Examples of errors detected by the V6020 diagnostic

V6020. Division or mod division by zero.

AutoMQ

V6020. Divide by zero. Denominator range ['0'..'2147483646']. Frequencies.java 104

/**
 * ....
 * @param buckets     the number of buckets; must be at least 1
 * ....
 */
public Frequencies(int buckets,
                   double min,
                   double max,
                   Frequency... frequencies) {
    ....
    if (buckets < 1) {
        throw new IllegalArgumentException("Must be at least 1 bucket");
    }
    if (buckets < frequencies.length) {
        throw new IllegalArgumentException("More frequencies than buckets");
    }
    ....
    double halfBucketWidth = (max - min) / (buckets - 1) / 2.0; // <=
}

ELKI

V6020 Divide by zero. The range of the 'referenceSetSize' denominator values includes zero. PreDeConNeighborPredicate.java(138)

protected PreDeConModel computeLocalModel(DoubleDBIDList neighbors, ....) {
    final int referenceSetSize = neighbors.size();
    ....
    // Shouldn't happen:
    if(referenceSetSize < 0) {
        LOG.warning("Empty reference set –
            should at least include the query point!");
        return new PreDeConModel(Integer.MAX_VALUE, DBIDUtil.EMPTYDBIDS);
    }
    ....
    for(int d = 0; d < dim; d++) {
        s[d] /= referenceSetSize;
        mvVar.put(s[d]);
    }
    ....
}

Apache Hive

V6020 Divide by zero. The range of the 'divisor' denominator values includes zero. SqlMathUtil.java(265)

public static long divideUnsignedLong(long dividend, long divisor) {
  if (divisor < 0L) {
    /*some comments*/
    return (compareUnsignedLong(dividend, divisor)) < 0 ? 0L : 1L;
  }

  if (dividend >= 0) { // Both inputs non-negative
    return dividend / divisor;                     // <=
  } else {
    ....
  }
}

Similar errors can be found in some other places:

• V6020 Mod by zero. The range of the 'divisor' denominator values includes zero. SqlMathUtil.java(309)
• V6020 Divide by zero. The range of the 'divisor' denominator values includes zero. SqlMathUtil.java(276)
• V6020 Divide by zero. The range of the 'divisor' denominator values includes zero. SqlMathUtil.java(312)