Program: 146600
Project: 146600
Buggy source:
/** 
 * Identify the itemset in the backend model, and create a set of SelectChoice objects at the current question reference based on the data in the model. Will modify the itemset binding to contain the relevant choices
 * @param itemset The binding for an itemset, where the choices will be populated
 * @param curQRef A reference to the current question's element, which will beused to determine the values to be chosen from.
 */
public void populateDynamicChoices(ItemsetBinding itemset,TreeReference curQRef){
  DataInstance formInstance;
  if (itemset.nodesetRef.getInstanceName() != null) {
    formInstance=getNonMainInstance(itemset.nodesetRef.getInstanceName());
    if (formInstance == null) {
      throw new XPathException("String_Node_Str" + itemset.nodesetRef.getInstanceName() + "String_Node_Str");
    }
  }
 else {
    formInstance=getMainInstance();
  }
  EvaluationContext ec=new EvaluationContext(exprEvalContext,itemset.contextRef.contextualize(curQRef));
  ReducingTraceReporter reporter=null;
  if (mProfilingEnabled) {
    reporter=new ReducingTraceReporter();
    ec.setDebugModeOn(reporter);
  }
  Vector<TreeReference> matches=itemset.nodesetExpr.evalNodeset(formInstance,ec);
  if (reporter != null) {
    InstrumentationUtils.printAndClearTraces(reporter,"String_Node_Str");
  }
  if (matches == null) {
    String instanceName=itemset.nodesetRef.getInstanceName();
    if (instanceName == null) {
      throw new XPathException("String_Node_Str" + itemset.nodesetRef + "String_Node_Str");
    }
 else {
      throw new XPathException("String_Node_Str" + instanceName + "String_Node_Str");
    }
  }
  Vector<SelectChoice> choices=new Vector<>();
  QueryContext newContext=ec.getCurrentQueryContext().checkForDerivativeContextAndReturn(matches.size());
  ec.setQueryContext(newContext);
  for (int i=0; i < matches.size(); i++) {
    choices.addElement(buildSelectChoice(matches.elementAt(i),itemset,formInstance,ec,i));
  }
  itemset.setChoices(choices);
}

Fixed version (ground truth):
/** 
 * Identify the itemset in the backend model, and create a set of SelectChoice objects at the current question reference based on the data in the model. Will modify the itemset binding to contain the relevant choices
 * @param itemset The binding for an itemset, where the choices will be populated
 * @param curQRef A reference to the current question's element, which will beused to determine the values to be chosen from.
 */
public void populateDynamicChoices(ItemsetBinding itemset,TreeReference curQRef){
  DataInstance formInstance;
  if (itemset.nodesetRef.getInstanceName() != null) {
    formInstance=getNonMainInstance(itemset.nodesetRef.getInstanceName());
    if (formInstance == null) {
      throw new XPathException("String_Node_Str" + itemset.nodesetRef.getInstanceName() + "String_Node_Str");
    }
  }
 else {
    formInstance=getMainInstance();
  }
  EvaluationContext ec=new EvaluationContext(exprEvalContext,itemset.contextRef.contextualize(curQRef));
  ReducingTraceReporter reporter=null;
  if (mProfilingEnabled) {
    reporter=new ReducingTraceReporter();
    ec.setDebugModeOn(reporter);
  }
  Vector<TreeReference> matches=itemset.nodesetExpr.evalNodeset(formInstance,ec);
  if (reporter != null) {
    InstrumentationUtils.printAndClearTraces(reporter,"String_Node_Str");
  }
  if (matches == null) {
    String instanceName=itemset.nodesetRef.getInstanceName();
    if (instanceName == null) {
      throw new XPathException("String_Node_Str" + itemset.nodesetRef + "String_Node_Str");
    }
 else {
      throw new XPathException("String_Node_Str" + instanceName + "String_Node_Str");
    }
  }
  Vector<SelectChoice> choices=new Vector<>();
  QueryContext newContext=ec.getCurrentQueryContext().checkForDerivativeContextAndReturn(matches.size());
  ec.setQueryContext(newContext);
  for (int i=0; i < matches.size(); i++) {
    choices.addElement(buildSelectChoice(matches.elementAt(i),itemset,formInstance,ec,reporter,i));
  }
  itemset.setChoices(choices);
}