On Tue, 26 Oct 2010 19:38:27 +0200 Tassilo Horn <tassilo@member.fsf.org> wrote: 

TH> I've tested it briefly: spam messages in spam groups aren't moved to the
TH> training spam groups.  Good.  Marking messages as spam in my non-spam
TH> groups moves them to my spam training group.  Good.

Great.

TH> Hm, but then I unmarked a message in my Junk Mail group as non-spam and
TH> it tried to move it to my ham training group, but that didn't seem to
TH> work.

> Copying to nnimap+Fastmail:INBOX: (11849)...
> Copying to nnimap+Fastmail:INBOX.training.ham: (11849)...
> Couldn't Copy article 11849: 
> 1 ham messages were registered by backend spam-use-move.

TH> The message was copied to the first ham process destination (INBOX), but
TH> not to the ham training group, most probably cause it tried to move a
TH> then non-existing message.

I see why that happened.  The copy/move logic depends on the number of
groups.  All but the last group get a copy and the last one gets a move.
But if we skip groups we break that logic.  Try the attached patch, it
just prefilters the groups list.

The patch is pretty large because I fixed formatting issues with
spam.el; sorry about that.

Ted