Program: 58406
Project: 58406
Buggy source:
private static byte[] writeWorldServer(String name,String transformedName,byte[] bytes,ClassReader cr){
  String[] names;
  if (LoadingPlugin.runtimeDeobfEnabled) {
    names=new String[]{"String_Node_Str","String_Node_Str","String_Node_Str","String_Node_Str"};
  }
 else {
    names=new String[]{"String_Node_Str","String_Node_Str","String_Node_Str","String_Node_Str"};
  }
  name=name.replace('.','/');
  ClassNode cn=new ClassNode(ASM5);
  cr.accept(cn,ClassReader.EXPAND_FRAMES);
  final String sig="String_Node_Str";
  l: {
    for (    MethodNode m : cn.methods) {
      if ("String_Node_Str".equals(m.name) && sig.equals(m.desc)) {
        break l;
      }
    }
    ClassWriter cw=new ClassWriter(ClassWriter.COMPUTE_FRAMES);
    cn.accept(cw);
    cw.newMethod(name,"String_Node_Str",sig,true);
    MethodVisitor mv=cw.visitMethod(ACC_PUBLIC,"String_Node_Str",sig,null,null);
    mv.visitCode();
    mv.visitVarInsn(ALOAD,0);
    mv.visitInsn(DUP);
    mv.visitInsn(DUP);
    mv.visitInsn(DUP);
    mv.visitInsn(DUP);
    mv.visitVarInsn(ALOAD,2);
    mv.visitVarInsn(ALOAD,3);
    mv.visitVarInsn(ALOAD,4);
    mv.visitVarInsn(ALOAD,5);
    mv.visitVarInsn(ALOAD,6);
    mv.visitMethodInsn(INVOKESPECIAL,"String_Node_Str","String_Node_Str","String_Node_Str",false);
    mv.visitVarInsn(ALOAD,1);
    mv.visitFieldInsn(PUTFIELD,name,names[0],"String_Node_Str");
    mv.visitInsn(ACONST_NULL);
    mv.visitFieldInsn(PUTFIELD,name,names[1],"String_Node_Str");
    mv.visitInsn(ACONST_NULL);
    mv.visitFieldInsn(PUTFIELD,name,names[2],"String_Node_Str");
    mv.visitInsn(ACONST_NULL);
    mv.visitFieldInsn(PUTFIELD,name,names[3],"String_Node_Str");
    mv.visitInsn(RETURN);
    mv.visitMaxs(11,10);
    mv.visitEnd();
    cw.visitEnd();
    bytes=cw.toByteArray();
  }
  return bytes;
}

Fixed version (ground truth):
private static byte[] writeWorldServer(String name,String transformedName,byte[] bytes,ClassReader cr){
  String[] names;
  if (LoadingPlugin.runtimeDeobfEnabled) {
    names=new String[]{"String_Node_Str","String_Node_Str","String_Node_Str","String_Node_Str"};
  }
 else {
    names=new String[]{"String_Node_Str","String_Node_Str","String_Node_Str","String_Node_Str"};
  }
  name=transformedName.replace('.','/');
  ClassNode cn=new ClassNode(ASM5);
  cr.accept(cn,ClassReader.EXPAND_FRAMES);
  final String sig="String_Node_Str";
  l: {
    for (    MethodNode m : cn.methods) {
      if ("String_Node_Str".equals(m.name) && sig.equals(m.desc)) {
        break l;
      }
    }
    ClassWriter cw=new ClassWriter(ClassWriter.COMPUTE_FRAMES);
    cn.accept(cw);
    cw.newMethod(name,"String_Node_Str",sig,true);
    MethodVisitor mv=cw.visitMethod(ACC_PUBLIC,"String_Node_Str",sig,null,null);
    mv.visitCode();
    mv.visitVarInsn(ALOAD,0);
    mv.visitInsn(DUP);
    mv.visitInsn(DUP);
    mv.visitInsn(DUP);
    mv.visitInsn(DUP);
    mv.visitVarInsn(ALOAD,2);
    mv.visitVarInsn(ALOAD,3);
    mv.visitVarInsn(ALOAD,4);
    mv.visitVarInsn(ALOAD,5);
    mv.visitVarInsn(ALOAD,6);
    mv.visitMethodInsn(INVOKESPECIAL,"String_Node_Str","String_Node_Str","String_Node_Str",false);
    mv.visitVarInsn(ALOAD,1);
    mv.visitFieldInsn(PUTFIELD,name,names[0],"String_Node_Str");
    mv.visitInsn(ACONST_NULL);
    mv.visitFieldInsn(PUTFIELD,name,names[1],"String_Node_Str");
    mv.visitInsn(ACONST_NULL);
    mv.visitFieldInsn(PUTFIELD,name,names[2],"String_Node_Str");
    mv.visitInsn(ACONST_NULL);
    mv.visitFieldInsn(PUTFIELD,name,names[3],"String_Node_Str");
    mv.visitInsn(RETURN);
    mv.visitMaxs(11,10);
    mv.visitEnd();
    cw.visitEnd();
    bytes=cw.toByteArray();
  }
  return bytes;
}