reduce heap allocation (#234)

config.go

@@ -249,7 +249,7 @@ var (
 			return strings.Split(f, ","), nil
 		}),
 		convert.WithHook[string, encoding.TextUnmarshaler](func(f string, t encoding.TextUnmarshaler) error {
-			return t.UnmarshalText([]byte(f)) //nolint:wrapcheck
+			return t.UnmarshalText(internal.String2ByteSlice(f)) //nolint:wrapcheck
 		}),
 	}
 	defaultConverter = convert.New(

default.go

@@ -70,6 +70,6 @@ var defaultConfig atomic.Pointer[Config] //nolint:gochecknoglobals
 func init() { //nolint:gochecknoinits
 	var config Config
 	// Ignore error as env loader does not return error.
-	_ = config.Load(env.Env{})
+	_ = config.Load(env.New())
 	defaultConfig.Store(&config)
 }

internal/convert/converter.go

@@ -9,6 +9,8 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
+
+	"github.com/nil-go/konf/internal"
 )
 
 type Converter struct {
@@ -413,7 +415,8 @@ func (c Converter) convertSlice(name string, fromVal, toVal reflect.Value) error
 
 		return errors.Join(errs...)
 	case fromVal.Kind() == reflect.String && toVal.Type().Elem().Kind() == reflect.Uint8:
-		toVal.SetBytes([]byte(fromVal.String()))
+		s := fromVal.String()
+		toVal.SetBytes(internal.String2ByteSlice(s))
 	case fromVal.Kind() == reflect.Map:
 		// Empty maps turn into empty arrays
 		if fromVal.Len() == 0 {
@@ -454,9 +457,10 @@ func (c Converter) convertString(name string, fromVal, toVal reflect.Value) erro
 	case fromVal.Kind() == reflect.Array && fromVal.Type().Elem().Kind() == reflect.Uint8:
 		bytes := make([]uint8, fromVal.Len()) //nolint:makezero
 		reflect.Copy(reflect.ValueOf(bytes), fromVal)
-		toVal.SetString(string(bytes))
+		toVal.SetString(internal.ByteSlice2String(bytes))
 	case fromVal.Kind() == reflect.Slice && fromVal.Type().Elem().Kind() == reflect.Uint8:
-		toVal.SetString(string(fromVal.Bytes()))
+		bytes := fromVal.Bytes()
+		toVal.SetString(internal.ByteSlice2String(bytes))
 	default:
 		return fmt.Errorf( //nolint:goerr113
 			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",

internal/credential/credentials.go

@@ -6,7 +6,8 @@ package credential
 import (
 	"fmt"
 	"regexp"
-	"unsafe"
+
+	"github.com/nil-go/konf/internal"
 )
 
 func Blur(name string, value any) string {
@@ -19,7 +20,7 @@ func Blur(name string, value any) string {
 	case string:
 		formatted = v
 	case []byte:
-		formatted = unsafe.String(unsafe.SliceData(v), len(v))
+		formatted = internal.ByteSlice2String(v)
 	default:
 		formatted = fmt.Sprint(value)
 	}

internal/string.go

@@ -0,0 +1,22 @@
+// Copyright (c) 2024 The konf authors
+// Use of this source code is governed by a MIT license found in the LICENSE file.
+
+package internal
+
+import "unsafe"
+
+func String2ByteSlice(str string) []byte {
+	if str == "" {
+		return nil
+	}
+
+	return unsafe.Slice(unsafe.StringData(str), len(str))
+}
+
+func ByteSlice2String(bs []byte) string {
+	if len(bs) == 0 {
+		return ""
+	}
+
+	return unsafe.String(unsafe.SliceData(bs), len(bs))
+}

provider/azappconfig/appconfig.go

@@ -131,15 +131,13 @@ func (p *clientProxy) load(ctx context.Context) (map[string]string, bool, error)
 	if p.client == nil {
 		if token, ok := p.credential.(*azidentity.DefaultAzureCredential); ok && reflect.ValueOf(*token).IsZero() {
 			var err error
-			credentialOptions := &azidentity.DefaultAzureCredentialOptions{}
-			if p.credential, err = azidentity.NewDefaultAzureCredential(credentialOptions); err != nil {
+			if p.credential, err = azidentity.NewDefaultAzureCredential(nil); err != nil {
 				return nil, false, fmt.Errorf("load default Azure credential: %w", err)
 			}
 		}
 
 		var err error
-		clientOptions := &azappconfig.ClientOptions{}
-		if p.client, err = azappconfig.NewClient(p.endpoint, p.credential, clientOptions); err != nil {
+		if p.client, err = azappconfig.NewClient(p.endpoint, p.credential, nil); err != nil {
 			return nil, false, fmt.Errorf("create Azure app configuration client: %w", err)
 		}
 	}
@@ -157,7 +155,7 @@ func (p *clientProxy) load(ctx context.Context) (map[string]string, bool, error)
 	if p.labelFilter != "" {
 		selector.LabelFilter = &p.labelFilter
 	}
-	pager := p.client.NewListSettingsPager(selector, &azappconfig.ListSettingsOptions{})
+	pager := p.client.NewListSettingsPager(selector, nil)
 
 	var (
 		values = make(map[string]string)

provider/azblob/blob.go

@@ -128,13 +128,12 @@ func (p *clientProxy) load(ctx context.Context) ([]byte, bool, error) { //nolint
 	if p.client == nil {
 		if token, ok := p.credential.(*azidentity.DefaultAzureCredential); ok && reflect.ValueOf(*token).IsZero() {
 			var err error
-			credentialOptions := &azidentity.DefaultAzureCredentialOptions{}
-			if p.credential, err = azidentity.NewDefaultAzureCredential(credentialOptions); err != nil {
+			if p.credential, err = azidentity.NewDefaultAzureCredential(nil); err != nil {
 				return nil, false, fmt.Errorf("load default Azure credential: %w", err)
 			}
 		}
 
-		client, err := azblob.NewClient(p.endpoint, p.credential, &azblob.ClientOptions{})
+		client, err := azblob.NewClient(p.endpoint, p.credential, nil)
 		if err != nil {
 			return nil, false, fmt.Errorf("create Azure blob client: %w", err)
 		}