Program: 30902
Project: 30902
Buggy source:
/** 
 * Replace the first item in the list that the provided predicate returns true for with the provided item. If no matching item is found, add the provided item into the list. <p> The   {@link Scheduler} used for this operation will be the one specified in{@link Builder#schedulingWith(Scheduler) schedulingWith()}.
 */
@NotNull public Single<List<T>> observeAddOrReplace(@NotNull final T value,@NotNull final ReplacePredicateFunc<T> predicateFunc){
  return Single.create(new Single.OnSubscribe<List<T>>(){
    @Override public void call(    SingleSubscriber<? super List<T>> subscriber){
      try {
        if (!file.exists())         throw new IOException("String_Node_Str");
        runInWriteLock(readWriteLock,new Runnable(){
          @Override public void run(){
            List<T> originalList=converter.read(file,type);
            if (originalList == null)             originalList=Collections.emptyList();
            int indexOfItemToReplace=-1;
            for (int i=0; i < originalList.size(); i++) {
              if (predicateFunc.shouldReplace(originalList.get(i))) {
                indexOfItemToReplace=i;
                break;
              }
            }
            int modifiedListSize=indexOfItemToReplace == -1 ? originalList.size() + 1 : originalList.size();
            List<T> modifiedList=new ArrayList<T>(modifiedListSize);
            modifiedList.addAll(originalList);
            if (indexOfItemToReplace == -1) {
              modifiedList.add(value);
            }
 else {
              modifiedList.remove(indexOfItemToReplace);
              modifiedList.add(indexOfItemToReplace,value);
            }
            converter.write(modifiedList,type,file);
            subscriber.onSuccess(modifiedList);
            updateSubject.onNext(modifiedList);
          }
        }
);
      }
 catch (      Exception e) {
        subscriber.onError(e);
      }
    }
  }
).subscribeOn(scheduler);
}

Fixed version (ground truth):
/** 
 * Replace the first item in the list that the provided predicate returns true for with the provided item. If no matching item is found, add the provided item into the list. <p> The   {@link Scheduler} used for this operation will be the one specified in{@link Builder#schedulingWith(Scheduler) schedulingWith()}.
 */
@NotNull public Single<List<T>> observeAddOrReplace(@NotNull final T value,@NotNull final ReplacePredicateFunc<T> predicateFunc){
  return Single.create(new Single.OnSubscribe<List<T>>(){
    @Override public void call(    final SingleSubscriber<? super List<T>> subscriber){
      try {
        if (!file.exists())         throw new IOException("String_Node_Str");
        runInWriteLock(readWriteLock,new Runnable(){
          @Override public void run(){
            List<T> originalList=converter.read(file,type);
            if (originalList == null)             originalList=Collections.emptyList();
            int indexOfItemToReplace=-1;
            for (int i=0; i < originalList.size(); i++) {
              if (predicateFunc.shouldReplace(originalList.get(i))) {
                indexOfItemToReplace=i;
                break;
              }
            }
            int modifiedListSize=indexOfItemToReplace == -1 ? originalList.size() + 1 : originalList.size();
            List<T> modifiedList=new ArrayList<T>(modifiedListSize);
            modifiedList.addAll(originalList);
            if (indexOfItemToReplace == -1) {
              modifiedList.add(value);
            }
 else {
              modifiedList.remove(indexOfItemToReplace);
              modifiedList.add(indexOfItemToReplace,value);
            }
            converter.write(modifiedList,type,file);
            subscriber.onSuccess(modifiedList);
            updateSubject.onNext(modifiedList);
          }
        }
);
      }
 catch (      Exception e) {
        subscriber.onError(e);
      }
    }
  }
).subscribeOn(scheduler);
}