What does `gathering loose threads' mean?

What does `gathering loose threads' mean?

[Kai Großjohann]

If I have two messages with the same subject (but otherwise
unrelated), they will be displayed near to each other in the summary
buffer.

Where does this come from?

Is this a result of loose threads gathering?  If so, the documentation
is confusing, because it talks about expired roots of threads and the
like.  This lead me to thinking that Gnus looks at the References
header of message 1 and at the References header of message 2 and if
MsgId foo occurs in both headers, then the two messages are in the
same thread.

Maybe the documentation should be changed to more explicitly point out
that loose threads gathering does NOT look at the References header,
but ONLY at the Subject header.


What is the minimum configuration that will do loose threads
gathering?  (I think it is sufficient to set
gnus-summary-make-false-root to a non-nil value, but I'm not sure.)

kai
-- 
I like BOTH kinds of music.

Re: What does `gathering loose threads' mean?

[Paul Jarc]

Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai =?iso-8859-1?q?Gro=DFjohann?=) writes:
> If I have two messages with the same subject (but otherwise
> unrelated), they will be displayed near to each other in the summary
> buffer.
> 
> Where does this come from?

Testing whether two articles are in the same thread is controlled by
the variable gnus-summary-thread-gathering-function.  Loose threads
are a somewhat separate matter, regarding the sorting of articles
within a thread, IIUC.

> This lead me to thinking that Gnus looks at the References header of
> message 1 and at the References header of message 2 and if MsgId foo
> occurs in both headers, then the two messages are in the same
> thread.

If that's what you want, you can do:
(setq gnus-summary-thread-gathering-function
      'gnus-gather-threads-by-references)
By default, it's set to gnus-gather-threads-by-subject.

> Maybe the documentation should be changed to more explicitly point out
> that loose threads gathering does NOT look at the References header,
> but ONLY at the Subject header.

gnus-summary-thread-gathering-function is documented at the end of the
`Loose Threads' node.

> What is the minimum configuration that will do loose threads
> gathering?  (I think it is sufficient to set
> gnus-summary-make-false-root to a non-nil value, but I'm not sure.)

That controls the insertion of dummy lines for missing articles in the
thread.  If you just want articles with common References: to be in
the same thread, without filling in gaps with dummy lines, then
setting gnus-summary-thread-gathering-function should suffice.


paul

Re: What does `gathering loose threads' mean?

[Kai Großjohann]

On 09 Aug 2000, Paul Jarc wrote:

> Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai
> =?iso-8859-1?q?Gro=DFjohann?=) writes:
>> If I have two messages with the same subject (but otherwise
>> unrelated), they will be displayed near to each other in the
>> summary buffer.
>> 
>> Where does this come from?
> 
> Testing whether two articles are in the same thread is controlled by
> the variable gnus-summary-thread-gathering-function.  Loose threads
> are a somewhat separate matter, regarding the sorting of articles
> within a thread, IIUC.

Sorting within a thread?  Hm.  The documentation seems to be talking
about comparing subject headers for equality (or fuzzy equality).

>> This lead me to thinking that Gnus looks at the References header
>> of message 1 and at the References header of message 2 and if MsgId
>> foo occurs in both headers, then the two messages are in the same
>> thread.
> 
> If that's what you want, you can do:
> (setq gnus-summary-thread-gathering-function
>       'gnus-gather-threads-by-references)
> By default, it's set to gnus-gather-threads-by-subject.

No, I think I want gnus-gather-threads-by-subject.

>> Maybe the documentation should be changed to more explicitly point
>> out that loose threads gathering does NOT look at the References
>> header, but ONLY at the Subject header.
> 
> gnus-summary-thread-gathering-function is documented at the end of
> the `Loose Threads' node.
> 
>> What is the minimum configuration that will do loose threads
>> gathering?  (I think it is sufficient to set
>> gnus-summary-make-false-root to a non-nil value, but I'm not sure.)
> 
> That controls the insertion of dummy lines for missing articles in
> the thread.  If you just want articles with common References: to be
> in the same thread, without filling in gaps with dummy lines, then
> setting gnus-summary-thread-gathering-function should suffice.

I want two articles with the same subject to be sorted together, even
if neither of them contains a References header.

Is it sufficient to set gnus-summary-thread-gathering-function to
gnus-gather-threads-by-subject to achieve this, or is it also
necessary to set gnus-summary-make-false-root?

kai
-- 
I like BOTH kinds of music.

Re: What does `gathering loose threads' mean?

[Paul Jarc]

Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai =?iso-8859-1?q?Gro=DFjohann?=) writes:
> I want two articles with the same subject to be sorted together, even
> if neither of them contains a References header.

Then you want gnus-summary-thread-gathering-function to be
gnus-gather-threads-by-subject, which I think is the default.

> Is it sufficient to set gnus-summary-thread-gathering-function to
> gnus-gather-threads-by-subject to achieve this, or is it also
> necessary to set gnus-summary-make-false-root?

Depends what you mean by `sorted together'.  Say you've got two
threads - they have the same subject, but they have no visible common
root.  If you want them to be totally independent (which you don't),
let gnus-summary-make-false-root be nil.  If you want them to be
separate threads, but adjacent in the summary buffer, let it be
`none'.  If you want them to be collected into a single thread, with
one <adopted by> (instead of being a [child of]) the other, let it be
`adopt'.  And so on.


paul

Re: What does `gathering loose threads' mean?

[Kai Großjohann]

On 09 Aug 2000, Paul Jarc wrote:

> Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai
> =?iso-8859-1?q?Gro=DFjohann?=) writes:
>> I want two articles with the same subject to be sorted together,
>> even if neither of them contains a References header.
> 
> Then you want gnus-summary-thread-gathering-function to be
> gnus-gather-threads-by-subject, which I think is the default.

Ah.  Well.

>> Is it sufficient to set gnus-summary-thread-gathering-function to
>> gnus-gather-threads-by-subject to achieve this, or is it also
>> necessary to set gnus-summary-make-false-root?
> 
> Depends what you mean by `sorted together'. [...]

They are displayed on adjacent lines in the summary buffer.

Okay, so the settings of two variables are important:
gnus-summary-thread-gathering-function and
gnus-summary-make-false-root.

Further improvement can be had by fiddling with the fuzzy and subject
simplification thingies.

Somebody in a German newsgroup continues to claim that setting
gnus-thread-ignore-subject to nil is a useful thing to do in the above
context.  But of course, it isn't.  Does something different
entirely.  Now I'll go back and try to explain again.

Thanks,
kai
-- 
I like BOTH kinds of music.

Re: What does `gathering loose threads' mean?

[Paul Jarc]

Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai =?iso-8859-1?q?Gro=DFjohann?=) writes:
> Somebody in a German newsgroup continues to claim that setting
> gnus-thread-ignore-subject to nil is a useful thing to do in the above
> context.  But of course, it isn't.  Does something different
> entirely.  Now I'll go back and try to explain again.

Well, it might be useful.  It's orthogonal, addressing a different
issue.  You've got a thread, determined by either Subject: or
References:.  You divine its internal structure from References:.  You
see that an article's Subject: does not match its parent's.  Should
this article be the root of a new thread?  That question need not be
related to your basic thread-gathering criterion.


paul