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https://issues.apache.org/jira/browse/FLINK-40672?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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dylanhz updated FLINK-40672:
----------------------------
Description:
h3. Description
A non-nullable VARIANT can contain a variant null. Casting it to a non-VARIANT
type returns SQL NULL, but Flink incorrectly infers a NOT NULL result.
For example:
{code:sql}
SELECT CAST(PARSE_JSON('null') AS INT);
{code}
This can cause runtime NOT NULL violations or incorrect optimization of {{IS
NULL}} and {{COALESCE}}.
Upstream Calcite already correctly makes casts from VARIANT to non-VARIANT
types nullable. Flink's copied {{SqlCastFunction}} does not preserve this
behavior.
h3. Expected behavior
Align with Calcite and consistently infer nullable results for casts from
VARIANT to non-VARIANT types in both SQL and Table API.
was:
*Description*
A non-nullable VARIANT can contain a variant null. Casting it to a non-VARIANT
type returns SQL NULL, but Flink incorrectly infers a NOT NULL result.
For example:
{code:java}
SELECT CAST(PARSE_JSON('null') AS INT); {code}
This can cause runtime NOT NULL violations or incorrect optimization of {{IS
NULL}} and {{{}COALESCE{}}}.
Upstream Calcite already correctly makes casts from VARIANT to non-VARIANT
types nullable. Flink’s copied {{SqlCastFunction}} does not preserve this
behavior.
*Expected behavior*
Align with Calcite and consistently infer nullable results for casts from
VARIANT to non-VARIANT types in both SQL and Table API.
> Incorrect nullability for CAST from VARIANT
> -------------------------------------------
>
> Key: FLINK-40672
> URL: https://issues.apache.org/jira/browse/FLINK-40672
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / API
> Reporter: dylanhz
> Priority: Major
>
> h3. Description
> A non-nullable VARIANT can contain a variant null. Casting it to a
> non-VARIANT type returns SQL NULL, but Flink incorrectly infers a NOT NULL
> result.
> For example:
> {code:sql}
> SELECT CAST(PARSE_JSON('null') AS INT);
> {code}
> This can cause runtime NOT NULL violations or incorrect optimization of {{IS
> NULL}} and {{COALESCE}}.
> Upstream Calcite already correctly makes casts from VARIANT to non-VARIANT
> types nullable. Flink's copied {{SqlCastFunction}} does not preserve this
> behavior.
> h3. Expected behavior
> Align with Calcite and consistently infer nullable results for casts from
> VARIANT to non-VARIANT types in both SQL and Table API.
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