNode) {
+                var asmapi=Java.type('net.minecraftforge.coremod.api.ASMAPI')
+                asmapi.redirectFieldToMethod(classNode, 'potion', 'getPotionRaw')
+                return classNode;
+            }
+        }
+    }
+}