diff -r db4911b0c721 -r 445e01aede7e vendor/github.com/spf13/viper/internal/encoding/dotenv/map_utils.go
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/spf13/viper/internal/encoding/dotenv/map_utils.go	Tue Aug 23 22:39:43 2022 +0200
@@ -0,0 +1,41 @@
+package dotenv
+
+import (
+	"strings"
+
+	"github.com/spf13/cast"
+)
+
+// flattenAndMergeMap recursively flattens the given map into a new map
+// Code is based on the function with the same name in tha main package.
+// TODO: move it to a common place
+func flattenAndMergeMap(shadow map[string]interface{}, m map[string]interface{}, prefix string, delimiter string) map[string]interface{} {
+	if shadow != nil && prefix != "" && shadow[prefix] != nil {
+		// prefix is shadowed => nothing more to flatten
+		return shadow
+	}
+	if shadow == nil {
+		shadow = make(map[string]interface{})
+	}
+
+	var m2 map[string]interface{}
+	if prefix != "" {
+		prefix += delimiter
+	}
+	for k, val := range m {
+		fullKey := prefix + k
+		switch val.(type) {
+		case map[string]interface{}:
+			m2 = val.(map[string]interface{})
+		case map[interface{}]interface{}:
+			m2 = cast.ToStringMap(val)
+		default:
+			// immediate value
+			shadow[strings.ToLower(fullKey)] = val
+			continue
+		}
+		// recursively merge to shadow map
+		shadow = flattenAndMergeMap(shadow, m2, fullKey, delimiter)
+	}
+	return shadow
+}