bug#12745: crash in bidi_pop_it during (idle) redisplay

[Eli Zaretskii]

> Date: Mon, 29 Oct 2012 22:24:12 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: alptekin.aker@gmail.com, 12745@debbugs.gnu.org
> 
> Anyway, the problem happened at position 1295, which I believe is the
> newline that ends this line.  I need to think...

Ami, can you put a breakpoint in the function init_from_display_pos
and see if it ever breaks in your usage of C++ buffers?  There's
something suspicious going on in this function, but since I cannot
trigger its entry here (I even tried several of the minor modes you
have on, including fci-mode, linum-mode, and hi-lock), I'm not sure if
looking into this isn't a wild goose chase.

If you succeed in triggering the breaks inside that function, please
show the backtrace and the values of it->current and of
it->n_overlay_strings when the function returns.