Program: 123731
Project: 123731
Buggy source:
public static void detachConnectionsSouce(AbstractNode treeNode,XmlMapData mapData,boolean detachChildren){
  TreeNode souceTreeNode=null;
  for (  Connection connection : treeNode.getIncomingConnections()) {
    AbstractNode source=connection.getSource();
    if (source.getOutgoingConnections().contains(connection)) {
      if (source instanceof TreeNode) {
        souceTreeNode=(TreeNode)source;
      }
      source.getOutgoingConnections().remove(connection);
      mapData.getConnections().remove(connection);
    }
  }
  treeNode.getIncomingConnections().clear();
  if (treeNode instanceof OutputTreeNode) {
    if (souceTreeNode != null && souceTreeNode instanceof TreeNode) {
      XmlMapUtil.getLoopFunctionData(XmlMapUtil.getLoopParentNode(souceTreeNode),(OutputTreeNode)treeNode);
    }
    OutputTreeNode outputTreeNode=(OutputTreeNode)treeNode;
    if (!XmlMapUtil.isExpressionEditable(outputTreeNode) && outputTreeNode.isAggregate()) {
      outputTreeNode.setAggregate(false);
    }
    if (detachChildren && !outputTreeNode.getChildren().isEmpty()) {
      for (int i=0; i < outputTreeNode.getChildren().size(); i++) {
        TreeNode child=outputTreeNode.getChildren().get(i);
        detachConnectionsSouce(child,mapData);
      }
    }
  }
  treeNode.setExpression("String_Node_Str");
}

Fixed version (ground truth):
public static void detachConnectionsSouce(AbstractNode treeNode,XmlMapData mapData,boolean detachChildren){
  TreeNode souceTreeNode=null;
  for (  Connection connection : treeNode.getIncomingConnections()) {
    AbstractNode source=connection.getSource();
    if (source.getOutgoingConnections().contains(connection)) {
      if (source instanceof TreeNode) {
        souceTreeNode=(TreeNode)source;
      }
      source.getOutgoingConnections().remove(connection);
      mapData.getConnections().remove(connection);
    }
  }
  treeNode.getIncomingConnections().clear();
  if (treeNode instanceof OutputTreeNode) {
    AbstractInOutTree abstractTree=XmlMapUtil.getAbstractInOutTree((TreeNode)treeNode);
    if (abstractTree != null && abstractTree instanceof OutputXmlTree) {
      List<TreeNode> sourceLoopNodes=new ArrayList<TreeNode>();
      if (XmlMapUtil.hasDocument(abstractTree)) {
        TreeNode targetLoopNode=XmlMapUtil.getLoopParentNode((TreeNode)treeNode);
        findChildSourceLoop(targetLoopNode,sourceLoopNodes);
      }
 else {
        for (        TreeNode node : ((OutputXmlTree)abstractTree).getNodes()) {
          findChildSourceLoop(node,sourceLoopNodes);
        }
      }
      if (souceTreeNode != null && souceTreeNode instanceof TreeNode) {
        TreeNode sourceLoopNode=XmlMapUtil.getLoopParentNode(souceTreeNode);
        if (sourceLoopNode != null && !sourceLoopNodes.contains(sourceLoopNode)) {
          XmlMapUtil.getLoopFunctionData(sourceLoopNode,(OutputTreeNode)treeNode);
        }
      }
    }
    OutputTreeNode outputTreeNode=(OutputTreeNode)treeNode;
    if (!XmlMapUtil.isExpressionEditable(outputTreeNode) && outputTreeNode.isAggregate()) {
      outputTreeNode.setAggregate(false);
    }
    if (detachChildren && !outputTreeNode.getChildren().isEmpty()) {
      for (int i=0; i < outputTreeNode.getChildren().size(); i++) {
        TreeNode child=outputTreeNode.getChildren().get(i);
        detachConnectionsSouce(child,mapData);
      }
    }
  }
  treeNode.setExpression("String_Node_Str");
}