Subject: 29.0.60; When nnselect-always-regenerate, group info gets out-of-date

From: Sean Whitton <[email-masked]>
Date: Wed, 15 Feb 2023 12:47:18 -0700

X-debbugs-cc: [email-masked]

1. Same setup described in #56592, but additionally set
   nnselect-always-regenerate to t for the groups.
2. Enter group.  Mark an unread article as read.

   (length gnus-newsgroup-selection) => 935
   (car (last (gnus-info-read (gnus-get-info gnus-newsgroup-name))))
       => (930 . 935)

3. Exit group.  Enter group again.

   (length gnus-newsgroup-selection) => 934
   (car (last (gnus-info-read (gnus-get-info gnus-newsgroup-name))))
       => (930 . 935)

4. Attempt to exit group again.  Then, while binding select-reads at the
   beginning of nnselect-push-info, nnselect-categorize signals
   args-out-of-range, because one of the inline functions it calls
   attempts to read the 935th element of gnus-newsgroup-selection.

I believe that the nnselect-always-regenerate branch of
nnselect-get-artlist needs to update the group info, because the
following hack seems to avoid the problem.

-- >8 --
diff --git a/lisp/gnus/nnselect.el b/lisp/gnus/nnselect.el
index 87cb1275313..fdb4956b8e6 100644
--- a/lisp/gnus/nnselect.el
+++ b/lisp/gnus/nnselect.el
@@ -303,7 +303,10 @@ nnselect-get-artlist
        (cond
         (override (funcall override ,group))
         ((gnus-group-get-parameter ,group 'nnselect-always-regenerate)
-         (nnselect-generate-artlist ,group))
+         (let* ((artlist (nnselect-generate-artlist ,group))
+                (gnus-newsgroup-selection artlist))
+           (nnselect-request-update-info ,group (gnus-get-info ,group))
+           artlist))
         (t
 	 (nnselect-uncompress-artlist
           (gnus-group-get-parameter ,group 'nnselect-artlist t)))))))

-- 
Sean Whitton