[CALCITE-1294] function gatherConstraint in class ReduceExpressionsRule throws NullPointerException when both left RexNode and right RexNode are NULL RexLiteral

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Fix Version/s: 1.14.0
• Component/s: core
• Assignee: Julian Hyde
• Reporter: chunwei
• Created: 16/Jun/16 03:45
• Updated: 27/Dec/17 19:13
• Resolved: 27/Dec/17 19:13

Description

function gatherConstraint in class ReduceExpressionsRule throw NullPointerException when both left RexNode and right RexNode are NULL RexLiteral.

ReduceExpressionsRule.java

  private static <C extends RexNode> void gatherConstraint(Class<C> clazz,
      RexNode left, RexNode right, Map<RexNode, C> map, Set<RexNode> excludeSet,
      RexBuilder rexBuilder) {
     ......
else {
      if (existedValue instanceof RexLiteral
          && constant instanceof RexLiteral
          && !((RexLiteral) existedValue).getValue()
              .equals(((RexLiteral) constant).getValue())) {
        // we found conflicting values, e.g. left = 10 and left = 20
        map.remove(left);
        excludeSet.add(left);
      }
    },

}

when existedValue and constant are NULL RexLiteral, getValue() returns null and null.equals(null) will throw NullPointerException.

It is better and safer to use

ObjectUtils.equals(((RexLiteral) existedValue).getValue(), ((RexLiteral) constant).getValue()) 

than

 ((RexLiteral) existedValue).getValue().equals(((RexLiteral) constant).getValue())

Issue Links

• duplicates: CALCITE-1860 Duplicate null predicates cause NullPointerException in RexUtil