bug#33222: Crash when visiting an org file from within Dired.

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Date: Thu, 01 Nov 2018 18:31:53 +0100
> Cc: 33222@debbugs.gnu.org
> 
> Lisp Backtrace:
> "redisplay_internal (C function)" (0x0)
> (gdb) p attrs
> $1 = {make_number(1), XIL(0x55883af632f3f300), XIL(0x6150), 
> make_number(1510779), XIL(0x7), XIL(0x7fffffff7f60), XIL(0x7fffffff7f58), 
> XIL(0x39b6300), XIL(0), XIL(0x2eaae00), make_number(1), 
>   XIL(0x7fffffff7dd0), XIL(0x28), XIL(0x55883af632f3f300), XIL(0), 
> XIL(0x7fffffff8090), XIL(0), XIL(0x1), XIL(0x1)}
> (gdb) p default_face
> $2 = (struct face *) 0x0
> 
> I have no idea how default_face can be NULL here.

Usually that means the frame's face cache stores less faces than the
face ID we are trying to use.  In which case we need to establish why
the face cache is freed between the time a face is created and the
time it is used.