Re: [Nmh-workers] thread mangling python-list mailing list to comp.lang.python google group

[Ken Hornstein]

>>From a skim of the headers, you could try making your In-Reply-To comply
>with RFC 2822.  IOW, have it contain just the message ID of the email
>you are replying to and not the human-readable gunk around it.  (It can
>actually have more than one message ID, but it's not References so you
>probably just want the MID of the email given to repl(1).)  See RFC
>2822, 3.6.4, `Identification fields'.

Ralph has given you the answer, but let me expand on it a bit.

Since in that message you refer to yourself as an 'old fart' and mention
programming in the 1970s, you've probably been using MH/nmh for approximately
forever.  Probably somewhere along the way you copied the MH-supplied
replcomps to your ~/Mail directory and modified it.  In doing that, you
copied the then-standard In-Reply-To format, which would generate things
like:

In-Reply-To: Message from Chris Angelico <address@hidden> of "Wed,
 18 Feb 2015 20:36:10 +1100."

Way back in RFC 822, this format was fine.  But nowadays things have
been tightened up and from RFC 2822 the official format for In-Reply-To
is that it should only contain a Message-ID; a lot of mail software use
that for threading purposes (they also use References).  By default nmh
will generate that ... except that people that have old replcomps around
are still sending out the old format.

So, that was the long answer.  Short answer: Replace/append these lines
to your replcomps:

%<{message-id}In-reply-to: %{message-id}\n%>\
%<{message-id}References: \
%<{references}%(void{references})%(trim)%(putstr) %>\
%(void{message-id})%(trim)%(putstr)\n%>\

And if you really want a 'in-reply-to' like header, use this:

Comments: In-reply-to \
%<{from}%(void{from})%?(void{apparently-from})%|%(void{sender})%>\
%(trim)%(putstr)\n\
   message dated "%<(nodate{date})%{date}%|%(tws{date})%>."

--Ken