languagetool-org/languagetool · error · RuntimeException

Incorrect number of fields: " + line

Error message

Incorrect number of fields: " + line

What it means

DativePluralsData.loadWords parses a semicolon-separated data file (Irish dative plurals) and requires exactly 4 fields per line. A line with any other field count throws this RuntimeException naming the offending line, so a malformed data resource fails fast at load time.

Source

Thrown at languagetool-language-modules/ga/src/main/java/org/languagetool/rules/ga/DativePluralsData.java:54

  public static Map<String, String> getSimpleReplacements() {
    return simpleReplacements;
  }

  /**
   * Load words.
   */
  private static Set<DativePluralsEntry> loadWords(String path) {
    Set<DativePluralsEntry> set = new HashSet<>();
    InputStream stream = JLanguageTool.getDataBroker().getFromRulesDirAsStream(path);
    try (Scanner scanner = new Scanner(stream, "utf-8")) {
      while (scanner.hasNextLine()) {
        String line = scanner.nextLine().trim();
        if (line.isEmpty() || line.charAt(0) == '#') {
          continue;
        }
        String[] parts = line.split(";");
        if (parts.length != 4) {
          throw new RuntimeException("Incorrect number of fields: " + line);
        }
        String form = parts[0];
        String formModern = null;
        if (form.contains(":")) {
          String[] forms = form.split(":");
          if (forms.length != 2) {
            throw new RuntimeException("Form has more than 1 modern form:" + line);
          }
          form = forms[0];
          formModern = forms[1];
        }
        String repl = parts[3];
        String replModern = null;
        if (repl.contains(":")) {
          String[] repls = repl.split(":");
          if (repls.length != 2) {
            throw new RuntimeException("Replacement has more than 1 modern form:" + line);
          }

View on GitHub (pinned to 2e990059ce)

Solutions

  1. Open the resource file (e.g. src/main/resources/.../ga/dative-plurals.txt) and fix the line printed in the message to have exactly 4 semicolon-separated fields.
  2. If extra data is needed, add a new column consistently to every line and update the parser, not just one line.
  3. Check whether a value itself contains a ';' that must be removed or escaped.
  4. Add a unit test that loads the data file so format drift is caught in CI.

Example fix

// before (3 fields)
abha; abh; NMOL
// after (4 fields)
abha:abhaí; abha; f; NMOL
Defensive patterns

Strategy: validation

Validate before calling

for (String line : Files.readAllLines(path)) {
  if (line.isBlank() || line.startsWith("#")) continue;
  if (line.split(";", -1).length != 4) throw new IllegalStateException("bad line: " + line);
}

Try / catch

try { DativesData.datives(); } catch (RuntimeException e) { log.error("Data file corrupt: " + e.getMessage()); throw e; }

Prevention

When it happens

Trigger: A line in the dative plurals resource file contains fewer or more than 4 semicolon-separated fields (e.g. a missing ';' or an extra one), and is not blank or commented with '#'.

Common situations: Manual edits to the .txt data file; contributors appending columns; CSV editors re-quoting or altering separators; copy-paste losing a trailing field.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of languagetool-org/languagetool@2e990059ce (2026-09-06). Data as JSON: /api/errors/90a30c4dcc8e6d2a. Report an issue: GitHub.