Program: 40453
Project: 40453
Buggy source:
public String executeUnsignCommand(Config config,User user,Locale localeForUser,String[] args,String help){
  String people=args[0];
  String userName=user.getName();
  if (args.length < 2 || args.length > 10) {
    throw new WrongNumberOfArgumentsException(user,localeService,2,args.length,help);
  }
  Integer numberOfPeople=Utils.assertNotTooManyOrNoNumber(user,localeService,people);
  StringBuilder gymNameBuilder=new StringBuilder();
  for (int i=1; i < args.length; i++) {
    gymNameBuilder.append(args[i]).append("String_Node_Str");
  }
  String gymName=gymNameBuilder.toString().trim();
  final Gym gym=gymRepository.search(user,gymName,config.getRegion());
  Raid raid=getActiveRaidOrFallbackToExRaid(gym,config.getRegion(),user);
  final RaidEntitySignUp signUp=findEntityByRaidId(raid.getId()).getSignUp(user.getName());
  raid=removeFromSignUp(raid.getId(),user,0,0,0,numberOfPeople,LocalDateTime.of(raid.getEndOfRaid().toLocalDate(),signUp.getArrivalTime()));
  final String currentSignupText=localeService.getMessageFor(LocaleService.CURRENT_SIGNUPS,localeForUser);
  final Set<SignUp> signUps=raid.getSignUps();
  Set<String> signUpNames=Utils.getNamesOfThoseWithSignUps(signUps,true);
  final String allSignUpNames=StringUtils.join(signUpNames,"String_Node_Str");
  final String signUpText=raid.getSignUps().size() > 1 ? currentSignupText + "String_Node_Str" + allSignUpNames : "String_Node_Str";
  return localeService.getMessageFor(LocaleService.UNSIGN,localeForUser,userName,gym.getName(),signUpText);
}

Fixed version (ground truth):
public String executeUnsignCommand(Config config,User user,Locale localeForUser,String[] args,String help){
  String people=args[0];
  String userName=user.getName();
  if (args.length < 2 || args.length > 10) {
    throw new WrongNumberOfArgumentsException(user,localeService,2,args.length,help);
  }
  Integer numberOfPeople=Utils.assertNotTooManyOrNoNumber(user,localeService,people);
  StringBuilder gymNameBuilder=new StringBuilder();
  for (int i=1; i < args.length; i++) {
    gymNameBuilder.append(args[i]).append("String_Node_Str");
  }
  String gymName=gymNameBuilder.toString().trim();
  final Gym gym=gymRepository.search(user,gymName,config.getRegion());
  Raid raid=getActiveRaidOrFallbackToExRaid(gym,config.getRegion(),user);
  final RaidEntitySignUp signUp=findEntityByRaidId(raid.getId()).getSignUp(user.getName());
  if (signUp == null) {
    throw new UserMessedUpException(user,localeService.getMessageFor(LocaleService.NO_SIGNUP_AT_GYM,localeForUser,user.getName(),gym.getName()));
  }
  raid=removeFromSignUp(raid.getId(),user,0,0,0,numberOfPeople,LocalDateTime.of(raid.getEndOfRaid().toLocalDate(),signUp.getArrivalTime()));
  final String currentSignupText=localeService.getMessageFor(LocaleService.CURRENT_SIGNUPS,localeForUser);
  final Set<SignUp> signUps=raid.getSignUps();
  Set<String> signUpNames=Utils.getNamesOfThoseWithSignUps(signUps,true);
  final String allSignUpNames=StringUtils.join(signUpNames,"String_Node_Str");
  final String signUpText=raid.getSignUps().size() > 1 ? currentSignupText + "String_Node_Str" + allSignUpNames : "String_Node_Str";
  return localeService.getMessageFor(LocaleService.UNSIGN,localeForUser,userName,gym.getName(),signUpText);
}