fix(compute/exec): do not carry a cached null count across ArraySpan.SetSlice

arrow/compute/exec/span.go

@@ -214,13 +214,13 @@ func (a *ArraySpan) SetSlice(off, length int64) {
 		return
 	}
 
+	// The cached null count describes the span as it was, not the slice.
+	// As in the C++ ArraySpan::SetSlice, a slice of anything with a validity
+	// bitmap has an unknown count until someone asks for it; only the null
+	// type and a span without a bitmap can be counted without looking.
 	if a.Type.ID() != arrow.NULL {
-		if a.Nulls != 0 {
-			if a.Nulls == a.Len {
-				a.Nulls = length
-			} else {
-				a.Nulls = array.UnknownNullCount
-			}
+		if a.Nulls != 0 || len(a.Buffers[0].Buf) != 0 {
+			a.Nulls = array.UnknownNullCount
 		}
 	} else {
 		a.Nulls = length

arrow/compute/exec/span_test.go

@@ -523,6 +523,8 @@ func TestArraySpan_SetSlice(t *testing.T) {
 		{"null type", fields{Type: arrow.Null}, args{5, 10}, 10},
 		{"not-null type", fields{Type: arrow.PrimitiveTypes.Int8}, args{5, 10}, 0},
 		{"not-null type with nulls", fields{Type: arrow.PrimitiveTypes.Int8, Nulls: -1}, args{5, 10}, array.UnknownNullCount},
+		{"no nulls but a validity bitmap", fields{Type: arrow.PrimitiveTypes.Int8, Len: 16, Buffers: [3]exec.BufferSpan{{Buf: []byte{0xff, 0xff}}}}, args{5, 10}, array.UnknownNullCount},
+		{"all null before the slice", fields{Type: arrow.PrimitiveTypes.Int8, Len: 16, Nulls: 16, Buffers: [3]exec.BufferSpan{{Buf: []byte{0, 0}}}}, args{5, 10}, array.UnknownNullCount},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

arrow/compute/scalar_boolean_chunksize_test.go

@@ -0,0 +1,76 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package compute_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/apache/arrow-go/v18/arrow"
+	"github.com/apache/arrow-go/v18/arrow/array"
+	"github.com/apache/arrow-go/v18/arrow/compute"
+	"github.com/apache/arrow-go/v18/arrow/memory"
+)
+
+// and_kleene and or_kleene over two boolean arrays with nulls, executed with
+// different ExecCtx.ChunkSize values; the result must not depend on ChunkSize.
+func TestKleeneChunkSizeIndependent(t *testing.T) {
+	mem := memory.NewCheckedAllocator(memory.DefaultAllocator)
+	defer mem.AssertSize(t, 0)
+
+	// left:  [true, null, true, null, false, true, null, true]
+	// right: [null, true, true, false, null, null, true, true]
+	lb := array.NewBooleanBuilder(mem)
+	lb.AppendValues([]bool{true, false, true, false, false, true, false, true}, []bool{true, false, true, false, true, true, false, true})
+	left := lb.NewArray()
+	lb.Release()
+	defer left.Release()
+	rb := array.NewBooleanBuilder(mem)
+	rb.AppendValues([]bool{false, true, true, false, false, false, true, true}, []bool{false, true, true, true, false, false, true, true})
+	right := rb.NewArray()
+	rb.Release()
+	defer right.Release()
+
+	for _, fn := range []string{"and_kleene", "or_kleene"} {
+		t.Run(fn, func(t *testing.T) { checkChunkSizeIndependent(t, mem, fn, left, right) })
+	}
+}
+
+func checkChunkSizeIndependent(t *testing.T, mem memory.Allocator, fn string, left, right arrow.Array) {
+	run := func(chunk int64) string {
+		ectx := compute.DefaultExecCtx()
+		ectx.ChunkSize = chunk
+		ctx := compute.SetExecCtx(compute.WithAllocator(context.Background(), mem), ectx)
+		out, err := compute.CallFunction(ctx, fn, nil, &compute.ArrayDatum{Value: left.Data()}, &compute.ArrayDatum{Value: right.Data()})
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer out.Release()
+		arr := out.(*compute.ArrayDatum).MakeArray()
+		defer arr.Release()
+		return arr.String()
+	}
+	ref := run(compute.DefaultMaxChunkSize)
+	t.Logf("ChunkSize default: %s", ref)
+	for _, n := range []int64{1, 2, 3, 4, 8} {
+		got := run(n)
+		t.Logf("ChunkSize %d: %s", n, got)
+		if got != ref {
+			t.Errorf("ChunkSize %d: got %s, want %s", n, got, ref)
+		}
+	}
+}