SonarSource/sonarqube · error · IllegalArgumentException

uuids can not be empty

Error message

uuids can not be empty

What it means

wildCardStringFor builds a SQL IN placeholder list for a batch of file uuids; an empty list cannot produce a valid IN clause, so it throws IllegalArgumentException. This is an internal pre-condition: the caller should never invoke it with zero uuids.

Solutions

1. Guard the caller: skip the query when the uuid batch list is empty.
2. If you modified the batching code, restore the non-empty-batch invariant before calling the helper.
3. If seen in stock SonarQube, report it with the CE task logs as a bug.

Example fix

// before
String placeholders = wildCardStringFor(uuidBatch);
// after
if (!uuidBatch.isEmpty()) {
  String placeholders = wildCardStringFor(uuidBatch);
  ...
}

if (uuids == null || uuids.isEmpty()) {
  return; // skip query entirely, no IN clause possible
}

boolean isNonEmptyBatch(List<String> uuids) {
  return uuids != null && !uuids.isEmpty();
}

try {
  placeholders = wildCardStringFor(uuids);
} catch (IllegalArgumentException e) {
  logger.warn("Empty uuid batch, skipping query");
}

When it happens

Trigger: Internally: calling wildCardStringFor(List.of()) — in practice only from a bug in ExportLineHashesStep's batching loop iterating an empty uuid batch, or when overridden/test code passes an empty list.

Common situations: Rarely seen in production; mostly surfaces from code modifications or custom forks that change the batching logic, or unit tests exercising the helper with empty input.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Analysis Export failed after processing
• Branch export failed after processing
• Component Export failed after processing
• Error during processing of row
• Failed to insert row with value

AI-assisted analysis of SonarSource/sonarqube@184c821202 (2026-09-09). Data as JSON: /api/errors/1a1796560c6f2eb0. Report an issue: GitHub.

Appendix: source

Thrown at server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectexport/file/ExportLineHashesStep.java:117

      " order by created_at, uuid";
    PreparedStatement stmt = dbClient.getMyBatis().newScrollingSelectStatement(dbSession, format(sql, wildCardStringFor(uuids)));
    try {
      int i = 1;
      for (String uuid : uuids) {
        stmt.setString(i, uuid);
        i++;
      }
      return stmt;
    } catch (Exception e) {
      DatabaseUtils.closeQuietly(stmt);
      throw e;
    }
  }

  private static String wildCardStringFor(List<String> uuids) {
    switch (uuids.size()) {
      case 0:
        throw new IllegalArgumentException("uuids can not be empty");
      case 1:
        return "?";
      default:
        return createWildCardStringFor(uuids);
    }
  }

  private static String createWildCardStringFor(List<String> uuids) {
    int size = (uuids.size() * 2) - 1;
    char[] res = new char[size];
    for (int j = 0; j < size; j++) {
      if (j % 2 == 0) {
        res[j] = '?';
      } else {
        res[j] = ',';
      }
    }
    return new String(res);

View on GitHub (pinned to 184c821202)