languagetool-org/languagetool · error · IllegalArgumentException

Dist to big: " + maxEditDistance

Error message

Dist to big: " + maxEditDistance

What it means

Parameter guard in SymSpell.lookup: the caller requested suggestions with a maximum edit distance larger than the edit distance the dictionary was built with (maxDictionaryEditDistance). Since the delete-based index only covers the built distance, a larger distance cannot be honored and the request is rejected.

Solutions

1. Call lookup with an edit distance less than or equal to the dictionary's max edit distance
2. Rebuild the SymSpell dictionary with a larger initial edit distance if a bigger lookup distance is required

When it happens

Trigger: Thrown at languagetool-core/src/main/java/org/languagetool/rules/spelling/symspell/implementation/SymSpell.java:321 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/e5819c98ee4603e9. Report an issue: GitHub.

Appendix: source

Thrown at languagetool-core/src/main/java/org/languagetool/rules/spelling/symspell/implementation/SymSpell.java:321

  public List<SuggestItem> lookup(String input, Verbosity verbosity) {
    return lookup(input, verbosity, maxDictionaryEditDistance);
  }

  /// <summary>Find suggested spellings for a given input word.</summary>
  /// <param name="input">The word being spell checked.</param>
  /// <param name="verbosity">The value controlling the quantity/closeness of the returned suggestions.</param>
  /// <param name="maxEditDistance">The maximum edit distance between input and suggested words.</param>
  /// <returns>A List of SymSpell.SuggestItem object representing suggested correct spellings for the input word,
  /// sorted by edit distance, and secondarily by count frequency.</returns>
  public List<SuggestItem> lookup(String input, Verbosity verbosity, int maxEditDistance) {
    //verbosity=Top: the suggestion with the highest term frequency of the suggestions of smallest edit distance found
    //verbosity=Closest: all suggestions of smallest edit distance found, the suggestions are ordered by term frequency
    //verbosity=All: all suggestions <= maxEditDistance, the suggestions are ordered by edit distance, then by term frequency (slower, no early termination)

    // maxEditDistance used in lookup can't be bigger than the maxDictionaryEditDistance
    // used to construct the underlying dictionary structure.
    if (maxEditDistance > maxDictionaryEditDistance) {
      throw new IllegalArgumentException("Dist to big: " + maxEditDistance);
    }

    List<SuggestItem> suggestions = new ArrayList<>();
    int inputLen = input.length();

    // early exit - word is too big to possibly match any words
    if (inputLen - maxEditDistance > maxLength) {
      return suggestions;
    }

    // deletes we've considered already
    HashSet<String> consideredDeletes = new HashSet<>();
    // suggestions we've considered already
    HashSet<String> consideredSuggestions = new HashSet<>();
    long suggestionCount;

    // quick look for exact match
    if (words.containsKey(input)) {

View on GitHub (pinned to 2e990059ce)