[CALCITE-2731] RexProgramBuilder makes unsafe simplifications to CASE expressions

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.18.0
• Assignee: Zoltan Haindrich
• Reporter: Zoltan Haindrich
• Created: 07/Dec/18 16:39
• Updated: 23/Dec/18 00:12
• Resolved: 13/Dec/18 07:57

Description

In CALCITE-1413 we were cautious to not simplify

CASE a=0 THEN 0 ELSE 1/a END

and it seemed good; however: RexProgramBuilder is also invokes simplify - but the protection at that point is not able to work, because it sees only references:

CASE $1 THEN $2 ELSE $3 END

testcase for conditions.iq:

with ax(s) as (values (1),(0))
select case when s=0 then false else 100/s > 0 end from ax;

!ok

resulting exception:

java.lang.AssertionError: Files differ: /home/kirk/projects/calcite/core/target/test-classes/sql/surefire/sql/conditions.iq /home/kirk/projects/calcite/core/target/test-classes/sql/conditions.iq
277a278,326
> Error while executing command OkCommand [sql: with ax(s) as (values (1),(0))
> select case when s=0 then false else 100/s > 0 end from ax]
> java.lang.ArithmeticException: / by zero
> 	at Baz$1$1.current(Unknown Source)
> 	at org.apache.calcite.linq4j.Linq4j$EnumeratorIterator.next(Linq4j.java:683)
> 	at org.apache.calcite.avatica.util.IteratorCursor.next(IteratorCursor.java:46)

Issue Links

• links to: pr