Subject: bug#8219: Effect of deletions on indirect buffers (Bug#8219)

From: Eli Zaretskii <[email-masked]>
Date: Sat, 12 Mar 2011 10:15:05 +0200

> From: Chong Yidong <[email-masked]>
> Cc: [email-masked], [email-masked]
> Date: Fri, 11 Mar 2011 15:58:57 -0500
> 
> Eli Zaretskii <[email-masked]> writes:
> 
> >> Hence, in the aftermath of a deletion, buffer B's values of PT (and
> >> BUF_BEGV and BUF_ZV) can be larger than BUF_ZV.
> >
> > Isn't that a bug, right there?  Why doesn't del_range_2 update the
> > indirect buffer (B) as well, when deletion removes text so that its PT
> > becomes invalid?
> 
> This is not currently easy.  We don't keep track of indirect buffers
> (looping over the buffer list each time we do a deletion would be rather
> inefficient), so this would need some new members of the buffer struct.

We could do that lazily, whenever something (including redisplay) is
done on a buffer that happens to be an indirect buffer.