Re: [Lurker-users] Threading question

[Wesley W. T. <we...@te...>]

On Sun, Jul 13, 2003 at 07:09:54PM -0400, Kevin Brosius wrote:
> I notice that threading usually happens, even when a message only
> matches in subject (meaning someone copied the subject line, rather than
> replying in a mail reader.)  I see one occurrence that confuses me
> though.  Take a look at http://kevb.net:3000/lurker/list/plug.html and
> the pair of entries for "Re: PLUG Picnic! (Really Re: [PLUG] The Next
> Step? -- was Community Service Project)"
>=20
> What's interesting, is that it looks like the person copying the subject
> left out a space, ie "Re: PLUG Picnic! (Really Re: [PLUG] The Next Step?
> -- was CommunityService Project)" causing threading to break.  That
> makes sense to me.  Then I noticed the "Old Topics" and "New Topics"
> lines added to the head of those messages when viewing the text.  They
> link the messages together anyway.  How does that work?

I will probably be flamed over this but, ... lurker decides if two messages
are in the same topic by roughly comparing subject. Empirically I found that
this is more reliable than looking at in-reply-to/references. So, first
lurker munges subjects in a way which is usually pretty smart. It ignores
stuff like Re: Fwd: [some-list] stuff on the front, and 'was:' stuff on the
end. Then it normalizes case and whitespace and does an md5 hash and some
more magic to get those 8 digit thread identifiers from the subject.

Unforunately, this person used 'was ...' instead of 'was: ' so lurker was
not able to discard the stuff after it. Then the missing space was enough to
make the subject just different enough that lurker considered it a new
thread.

However, lurker is not totally niave. If it has in-reply-to/references data
which links a different subject to another subject, it considers this a new
topic / old topic link. So, if you wrote a message 'about cats' and I
replied with a subject of 'about dogs (was: about cats)' then lurker will
put these in seperate threads, but link my message to yours with old/new
topic links.

I would wager that in this case a person replied in a mail reader
(establishing the in-reply-to) and then accidentaly editted the subject
line.

--=20
Wesley W. Terpstra <we...@te...>