Re: Working around IMAP server b0rk3n-ness

[Gaute B Strokkenes <biggaute@uwc.net>]

On 27 jun 2003, dmaze@mit.edu wrote:

> When using Gnus with an IMAP mail-source, it goes through, reads one
> message at a time, sorts them away, and then tries to do a bulk
> delete of all of the messages it's read.  This is all fine and
> within the bounds of the IMAP spec; unfortunately, not all software
> is.  I somewhat regularly wind up using an imtest binary with a
> 500-byte line limit, and if I get around that, the local server has
> a 16K line limit, which I do run into with enough mail.
>
> It'd be nice if there was a switch or fallback mode or something
> such that Gnus didn't always lose in exciting ways when it hit this.

You're not alone, if it makes you feel any better.  I have a similar
problem every morning when I try to get ~500 new messages.  Gnus
constructs a line of ~2000 bytes; the process then hangs indefinitely.
I haven't quite tracked down what's going wrong, but the prime suspect
is uw-imapd not being able to cope with long lines (we all know how
robust c-client and friends are in that respect) with some sort of
openssl / emacs sub-process brokenness as a more distant second.
Usually I just run fetchmail once every morning.

> The "I'm away for a week so it's sure to die, slow and correct is
> better than fast and broken" patch is:
> 
> Index: mail-source.el
> ===================================================================
> RCS file: /usr/local/cvsroot/gnus/lisp/mail-source.el,v
> retrieving revision 6.36
> diff -u -r6.36 mail-source.el
> --- mail-source.el      13 May 2003 22:58:29 -0000      6.36
> +++ mail-source.el      27 Jun 2003 18:29:58 -0000
> @@ -1005,9 +1005,10 @@
> (nnheader-ms-strip-cr))
> (incf found (mail-source-callback callback server))
> (when (and remove fetchflag)
> -             (imap-message-flags-add
> -              (imap-range-to-message-set (gnus-compress-sequence remove))
> -              fetchflag nil buf))
> +             (dolist (uid remove)
> +               (imap-message-flags-add
> +                (imap-list-to-message-set (list uid))
> +                fetchflag nil buf)))
> (if dontexpunge
> (imap-mailbox-unselect buf)
> (imap-mailbox-close nil buf))
>
> ...but I don't actually want that all the time.

This may help:

*** mail-source.el.~6.38.~	1970-01-01 01:00:01.000000000 +0100
--- mail-source.el	2003-08-28 12:42:48.000000000 +0100
***************
*** 1006,1011 ****
--- 1005,1011 ----
  	      (nnheader-ms-strip-cr))
  	    (incf found (mail-source-callback callback server))
  	    (when (and remove fetchflag)
+ 	      (setq remove (nreverse remove))
  	      (imap-message-flags-add
  	       (imap-range-to-message-set (gnus-compress-sequence remove))
  	       fetchflag nil buf))

What's going on here is that remove is a list of message numbers that
should be expunged.  The imap-range-to-message-set /
gnus-compress-sequence combo is supposed to create a compact
representation using the imap range syntax (i.e. "1:5" rather than
"1,2,3,4,5").  However, gnus constructs remove by repeatedly pushing
message numbers on to it--and since gnus fetches messages in sequence,
the list of message numbers will be in reverse order, which defeats
gnus-compress-sequence ("5,4,3,2,1").

This won't help you much if the message numbers are not continuous,
but it's a start.

-- 
Gaute Strokkenes                        http://www.srcf.ucam.org/~gs234/
I'm DESPONDENT...  I hope there's something DEEP-FRIED under this
 miniature DOMED STADIUM...