bug#39658: 26.3; can't edit file with terminal escape sequences

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Thu, 20 Feb 2020 14:36:17 +0100
> Cc: Robert Pluim <rpluim@gmail.com>, 39658@debbugs.gnu.org, frederik@ofb.net
> 
> 19 feb. 2020 kl. 18.47 skrev Eli Zaretskii <eliz@gnu.org>:
> 
> > Ah, yes.  Set bidi-inhibit-bpa non-nil, and Bob's your uncle.
> 
> Fine, so how do we proceed from here? I presume that the bug triggers when 
> the bidi cache limit of 50000 elements is reached (or maybe MAX_BPA_STACK). 
> Turn off BPA temporarily, for the current line or paragraph, when this 
> occurs? Or for the entire buffer, on the grounds that it's hardly 
> right-to-left text anyway?

I think so-long-mode already handles this the best we could do in
general.  I don't know how to solve these pathological cases better,
except advise the user to visit such files literally to begin with.