Fix config loading for "hugo mod init"

We have some commands that will continue even if the config loading fails (e.g. because a module can not be found). In Hugo 0.84.0 we introduced a new `_merge` flag that we removed once the configuration was loaded. But we did not do that in error situations, leading to failures in some situations.

This commit fixes that by making sure the configuration is always cleaned before return, even in error situations.

Fixes #8697

hugolib/config.go

@@ -63,6 +63,10 @@ func LoadConfig(d ConfigSourceDescriptor, doWithConfig ...func(cfg config.Provid
 	var configFiles []string
 
 	l := configLoader{ConfigSourceDescriptor: d, cfg: config.New()}
+	// Make sure we always do this, even in error situations,
+	// as we have commands (e.g. "hugo mod init") that will
+	// use a partial configuration to do its job.
+	defer l.deleteMergeStrategies()
 
 	for _, name := range d.configFilenames() {
 		var filename string
@@ -125,10 +129,7 @@ func LoadConfig(d ConfigSourceDescriptor, doWithConfig ...func(cfg config.Provid
 	collectHook := func(m *modules.ModulesConfig) error {
 		// We don't need the merge strategy configuration anymore,
 		// remove it so it doesn't accidentaly show up in other settings.
-		l.cfg.WalkParams(func(params ...config.KeyParams) bool {
-			params[len(params)-1].Params.DeleteMergeStrategy()
-			return false
-		})
+		l.deleteMergeStrategies()
 
 		if err := l.loadLanguageSettings(nil); err != nil {
 			return err
@@ -461,6 +462,13 @@ func (l configLoader) loadConfig(configName string) (string, error) {
 	return filename, nil
 }
 
+func (l configLoader) deleteMergeStrategies() {
+	l.cfg.WalkParams(func(params ...config.KeyParams) bool {
+		params[len(params)-1].Params.DeleteMergeStrategy()
+		return false
+	})
+}
+
 func (l configLoader) loadLanguageSettings(oldLangs langs.Languages) error {
 	_, err := langs.LoadLanguageSettings(l.cfg, oldLangs)
 	return err