bug#26952: 25.1; loops eating all memory while yanking big rectangle

[Eli Zaretskii <eliz@gnu.org>]

> From: npostavs@users.sourceforge.net
> Date: Fri, 19 May 2017 20:24:03 -0400
> Cc: 26952@debbugs.gnu.org
> 
> > $ emacs -Q -nw
> >
> > I find a big text file that you can download from
> > <http://fly.isti.cnr.it/tmp/bigfile.txt.xz>
> >
> > Once decompressed, the file is 80 MB long, composed of over 600000 lines
> > around 150 characters long each
> >
> > Then I do this:
> >
> > C-u 29 M-f		--> point is on the tab after "21"
> > M->
> > C-b
> > C-u 30 SPC
> > M-x kill-rectangle	--> Emacs discards the undo buffer
> > C-x b aa		--> create a scratch buffer
> > M-x yank-rectangle
> >
> > at this point, Emacs freezes and starts growing in size.  On my system,
> > it started from less than 1GB vmem and grew to over 10GB when I killed
> > it.  Only kill -9 succeded to kill it.
> 
> I see the issue also with 25.2, but not with master (no idea what might
> have fixed it though).

Thanks for looking into this.  Can you tell more about where it is
looping in Emacs 25.2?  I'm uneasy about not knowing what fixed this.