Re: newline cache

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 21 May 2014 10:41:13 +0200
> From: Damien Wyart <damien.wyart@gmail.com>
> Cc: emacs-devel@gnu.org
> 
> > > Based on the few incidents I had until now, it looks like the cache
> > > gets corrupted after deleting several mails, then saving the mailbox
> > > buffer. Not sure yet what exactly causes this.
> 
> * Eli Zaretskii <eliz@gnu.org> [2014-04-27 05:42]:
> > One more important fact: not each time I delete messages and then save
> > the mailbox, I get the cache corrupted. So some other factor is at
> > work here.
> 
> Hi Eli,
> 
> Was there some progress on this problem?
> 
> 24.4 is approaching and I think killing this bug before would be nice.

No real progress, unfortunately.  The bug is very elusive, almost a
Heisenbug, so I cannot reliably reproduce it, and thus still don't
have a simple recipe starting from "emacs -Q" that I could use to
investigate it and verify that it's fixed.

Without a simple reliable recipe, it is extremely hard to find the
root cause, because the newline cache is consulted _a_lot_, and on top
of that Rmail swaps buffer text, which makes traces even harder to
understand and interpret.

I'm beginning to think that maybe the only practical solution, at
least for 24.4, is to disable caching in Rmail buffers (since I saw no
reports of similar problems in any other modes).

Volunteers are welcome to help debug this, or provide additional
details.