stanfordnlp/CoreNLP · error · ParseException

Unrecognized compound relation

Error message

Unrecognized compound relation

What it means

This ParseException is the final else branch of the numeric getRelation(String,String,int,String,String) overload: the relation is neither '>>' nor '<<' nor any known relation, so it is an unrecognized compound relation and the reln string plus the relation type are reported. It means the parser encountered an operator string that does not exist in Semgrex at all while a numeric argument was present.

Solutions

  1. Check the relation spelling against GraphRelation.isKnownRelation ('>', '<', '>>', '<<', '<>', '@', '==', '$+', '$++', '$-', '$--', '.', '..', '-', '--', '>++', '>--', '<++', '<--').
  2. If a count is intended, only '>>' and '<<' accept it; fix the operator to one of those.
  3. Upgrade the CoreNLP version if the relation was added in a newer release.
  4. Print the full pattern and locate the malformed operator near the numeric argument.

Example fix

// before
GraphRelation r = GraphRelation.getRelation("<>>", null, 2, name, null); // throws
// after
GraphRelation r = GraphRelation.getRelation(">>", null, 2, name, null); // corrected operator
Defensive patterns

Strategy: validation

Validate before calling

static final Set<String> KNOWN = Set.of(">", "<", ">>", "<<", "<>", "@", "==",
    "$+", "$++", "$-", "$--", ".", "..", "-", "--", ">++", ">--", "<++", "<--");
if (!KNOWN.contains(reln)) {
  throw new IllegalArgumentException("Unrecognized relation: " + reln);
}

Try / catch

try {
  GraphRelation r = GraphRelation.getRelation(reln, type, num, name, null);
} catch (ParseException e) {
  if (e.getMessage().startsWith("Unrecognized compound relation")) {
    throw new IllegalArgumentException("Invalid Semgrex operator in pattern: " + reln, e);
  }
}

Prevention

When it happens

Trigger: Calling getRelation(">>*", type, 2, name, null), getRelation("~obj", type, 1, name, null), or any misspelled/unknown operator with the int overload. Parsing a Semgrex pattern containing a malformed operator such as '<>>' routed into the compound relation path.

Common situations: Typos in hand-written Semgrex patterns; using relation syntax from a different version or a different library (e.g. tregex-style operators); copy-pasted patterns from documentation of newer CoreNLP versions into older jars.

Related errors

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/bc92a1d87c72d63f. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/semgraph/semgrex/GraphRelation.java:1531

  public static GraphRelation getRelation(String reln,
                                          String type,
                                          int num,
                                          String name,
                                          String edgeName) throws ParseException {
    if (edgeName != null) {
      throw new ParseException("Relation " + reln + " does not allow for named edges");
    }
    if (reln == null && type == null)
      return null;
    if (reln.equals(">>"))
      return new LIMITED_GRANDPARENT(type, name, num, num);
    else if (reln.equals("<<"))
      return new LIMITED_GRANDKID(type, name, num, num);
    else if (isKnownRelation(reln))
      throw new ParseException("Relation " + reln +
                               " does not use numeric arguments");
    else //error
      throw new ParseException("Unrecognized compound relation " + reln + " "
                               + type);
  }

  public static GraphRelation getRelation(String reln,
                                          String type,
                                          int num, int num2,
                                          String name,
                                          String edgeName) throws ParseException {
    if (edgeName != null) {
      throw new ParseException("Relation " + reln + " does not allow for named edges");
    }
    if (reln == null && type == null)
      return null;
    if (reln.equals(">>"))
      return new LIMITED_GRANDPARENT(type, name, num, num2);
    else if (reln.equals("<<"))
      return new LIMITED_GRANDKID(type, name, num, num2);
    else if (isKnownRelation(reln))

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