Re: posting without being subscribed

[Solar Designer <solar () openwall com>]

I think this is no longer of sufficient relevance to oss-security
subscribers for us to continue this sub-thread CC'ing the list, so it's
probably/hopefully the last message one of us sends on this in here.

On Sat, Feb 11, 2017 at 08:14:50PM +0100, pali () cpan org wrote:
> On Saturday 11 February 2017 19:14:52 Solar Designer wrote:
> > Another issue is that now that you brought the reply back to the
> > list, you almost broke the thread.  I fixed that by manually editing
> > the headers on your message before approving it (as a list admin).
> > Sometimes I do that, although I don't consider it to be part of my
> > "job".  If a co-moderator were to approve your message first, then
> > your message would have started a new thread rather than being added
> > to the existing thread.  That's not great.
>
> Hm... breaking thread should not happen... at least with non-broken 
> email clients. If everybody in discussion correctly set In-Reply-To 
> header then whole thread (correctly tree) will be preserved. And if 
> everybody correctly set References header then even missing emails does 
> not break threading visualization. Information from References headers 
> provide transitive closure of thread tree from which original tree can 
> be reconstructed... But if somebody does not fill References or In-
> Reply-To headers then thread will be broken independently of 
> subscription to list.
>
> Now I see that message to which I replied was without In-Reply-To and 
> also without References headers. So thread was already broken.
>
> I understand that breaking threading is bad and cause problems, but in 
> lot of times it is problem of broken email clients which do not fill 
> needed headers :-(

There are several issues here (besides those you mention):

1. Threads get broken when someone forwards an e-mail, rather than
replies.  In a sense, I am at fault for forwarding you Simon's reply,
instead of "replying" to his reply, over-quoting it, and CC'ing you on
that.  I'd introduce an extra layer of quoting (unless I were to undo
it prior to sending), but at least the References headers could have a
chance of maintaining the thread.

2. The blists software we use for the official oss-security archives
currently only uses In-Reply-To or one entry from References; it does
not fully parse the References.  And fixing this in the code amounts to
more than just parsing that header more fully.

What this means is that to maintain the thread I should have probably
CC'ed you _and_ the list on that "reply" to Simon's message, where I'd
merely quote the entire message for you.  That's not great indeed, but
since Simon's message was such that I could reasonably have expected you
wanting to reply to the list, maybe I should have done that.

Alexander