Notification level validation should live in resolve method

cmd/backup/config.go

@@ -240,6 +240,11 @@ func (c *Config) resolve() (reset func() error, warnings []string, err error) {
 		return
 	}
 
+	if _, ok := hookLevels[c.NotificationLevel]; !ok {
+		err = errwrap.Wrap(nil, fmt.Sprintf("unknown NOTIFICATION_LEVEL %s", c.NotificationLevel))
+		return
+	}
+
 	if c.BackupFilenameExpand {
 		c.BackupFilename = os.ExpandEnv(c.BackupFilename)
 		c.BackupLatestSymlink = os.ExpandEnv(c.BackupLatestSymlink)

cmd/backup/script.go

@@ -78,12 +78,7 @@ func (s *script) init() error {
 		return nil
 	})
 	// Register notifications first so they can fire in case of other init errors.
-
-	hookLevel, ok := hookLevels[s.c.NotificationLevel]
-	if !ok {
-		return errwrap.Wrap(nil, fmt.Sprintf("unknown NOTIFICATION_LEVEL %s", s.c.NotificationLevel))
-	}
-	s.hookLevel = hookLevel
+	s.hookLevel = hookLevels[s.c.NotificationLevel]
 
 	if len(s.c.NotificationURLs) > 0 {
 		sender, senderErr := shoutrrr.CreateSender(s.c.NotificationURLs...)