[Dovecot] Dovecot LMTP - Delivered-To header weirdness

[Daniel Piddock]

Hi,

I'm not sure if this is a deliberate design decision or a technical
limitation that I've missed. Please briefly explain if so :). Or a bug
or feature request?

When LMTP receives a mail with a single recipient it adds a Delivered-To
header. However if the message is delivered in a batch that header isn't
added. At first I thought maybe the LMTP was doing something with
hardlinks but that doesn't appear to be the case (for rather obvious
reasons.)

Sample headers (single recipient):
Return-Path: <user at domain.test>
Delivered-To: <user at domain.test>
Received: from mx.domain.test ([127.0.0.1])
    by domain.test (Dovecot) with LMTP id ZNTPFX2NI1CcCwAAVMeomg
    for <user at domain.test>; Thu, 09 Aug 2012 11:14:21 +0100
Envelope-to: user at domain.test
Delivery-date: Thu, 09 Aug 2012 11:14:21 +0100
Received: from host.domain.test ([172.16.252.1]:44058)
    by relay.domain.test ([172.16.252.120]:25)
    with esmtp id 1SzPkz-0000lz-7v (Exim 4.80) for user at domain.test
    (return-path <user at domain.test>); Thu, 09 Aug 2012 11:14:21 +0100
Message-ID: <50238D7D.2000707 at domain.test>
Date: Thu, 09 Aug 2012 11:14:21 +0100
From: User <user at domain.test>
To: User <user at domain.test>
Subject: test

And an expansion list:
Return-Path: <user at domain.test>
Received: from mx.domain.test ([127.0.0.1])
    by domain.test (Dovecot) with LMTP id Gf+yBmiNI1CECwAAVMeomg
    ; Thu, 09 Aug 2012 11:14:00 +0100
Envelope-to: expansion at domain.test
Delivery-date: Thu, 09 Aug 2012 11:14:00 +0100
Received: from host.domain.test ([172.16.252.1]:44053)
    by relay.domain.test ([172.16.252.120]:25)
    with esmtp id 1SzPkd-0000ls-Qr (Exim 4.80) for expansion at domain.test
    (return-path <user at domain.test>); Thu, 09 Aug 2012 11:13:59 +0100
Message-ID: <50238D67.3090802 at domain.test>
Date: Thu, 09 Aug 2012 11:13:59 +0100
From: User <user at domain.test>
To: Expansion <expansion at domain.test>
Subject: test

At the moment we've turned off batch delivery in the exim smtp transport
(max_rcpt=1).

Cheers,
Dan
-- 
Daniel Piddock, Systems Administrator, CoreFiling Limited
http://www.corefiling.com