On Mon 2019-06-03 16:02:48 +0200, Ralph Seichter wrote:
> Not meaning to complicate things, but Notmuch does not receive messages
> at all. ;-) One needs to rely on some software to populate the Maildir
> tree (Dovecot LMTP in my case, Postfix or some other MTA for local
> delivery in other cases). Any software transporting the raw messages
> can, and sometimes must, manipulate the header data, and the order in
> which files within the Maildir tree are created is also not determined
> by Notmuch.
>
> As an example: My nightly backup script disables local delivery for the
> duration of the backup process. Once reactivated, delivery of queued
> messages resumes, but it is not guaranteed to happen in the order of
> arrival. So even the local MTA, although trusted, might induce issues in
> terms of delivery time.

I agree with you!  the e-mail system, like any other store-and-forward
ecosystem, offers no guarantees of message delivery.

fwiw, i'm not claiming that the time notmuch receives the message is
guaranteed to be close to the time that the message was sent.

but i can guarantee two things:

 * notmuch cannot receive the message *before* it was sent :)

 * if the local system clock is correct, notmuch can place a plausible
   upper bound on the Date: header that is included in the message.

This alone is useful data.

     --dkg