bug#36697: 27.0.50; gnus: some articles with score 0 are killed

[Lars Ingebrigtsen <larsi@gnus.org>]

Sam Steingold <sds@gnu.org> writes:

> `gnus-score-string' is called from `gnus-score-headers',
> `search-func` is `re-search-backward'
> It is called on line 2148 on `match' which is "[^a-z]\\{50\\}".
> So, it matches for _all_ subjects - _before_ the last 3 - because it
> searches _across_ lines!

Oh, yeah, I had forgotten that -- it's a neat hack to speed up the time
to score big groups: Calling re-search-backward is much, much faster
than looping over the headers and using string-match.  But it does mean
that if you have regexps like [^a-z], they have to have a \n in them,
too.

> PS. The code in gnus-score.el seems to avoid modern Emacs-Lisp features
> like `dolist' and `when'.  Is there a (non-historical) reason for that?
> Also, the functions are very long and thus hard to edebug.

It's just very, very old code, trying to be maximally fast.

> I had to extract some loops into separate functions to speed up stepping.
> Is it okay to commit?

Is there a performance impact?  

-- 
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   bloggy blog: http://lars.ingebrigtsen.no