(arrow-go) branch main updated: fix(array): make SetNull idempotent and track null count (#905)

[zeroshade]

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


The following commit(s) were added to refs/heads/main by this push:
     new 777b66ab fix(array): make SetNull idempotent and track null count 
(#905)
777b66ab is described below

commit 777b66abfe923de834c01614920652349655656e
Author: Minh Vu <vuhoangmin...@gmail.com>
AuthorDate: Thu Jul 9 21:01:06 2026 +0200

    fix(array): make SetNull idempotent and track null count (#905)
---
 arrow/array/builder.go      | 3 +++
 arrow/array/builder_test.go | 5 +++++
 arrow/array/map_test.go     | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/arrow/array/builder.go b/arrow/array/builder.go
index 0b3a4e9a..ed4f08e7 100644
--- a/arrow/array/builder.go
+++ b/arrow/array/builder.go
@@ -133,6 +133,9 @@ func (b *builder) SetNull(i int) {
        if i < 0 || i >= b.length {
                panic("arrow/array: index out of range")
        }
+       if bitutil.BitIsSet(b.nullBitmap.Bytes(), i) {
+               b.nulls++
+       }
        bitutil.ClearBit(b.nullBitmap.Bytes(), i)
 }
 
diff --git a/arrow/array/builder_test.go b/arrow/array/builder_test.go
index 2fb47b5c..045317dc 100644
--- a/arrow/array/builder_test.go
+++ b/arrow/array/builder_test.go
@@ -112,6 +112,11 @@ func TestBuilder_SetNull(t *testing.T) {
                        b.SetNull(i)
                }
        }
+       assert.Equal(t, n/2, b.NullN())
+
+       // idempotent SetNull
+       b.SetNull(0)
+       assert.Equal(t, n/2, b.NullN())
 
        for i := 0; i < n; i++ {
                if i%2 == 0 {
diff --git a/arrow/array/map_test.go b/arrow/array/map_test.go
index 13b0c46e..3727e565 100644
--- a/arrow/array/map_test.go
+++ b/arrow/array/map_test.go
@@ -244,6 +244,10 @@ func TestMapBuilder_SetNull(t *testing.T) {
 
        bldr.SetNull(0)
        bldr.SetNull(3)
+       assert.EqualValues(t, 2, bldr.NullN())
+
+       bldr.SetNull(3) // idempotent
+       assert.EqualValues(t, 2, bldr.NullN())
 
        arr = bldr.NewMapArray()
        defer arr.Release()