[CALCITE-2929] Simplification of IS NULL checks are incorrectly assuming that CAST-s are possible

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.18.0
• Fix Version/s: 1.19.0
• Labels: pull-request-available
• Assignee: Zoltan Haindrich
• Reporter: Zoltan Haindrich
• Created: 18/Mar/19 08:36
• Updated: 23/Apr/19 13:16
• Resolved: 20/Mar/19 15:11

Description

Example:

with ax(s) as (values ('xxx'),(cast(null as character varying)))
select cast(s as int) IS NULL from ax;

returns a result set; which evaluates
however 'xxx' is not a valid integer; so an error should be recieved instead

Another class of almost the same issue:

select cast('xxx' as int) IS NULL;

is also problematic; in that case the not nullability is deduced from the fact that the literal's type is not nullable

Issue Links

• blocks: CALCITE-2911 Release Calcite 1.19.0
• causes: DRILL-7195 Query returns incorrect result or does not fail when cast with is null is used in filter condition
• relates to: CALCITE-2469 RexSimplify should optimize '(NOT x) IS NULL' to 'x IS NULL'
• links to: GitHub Pull Request #1116