feat: new settings for viper, edit processing of an aliases

viper.go

@@ -206,6 +206,8 @@ type Viper struct {
 	automaticEnvApplied bool
 	envKeyReplacer      StringReplacer
 	allowEmptyEnv       bool
+	aliasesFirstly 		bool
+	aliasesStepByStep	bool
 
 	parents        []string
 	config         map[string]any
@@ -241,6 +243,8 @@ func New() *Viper {
 	v.pflags = make(map[string]FlagValue)
 	v.env = make(map[string][]string)
 	v.aliases = make(map[string]string)
+	v.aliasesFirstly = true
+	v.aliasesStepByStep = false
 	v.typeByDefValue = false
 	v.logger = slog.New(&discardHandler{})
 
@@ -539,6 +543,25 @@ func (v *Viper) mergeWithEnvPrefix(in string) string {
 	return strings.ToUpper(in)
 }
 
+// AliasesFirstly changes the order of processing aliases.
+// If TRUE is passed, values will be searched by alias.
+// If FALSE is passed, the standard key is processed first,
+// and if the value is not found, an alias search will be performed.
+func AliasesFirstly(firstly bool) { v.AliasesFirstly(firstly) }
+
+func (v *Viper) AliasesFirstly(firstly bool) {
+	v.aliasesFirstly = firstly
+}
+
+// AliasesStepByStep changes the processing of nested aliases.
+// If TRUE is passed, the values will be searched at each nesting level of the alias.
+// If FALSE is passed, the values will be searched at the last nesting level of the aliases
+func AliasesStepByStep(enable bool) { v.AliasesStepByStep(enable) }
+
+func (v *Viper) AliasesStepByStep(enable bool) {
+	v.aliasesStepByStep = enable
+}
+
 // AllowEmptyEnv tells Viper to consider set,
 // but empty environment variables as valid values instead of falling back.
 // For backward compatibility reasons this is false by default.
@@ -1294,8 +1317,8 @@ func (v *Viper) MustBindEnv(input ...string) {
 // Note: this assumes a lower-cased key given.
 func (v *Viper) find(lcaseKey string, flagDefault bool) any {
 	var (
+		lastKey string
 		val    any
-		exists bool
 		path   = strings.Split(lcaseKey, v.keyDelim)
 		nested = len(path) > 1
 	)
@@ -1305,10 +1328,14 @@ func (v *Viper) find(lcaseKey string, flagDefault bool) any {
 		return nil
 	}
 
+	for lastKey != lcaseKey {
+		if v.aliasesFirstly {
 			// if the requested key is an alias, then return the proper key
+			lastKey = lcaseKey
 			lcaseKey = v.realKey(lcaseKey)
 			path = strings.Split(lcaseKey, v.keyDelim)
 			nested = len(path) > 1
+		}
 
 		// Set() override first
 		val = v.searchMap(v.override, path)
@@ -1438,6 +1465,15 @@ func (v *Viper) find(lcaseKey string, flagDefault bool) any {
 				}
 			}
 			// last item, no need to check shadowing
+
+			if !v.aliasesFirstly {
+				// if the requested key is an alias, then return the proper key
+				lastKey = lcaseKey
+				lcaseKey = v.realKey(lcaseKey)
+				path = strings.Split(lcaseKey, v.keyDelim)
+				nested = len(path) > 1
+			}
+		}
 	}
 
 	return nil
@@ -1571,7 +1607,9 @@ func (v *Viper) realKey(key string) string {
 	newkey, exists := v.aliases[key]
 	if exists {
 		v.logger.Debug("key is an alias", "alias", key, "to", newkey)
-
+		if v.aliasesStepByStep {
+			return newkey
+		}
 		return v.realKey(newkey)
 	}
 	return key