Re: [PATCH] lib: consider all instances of Delivered-To header

[David Bremner <david@tethera.net>]

Hannu Hartikainen <hannu@hrtk.in> writes:

> When using notmuch-reply and guessing the From: address from
> Delivered-To headers, I had the wrong address chosen today. This was
> because the messages from the notmuch list contain these headers in this
> order:
>
> Delivered-To: hannu.hartikainen@gmail.com
> ...
> Delivered-To: hannu@hrtk.in
>
> In my .notmuch-config I have the following configuration:
>
> primary_email=hannu@hrtk.in
> other_email=hannu.hartikainen@gmail.com;...
>
> Before this change, notmuch-reply would guess From: @gmail.com because
> that is the first Delivered-To header present. After the change, the
> primary address is chosen as I would expect.
> ---

Delivered-to seems to be a dark corner of (non)-standardization, but it
does seem that multiple deliver-to headers are relatively common and
more or less make sense:

     https://datatracker.ietf.org/doc/draft-crocker-email-deliveredto/

>  lib/message-file.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/lib/message-file.c b/lib/message-file.c
> index 647ccf3a..7e8ea09c 100644
> --- a/lib/message-file.c
> +++ b/lib/message-file.c
> @@ -291,11 +291,15 @@ _notmuch_message_file_get_header (notmuch_message_file_t *message,
>      if (value)
>  	return value;
>  
> -    if (strcasecmp (header, "received") == 0) {
> +    if (strcasecmp (header, "received") == 0 ||
> +            strcasecmp (header, "delivered-to") == 0) {

uncrustify suggests the following indentation change

-            strcasecmp (header, "delivered-to") == 0) {
+       strcasecmp (header, "delivered-to") == 0) {


>  	/*
> -	 * The Received: header is special. We concatenate all
> -	 * instances of the header as we use this when analyzing the
> -	 * path the mail has taken from sender to recipient.
> +	 * The Received: header is special. We concatenate all instances of the
> +	 * header as we use this when analyzing the path the mail has taken
> +	 * from sender to recipient.
> +	 *
> +	 * Similarly, multiple instances of Delivered-To may be present. We
> +	 * concatenate them so the one with highest priority may be picked.
>  	 */

Highest priority seems a bit vague here. Do you mean most recent?

It seems like the commentary in notmuch-reply should also be updated
since it claims received header is special in being concatenated

I would like to see a new test here, especially since the fix is far
from the effect.

The following change is enough to trigger the problem you had

diff --git a/test/T220-reply.sh b/test/T220-reply.sh
index b6d8f42a..0d245497 100755
--- a/test/T220-reply.sh
+++ b/test/T220-reply.sh
@@ -232,7 +232,8 @@ add_message '[from]="Sender <sender@example.com>"' \
            '[subject]="From guessing"' \
            '[date]="Tue, 05 Jan 2010 15:43:56 -0000"' \
            '[body]="From guessing"' \
-           '[header]="Delivered-To: test_suite_other@notmuchmail.org"'
+           '[header]="Delivered-To: test_suite_other2@notmuchmail.org
+Delivered-To: test_suite_other@notmuchmail.org"'

OTOH, it probably makes sense to test the case of multiple Delivered-to
headers seperately.

The idiomatic (for notmuch) thing to do for a bug fix is first to add a
test with "test_subtest_known_broken", then to remove that line in the
commit you fix the bug.

d