languagetool-org/languagetool · error · RuntimeException

Месец ' ' не постоји.

Error message

Месец '<monthStr>' не постоји.

What it means

DateCheckFilter for Serbian maps a month token (Serbian month name/inflected form or Roman numeral like 'VII') to a month number. If the string matches none of the accepted names, abbreviations, or Roman numerals, getMonth throws this RuntimeException indicating an unrecognized month value.

Solutions

1. Verify the month string is one of the accepted Serbian names/abbreviations or Roman numerals I–XII.
2. Normalize case and trim whitespace before calling the filter.
3. If Latin-script dates must be supported, add the missing Latin month forms to getMonth.
4. Validate the month token in the calling rule before invoking DateCheckFilter.

Example fix

// before: unguarded call
int month = filter.getMonth(monthStr);
// after: normalize and pre-validate
String mon = monthStr.trim().toLowerCase(Locale.forLanguageTag("sr"));
Set<String> known = Set.of("јануар","фебруар","март","април","мај","јун","јул","август","септембар","октобар","новембар","децембар");
if (!known.contains(mon) && !mon.matches("^(?i)(I|II|III|IV|V|VI|VII|VIII|IX|X|XI|XII)$")) {
  throw new IllegalArgumentException("Unrecognized month: " + monthStr);
}

private static final Set<String> SR_MONTHS = Set.of("јануар","фебруар","март","април","мај","јун","јул","август","септембар","октобар","новембар","децембар");
boolean isRecognizedSerbianMonth(String monthStr) {
  String m = monthStr == null ? "" : monthStr.trim().toLowerCase(Locale.forLanguageTag("sr"));
  return SR_MONTHS.contains(m) || m.matches("^(?i)(I|II|III|IV|V|VI|VII|VIII|IX|X|XI|XII)$");
}

try {
  int month = filter.getMonth(monthStr);
} catch (RuntimeException e) {
  logger.warn("Unrecognized Serbian month token: {}", monthStr);
  // reject the date match
}

When it happens

Trigger: Passing a month string such as 'maj' (Latin for May, not covered), an unrecognized abbreviation, wrong case ('Јул'), a Latin-script form when only Cyrillic entries exist, or an out-of-range Roman numeral into getMonth.

Common situations: Rules matching dates written in Latin Serbian script while the filter's month list only covers Cyrillic forms; month names in genitive forms not listed (e.g. 'јула' is listed but others may not cover all inflections); typos in custom grammar rules.

Related errors

• Редни број дана у недељи за
• Could not find day of week for
• Could not find day of week for
• Could not find day of week for
• Could not find day of week for '" + dayStr + "'

AI-assisted analysis of languagetool-org/languagetool@2e990059ce (2026-09-06). Data as JSON: /api/errors/ef9a6b7da2db3edf. Report an issue: GitHub.

Appendix: source

Thrown at languagetool-language-modules/sr/src/main/java/org/languagetool/rules/sr/DateCheckFilter.java:73

  }

  @SuppressWarnings({"ControlFlowStatementWithoutBraces", "MagicNumber"})
  @Override
  protected int getMonth(String monthStr) {
    String mon = monthStr.toLowerCase();
    if (mon.equals("јануар") || monthStr.equals("I") || mon.equals("јануара") || mon.equals("јан")) return 1;
    if (mon.equals("фебруар") || monthStr.equals("II") || mon.equals("фебруара") || mon.equals("феб")) return 2;
    if (mon.equals("март") || monthStr.equals("III") || mon.equals("марта") || mon.equals("мар")) return 3;
    if (mon.equals("април") || monthStr.equals("IV") || mon.equals("априла") || mon.equals("апр")) return 4;
    if (mon.equals("мај") || monthStr.equals("V") || mon.equals("маја")) return 5;
    if (mon.equals("јун") || monthStr.equals("VI") || mon.equals("јуна") || mon.equals("јун")) return 6;
    if (mon.equals("јул") || monthStr.equals("VII") || mon.equals("јула") || mon.equals("јул")) return 7;
    if (mon.equals("август") || monthStr.equals("VIII") || mon.equals("августа") || mon.equals("авг")) return 8;
    if (mon.equals("септембар") || monthStr.equals("IX") || mon.equals("септембра") || mon.equals("сеп")) return 9;
    if (mon.equals("октобар") || monthStr.equals("X") || mon.equals("октобра") || mon.equals("окт")) return 10;
    if (mon.equals("новембар") || monthStr.equals("XI") || mon.equals("новембра") || mon.equals("нов")) return 11;
    if (mon.equals("децембар") || monthStr.equals("XII") || mon.equals("децембра") || mon.equals("дец")) return 12;
    throw new RuntimeException("Месец '" + monthStr + "' не постоји.");
  }
}

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