fix fuzzer issue #7074 (#7077)

maybe?

Signed-off-by: Joe Isaacs <joe.isaacs@live.co.uk>

Author: joseph-isaacs

vortex-array/src/aggregate_fn/fns/min_max/bool.rs

@@ -13,6 +13,10 @@ use crate::dtype::Nullability::NonNullable;
 use crate::scalar::Scalar;
 
 pub(super) fn accumulate_bool(partial: &mut MinMaxPartial, array: &BoolArray) -> VortexResult<()> {
+    if array.is_empty() {
+        return Ok(());
+    }
+
     let mask = array.validity_mask()?;
     let true_non_null = match &mask {
         Mask::AllTrue(_) => array.to_bit_buffer(),

vortex-array/src/aggregate_fn/fns/min_max/mod.rs

@@ -610,6 +610,40 @@ mod tests {
         Ok(())
     }
 
+    /// Regression test for <https://github.com/vortex-data/vortex/issues/7074>.
+    ///
+    /// A chunked all-true bool array with an empty first chunk returned min=false because
+    /// `accumulate_bool` on the empty chunk incorrectly merged min=false,max=false into the
+    /// partial state.
+    #[test]
+    fn test_bool_chunked_with_empty_chunk() -> VortexResult<()> {
+        let mut ctx = LEGACY_SESSION.create_execution_ctx();
+
+        let empty = BoolArray::new(BitBuffer::from([].as_slice()), Validity::NonNullable);
+        let chunk1 = BoolArray::new(
+            BitBuffer::from([true, true].as_slice()),
+            Validity::NonNullable,
+        );
+        let chunk2 = BoolArray::new(
+            BitBuffer::from([true, true, true].as_slice()),
+            Validity::NonNullable,
+        );
+        let chunked = ChunkedArray::try_new(
+            vec![empty.into_array(), chunk1.into_array(), chunk2.into_array()],
+            DType::Bool(Nullability::NonNullable),
+        )?;
+
+        let result = min_max(&chunked.into_array(), &mut ctx)?;
+        assert_eq!(
+            result,
+            Some(MinMaxResult {
+                min: Scalar::bool(true, Nullability::NonNullable),
+                max: Scalar::bool(true, Nullability::NonNullable),
+            })
+        );
+        Ok(())
+    }
+
     #[test]
     fn test_varbin_all_nulls() -> VortexResult<()> {
         let array = VarBinArray::from_iter(