Program: 144717
Project: 144717
Buggy source:
public void processAction(FormDef model,TreeReference contextRef){
  TreeReference qualifiedReference=contextRef == null ? target : target.contextualize(contextRef);
  if (contextRef != null) {
    if (!contextRef.isParentOf(qualifiedReference,false)) {
      return;
    }
  }
  EvaluationContext context=new EvaluationContext(model.getEvaluationContext(),qualifiedReference);
  Object result;
  if (explicitValue != null) {
    result=explicitValue;
  }
 else {
    result=XPathFuncExpr.unpack(value.eval(model.getMainInstance(),context));
  }
  String failMessage="String_Node_Str" + target.toString(true) + "String_Node_Str";
  if (qualifiedReference.hasPredicates()) {
    Vector<TreeReference> references=context.expandReference(qualifiedReference);
    if (references.size() == 0) {
      throw new NullPointerException(failMessage);
    }
 else     if (references.size() > 1) {
      throw new XPathTypeMismatchException("String_Node_Str" + XPathNodeset.printNodeContents(references) + "String_Node_Str");
    }
 else {
      qualifiedReference=references.elementAt(0);
    }
  }
  AbstractTreeElement node=context.resolveReference(qualifiedReference);
  if (node == null) {
    throw new NullPointerException(failMessage);
  }
  int dataType=node.getDataType();
  IAnswerData val=Recalculate.wrapData(result,dataType);
  model.setValue(val == null ? null : AnswerDataFactory.templateByDataType(dataType).cast(val.uncast()),qualifiedReference);
}

Fixed version (ground truth):
public void processAction(FormDef model,TreeReference contextRef){
  TreeReference qualifiedReference=contextRef == null ? target : target.contextualize(contextRef);
  if (contextRef != null) {
    if (!contextRef.isParentOf(qualifiedReference,false)) {
      return;
    }
  }
  EvaluationContext context=new EvaluationContext(model.getEvaluationContext(),qualifiedReference);
  String failMessage="String_Node_Str" + target.toString(true) + "String_Node_Str";
  if (qualifiedReference.hasPredicates()) {
    Vector<TreeReference> references=context.expandReference(qualifiedReference,true);
    if (references.size() == 0) {
      throw new NullPointerException(failMessage);
    }
 else     if (references.size() > 1) {
      TreeReference singleFullyQualifiedRef=null;
      for (      TreeReference ref : references) {
        if (!ref.isTemplateRef()) {
          if (singleFullyQualifiedRef == null) {
            singleFullyQualifiedRef=ref;
          }
 else {
            throw new XPathTypeMismatchException("String_Node_Str" + XPathNodeset.printNodeContents(references) + "String_Node_Str");
          }
        }
      }
      if (singleFullyQualifiedRef == null) {
        return;
      }
    }
 else {
      qualifiedReference=references.elementAt(0);
    }
  }
  if (qualifiedReference.isTemplateRef()) {
    return;
  }
  AbstractTreeElement node=context.resolveReference(qualifiedReference);
  if (node == null) {
    if (model.getMainInstance().hasTemplatePath(target)) {
      return;
    }
 else {
      throw new NullPointerException(failMessage);
    }
  }
  Object result;
  if (explicitValue != null) {
    result=explicitValue;
  }
 else {
    result=XPathFuncExpr.unpack(value.eval(model.getMainInstance(),context));
  }
  int dataType=node.getDataType();
  IAnswerData val=Recalculate.wrapData(result,dataType);
  model.setValue(val == null ? null : AnswerDataFactory.templateByDataType(dataType).cast(val.uncast()),qualifiedReference);
}