DATE_SUB/DATE_ADD with INTERVAL NULL crashes with BatchPrimitiveProcessor error instead of returning NULL

Summary

DATE_SUB(column, INTERVAL NULL <unit>) and DATE_ADD(column, INTERVAL NULL <unit>) on a Columnstore table fail with:

ERROR 1815 (HY000): Internal error: An unexpected condition within the query

caused an internal processing error within Columnstore.

Additional Information: error in BatchPrimitiveProcessor

InnoDB correctly returns NULL for the same query. All INTERVAL unit types are affected.

Minimal Reproduction

CREATE TABLE t_null (dt DATETIME) ENGINE=Columnstore;

INSERT INTO t_null VALUES ('2020-01-01 12:00:00');

-- Expected: NULL. Actual: ERROR 1815

SELECT DATE_SUB(dt, INTERVAL NULL DAY) FROM t_null;

All interval types fail: SECOND, MINUTE, HOUR, DAY, MONTH, YEAR, DAY_HOUR, DAY_MINUTE, HOUR_SECOND, MINUTE_MICROSECOND, etc.
DATE_ADD is also affected. Literal DATE_SUB('2020-01-01', INTERVAL NULL DAY) works (returns NULL).

InnoDB comparison

CREATE TABLE t_null_i (dt DATETIME) ENGINE=InnoDB;

INSERT INTO t_null_i VALUES ('2020-01-01 12:00:00');

SELECT dt, DATE_SUB(dt, INTERVAL NULL DAY), DATE_SUB(dt, INTERVAL NULL SECOND), DATE_ADD(dt, INTERVAL NULL MONTH) FROM t_null_i;

-- Returns: NULL, NULL, NULL  (correct)

Probable Root Cause

utils/funcexp/func_date_add.cpp, line 826: after evaluating parm[1]>data()>getStrVal(row, isNull), there is no check of isNull before calling helpers::dateAdd(). When the interval is NULL, getStrVal sets isNull=true and returns an empty string. getNumbers("") returns index ≤ 0, and line 94 throws runtime_error("expression type is not supported") which propagates as a BPP error.

Fix: check isNull after line 826, return 0 before calling dateAdd.

Version

MariaDB Columnstore 25.10.4 (stable-23.10)