[Rust]: Comparison of list arrays with differing offsets fails

[alamb]

Note: migrated from original JIRA: https://issues.apache.org/jira/browse/ARROW-11267

Found this while reviewing the fix for ARROW-11239. The reason for the failure seems to be related to the combining of null bitmaps of parent/child data. When I changed create_list_array to not include null buffers the test passes.
{code:java}
#[test]
fn test_list_different_offsets() {
let a =
create_list_array(&[Some(&[0, 0]), Some(&[1, 2]), Some(&[3, 4])]);
let b =
create_list_array(&[Some(&[1, 2]), Some(&[3, 4]), Some(&[5, 6])]); let a_slice = a.slice(1, 2);
let b_slice = b.slice(0, 2);
test_equal(&a_slice, &b_slice, true);
} {code}
[~jorgecarleitao] [~nevi_me] FYI

[alamb]

Comment from Andrew Lamb(alamb) @ 2021-01-19T21:13:19.582+0000:

When I tested on https://github.com/apache/arrow/pull/9211/files -- this test case still fails (aka https://github.com/apache/arrow/pull/9211 does not seem to fix it)

[tustvold]

I think this was fixed by #1589

At the very least this now passes

#[test]
    fn test_list_different_offsets() {
        let a = ListArray::from_iter_primitive::<Int32Type, _, _>([
            Some([Some(0), Some(0)]),
            Some([Some(1), Some(2)]),
            Some([None, None]),
        ]);
        let b = ListArray::from_iter_primitive::<Int32Type, _, _>([
            Some([Some(1), Some(2)]),
            Some([None, None]),
            Some([None, None]),
        ]);
        let a_slice = a.slice(1, 2);
        let b_slice = b.slice(0, 2);
        assert_eq!(&a_slice, &b_slice);
    }

And variations of the same

[alamb]

I ported the test above into a PR #1756