notmuch-reply doesn't use Reply-To

[Jani Nikula]

On Fri, 04 Dec 2015, Damien Cassou <damien at cassou.me> wrote:
> David Bremner <david at tethera.net> writes:
>
>> Damien Cassou <damien at cassou.me> writes:
>>
>>>                    "To" : "rmod at inria.fr",
>>>                    "Reply-To" : "rmod at inria.fr",
>>>                    "From" : "seaside at rmod.inria.fr",
>>>                    "Subject" : "[rmod] [Mm10s] 2015-11-30",
>>>                    "Date" : "Mon, 30 Nov 2015 07:00:01 +0100"
>>
>> A quick look at the code suggests this is falling victim to the
>> "reply-to munging" detection code, which considers a reply-to field
>> redudant if it duplicates one of the other fields. From the source
>>
>>     /* Some mailing lists munge the Reply-To header despite it being A Bad
>>      * Thing, see http://www.unicom.com/pw/reply-to-harmful.html
>>      *
>>      * The munging is easy to detect, because it results in a
>>      * redundant reply-to header, (with an address that already exists
>>      * in either To or Cc). So in this case, we ignore the Reply-To
>>      * field and use the From header. This ensures the original sender
>>      * will get the reply even if not subscribed to the list. Note
>>      * that the address in the Reply-To header will always appear in
>>      * the reply.
>>      */
>
>
> The last sentence seems to contradict my example:
>
>     Note that the address in the Reply-To header will always appear in
>     the reply.
>
> Here is the reply message, and it does not contain the address in Reply-To.

This was true way back when notmuch reply only knew about reply all. For
--reply-to=sender, it's broken. The simplest "fix" might be

diff --git a/notmuch-reply.c b/notmuch-reply.c
index 6df54fc992bb..ed0f9cca5c00 100644
--- a/notmuch-reply.c
+++ b/notmuch-reply.c
@@ -334,7 +334,7 @@ add_recipients_from_message (GMimeMessage *reply,
      * that the address in the Reply-To header will always appear in
      * the reply.
      */
-    if (reply_to_header_is_redundant (message)) {
+    if (reply_to_header_is_redundant (message) && reply_all) {
        reply_to_map[0].header = "from";
        reply_to_map[0].fallback = NULL;
     }


BR,
Jani.