fix: add nil-pointer guard to the bind for driver.Valuer args

bind.go

@@ -17,6 +17,11 @@ var (
 	ErrInvalidTimezone = errors.New("invalid timezone value")
 )
 
+func isNilPointer(v any) bool {
+	rv := reflect.ValueOf(v)
+	return rv.Kind() == reflect.Pointer && rv.IsNil()
+}
+
 func Named(name string, value any) driver.NamedValue {
 	return driver.NamedValue{
 		Name:  name,
@@ -124,7 +129,9 @@ func bindPositional(tz *time.Location, query string, args ...any) (_ string, err
 				if argIndex < len(args) {
 					v := args[argIndex]
 					if fn, ok := v.(std_driver.Valuer); ok {
-						if v, err = fn.Value(); err != nil {
+						if isNilPointer(v) {
+							v = nil
+						} else if v, err = fn.Value(); err != nil {
 							return "", nil
 						}
 					}
@@ -167,7 +174,9 @@ func bindNumeric(tz *time.Location, query string, args ...any) (_ string, err er
 	)
 	for i, v := range args {
 		if fn, ok := v.(std_driver.Valuer); ok {
-			if v, err = fn.Value(); err != nil {
+			if isNilPointer(v) {
+				v = nil
+			} else if v, err = fn.Value(); err != nil {
 				return "", nil
 			}
 		}
@@ -202,7 +211,9 @@ func bindNamed(tz *time.Location, query string, args ...any) (_ string, err erro
 		case driver.NamedValue:
 			value := v.Value
 			if fn, ok := v.Value.(std_driver.Valuer); ok {
-				if value, err = fn.Value(); err != nil {
+				if isNilPointer(v.Value) {
+					value = nil
+				} else if value, err = fn.Value(); err != nil {
 					return "", err
 				}
 			}
@@ -314,9 +325,7 @@ func format(tz *time.Location, scale TimeUnit, v any) (string, error) {
 		}
 		return fmt.Sprintf("[%s]", val), nil
 	case fmt.Stringer:
-		if v := reflect.ValueOf(v); v.Kind() == reflect.Pointer &&
-			v.IsNil() &&
-			v.Type().Elem().Implements(reflect.TypeOf((*fmt.Stringer)(nil)).Elem()) {
+		if isNilPointer(v) {
 			return "NULL", nil
 		}
 		return quote(v.String()), nil

bind_test.go

@@ -1,6 +1,8 @@
 package clickhouse
 
 import (
+	std_driver "database/sql/driver"
+	"fmt"
 	"testing"
 	"time"
 
@@ -496,3 +498,32 @@ func BenchmarkBindNamed(b *testing.B) {
 		}
 	}
 }
+
+// valuerType implements driver.Valuer with a value receiver,
+// so a nil *valuerType satisfies the interface but panics on call.
+type valuerType [16]byte
+
+func (v valuerType) Value() (std_driver.Value, error) {
+	return fmt.Sprintf("%x", v[:]), nil
+}
+
+func TestBindPositionalNilDriverValuer(t *testing.T) {
+	var nilPtr *valuerType
+	actual, err := bind(time.Local, "SELECT ?", nilPtr)
+	require.NoError(t, err)
+	assert.Equal(t, "SELECT NULL", actual)
+}
+
+func TestBindNumericNilDriverValuer(t *testing.T) {
+	var nilPtr *valuerType
+	actual, err := bind(time.Local, "SELECT $1", nilPtr)
+	require.NoError(t, err)
+	assert.Equal(t, "SELECT NULL", actual)
+}
+
+func TestBindNamedNilDriverValuer(t *testing.T) {
+	var nilPtr *valuerType
+	actual, err := bind(time.Local, "SELECT @col", Named("col", nilPtr))
+	require.NoError(t, err)
+	assert.Equal(t, "SELECT NULL", actual)
+}

tests/issues/1823_test.go

@@ -0,0 +1,102 @@
+package issues
+
+import (
+	"context"
+	"database/sql"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+
+	"github.com/ClickHouse/clickhouse-go/v2"
+	clickhouse_tests "github.com/ClickHouse/clickhouse-go/v2/tests"
+)
+
+// Test1823 verifies that passing a typed nil pointer to a type implementing
+// driver.Valuer with a value receiver (e.g. *uuid.UUID) is bound as NULL
+// rather than panicking inside fn.Value().
+func Test1823(t *testing.T) {
+	const ddl = "CREATE TABLE IF NOT EXISTS test_1823 (id UUID, ref_id Nullable(UUID)) Engine Memory"
+
+	t.Run("native_select", func(t *testing.T) {
+		conn, err := clickhouse_tests.GetConnectionTCP("issues", clickhouse.Settings{
+			"max_execution_time": 60,
+		}, nil, &clickhouse.Compression{Method: clickhouse.CompressionLZ4})
+		require.NoError(t, err)
+
+		ctx := context.Background()
+		var nilUUID *uuid.UUID
+
+		require.NotPanics(t, func() {
+			var got *uuid.UUID
+			require.NoError(t, conn.QueryRow(ctx, "SELECT ?", nilUUID).Scan(&got))
+			require.Nil(t, got)
+		})
+	})
+
+	t.Run("native_insert", func(t *testing.T) {
+		conn, err := clickhouse_tests.GetConnectionTCP("issues", clickhouse.Settings{
+			"max_execution_time": 60,
+		}, nil, &clickhouse.Compression{Method: clickhouse.CompressionLZ4})
+		require.NoError(t, err)
+
+		ctx := context.Background()
+		require.NoError(t, conn.Exec(ctx, ddl))
+		defer conn.Exec(ctx, "DROP TABLE IF EXISTS test_1823")
+
+		id := uuid.New()
+		var nilUUID *uuid.UUID
+
+		require.NotPanics(t, func() {
+			require.NoError(t, conn.Exec(ctx, "INSERT INTO test_1823 (id, ref_id) VALUES (?, ?)", id, nilUUID))
+		})
+
+		var gotRef *uuid.UUID
+		require.NoError(t, conn.QueryRow(ctx, "SELECT ref_id FROM test_1823 WHERE id = ?", id).Scan(&gotRef))
+		require.Nil(t, gotRef)
+	})
+
+	t.Run("std_select", func(t *testing.T) {
+		env, err := clickhouse_tests.GetTestEnvironment("issues")
+		require.NoError(t, err)
+		opts := clickhouse_tests.ClientOptionsFromEnv(env, clickhouse.Settings{}, false)
+		db, err := sql.Open("clickhouse", clickhouse_tests.OptionsToDSN(&opts))
+		require.NoError(t, err)
+		defer db.Close()
+
+		ctx := context.Background()
+		var nilUUID *uuid.UUID
+
+		require.NotPanics(t, func() {
+			var got uuid.NullUUID
+			require.NoError(t, db.QueryRowContext(ctx, "SELECT ?", nilUUID).Scan(&got))
+			require.False(t, got.Valid)
+		})
+	})
+
+	t.Run("std_insert", func(t *testing.T) {
+		env, err := clickhouse_tests.GetTestEnvironment("issues")
+		require.NoError(t, err)
+		opts := clickhouse_tests.ClientOptionsFromEnv(env, clickhouse.Settings{}, false)
+		db, err := sql.Open("clickhouse", clickhouse_tests.OptionsToDSN(&opts))
+		require.NoError(t, err)
+		defer db.Close()
+
+		ctx := context.Background()
+		_, err = db.ExecContext(ctx, ddl)
+		require.NoError(t, err)
+		defer db.ExecContext(ctx, "DROP TABLE IF EXISTS test_1823")
+
+		id := uuid.New()
+		var nilUUID *uuid.UUID
+
+		require.NotPanics(t, func() {
+			_, err := db.ExecContext(ctx, "INSERT INTO test_1823 (id, ref_id) VALUES (?, ?)", id, nilUUID)
+			require.NoError(t, err)
+		})
+
+		var gotRef uuid.NullUUID
+		require.NoError(t, db.QueryRowContext(ctx, "SELECT ref_id FROM test_1823 WHERE id = ?", id).Scan(&gotRef))
+		require.False(t, gotRef.Valid)
+	})
+}