stanfordnlp/CoreNLP · error · SsurgeonParseException

Cannot make a Lemmatize with no nodeName

Error message

Cannot make a Lemmatize with no nodeName

What it means

Lemmatize re-lemmatizes the word of a matched node, so it requires the name of a node in the semgrex match. Constructing it with a null nodeName throws SsurgeonParseException. English variants are normalized to Language.English; Unknown falls back per the constructor logic.

Solutions

1. Pass the name of a node from the semgrex pattern as nodeName.
2. Ensure the -node argument is present in the lemmatize instruction in the rule file.
3. Add a null/empty check before constructing Lemmatize and report the rule name for easier debugging.

Example fix

// before
new Lemmatize(null, Language.UniversalEnglish);

// after
new Lemmatize("word", Language.UniversalEnglish); // "word" is a node in the pattern

// Java
if (nodeName == null || nodeName.isBlank()) {
  throw new IllegalArgumentException("lemmatize requires a -node argument naming a matched node");
}

// Java
static boolean hasNodeName(String nodeName) {
  return nodeName != null && !nodeName.isBlank();
}

// Java
try {
  Lemmatize op = new Lemmatize(nodeName, language);
} catch (SsurgeonParseException e) {
  log.severe("Invalid lemmatize rule: " + e.getMessage());
}

When it happens

Trigger: new Lemmatize(null, language) — e.g. an Ssurgeon lemmatize instruction missing its -node argument, or code passing a variable that was never assigned a matched node name.

Common situations: Hand-written .ssurgeon rules with the node argument dropped; automated rule generation where match-group names come back null.

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AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/050719020c1d4507. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/semgraph/semgrex/ssurgeon/Lemmatize.java:29

/**
 * Add the output of the English lemmatizer to the word in question.
 * Currently this only supports English!  You can add a known lemma
 * for a different language by using EditNode and setting the lemma
 * attribute
 *
 * @author John Bauer
 */
public class Lemmatize extends SsurgeonEdit {
  public static final String LABEL = "lemmatize";

  final String nodeName;
  final Morphology morphology;
  final Language language;

  public Lemmatize(String nodeName, Language language) {
    if (nodeName == null) {
      throw new SsurgeonParseException("Cannot make a Lemmatize with no nodeName");
    }
    this.nodeName = nodeName;

    if (language == Language.UniversalEnglish || language == Language.English) {
      this.language = Language.English;
    } else if (language == Language.Unknown) {
      // log something here?
      this.language = Language.English;
    } else {
      throw new SsurgeonParseException("Lemmatizing " + language + " is not supported");
    }

    this.morphology = new Morphology();
  }

  @Override
  public String toEditString() {
    StringBuilder buf = new StringBuilder();

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