languagetool-org/languagetool · error · UnsupportedPatternRuleException

<or> not yet supported.

Error message

<or> not yet supported.

What it means

Search-index guard in checkUnsupportedElement: the pattern token is part of an <or> token group, which the query builder cannot map to Lucene clauses yet.

Source

Thrown at languagetool-wikipedia/src/main/java/org/languagetool/dev/index/PatternRuleQueryBuilder.java:246

        Term newTerm = new Term(term.field(), simplifyRegex(term.text()));
        return new RegexpQuery(newTerm);
      }
      if (str.contains("?iu") || str.contains("?-i")) {
        // Lucene's RegexpQuery doesn't seem to support this
        throw new UnsupportedPatternRuleException("Regex constructs like '?iu' and '?-i' are not supported: " + patternToken);
      }
      return new RegexpQuery(term);
    } catch (IllegalArgumentException e) {
      // constructs like "\p{Punct}" not supported by Lucene RegExp:
      throw new UnsupportedPatternRuleException("Advanced regex like '\\p{Punct}' are not supported: " + patternToken);
    }
  }

  private void checkUnsupportedElement(PatternToken patternPatternToken)
      throws UnsupportedPatternRuleException {
    if (patternPatternToken.hasOrGroup()) {
      // TODO: this is not enough: the first of the tokens in the <or> group will not get into this branch
      throw new UnsupportedPatternRuleException("<or> not yet supported.");
    }
    if (patternPatternToken.isUnified()) {
      throw new UnsupportedPatternRuleException("Elements with unified tokens are not supported.");
    }
    if (patternPatternToken.getString() != null && patternPatternToken.getString().matches("\\\\\\d+")) { // e.g. "\1"
      throw new UnsupportedPatternRuleException("Elements with only match references (e.g. \\1) are not supported.");
    }
  }

}

View on GitHub (pinned to 2e990059ce)

Solutions

1. Flatten the <or> group into separate rules or alternatives
2. Skip the rule for index-based search
3. Extend the builder to handle or-groups

When it happens

Trigger: Thrown at languagetool-wikipedia/src/main/java/org/languagetool/dev/index/PatternRuleQueryBuilder.java:246 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of languagetool-org/languagetool@2e990059ce (2026-09-06). Data as JSON: /api/errors/dbfe5c1c3ff661fa. Report an issue: GitHub.