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https://issues.apache.org/jira/browse/FLINK-40182?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
ASF GitHub Bot updated FLINK-40182:
-----------------------------------
Labels: pull-request-available (was: )
> ArrayToArray and MapToMap cast rules generate code which might fail with NPE
> ----------------------------------------------------------------------------
>
> Key: FLINK-40182
> URL: https://issues.apache.org/jira/browse/FLINK-40182
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / Planner
> Reporter: Sergey Nuyanzin
> Assignee: Sergey Nuyanzin
> Priority: Major
> Labels: pull-request-available
>
> {{ArrayToArrayCastRule}}, {{MapToMapAndMultisetToMultisetCastRule}} generate
> code that trusted the target type's declared NOT NULL nullability instead of
> checking the actual runtime value. When the source array/map element was
> actually null (a cast doesn't enforce constraints, so a NOT NULL target type
> is not a runtime guarantee), the generated code would either throw an NPE
> (e.g., unboxing a null) or, for primitive-backed arrays, silently write a
> default value (e.g., 0) instead of preserving/rejecting the null — masking
> data corruption.
> repro
> {code:sql}
> SELECT CAST(
> ARRAY_SLICE(
> test_array,
> 1,
> LEAST( CARDINALITY(JSON_QUERY(b, 'lax $[*]' RETURNING ARRAY<STRING>)),
> 10 )
> )
> as ARRAY<ROW<`id` STRING NOT NULL> NOT NULL>)
> FROM (
> SELECT
> *,
> ARRAY[
> ROW(JSON_VALUE(a.b, '$[0].id' RETURNING VARCHAR ERROR ON EMPTY)),
> CASE WHEN JSON_EXISTS(a.b, '$[1]') THEN
> ROW(JSON_VALUE(a.b, '$[1].id' RETURNING VARCHAR ERROR ON EMPTY))
> END,
> ROW(JSON_VALUE(a.b, '$[2].id' RETURNING VARCHAR ERROR ON EMPTY)),
> CASE WHEN JSON_EXISTS(a.b, '$[3]') THEN
> ROW(JSON_VALUE(a.b, '$[3].id' RETURNING VARCHAR ERROR ON EMPTY))
> END
> ] as test_array
> FROM (VALUES (
> '[{"id":"S1"},null,{"id":"S3"}]'
> )) AS a(b)
> ) AS test_array;{code}
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