Unexpected result when using empty `OBJECT` literal

[suyZhong]

CrateDB version

CrateDB 5.9.0-SNAPSHOT built 5940044

CrateDB setup information

Manual build following the instructions here: https://github.com/crate/crate/blob/master/devs/docs/basics.rst

Problem description

Consider the following test case. As the second query returns NULL, the expression of the WHERE filter should be evaluated to NULL, and thus the third query should return an empty table. However, a row is fetched. Either the result of the second query or the third query should be wrong.

Steps to Reproduce

DROP TABLE IF EXISTS t0;

CREATE  TABLE  t0(c0 OBJECT);
INSERT INTO t0(c0) VALUES (NULL);
REFRESH TABLE t0;

SELECT * FROM t0; -- NULL
SELECT (c0 != {}) FROM t0; -- NULL
SELECT * FROM t0 WHERE (c0 != {});
-- Expected: empty result set
-- Actual: NULL

-- I orignally found by this query:
SELECT * FROM t0 WHERE (c0 != CAST('1' AS OBJECT));

Actual Result

NULL

Expected Result

An empty table

[jeeminso]

Thanks alot for reporting @suyZhong. There is another bugfix in progress which would handle this bug as well, specifically by 1822dd8#diff-b98ffbe4dd33f483188fef958602ca8513268138164548a489a98b25e2da00bcR237-R241

[jeeminso]

The fix will be available with 5.9 release, Thank you!