Re: [exim] Getting duplicate deliveries with redirect router

On 11/12/20 6:55 AM, Gedalya via Exim-users wrote:
> Hi,
>
> When user1 sends a message to user2 and user3, and user3 also gets generated *twice* by a redirect router, user3 ends up getting the message twice.
>

> bcc:
>   debug_print = "R: bcc for $local_part@$domain"
>   driver = redirect
>   data = ${lookup{$local_part}lsearch{CONFDIR/bcc}}
>   verify = false
>   unseen = true
>   repeat_use = false
>

I was able to work around the issue, by doing the deduplication myself:

outgoing_bcc:
  debug_print = "R: outgoing_bcc for $local_part@$domain"
  driver = redirect
  data = ${reduce \
    {${addresses:>:${lookup mysql{.....}}}} \
    {} \
    {${if eqi{$item}{${quote_local_part:$local_part}@$domain}{$value}{$value, $item}}} \
  }


(Note: the key to the lookup is actually the $authenticated_id, in case someone is trying to find the logic / motivation here)

However, I'm still puzzled as to what the issue is. Is it the fact that the same address is generated separately as a child address of two recipients? Is it that it is generated as a child address of itself, and also as a child address of another address? The documentation simply states that exim does not do duplicate deliveries, while here it seems it does.

Can someone please help and explain, is this a bug, or am I misunderstanding something?

Thanks,

Gedalya