public static Boolean orBoolOperand(Boolean o, Boolean a) {
    // pick up unknown case
    if (o == null) {
      if ((a == null) || !a) {
        return null;
      } else {
        return a;
      }
    } else if (a == null) {
      return null;
    }

    return (o || a);
  }
or 2 Boolean operands in the context of pruning match

Operand one|Operand another | or result
unknown | T | T
unknown | F | unknown
unknown | unknown | unknown
T | T | T
T | F | T
T | unknown | unknown
F | T | T
F | F | F
F | unknown | unknown
ql/src/java/org/apache/hadoop/hive/ql/optimizer/listbucketingpruner/ListBucketingPrunerUtils.java