stanfordnlp/CoreNLP · error · RuntimeException

Unknown grammatical relation '

Error message

Unknown grammatical relation '

What it means

readDeps parses a dependency file where each line names a grammatical relation; the relation string is mapped to an EnglishGrammaticalRelations object (including conj_<x> handling). If no mapping is found (grel == null) the string is not a known English grammatical relation, so it throws with the offending relation name.

Solutions

  1. Correct the relation name in the input file to a valid EnglishGrammaticalRelations name.
  2. Match the reader to your data format — use the UniversalDependencies scoring variant or convert relations (e.g. nsubj:pass -> agent/auxpass equivalents) before scoring.
  3. Regenerate system output with a matching GrammaticalStructureFactory so relation names agree with the scorer.

Example fix

// before (input line)
5	obl:tmod	3
// after
5	tmod	3
Defensive patterns

Strategy: validation

Validate before calling

if (EnglishGrammaticalRelations.valueOf(depName) == null && !depName.startsWith("conj_")) { throw new IllegalArgumentException("unknown rel: " + depName); }

Try / catch

try { scoring = new DependencyScoring(goldPath, ...); } catch (RuntimeException e) { if (e.getMessage().startsWith("Unknown grammatical relation")) { convertRelations(goldPath); scoring = new DependencyScoring(goldPath, ...); } }

Prevention

When it happens

Trigger: Scoring a dependency file whose relation column contains a relation not in EnglishGrammaticalRelations — e.g. SD-style names not matching the loaded grammar, universal-dependencies names (nsubj:pass, obl:*) against the non-UD relation set, typos, or relations from another language.

Common situations: Mixing Universal Dependencies output with English (Stanford Dependencies) scoring; custom relations added by a parser; scoring CoNLL data with short names (nsubj vs. subj) that this reader doesn't accept; version drift between tool output and library relation inventory.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/faac8336e903d7c3. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/trees/DependencyScoring.java:217

      int commaSpace = line.indexOf(", ");
      String depName = line.substring(0, firstParen);
      String govName = line.substring(firstParen + 1, commaSpace);
      String childName = line.substring(commaSpace+2, line.length() - 1);
      GrammaticalRelation grel = GrammaticalRelation.valueOf(depName);
      if (depName.startsWith("prep_")) {
        String prep = depName.substring(5);
        grel = EnglishGrammaticalRelations.getPrep(prep);
      }
      if (depName.startsWith("prepc_")) {
        String prepc = depName.substring(6);
        grel = EnglishGrammaticalRelations.getPrepC(prepc);
      }
      if (depName.startsWith("conj_")) {
        String conj = depName.substring(5);
        grel = EnglishGrammaticalRelations.getConj(conj);
      }
      if (grel == null) {
        throw new RuntimeException("Unknown grammatical relation '" + depName+"'");
      }

      //Word govWord = new Word(govName.substring(0, govDash));
      IndexedWord govWord = new IndexedWord();
      govWord.setValue(normalizeNumbers(govName));
      govWord.setWord(govWord.value());
      //Word childWord = new Word(childName.substring(0, childDash));
      IndexedWord childWord = new IndexedWord();
      childWord.setValue(normalizeNumbers(childName));
      childWord.setWord(childWord.value());
      TypedDependency dep = new TypedDependencyStringEquality(grel, govWord, childWord);
      deps.add(dep);
      } catch (Exception e) {
        breader.close();
        throw new RuntimeException("Error on line "+breader.getLineNumber()+":\n\n"+e);
      }
    }
    if (deps.size() != 0) {

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