puppet_exclude.txt now always created.

manifests/init.pp

@@ -2,7 +2,7 @@
 class lysbackup (
   String $backup_user,
   String $user = 'root',
-  Optional[Array[String]] $exclude = undef,
+  Optional[Array[String]] $exclude = [],
 ) {
 
   package { 'borgbackup':
@@ -14,15 +14,10 @@ class lysbackup (
     recurse => true,
     mode    => '0744',
     source  => 'puppet:///modules/lysbackup/opt/lysbackup/',
-  }
-
-  if $exclude != undef {
-    file { '/opt/lysbackup/puppet_exclude.txt':
+  } -> file { '/opt/lysbackup/puppet_exclude.txt':
     ensure  => file,
     # << '' for trailing newline
     content => join($exclude << '', "\n"),
-      after => File['/opt/lysbackup'],
-    }
   }
 
   cron { 'borgbackup':