Handle double pointers for Nullable columns when batch inserting

lib/column/nullable.go

@@ -111,7 +111,15 @@ func (col *Nullable) Append(v interface{}) ([]uint8, error) {
 }
 
 func (col *Nullable) AppendRow(v interface{}) error {
-	if v == nil || (reflect.ValueOf(v).Kind() == reflect.Ptr && reflect.ValueOf(v).IsNil()) {
+	// Might receive double pointers like **String, because of how Nullable columns are read
+	// Unpack because we can't write double pointers
+	rv := reflect.ValueOf(v)
+	if v != nil && rv.Kind() == reflect.Pointer && !rv.IsNil() && rv.Elem().Kind() == reflect.Pointer {
+		v = rv.Elem().Interface()
+		rv = reflect.ValueOf(v)
+	}
+
+	if v == nil || (rv.Kind() == reflect.Pointer && rv.IsNil()) {
 		col.nulls.Append(1)
 		// used to detect sql.Null* types
 	} else if val, ok := v.(driver.Valuer); ok {

tests/issues/777_test.go

@@ -0,0 +1,68 @@
+package issues
+
+import (
+	"context"
+	"github.com/ClickHouse/clickhouse-go/v2"
+	"github.com/ClickHouse/clickhouse-go/v2/lib/driver"
+	clickhouse_tests "github.com/ClickHouse/clickhouse-go/v2/tests"
+	"github.com/stretchr/testify/require"
+	"reflect"
+	"testing"
+)
+
+func TestInsertNullableString(t *testing.T) {
+	var (
+		conn, err = clickhouse_tests.GetConnection("issues", clickhouse.Settings{
+			"max_execution_time": 60,
+		}, nil, &clickhouse.Compression{
+			Method: clickhouse.CompressionLZ4,
+		})
+	)
+	ctx := context.Background()
+	require.NoError(t, err)
+	const ddl = `
+		CREATE TABLE test_nullable_string_insert (
+			  Col1 String
+			, Col2 Nullable(String)
+		) Engine Memory
+		`
+	defer func() {
+		conn.Exec(ctx, "DROP TABLE IF EXISTS test_nullable_string_insert")
+	}()
+	require.NoError(t, conn.Exec(ctx, ddl))
+	const baseValues = `
+		INSERT INTO test_nullable_string_insert (Col1, Col2) VALUES ('Val1', 'Val2'), ('Val11', NULL)
+		`
+	require.NoError(t, conn.Exec(ctx, baseValues))
+
+	rows, err := conn.Query(ctx, "SELECT * FROM test_nullable_string_insert")
+	require.NoError(t, err)
+	defer func(rows driver.Rows) {
+		_ = rows.Close()
+	}(rows)
+
+	records := make([][]any, 0)
+	for rows.Next() {
+		record := make([]any, 0, len(rows.ColumnTypes()))
+		for _, ct := range rows.ColumnTypes() {
+			record = append(record, reflect.New(ct.ScanType()).Interface())
+		}
+		err = rows.Scan(record...)
+		require.NoError(t, err)
+
+		records = append(records, record)
+	}
+	require.Greater(t, len(records), 0)
+
+	// Try to insert records in the same format as queried above
+	batch, err := conn.PrepareBatch(ctx, "INSERT INTO test_nullable_string_insert")
+	require.NoError(t, err)
+
+	for _, r := range records {
+		err = batch.Append(r...)
+		require.NoError(t, err)
+	}
+
+	err = batch.Send()
+	require.NoError(t, err)
+}

tests/resources/custom.xml

@@ -1,8 +1,9 @@
 <?xml version="1.0" ?>
 <clickhouse>
     <listen_host>::</listen_host>
-    <listen_host>0.0.0.0</listen_host>
     <listen_try>1</listen_try>
+    <https_port>8443</https_port>
+    <tcp_port_secure>9440</tcp_port_secure>
     <logger>
         <console>1</console>
     </logger>
@@ -30,7 +31,4 @@
         </client>
     </openSSL>
     <display_name>clickhouse</display_name>
-    <listen_host>0.0.0.0</listen_host>
-    <https_port>8443</https_port>
-    <tcp_port_secure>9440</tcp_port_secure>
 </clickhouse>

tests/utils.go

@@ -155,9 +155,12 @@ func CreateClickHouseTestEnvironment(testSet string) (ClickHouseTestEnvironment,
 		Image:        fmt.Sprintf("clickhouse/clickhouse-server:%s", GetClickHouseTestVersion()),
 		Name:         fmt.Sprintf("clickhouse-go-%s-%d", strings.ToLower(testSet), time.Now().UnixNano()),
 		ExposedPorts: []string{"9000/tcp", "8123/tcp", "9440/tcp", "8443/tcp"},
-		WaitingFor: wait.ForAll(wait.ForLog("Ready for connections").WithStartupTimeout(time.Second*time.Duration(120)), wait.ForSQL("9000/tcp", "clickhouse", func(port nat.Port) string {
-			return fmt.Sprintf("clickhouse://default:ClickHouse@localhost:%s", port.Port())
-		})).WithStartupTimeout(time.Second * time.Duration(120)),
+		WaitingFor: wait.ForAll(
+			wait.ForLog("Ready for connections").WithStartupTimeout(time.Second*time.Duration(120)),
+			wait.ForSQL("9000/tcp", "clickhouse", func(port nat.Port) string {
+				return fmt.Sprintf("clickhouse://default:[email protected]:%s", port.Port())
+			}),
+		).WithStartupTimeout(time.Second * time.Duration(120)),
 		Mounts: []testcontainers.ContainerMount{
 			testcontainers.BindMount(path.Join(basePath, "./resources/custom.xml"), "/etc/clickhouse-server/config.d/custom.xml"),
 			testcontainers.BindMount(path.Join(basePath, "./resources/admin.xml"), "/etc/clickhouse-server/users.d/admin.xml"),
@@ -185,7 +188,7 @@ func CreateClickHouseTestEnvironment(testSet string) (ClickHouseTestEnvironment,
 		HttpPort:  hp.Int(),
 		SslPort:   sslPort.Int(),
 		HttpsPort: hps.Int(),
-		Host:      "localhost",
+		Host:      "127.0.0.1",
 		// we set this explicitly - note its also set in the /etc/clickhouse-server/users.d/admin.xml
 		Username:  "default",
 		Password:  "ClickHouse",