We sometimes send messages to some mailing lists while CC-ing relevant maintainers or projects, in case they were not subscribed. Sadly, this means that (if they're still unsubscribed), their replies do not have it to the mailing lists (and the archives). As a result, we end up with shattered threads that are hard to follow [ex:1,2]. I think it'd be reasonable to pass replies to mailing list messages through, independently of whether the sender is subscribed. In other words, match them via in-reply-to to the previous messages on the mailing list. [1]:https://archives.gentoo.org/gentoo-musl/message/fa2be8ac57d3ce342907a036e86c33a5 [2]:https://archives.gentoo.org/gentoo-musl/message/b90569f3b6dfaf348f3fa7ee9ff50c1c
Michał, I think that will be dangerous as it'll make easier to send spam to the mls. This would deny the subscribers logic of the mls software.
I think you're overestimating the value of spamming Gentoo mailing lists. I don't really see people going all the way to implement custom spamming solutions just to abuse this feature. And even if that happens, we can just disable it back. On the other hand, the subscription logic is pretty easy to work around. Especially that it's commonly deployed and pretty much the same for all instances of mlmmj, i.e. exploitable with a generic solution.
This would be significant development for mlmmj, which has zero knowledge of the Message-ID values. At best, you could hack it via a pre-processing layer that detected a known Message-ID and added a header to allow mlmmj to pass-through, but it would be significant development, and a heavy lookup, as it needs to have most of the messages IDs for all of history (replying to a month-old thread DOES happen). Rather than the dropped mail, a long time ago I proposed that we get better bounce messages instead of mlmmj silently dropping unsubscribed email: If you are not subscribed to a list, and you email it, you should get an SMTP error about being not subscribed (and your local mailserver should generate a bounce).
