entering group hangs, `gnus-summary-hide-all-threads' loops forever

entering group hangs, `gnus-summary-hide-all-threads' loops forever

[Ted Zlatanov]

RET on a nnmaildir group hangs forever.  This is due to
`gnus-summary-hide-all-threads'.

This happens in only one group.  With the following modification, I can
see that it's doing millions of iterations in the loop, and there are
only a few articles in the group I'm entering.

(defun gnus-summary-hide-all-threads (&optional predicate)
  "Hide all thread subtrees.
If PREDICATE is supplied, threads that satisfy this predicate
will not be hidden."
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (let ((end nil)
          (count 0))
      (while (not end)
        (incf count)
        (when (zerop (mod count 1000))
          (message "Hiding all threads... %d" count))
	(when (or (not predicate)
		  (gnus-map-articles
		   predicate (gnus-summary-article-children)))
	    (gnus-summary-hide-thread))
	(setq end (not (zerop (gnus-summary-next-thread 1 t)))))))
  (gnus-summary-position-point))

Here's the backtrace with `toggle-debug-on-quit':

Debugger entered--Lisp error: (quit)
  gnus-summary-go-to-next-thread(nil)
  gnus-summary-next-thread(1 t)
  (zerop (gnus-summary-next-thread 1 t))
  (not (zerop (gnus-summary-next-thread 1 t)))
  (setq end (not (zerop (gnus-summary-next-thread 1 t))))
  (while (not end) (incf count) (when (zerop (mod count 100)) (message "Hiding all threads... %d" count)) (when (or (not predicate) (gnus-map-articles predicate (gnus-summary-article-children))) (gnus-summary-hide-thread)) (setq end (not (zerop (gnus-summary-next-thread 1 t)))))
  (let ((end nil) (count 0)) (while (not end) (incf count) (when (zerop (mod count 100)) (message "Hiding all threads... %d" count)) (when (or (not predicate) (gnus-map-articles predicate (gnus-summary-article-children))) (gnus-summary-hide-thread)) (setq end (not (zerop (gnus-summary-next-thread 1 t))))))
  (save-excursion (goto-char (point-min)) (let ((end nil) (count 0)) (while (not end) (incf count) (when (zerop (mod count 100)) (message "Hiding all threads... %d" count)) (when (or (not predicate) (gnus-map-articles predicate (gnus-summary-article-children))) (gnus-summary-hide-thread)) (setq end (not (zerop (gnus-summary-next-thread 1 t)))))))
  gnus-summary-hide-all-threads(nil)
  gnus-summary-maybe-hide-threads()
  gnus-summary-read-group-1("it" nil t nil nil nil)
  gnus-summary-read-group("it" nil t nil nil nil nil)
  gnus-group-read-group(nil t)
  gnus-group-select-group(nil)
  gnus-topic-select-group(nil)
  call-interactively(gnus-topic-select-group nil nil)

I won't touch this group to preserve the bug.  But the whole 
(not (zerop (next-thread))) logic is hard to understand, especially
since `gnus-summary-next-thread' does differential updates and is pretty
complicated.  So I need help to figure out where it's hanging.

Ted

Re: entering group hangs, `gnus-summary-hide-all-threads' loops forever

[Lars Magne Ingebrigtsen]

Ted Zlatanov <tzz@lifelogs.com> writes:

> I won't touch this group to preserve the bug.  But the whole 
> (not (zerop (next-thread))) logic is hard to understand, especially
> since `gnus-summary-next-thread' does differential updates and is pretty
> complicated.  So I need help to figure out where it's hanging.

Could you put the few articles in an nnmh group, and see whether it
still loops there?  If it does, tar up the nnmh group and mail it to me,
and I'll give it a whirl...

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/

Re: entering group hangs, `gnus-summary-hide-all-threads' loops forever

[Ted Zlatanov]

On Mon, 30 May 2011 20:46:56 +0200 Lars Magne Ingebrigtsen <larsi@gnus.org> wrote: 

LMI> Ted Zlatanov <tzz@lifelogs.com> writes:
>> I won't touch this group to preserve the bug.  But the whole 
>> (not (zerop (next-thread))) logic is hard to understand, especially
>> since `gnus-summary-next-thread' does differential updates and is pretty
>> complicated.  So I need help to figure out where it's hanging.

LMI> Could you put the few articles in an nnmh group, and see whether it
LMI> still loops there?  If it does, tar up the nnmh group and mail it to me,
LMI> and I'll give it a whirl...

I can't duplicate it anymore.  The algorithm of "keep going forward,
possibly jumping backwards, and hope you get to the end of the buffer
someday" is IMO broken so please leave my fix in there.

Ted

Re: entering group hangs, `gnus-summary-hide-all-threads' loops forever

[Lars Magne Ingebrigtsen]

Ted Zlatanov <tzz@lifelogs.com> writes:

> I can't duplicate it anymore.  The algorithm of "keep going forward,
> possibly jumping backwards, and hope you get to the end of the buffer
> someday" is IMO broken so please leave my fix in there.

Sure.  :-)

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/