stanford-oval/storm · error · Exception

Insert node error. Node {child_node_name} already exists und

Error message

Insert node error. Node {child_node_name} already exists under its parent node {self.name}.

What it means

KnowledgeNode.add_child refuses to insert a child whose name already exists under the node when duplicate_handling is 'raise error' (the default strict mode); 'skip' instead returns the existing child.

Source

Thrown at knowledge_storm/dataclass.py:150

    def has_child(self, child_node_name: str):
        """
        Check if the node has the child of given name.
        """
        return child_node_name in [child.name for child in self.children]

    def add_child(self, child_node_name: str, duplicate_handling: str = "skip"):
        """
        Adds a child node to the current node.
        duplicate_handling (str): How to handle duplicate nodes. Options are "skip", "none", and "raise error".
        """
        if self.has_child(child_node_name):
            if duplicate_handling == "skip":
                for child in self.children:
                    if child.name == child_node_name:
                        return child
            elif duplicate_handling == "raise error":
                raise Exception(
                    f"Insert node error. Node {child_node_name} already exists under its parent node {self.name}."
                )
        child_node = KnowledgeNode(name=child_node_name, parent=self)
        self.children.append(child_node)
        return child_node

    def get_parent(self):
        """
        Returns the parent node of the current node.

        Returns:
            KnowledgeNode: The parent node of the current node.
        """
        return self.parent

    def get_children(self):
        """
        Returns the children of the current node.

View on GitHub (pinned to fb951af774)

Solutions

1. Pass duplicate_handling='skip' to reuse the existing node
2. Normalize names (strip/casefold) before inserting
3. Check node.has_child(name) first and reuse the existing child

Example fix

# before
node.add_child('History')  # raises if 'History' exists

# after
child = node.add_child('History', duplicate_handling='skip')

if node.has_child(name):
    child = next(c for c in node.children if c.name == name)
else:
    child = node.add_child(name)

try:
    child = node.add_child(name)
except Exception as e:
    if 'already exists' not in str(e):
        raise
    child = node.add_child(name, duplicate_handling='skip')

When it happens

Trigger: Calling add_child (directly or via insert_node/find_node_by_path) with a name that has_child() already reports, while duplicate_handling='raise error'.

Common situations: Inserting information whose computed node name collides with an existing node (case differences, trailing whitespace), or re-running insertion over an already-populated knowledge base without dedup.

AI-assisted analysis of stanford-oval/storm@fb951af774 (2026-08-28). Data as JSON: /api/errors/47c286d0937ab90d. Report an issue: GitHub.