feat: control finder behavior by experimental feature flag

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

file.go

@@ -1,5 +1,3 @@
-//go:build !viper_finder
-
 package viper
 
 import (
@@ -7,14 +5,19 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/sagikazarmark/locafero"
 	"github.com/spf13/afero"
 )
 
-// Search all configPaths for any config file.
+// ExperimentalFinder tells Viper to use the new Finder interface for finding configuration files.
-// Returns the first path that exists (and is a config file).
+func ExperimentalFinder() Option {
-func (v *Viper) findConfigFile() (string, error) {
+	return optionFunc(func(v *Viper) {
-	if v.finder != nil {
+		v.experimentalFinder = true
-		results, err := v.finder.Find(v.fs)
+	})
+}
+
+func (v *Viper) findConfigFileWithFinder(finder Finder) (string, error) {
+	results, err := finder.Find(v.fs)
 	if err != nil {
 		return "", err
 	}
@@ -24,6 +27,31 @@ func (v *Viper) findConfigFile() (string, error) {
 	}
 
 	return results[0], nil
+}
+
+// Search all configPaths for any config file.
+// Returns the first path that exists (and is a config file).
+func (v *Viper) findConfigFile() (string, error) {
+	finder := v.finder
+
+	if finder == nil && v.experimentalFinder {
+		var names []string
+
+		if v.configType != "" {
+			names = locafero.NameWithOptionalExtensions(v.configName, SupportedExts...)
+		} else {
+			names = locafero.NameWithExtensions(v.configName, SupportedExts...)
+		}
+
+		finder = locafero.Finder{
+			Paths: v.configPaths,
+			Names: names,
+			Type:  locafero.FileTypeFile,
+		}
+	}
+
+	if finder != nil {
+		return v.findConfigFileWithFinder(finder)
 	}
 
 	v.logger.Info("searching for config in paths", "paths", v.configPaths)

file_finder.go

@@ -1,42 +0,0 @@
-//go:build viper_finder
-
-package viper
-
-import (
-	"fmt"
-
-	"github.com/sagikazarmark/locafero"
-)
-
-// Search all configPaths for any config file.
-// Returns the first path that exists (and is a config file).
-func (v *Viper) findConfigFile() (string, error) {
-	finder := v.finder
-
-	if finder == nil {
-		var names []string
-
-		if v.configType != "" {
-			names = locafero.NameWithOptionalExtensions(v.configName, SupportedExts...)
-		} else {
-			names = locafero.NameWithExtensions(v.configName, SupportedExts...)
-		}
-
-		finder = locafero.Finder{
-			Paths: v.configPaths,
-			Names: names,
-			Type:  locafero.FileTypeFile,
-		}
-	}
-
-	results, err := finder.Find(v.fs)
-	if err != nil {
-		return "", err
-	}
-
-	if len(results) == 0 {
-		return "", ConfigFileNotFoundError{v.configName, fmt.Sprintf("%s", v.configPaths)}
-	}
-
-	return results[0], nil
-}

finder.go

@@ -13,13 +13,6 @@ func WithFinder(f Finder) Option {
 	})
 }
 
-// ExperimentalFinder tells Viper to use the new Finder interface for finding configuration files.
-func ExperimentalFinder() Option {
-	return optionFunc(func(v *Viper) {
-		v.experimentalFinder = true
-	})
-}
-
 // Finder looks for files and directories in an [afero.Fs] filesystem.
 type Finder interface {
 	Find(fsys afero.Fs) ([]string, error)

finder_example_test.go

@@ -1,5 +1,3 @@
-//go:build viper_finder
-
 package viper_test
 
 import (

internal/features/finder.go

@@ -0,0 +1,5 @@
+//go:build viper_finder
+
+package features
+
+const Finder = true

internal/features/finder_default.go

@@ -0,0 +1,5 @@
+//go:build !viper_finder
+
+package features
+
+const Finder = false

viper.go

@@ -218,6 +218,8 @@ func New() *Viper {
 
 	v.resetEncoding()
 
+	v.experimentalFinder = features.Finder
+
 	return v
 }