[jira] [Commented] (ARROW-11160) [Rust] pitfall in xxx_equal functions

["meng qingyou (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARROW-11160?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17260431#comment-17260431 ] 

meng qingyou commented on ARROW-11160:
--------------------------------------

I did some updates to demonstrate possible fix or questions. See

https://github.com/apache/arrow/compare/master...mqy:array-equal

> [Rust] pitfall in xxx_equal functions
> -------------------------------------
>
>                 Key: ARROW-11160
>                 URL: https://issues.apache.org/jira/browse/ARROW-11160
>             Project: Apache Arrow
>          Issue Type: Improvement
>            Reporter: meng qingyou
>            Priority: Major
>
> Functions `pub(super) fn xxxx_equal` in rust/src/array/equal/ MUST fail if called directly instead of from `equal`.  boolean.rs as  example:
> {code:java}
> lhs_is_null || (lhs_is_null == rhs_is_null)
>  && equal_bits(...){code}
>  
>  The bug is not seen in tests at present because `equal` shortcuts the condition: zero null s v.s. nulls
>   
>  To verify this problem , adds a new test in `mod.rs`
>   
> {code:java}
> #[test]
> fn test_direct_call_boolean_equal() {
>     let a = BooleanArray::from(vec![Some(true)]).data();
>     let b = BooleanArray::from(vec![Some(false)]).data();
>     let lhs = a.as_ref();
>     let rhs = b.as_ref();
>     let lhs_nulls = lhs.null_buffer();
>     let rhs_nulls = rhs.null_buffer();
>     assert_eq!(boolean::boolean_equal(lhs, rhs, lhs_nulls, rhs_nulls, 0, 0, lhs.len()), false);
> }
> {code}



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