Re: filling the References header

[Sudish Joseph <sj@eng.mindspring.net>]

Sudish Joseph writes:
> be done in such cases -- off the top of my head, the first two msg-ids
> must be preserved and those closest to the end of the list should also
> be preserved.

Since I've already dug up so1036 once today, I might as correct
myslef.  Here're the relevant bits:

1036bis> Followup agents SHOULD not shorten References  headers.   If
1036bis> it  is absolutely necessary to shorten the header, as a des-
1036bis> perate last resort, a followup agent MAY do this by deleting
1036bis> some  of  the  message IDs.  However, it MUST not delete the
1036bis> first message ID, the last three message IDs (including that
1036bis> of  the immediate precursor), or any message ID mentioned in
1036bis> the body of the followup.

1036bis> [...] 

1036bis> When a References header is shortened, at least three blanks
1036bis> SHOULD be left between adjacent message IDs  at  each  point
1036bis> where  deletions  were  made.  Software preparing new Refer-
1036bis> ences headers SHOULD preserve multiple blanks in older  Ref-
1036bis> erences content.

1036bis>      NOTE:  It's desirable to have some marker of where
1036bis>      deletions occurred, but the restricted  syntax  of
1036bis>      the  header  makes  this  difficult.   Extra white
1036bis>      space is not a very good marker, since it  may  be
1036bis>      deleted  by  software  that ill-advisedly rewrites
1036bis>      headers, but at least it  doesn't  break  existing
1036bis>      software.

See <URL:ftp://zoo.toronto.edu/pub/news.txt.Z>, it's very well written
(gives background and justifications for lots of seemingly weird
decisions), if incomplete.

-Sudish