DWiki can now restrict what sorts of VirtualDirs advertise AtomFeeds (both in SyndicationDiscovery and in the Atom toolbar) and/or provide them if they're requested by URL.
It turns out that when you have a fair amount of content in a DWiki your VirtualDirs and thus your AtomFeeds proliferate like over-active rabbits. Then SyndicationDiscovery kicks in so that anyone who looks at a virtual directory can discover its Atom feed and either start polling it or just crawl it. Once your DWiki gets big enough this becomes not really a good thing, as Chris has found out with his techblog.
This is implemented with the new atomfeed-virt-only-adv and
atomfeed-virt-only-in configuration file directives, documented in
ConfigurationFile. This affects only the Atom page feed; the Atom
comment feed handling is unchanged.
Virtual dirs that have advertisement disabled actually advertise the feed URL of the real directory instead (instead of omitting it entirely). This seems to be sensible behavior and is probably what real blog engines do.
A disallowed Atom request for a range or latest virtual dir returns a redirection to the real directory's Atom feed. Partly this is because it's justifiable and sensible behavior (the real feed is pretty close to those things) and partly because there appear to be real people pulling such feeds from ChrisSiebenmann's main DWiki instance. Other disallowed Atom feeds are treated as if they didn't exist, generating 404 'no such page' errors. This too makes sense since the real directory's feed is not really anything like the feed for, say, last year.
You should not normally disable Atom feeds for the latest virtual
dir, since they have a sensible use in pulling a smaller than normal
feed from DWiki. For example, using 'dir/latest/10/?atom' instead of
'dir/?atom' will get you a feed with only ten items in it. Atom feeds
of other virtual dirs make somewhat less sense, especially feeds from
things that are unlikely to change (such as past years or past months).
(In the future DWiki may allow feeds of current calendar things but not past calendar things.)