I am using ob_gzhandler() to dynamically handle GZIP compression on a server which doesn't allow it done by htaccess.
It adds "Accept-encoding" to the Vary: header, as it should, when the body is Gzipped.
However when the client sends no Accept-Encoding: header, and the response is accordingly uncompressed, it does not add this Vary header.
This causes various bug checking tools to complain, and could mess up caching.
I know I can manually add Vary: Accept-encoding, and I am, but is that my only solution - just confirming this is a bug and I'm not missing something?