Re: A T does not work in nnml ...

[Andrew Cohen <cohen@andy.bu.edu>]

>>>>> "Lars" == Lars Magne Ingebrigtsen <larsi@gnus.org> writes:

    Lars> Andrew Cohen <cohen@andy.bu.edu> writes:
    >> Thread-referral has always been sub-optimal for nnml. The current
    >> (and previous) behavior is to just download a bunch of headers
    >> and hope that the thread is among them. For nnml I suspect there
    >> is a better way...

    Lars> Perhaps the number of headers it downloads should be doubled
    Lars> or something?

Hmm, it appears there is an underlying bug which manifests whenever the
headers are retrieved as nov.  I kind of know what's going on but I
don't yet fully understand the way dependencies work.

The Problem:
Even when the headers for the articles in the thread have been retrieved
the articles don't make their way into the summary buffer. 

"A T" (aka gnus-summary-refer-thread) retrieves the headers, calls
gnus-build-all-threads and finally
gnus-summary-limit-include-thread. Now gnus-build-all-threads parses
each header (in nov format) and calls gnus-dependencies-add-header. This
function checks to see if the header is already in the dependencies
hash. If not, it adds it and then pushes the header onto
gnus-newsgroup-headers. If the header is already present it just skip
these steps.

This is the problem---there may already be an entry in the dependencies
list if the article is already present but refers to other articles in
the thread that haven't yet been retrieved. But then the article id of
these "other" articles is a negative number (reflecting the fact that
they haven't been retrieved) and never gets updated to the actual
article id. And the newly fetched headers for these articles doesn't get
pushed onto gnus-newsgroup-headers, hence the problem.

I thought I could fix it by calling gnus-dependencies-add-header with
the force-new flag. This works better, but still shows some odd
behavior. 

I'll keep plugging away at this, but someone who knows more about
dependencies and threading might find the fix faster.