Expiry targets groups, and automatically closing buffers

[Luca Saiu]

Hello people, and thanks for Gnus :-).

I like to keep copies of all my messages, both saved and received.
Before migrating to Gnus I want to set it up to do that automatically.

I've set nnmail-expiry-target to be a function taking a group name and
returning the name of the corresponding group for archived messages,
including the "nnfolder:" prefix.  The thing works: at expire time
articles are correctly moved from the source group (let's say for
example "nnml:Work") to the right place (for example
"nnfolder:exp--Work--2010-08"); the only problem is that the
modifications to the target group due to appending just-expired articles
are not automatically saved to disk: there remains an Emacs buffer for
the target group, open ("exp--Work--2010-08").  Emacs asks me whether I
want to save it only when I exit Emacs, and I find that very
inconvenient.  I don't think the performance improvement of avoiding
some save operations is worth the trouble.

I didn't find an obvious way to automatically save and close such
buffers after expiring, but I'm pretty sure it must exist.

Thanks in advance,

-- 
Luca Saiu
http://www-lipn.univ-paris13.fr/~saiu
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://www.marionnet.org