bug#23871: 25.1.50; Undo unexpectedly leads to blank buffer

[Phillip Lord]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: phillip.lord@russet.org.uk (Phillip Lord)
>> Cc: Eli Zaretskii <eliz@gnu.org>,  23871@debbugs.gnu.org
>> Date: Sun, 03 Jul 2016 13:55:48 +0100
>> 
>> I've tried to reproduce #23871, but unfortunately, swiprolog crashes as
>> shown below.
>
> I very much hope that the problem could be reproduced without using
> Prolog at all, by just invoking a program like 'cat' to insert some
> text into the buffer.  I cannot see how Prolog can be possibly
> relevant to this, as all it does is insert text into the buffer.

That might be true, unless there is something odd about the way prolog
produces text in terms of timing. Or something happening in the other
buffers it opens. 

>
>> The packaged version of swiprolog on my machine is 6.6.4, rather than >
>> 7.2. I'm not keen on trying to update to 7.2.
>
> Actually, the recipe asks for 7.3.

Both are a long way of 6.6.4!