dovecot - Oct 2022 - Pigeonhole redirect is adding a message-id header when it already exists

> >
> >How are you redirecting, like this[1]? I tested this ages ago. I am
> mostly testing with own gmail account, so  can't imagine this not
> working. It was an older 2.2 server I was testing this on.
> >
> >
> >[1]
> >if false # true
> >{
> >     redirect :copy "shit at gmail.com";
> >}
> >
> Hello Marc,
> 
> It's redirected using the rule added by SOGo when you enable mail
> forwarding for the mailbox.
> Basically it's only this line:
> 
> redirect "stuff at gmail.com";
> 
> The redirect works, the problem is gmail changed their anti spam
> policies and are since a few months rejecting messages that have
> duplicate mail headers and in this particular case, Message-ID.
> 
> So all the incoming mails that have a non-RFC compliant Message-ID are
> being added a secondary Message-ID by pigeonhole, before it is relayed
> to the target mailbox.
Oct  1 13:31:46 xxxx sendmail[30321]: 291BVjjx030318: to=<xxxx at
gmail.com>, delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=122536,
relay=gmail-smtp-in.l.google.com. [142.250.102.27], dsn=2.0.0, stat=Sent (OK 
1664623906 gs19-20020a1709072d1300b00777a40d515dsi4096082ejc.456 - gsmtp)

I just tested for you, enabled the sieve forward, send test mail and the forward
is being accepted by google.

>
>Oct  1 13:31:46 xxxx sendmail[30321]: 291BVjjx030318: to=<xxxx at
gmail.com>, delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=122536,
relay=gmail-smtp-in.l.google.com. [142.250.102.27], dsn=2.0.0, stat=Sent (OK 
1664623906 gs19-20020a1709072d1300b00777a40d515dsi4096082ejc.456 - gsmtp)
>
>I just tested for you, enabled the sieve forward, send test mail and the
forward is being accepted by google.
>
>
Thanks for the test. However, does your test mail had a "bogus" 
Message-ID header in it like I tried to explain ?

For example try to send a mail that has the following Message-ID header:

Message-ID: 
1883biz_pay_after_purchase:0:0_572392900$ae7ed6e4d53b424c84aaf83b30c507e7

>Oct  1 13:31:46 xxxx sendmail[30321]: 291BVjjx030318: to=<xxxx at
gmail.com>, delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=122536,
relay=gmail-smtp-in.l.google.com. [142.250.102.27], dsn=2.0.0, stat=Sent (OK 
1664623906 gs19-20020a1709072d1300b00777a40d515dsi4096082ejc.456 - gsmtp)
>
>I just tested for you, enabled the sieve forward, send test mail and the
forward is being accepted by google.
>
>
It looks to me you're dismissing the fact that it only concerns the 
forwarding of mails that have originally a "bogus" Message-ID.

That's the only way to trigger the issue. Other mails (that are missing 
Message-ID or having RFC compliant Message-ID are forwarded and accepted 
just fine by gmail :)