Program: 23325
Project: 23325
Buggy source:
private List<Variables> processSource(String ruleId,TransformContext context,Variables vars,StructureMapGroupRuleSourceComponent src) throws FHIRException {
  Base b=vars.get(VariableMode.INPUT,src.getContext());
  if (b == null)   throw new FHIRException("String_Node_Str" + src.getContext());
  if (src.hasCondition()) {
    ExpressionNode expr=(ExpressionNode)src.getUserData(MAP_WHERE_EXPRESSION);
    if (expr == null) {
      expr=fpe.parse(src.getCondition());
      src.setUserData(MAP_WHERE_EXPRESSION,expr);
    }
    if (!fpe.evaluateToBoolean(vars,null,b,expr))     return null;
  }
  if (src.hasCheck()) {
    ExpressionNode expr=(ExpressionNode)src.getUserData(MAP_WHERE_CHECK);
    if (expr == null) {
      expr=fpe.parse(src.getCheck());
      src.setUserData(MAP_WHERE_CHECK,expr);
    }
    if (!fpe.evaluateToBoolean(null,b,expr))     throw new FHIRException("String_Node_Str" + ruleId + "String_Node_Str");
  }
  List<Base> items=new ArrayList<Base>();
  if (!src.hasElement())   items.add(b);
 else {
    getChildrenByName(b,src.getElement(),items);
    if (items.size() == 0 && src.hasDefaultValue())     items.add(src.getDefaultValue());
  }
  if (src.hasType()) {
    List<Base> remove=new ArrayList<Base>();
    for (    Base item : items) {
      if (!isType(item,src.getType())) {
        remove.add(item);
      }
    }
    items.removeAll(remove);
  }
  if (src.hasListMode()) {
switch (src.getListMode()) {
case FIRST:
      Base bt=items.get(0);
    items.clear();
  items.add(bt);
break;
case NOTFIRST:
if (items.size() > 1) items.remove(0);
break;
case LAST:
bt=items.get(items.size() - 1);
items.clear();
items.add(bt);
break;
case NOTLAST:
if (items.size() > 1) items.remove(items.size() - 1);
break;
case ONLYONE:
if (items.size() > 1) items.clear();
break;
case NULL:
}
}
List<Variables> result=new ArrayList<Variables>();
for (Base r : items) {
Variables v=vars.copy();
if (src.hasVariable()) v.add(VariableMode.INPUT,src.getVariable(),r);
result.add(v);
}
return result;
}

Fixed version (ground truth):
private List<Variables> processSource(String ruleId,TransformContext context,Variables vars,StructureMapGroupRuleSourceComponent src) throws FHIRException {
  Base b=vars.get(VariableMode.INPUT,src.getContext());
  if (b == null)   throw new FHIRException("String_Node_Str" + src.getContext());
  if (src.hasCondition()) {
    ExpressionNode expr=(ExpressionNode)src.getUserData(MAP_WHERE_EXPRESSION);
    if (expr == null) {
      expr=fpe.parse(src.getCondition());
      src.setUserData(MAP_WHERE_EXPRESSION,expr);
    }
    if (!fpe.evaluateToBoolean(vars,null,b,expr))     return null;
  }
  if (src.hasCheck()) {
    ExpressionNode expr=(ExpressionNode)src.getUserData(MAP_WHERE_CHECK);
    if (expr == null) {
      expr=fpe.parse(src.getCheck());
      src.setUserData(MAP_WHERE_CHECK,expr);
    }
    if (!fpe.evaluateToBoolean(null,b,expr))     throw new FHIRException("String_Node_Str" + ruleId + "String_Node_Str");
  }
  List<Base> items=new ArrayList<Base>();
  if (!src.hasElement())   items.add(b);
 else {
    getChildrenByName(b,src.getElement(),items);
    if (items.size() == 0 && src.hasDefaultValue())     items.add(src.getDefaultValue());
  }
  if (src.hasType()) {
    List<Base> remove=new ArrayList<Base>();
    for (    Base item : items) {
      if (item != null && !isType(item,src.getType())) {
        remove.add(item);
      }
    }
    items.removeAll(remove);
  }
  if (src.hasListMode()) {
switch (src.getListMode()) {
case FIRST:
      Base bt=items.get(0);
    items.clear();
  items.add(bt);
break;
case NOTFIRST:
if (items.size() > 1) items.remove(0);
break;
case LAST:
bt=items.get(items.size() - 1);
items.clear();
items.add(bt);
break;
case NOTLAST:
if (items.size() > 1) items.remove(items.size() - 1);
break;
case ONLYONE:
if (items.size() > 1) items.clear();
break;
case NULL:
}
}
List<Variables> result=new ArrayList<Variables>();
for (Base r : items) {
Variables v=vars.copy();
if (src.hasVariable()) v.add(VariableMode.INPUT,src.getVariable(),r);
result.add(v);
}
return result;
}