From d9e95c5776e0bfb293c10e9441db2b95983f10b2 Mon Sep 17 00:00:00 2001
From: Yevgeny Pats <16490766+yevgenypats@users.noreply.github.com>
Date: Fri, 7 Apr 2023 16:50:44 +0300
Subject: [PATCH 1/2] GH-34966: Add InsertField and FieldIndex to Schema object

---
 go/arrow/schema.go      | 20 ++++++++++++++++++++
 go/arrow/schema_test.go | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/go/arrow/schema.go b/go/arrow/schema.go
index 1936cea989f..a3c9cc13508 100644
--- a/go/arrow/schema.go
+++ b/go/arrow/schema.go
@@ -197,6 +197,26 @@ func (sc *Schema) FieldIndices(n string) []int {
 	return sc.index[n]
 }
 
+// FieldIndex return index of the unique field with the given name.
+// Returns -1 if the name isn’t found or there are several fields with the given name.
+func (sc *Schema) FieldIndex(name string) int {
+	indices := sc.index[name]
+	if len(indices) != 1 {
+		return -1
+	}
+	return indices[0]
+}
+
+func (sc *Schema) InsertField(i int, f Field) *Schema {
+	if f.Type == nil {
+		panic("arrow: field with nil DataType")
+	}
+	fields := make([]Field, len(sc.fields)+1)
+	copy(fields[:i], sc.fields[:i])
+	copy(fields[i+1:], sc.fields[i:])
+	fields[i] = f
+	return NewSchemaWithEndian(fields, &sc.meta, sc.endianness)
+}
 func (sc *Schema) HasField(n string) bool { return len(sc.FieldIndices(n)) > 0 }
 func (sc *Schema) HasMetadata() bool      { return len(sc.meta.keys) > 0 }
 
diff --git a/go/arrow/schema_test.go b/go/arrow/schema_test.go
index af9576003e1..ecf5b986664 100644
--- a/go/arrow/schema_test.go
+++ b/go/arrow/schema_test.go
@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"github.com/apache/arrow/go/v12/arrow/endian"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestMetadata(t *testing.T) {
@@ -292,6 +293,15 @@ func TestSchema(t *testing.T) {
 				}
 			}
 
+			if s.FieldIndex("dup") != -1 {
+				t.Fatalf("invalid FieldIndex(dup): got=%d, want=-1", s.FieldIndex("dup"))
+			}
+			if s.HasField("f1") {
+				if s.FieldIndex("f1") != 0 {
+					t.Fatalf("invalid FieldIndex(f1): got=%d, want=0", s.FieldIndex("f1"))
+				}
+			}
+
 			if got, want := s.String(), tc.serialize; got != want {
 				t.Fatalf("invalid stringer: got=%q, want=%q", got, want)
 			}
@@ -413,3 +423,25 @@ func TestSchemaEqual(t *testing.T) {
 		})
 	}
 }
+
+func TestSchemaInsertField(t *testing.T) {
+	fields := []Field{
+		{Name: "f1", Type: PrimitiveTypes.Int32},
+		{Name: "f2", Type: PrimitiveTypes.Int64},
+	}
+	md := func() *Metadata {
+		md := MetadataFrom(map[string]string{"k1": "v1", "k2": "v2"})
+		return &md
+	}()
+	sc := NewSchema(fields, md)
+	sc1 := sc.InsertField(0, Field{Name: "f0", Type: PrimitiveTypes.Int32})
+	assert.False(t, sc.Equal(sc1))
+
+	fields1 := []Field{
+		{Name: "f0", Type: PrimitiveTypes.Int32},
+		{Name: "f1", Type: PrimitiveTypes.Int32},
+		{Name: "f2", Type: PrimitiveTypes.Int64},
+	}
+	sc2 := NewSchema(fields1, md)
+	assert.True(t, sc1.Equal(sc2))
+}

From 2a9db68ee2e45f08edfeb92b29390148d57ee136 Mon Sep 17 00:00:00 2001
From: Yevgeny Pats <16490766+yevgenypats@users.noreply.github.com>
Date: Fri, 7 Apr 2023 17:47:39 +0300
Subject: [PATCH 2/2] remove duplicate

---
 go/arrow/schema.go      | 10 ----------
 go/arrow/schema_test.go | 23 -----------------------
 2 files changed, 33 deletions(-)

diff --git a/go/arrow/schema.go b/go/arrow/schema.go
index a3c9cc13508..f95c3336522 100644
--- a/go/arrow/schema.go
+++ b/go/arrow/schema.go
@@ -207,16 +207,6 @@ func (sc *Schema) FieldIndex(name string) int {
 	return indices[0]
 }
 
-func (sc *Schema) InsertField(i int, f Field) *Schema {
-	if f.Type == nil {
-		panic("arrow: field with nil DataType")
-	}
-	fields := make([]Field, len(sc.fields)+1)
-	copy(fields[:i], sc.fields[:i])
-	copy(fields[i+1:], sc.fields[i:])
-	fields[i] = f
-	return NewSchemaWithEndian(fields, &sc.meta, sc.endianness)
-}
 func (sc *Schema) HasField(n string) bool { return len(sc.FieldIndices(n)) > 0 }
 func (sc *Schema) HasMetadata() bool      { return len(sc.meta.keys) > 0 }
 
diff --git a/go/arrow/schema_test.go b/go/arrow/schema_test.go
index ecf5b986664..63929570ccd 100644
--- a/go/arrow/schema_test.go
+++ b/go/arrow/schema_test.go
@@ -22,7 +22,6 @@ import (
 	"testing"
 
 	"github.com/apache/arrow/go/v12/arrow/endian"
-	"github.com/stretchr/testify/assert"
 )
 
 func TestMetadata(t *testing.T) {
@@ -423,25 +422,3 @@ func TestSchemaEqual(t *testing.T) {
 		})
 	}
 }
-
-func TestSchemaInsertField(t *testing.T) {
-	fields := []Field{
-		{Name: "f1", Type: PrimitiveTypes.Int32},
-		{Name: "f2", Type: PrimitiveTypes.Int64},
-	}
-	md := func() *Metadata {
-		md := MetadataFrom(map[string]string{"k1": "v1", "k2": "v2"})
-		return &md
-	}()
-	sc := NewSchema(fields, md)
-	sc1 := sc.InsertField(0, Field{Name: "f0", Type: PrimitiveTypes.Int32})
-	assert.False(t, sc.Equal(sc1))
-
-	fields1 := []Field{
-		{Name: "f0", Type: PrimitiveTypes.Int32},
-		{Name: "f1", Type: PrimitiveTypes.Int32},
-		{Name: "f2", Type: PrimitiveTypes.Int64},
-	}
-	sc2 := NewSchema(fields1, md)
-	assert.True(t, sc1.Equal(sc2))
-}