Disabling autolearn on given rule

[Matt Corallo]

Hi!

I recently noticed my bayes was rarely matching any spam, and it turns out this was due to 
autolearn=ham'ing occurring on lots of list traffic that I only occasionally read, some of which was 
blatant spam. Sadly, list traffic can be pretty hard to categorize and ends up getting through due 
to good sending IP and domain reputation.

While correcting the filter through sa-learn solves this issue temporarily, I don't want to have to 
always read lists that I previously only occasionally read just to re-classify spam. Thus, I'd like 
to disable autolearn entirely for mails that match a given rule (eg MAILING_LIST_MULTI).

"tflags MAILING_LIST_MULTI noautolearn" doesn't seem like quite what I want, it just reduces the 
score used to decide whether to learn. There's some old bugzilla mentions asking for this feature, 
but it seems the response was "write a plugin". Is there a plugin available for this or how would 
one go about writing one?

Thanks,
Matt