[PIG-3374] CASE and IN fail when expression includes dereferencing operator

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.12.0
• Component/s: parser
• Assignee: Cheolsoo Park
• Reporter: Cheolsoo Park
• Created: 05/Jul/13 19:27
• Updated: 14/Oct/13 16:46
• Resolved: 30/Aug/13 22:42

Description

This is another bug that I discovered after deploying CASE/IN expressions internally.

The current implementation of CASE/IN expression assumes that the 1st operand is a single expression. But this is not true, for example, if it contains a dereferencing operator. The following example demonstrates the problem:

A = LOAD 'foo' AS (k1:chararray, k2:chararray, v:int);
B = GROUP A BY (k1, k2);
C = FILTER B BY group.k1 IN ('a', 'b');
DUMP C;

This fails with the following error:

Caused by: java.lang.IndexOutOfBoundsException: Index: 5, Size: 5
    at java.util.ArrayList.RangeCheck(ArrayList.java:547)
    at java.util.ArrayList.get(ArrayList.java:322)
    at org.apache.pig.parser.LogicalPlanGenerator.in_eval(LogicalPlanGenerator.java:8624)
    at org.apache.pig.parser.LogicalPlanGenerator.cond(LogicalPlanGenerator.java:8405)
    at org.apache.pig.parser.LogicalPlanGenerator.filter_clause(LogicalPlanGenerator.java:7564)
    at org.apache.pig.parser.LogicalPlanGenerator.op_clause(LogicalPlanGenerator.java:1403)
    at org.apache.pig.parser.LogicalPlanGenerator.general_statement(LogicalPlanGenerator.java:821)
    at org.apache.pig.parser.LogicalPlanGenerator.statement(LogicalPlanGenerator.java:539)
    at org.apache.pig.parser.LogicalPlanGenerator.query(LogicalPlanGenerator.java:414)
    at org.apache.pig.parser.QueryParserDriver.parse(QueryParserDriver.java:181)

Here is the relavant code that causes trouble:

QueryParser.g

if(tree.getType() == IN) {
  Tree lhs = tree.getChild(0); // lhs is not a single node!
  for(int i = 2; i < tree.getChildCount(); i = i + 2) {
    tree.insertChild(i, deepCopy(lhs));
  }
}