stanfordnlp/CoreNLP · error · SsurgeonParseException

Cannot make a DeleteLeaf out of " + argsBox.nodes.size() +…

Error message

Cannot make a DeleteLeaf out of " + argsBox.nodes.size() + " nodes

What it means

DeleteLeaf deletes exactly one leaf node, so parseEditLine requires argsBox.nodes.size() == 1. Any other count (0 or multiple -node flags) raises SsurgeonParseException('Cannot make a DeleteLeaf out of N nodes').

Solutions

  1. Supply exactly one -node <name> flag for deleteleaf.
  2. Remove redundant -node flags; issue one deleteleaf edit per leaf to remove.
  3. Confirm the node name was defined by an earlier pattern named group or addnode/edit in the same rule.

Example fix

// before
deleteleaf
// after
deleteleaf -node child
Defensive patterns

Strategy: validation

Validate before calling

int count = countFlagOccurrences(line, "-node");
if (line.startsWith("deleteleaf") && count != 1)
  throw new IllegalArgumentException("deleteleaf needs exactly one -node, got " + count);

Try / catch

try { parseEditLine(line, attrs, lang); } catch (SsurgeonParseException e) { if (e.getMessage().startsWith("Cannot make a DeleteLeaf")) log.error("deleteleaf requires exactly one -node: " + line); }

Prevention

When it happens

Trigger: A 'deleteleaf' edit line with no -node flag or with two or more -node flags.

Common situations: Copy-pasting delete rules and stacking -node flags; assuming deleteleaf accepts a node list like MergeNodes does; missing the -node flag when writing the rule from scratch.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/6698deab6aed337c. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/semgraph/semgrex/ssurgeon/Ssurgeon.java:636

        return new AddDep(argsBox.govNodeName, reln, argsBox.annotations, argsBox.position);
      } else if (command.equalsIgnoreCase(AddNode.LABEL)) {
        return AddNode.createAddNode(argsBox.nodeString, argsBox.name);
      } else if (command.equalsIgnoreCase(AddEdge.LABEL)) {
        if (argsBox.reln == null) {
          throw new SsurgeonParseException("Relation not specified for AddEdge");
        }
        GrammaticalRelation reln = GrammaticalRelation.valueOf(language, argsBox.reln);
        return new AddEdge(argsBox.govNodeName, argsBox.dep, reln, argsBox.weight);
      } else if (command.equalsIgnoreCase(ReattachNamedEdge.LABEL)) {
          return new ReattachNamedEdge(argsBox.edge, argsBox.govNodeName, argsBox.dep);
      } else if (command.equalsIgnoreCase(DeleteGraphFromNode.LABEL)) {
        if (argsBox.nodes.size() != 1) {
          throw new SsurgeonParseException("Cannot make a DeleteGraphFromNode out of " + argsBox.nodes.size() + " nodes");
        }
        return new DeleteGraphFromNode(argsBox.nodes.get(0));
      } else if (command.equalsIgnoreCase(DeleteLeaf.LABEL)) {
        if (argsBox.nodes.size() != 1) {
          throw new SsurgeonParseException("Cannot make a DeleteLeaf out of " + argsBox.nodes.size() + " nodes");
        }
        return new DeleteLeaf(argsBox.nodes.get(0));
      } else if (command.equalsIgnoreCase(EditNode.LABEL)) {
        if (argsBox.nodes.size() != 1) {
          throw new SsurgeonParseException("Cannot make an EditNode out of " + argsBox.nodes.size() + " nodes.  Please use exactly one -node");
        }
        return new EditNode(argsBox.nodes.get(0), argsBox.annotations, argsBox.updateMorphoFeatures, argsBox.remove, argsBox.removeMorphoFeatures);
      } else if (command.equalsIgnoreCase(Lemmatize.LABEL)) {
        if (argsBox.nodes.size() != 1) {
          throw new SsurgeonParseException("Cannot make a Lemmatize out of " + argsBox.nodes.size() + " nodes.  Please use exactly one -node");
        }
        return new Lemmatize(argsBox.nodes.get(0), language);
      } else if (command.equalsIgnoreCase(MergeNodes.LABEL)) {
        if (argsBox.nodes.size() < 2) {
          throw new SsurgeonParseException("Cannot make a MergeNodes out of fewer than 2 nodes (got " + argsBox.nodes.size() + ")");
        }
        return new MergeNodes(argsBox.nodes, argsBox.annotations);
      } else if (command.equalsIgnoreCase(RelabelNamedEdge.LABEL)) {

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