(arrow-rs) branch main updated: fix: preserve zero-width FixedSizeBinary length when filtering (#11042)

[jeffreyvo]

This is an automated email from the ASF dual-hosted git repository.

Jefffrey pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow-rs.git


The following commit(s) were added to refs/heads/main by this push:
     new 911721c69e fix: preserve zero-width FixedSizeBinary length when 
filtering (#11042)
911721c69e is described below

commit 911721c69e21a2c6921b0bdb6097ba11cc101c22
Author: RIchard Baah <137434454+rich-t-...@users.noreply.github.com>
AuthorDate: Tue Sep 15 01:04:27 2026 -0400

    fix: preserve zero-width FixedSizeBinary length when filtering (#11042)
    
    # Which issue does this PR close?
    
    <!--
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    enhancements and this helps us generate change logs for our releases.
    You can link an issue to this PR using the GitHub syntax.
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    - Closes None.
    
    # Rationale for this change
    edge case that currently isnt covered
    <!--
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    in the issue then this section is not needed.
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    # What changes are included in this PR?
    
    checks for if array is empty and has no nulls, if so set the len
    outright
    
    
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    # Are these changes tested?
    yes
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    # Are there any user-facing changes?
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---
 arrow-select/src/filter.rs | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/arrow-select/src/filter.rs b/arrow-select/src/filter.rs
index 85b21df03c..0e67ad7994 100644
--- a/arrow-select/src/filter.rs
+++ b/arrow-select/src/filter.rs
@@ -1017,7 +1017,13 @@ fn filter_fixed_size_binary(
 
     let nulls = predicate.filter_nulls(array.nulls());
 
-    FixedSizeBinaryArray::new(array.value_length(), buffer.into(), nulls)
+    FixedSizeBinaryArray::try_new_with_len(
+        array.value_length(),
+        buffer.into(),
+        nulls,
+        predicate.count,
+    )
+    .unwrap()
 }
 
 /// `filter` implementation for dictionaries
@@ -2106,6 +2112,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_filter_zero_width_fixed_size_binary() {
+        // value_length=0 with no nulls: row count cannot be inferred from the 
empty
+        // buffer, so filter must preserve it explicitly.
+        let array = FixedSizeBinaryArray::try_new_with_len(
+            0,
+            Buffer::from_slice_ref(&[] as &[u8]),
+            None,
+            3,
+        )
+        .unwrap();
+        let filter_array = BooleanArray::from(vec![true, false, true]);
+        let result = filter(&array, &filter_array).unwrap();
+        assert_eq!(result.len(), 2);
+    }
+
     fn test_filter_union_array(array: UnionArray) {
         let filter_array = BooleanArray::from(vec![true, false, false]);
         let c = filter(&array, &filter_array).unwrap();