From: John Stanley (stanley@peak.org)
Date: Tue Jun 03 2003 - 12:49:58 CDT
Charles Lindsey (chl@clerew.man.ac.uk):
>Yes, things do break. Much existing software that sorts articles by
>Subject and other similar things assumes that coping with one "Re: " will
>suffice.
I am not concerned in the least with software that ignores the
one header defined for threading messages just so it can guess at how
to thread things. That software is, itself, broken. So what if it cannot
handle the kludge that is has been relying on instead of the best
information?
>No, it just recognizes that many existing agents _choose_ to bother with
>one.
What broken software _chooses_ to do does not merit MUST or MUST NOT
language. There is NO justification for such language, and repeating the
mantra that "some (broken) software does it" doesn't provide any. You
cannot avoid the fact that References headers are MANDATORY specifically
for the purposes of 1) identifying followups and 2) allowing those
followups to be threaded. That fact removes any requirement upon the
Subject header to provide this information.