e3.0.1 Bug fix.

.gitignore

@@ -2,5 +2,7 @@
 data
 dev
 log
+logs
+script
 *.log
 bin

builder.go

@@ -2,6 +2,7 @@
 package config
 
 import (
+	"errors"
 	"fmt"
 	"os"
 )
@@ -10,7 +11,7 @@ import (
 type Builder struct {
 	cfg      *Config
 	opts     LoadOptions
-	defaults interface{}
+	defaults any
 	prefix   string
 	file     string
 	args     []string
@@ -27,7 +28,7 @@ func NewBuilder() *Builder {
 }
 
 // WithDefaults sets the struct containing default values
-func (b *Builder) WithDefaults(defaults interface{}) *Builder {
+func (b *Builder) WithDefaults(defaults any) *Builder {
 	b.defaults = defaults
 	return b
 }
@@ -94,7 +95,9 @@ func (b *Builder) Build() (*Config, error) {
 
 	// Load configuration
 	if err := b.cfg.LoadWithOptions(b.file, b.args, b.opts); err != nil {
-		return nil, err
+		// The error might be non-fatal (e.g., file not found).
+		// Return the config object so it can be used with other sources.
+		return b.cfg, err
 	}
 
 	return b.cfg, nil
@@ -104,7 +107,11 @@ func (b *Builder) Build() (*Config, error) {
 func (b *Builder) MustBuild() *Config {
 	cfg, err := b.Build()
 	if err != nil {
-		panic(fmt.Sprintf("config build failed: %v", err))
+		// Ignore ErrConfigNotFound as it is not a fatal error for MustBuild.
+		// The application can proceed with defaults/env vars.
+		if !errors.Is(err, ErrConfigNotFound) {
+			panic(fmt.Sprintf("config build failed: %v", err))
+		}
 	}
 	return cfg
 }

convenience.go

@@ -12,7 +12,7 @@ import (
 
 // Quick creates a fully configured Config instance with a single call
 // This is the recommended way to initialize configuration for most applications
-func Quick(structDefaults interface{}, envPrefix, configFile string) (*Config, error) {
+func Quick(structDefaults any, envPrefix, configFile string) (*Config, error) {
 	cfg := New()
 
 	// Register defaults from struct if provided
@@ -31,7 +31,7 @@ func Quick(structDefaults interface{}, envPrefix, configFile string) (*Config, e
 }
 
 // QuickCustom creates a Config with custom options
-func QuickCustom(structDefaults interface{}, opts LoadOptions, configFile string) (*Config, error) {
+func QuickCustom(structDefaults any, opts LoadOptions, configFile string) (*Config, error) {
 	cfg := NewWithOptions(opts)
 
 	// Register defaults from struct if provided
@@ -46,7 +46,7 @@ func QuickCustom(structDefaults interface{}, opts LoadOptions, configFile string
 }
 
 // MustQuick is like Quick but panics on error
-func MustQuick(structDefaults interface{}, envPrefix, configFile string) *Config {
+func MustQuick(structDefaults any, envPrefix, configFile string) *Config {
 	cfg, err := Quick(structDefaults, envPrefix, configFile)
 	if err != nil {
 		panic(fmt.Sprintf("config initialization failed: %v", err))

go.mod

@@ -1,6 +1,6 @@
 module github.com/lixenwraith/config
 
-go 1.24.2
+go 1.24.5
 
 require (
 	github.com/BurntSushi/toml v1.5.0

register.go

@@ -101,7 +101,7 @@ func (c *Config) Unregister(path string) error {
 // RegisterStruct registers configuration values derived from a struct.
 // It uses struct tags (`toml:"..."`) to determine the configuration paths.
 // The prefix is prepended to all paths (e.g., "log."). An empty prefix is allowed.
-func (c *Config) RegisterStruct(prefix string, structWithDefaults interface{}) error {
+func (c *Config) RegisterStruct(prefix string, structWithDefaults any) error {
 	v := reflect.ValueOf(structWithDefaults)
 
 	// Handle pointer or direct struct value
@@ -129,7 +129,7 @@ func (c *Config) RegisterStruct(prefix string, structWithDefaults interface{}) e
 }
 
 // RegisterStructWithTags is like RegisterStruct but allows custom tag names
-func (c *Config) RegisterStructWithTags(prefix string, structWithDefaults interface{}, tagName string) error {
+func (c *Config) RegisterStructWithTags(prefix string, structWithDefaults any, tagName string) error {
 	// Save current tag preference
 	oldTag := "toml"