What causes "Quality Gate: Unable to parse value '%s' to compare against %s" in SonarSource/sonarqube?

Edit the Quality Gate condition and set the error threshold to a plain decimal number (e.g. '85' not '85%', use '.' not ',')

SonarSource/sonarqube · error · IllegalArgumentException

Quality Gate: Unable to parse value '%s' to compare against

Error message

Quality Gate: Unable to parse value '%s' to compare against %s

What it means

ConditionEvaluator.evaluateCondition() compares a measure against a Quality Gate condition's error threshold. parseConditionValue() throws NumberFormatException when either the threshold or the measure is not a parseable number; the catch block rethrows it as IllegalArgumentException 'Quality Gate: Unable to parse value ...'. The message reports the error threshold and metric name that could not be compared numerically.

Source

Thrown at server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/qualitygate/ConditionEvaluator.java:65

    Comparable measureComparable = parseMeasure(measure);
    if (measureComparable == null) {
      return new EvaluationResult(Measure.Level.OK, null);
    }

    return evaluateCondition(condition, measureComparable)
      .orElseGet(() -> new EvaluationResult(Measure.Level.OK, measureComparable));
  }

  private static Optional<EvaluationResult> evaluateCondition(Condition condition, Comparable<?> measureComparable) {
    try {
      Comparable conditionComparable = parseConditionValue(condition.getMetric(), condition.getErrorThreshold());
      if (doesReachThresholds(measureComparable, conditionComparable, condition)) {
        return of(new EvaluationResult(Measure.Level.ERROR, measureComparable));
      }
      return Optional.empty();
    } catch (NumberFormatException badValueFormat) {
      throw new IllegalArgumentException(String.format(
        "Quality Gate: Unable to parse value '%s' to compare against %s",
        condition.getErrorThreshold(), condition.getMetric().getName()));
    }
  }

  private static boolean doesReachThresholds(Comparable measureValue, Comparable criteriaValue, Condition condition) {
    int comparison = measureValue.compareTo(criteriaValue);
    switch (condition.getOperator()) {
      case GREATER_THAN:
        return comparison > 0;
      case LESS_THAN:
        return comparison < 0;
      default:
        throw new IllegalArgumentException(String.format("Unsupported operator '%s'", condition.getOperator()));
    }
  }

  private static Comparable parseConditionValue(Metric metric, String value) {

View on GitHub (pinned to 184c821202)

Solutions

Edit the Quality Gate condition and set the error threshold to a plain decimal number (e.g. '85' not '85%', use '.' not ',')
Check the metric: conditions only make sense on numeric metrics; move the condition to a numeric metric (e.g. coverage, duplicated_lines_density)
If set via API, POST numeric thresholds without units or thousands separators

Example fix

// before: threshold with unit / comma decimal
"coverage": "85%"        // fails
"new_violations": "1,5"  // fails
// after
"coverage": "85"
"new_violations": "1.5"

Defensive patterns

Strategy: validation

Validate before calling

static boolean isNumericThreshold(String threshold) {
  if (threshold == null || threshold.isBlank()) return false;
  try { Double.parseDouble(threshold.trim()); return true; } catch (NumberFormatException e) { return false; }
}
// before creating a condition: if (!isNumericThreshold("85")) strip units/locale commas;

Type guard

static Optional<Double> asDouble(String s) {
  try { return Optional.of(Double.parseDouble(s.trim())); } catch (NumberFormatException | NullPointerException e) { return Optional.empty(); }
}

Try / catch

try {
  Optional<EvaluationResult> r = evaluator.evaluate(condition, measure);
} catch (IllegalArgumentException e) {
  if (e.getMessage().startsWith("Quality Gate: Unable to parse value")) {
    throw new ConfigurationException("Fix threshold: plain decimal, no % or comma: " + condition.getErrorThreshold());
  }
  throw e;
}

Prevention

Enter Quality Gate thresholds as plain decimals: '85' not '85%'
Use '.' as decimal separator regardless of server locale
Only attach conditions to numeric metrics
When creating conditions via api/qualitygates, validate the value with parseDouble first

When it happens

Trigger: A Quality Gate condition on a numeric metric (e.g. coverage, lines) has an error threshold that is not a plain number — like '85%', '1.5h', empty string, or a comma decimal '99,9' — while evaluating conditions in computeQualityGateSteps for a project's measures.

Common situations: Admins typing thresholds with units ('80%') or locale commas in the Quality Gate editor, conditions created via API/web service with malformed values, or string/duration metrics used with numeric comparison operators.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of SonarSource/sonarqube@184c821202 (2026-09-09). Data as JSON: /api/errors/586a2f84005b26b1. Report an issue: GitHub.