bug#23813: 24.5; undo warning while find-file

[Eli Zaretskii]

> Date: Sat, 09 Jul 2016 15:27:47 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 23813@debbugs.gnu.org
> 
> > From: ynyaaa@gmail.com
> > Date: Tue, 21 Jun 2016 20:48:30 +0900
> > 
> > When `post-read-conversion' changes the buffer many times,
> > undo warning buffer popups.
> > This may occur while `find-file', even though undo info is not needed.
> > 
> > (let ((tmpfile "/tmp/test-hz.txt"))
> >   (with-temp-buffer
> >     (dotimes (i 100000) (insert "~{R;~}\n"))
> >     (write-region (point-min) (point-max) tmpfile)
> >     (let ((coding-system-for-read 'hz))
> >       (find-file tmpfile))))
> > 
> > Evaluating the form above, *Warnings* buffer shows this text.
> >   Warning (undo): Buffer `test-hz.txt' undo info was 12765470 bytes long.
> >   The undo info was discarded because it exceeded `undo-outer-limit'.
> >   
> >   This is normal if you executed a command that made a huge change
> >   to the buffer.  In that case, to prevent similar problems in the
> >   future, set `undo-outer-limit' to a value that is large enough to
> >   cover the maximum size of normal changes you expect a single
> >   command to make, but not so large that it might exceed the
> >   maximum memory allotted to Emacs.
> >   
> >   If you did not execute any such command, the situation is
> >   probably due to a bug and you should report it.
> >   
> >   You can disable the popping up of this buffer by adding the entry
> >   (undo discard-info) to the user option `warning-suppress-types',
> >   which is defined in the `warnings' library.
> 
> Phillip, what do you think about the patch below?

No comments, so I pushed the proposed change to the master branch, and
I'm marking this bug done.

Thanks.