morrySnow opened a new pull request, #67730:
URL: https://github.com/apache/doris/pull/67730
## Problem
A comparison whose left side is an overflowing `TRY_CAST` can be simplified
to a non-null boolean constant even though the cast evaluates to `NULL`. For
example, with a non-null `BIGINT` value of `128`, this predicate must produce
`NULL`:
```sql
TRY_CAST(k AS TINYINT) > 127
```
The incorrect simplification also makes `(... > 127) IS NULL` false and can
filter out rows that should match.
## Root cause
The type-range comparison simplifier unwraps a cast to inspect the source
type and tighten the possible numeric range. It then reuses that unwrapped
child to decide whether an always-true or always-false result can be null. A
non-nullable child does not capture `TRY_CAST` semantics: a failed conversion
can introduce `NULL` independently of child nullability.
## Reproduction
```sql
CREATE TABLE t (
id INT NOT NULL,
k BIGINT NOT NULL
)
DUPLICATE KEY(id)
DISTRIBUTED BY HASH(id) BUCKETS 1
PROPERTIES ("replication_num" = "1");
INSERT INTO t VALUES (1, 128), (2, 1);
SELECT id,
TRY_CAST(k AS TINYINT),
TRY_CAST(k AS TINYINT) > 127,
(TRY_CAST(k AS TINYINT) > 127) IS NULL
FROM t
ORDER BY id;
```
Before this change, the comparison for `id = 1` is simplified to `FALSE`.
The correct result is `NULL`, and the final `IS NULL` expression is `TRUE`.
## Fix
Separate the expression used for numeric range inference from the expression
used for nullability. The cast child remains the range source, but an original
`TRY_CAST` is retained when producing null-aware boolean constants. Regular
`CAST` expressions keep their existing child-based normalization.
## Tests
- Extended `SimplifyComparisonPredicateTest` with out-of-range comparisons
over a non-nullable source wrapped by `TRY_CAST`, covering both true-or-null
and false-or-null simplifications.
- Ran the complete test class: 14 tests passed.
- Deployed the FE to a local sandbox and verified the SQL reproduction
returns `NULL` for the overflow comparison and returns the row through an `IS
NULL` filter.
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