Tariffs: fix panic with invalid custom tariff

cmd/setup.go

@@ -878,18 +878,18 @@ func configureSolarTariff(conf []config.Typed, t *api.Tariff) error {
 }
 
 func configureTariffs(conf *globalconfig.Tariffs) (*tariff.Tariffs, error) {
+	tariffs := tariff.Tariffs{
+		Currency: currency.EUR,
+	}
+
 	// migrate settings
 	if settings.Exists(keys.Tariffs) {
 		*conf = globalconfig.Tariffs{}
 		if err := settings.Yaml(keys.Tariffs, new(map[string]any), &conf); err != nil {
-			return nil, err
+			return &tariffs, err
 		}
 	}
 
-	tariffs := tariff.Tariffs{
-		Currency: currency.EUR,
-	}
-
 	if conf.Currency != "" {
 		tariffs.Currency = currency.MustParseISO(conf.Currency)
 	}