Re: some issues with message expiration

[Dirk-Jan C. Binnema <djcb.bulk@gmail.com>]

>>>>> On Sun, 18 Jul 2010 22:03:19 +0200, David Maus ("DM") wrote:

[expire]

  >> ("^\\.system$"               (date 3) remove)

  >> First it updates the message
  >> db, then I get the 'Wrong type argument: listp, nil'. However, I do /not/ get
  >> any backtrace. When I then try to enter the folder, or do anything (even when
  >> trying M-x toggle-debug-on-error), I either get that same error again. And I
  >> cannot move the cursor anymore. Emacs menus are still accessible though, it's
  >> not a general hang. But just about whatever I do gives me 'Wrong type
  >> argument: listp, nil'.

  DM> Interesting.  Do you call expire in Folder mode or Summary mode?  Here
  DM> expiring a maildir folder works perfectly in Summary mode, but in
  DM> Folder mode I get an error -- although a different one (WL not being
  DM> capable of finding the file the correspondents to a maildir message
  DM> number).

This is in Folder mode; I just reproduced it with the latest Wanderlust from
Dave Abrahams repo. Interestingly, when I do that in summary mode
(wl-summary-expire), the same thing does not happen; in fact, it seems to work
without any problem in that case.

Interestingly, after doing the summary-mode expire, I can try folder-mode
expire without any further trouble -- I think this is because there is no
msgdb update involved now.

  DM> A question about this one:

  >> - when trying to expire my 'System' folder, I get
  >> "Wrong type argument: listp, nil"
  >> but
  >> when I try to enter the folder afterwards I get:
  >> "Format specifier doesn't match argument type", after which WL (or emacs)
  >> is not very useful anymore, and tells me
  >> "Symbol's value as variable is void: nil". After that, I cannot even close
  >> emacs properly, but have to kill it.

  DM> Do you have a way to reproduce this behavior?  IIRC I hit a problem
  DM> with the same symptoms occasionally and "Symbol's value as variable is
  DM> void: nil" sound horrible: Meaning that Emacs somehow forgot that the
  DM> symbol nil is ... nil.  What ever WL might do wrong: THIS should not
  DM> never happen :( (read: It could be a Emacs bug).

Yes, this easily reproducible, it happens every time I try to expire in Folder
Mode when the folder needs to be updated. Indeed, the nil thing seems very
scary. Do you have any idea on how I could debug this? (as mentioned,
toggle-debug-on-error does not work).

After glancing at the sources (wl-summary-expire vs wl-folder-expire-entity),
it seem that the main difference is that the latter updates the msgdb first;
and I get the errors somewhere during or after update takes place.
But, if I enter the folder (which involves a msgdb update as well), and the
use expire in the summary mode, things work well.

So my current hypothesis is that for some reason, msg-updating works in some
different and wrong way when it's triggered by folder-mode expire. Digging
further...

Best wishes,
Dirk.

-- 
Dirk-Jan C. Binnema                  Helsinki, Finland
e:djcb@djcbsoftware.nl           w:www.djcbsoftware.nl
pgp: D09C E664 897D 7D39 5047 A178 E96A C7A1 017D DA3C