Re: A new(?) warning of erase-buffer, which was not seen before.

[ishikawa <chiaki.ishikawa@ubin.jp>]

Kim F. Storm wrote:
> ishikawa <chiaki.ishikawa@ubin.jp> writes:
> 
>> It is only that I am a little puzzled that I didn't get this warning
>> in the previous versions 21.x (and prior), and I am wondering
>> if there is a better memory allocation/checking introduced in 22.0
>> which causes this warning to appear. In the older versions, say 21.x
>> (and prior), I have not seen this message.
> 
> Those warnings are new in Emacs 22.
> 
> In Emacs 21 and before, there is a risk of running out of memory and
> Emacs crashing.
> 
> In Emacs 22, more checks and automatic measures like undo-outer-limit
> have been added to prevent running out of memory, and to give feedback
> to the user when those measures kick in.
> 
> Here's what C-h C-n (aka NEWS) says about it:
> 
> ** When the undo information of the current command gets really large
> (beyond the value of `undo-outer-limit'), Emacs discards it and warns
> you about it.
> 

Thank you again.

After tinkering with new emacs, here is my suggestion for a slight improvement 
for the particular warning message.

AT the end (that is,
after "You can disable the popping up of this buffer by adding the entry
(undo discard-info) to the user option `warning-suppress-types'."),
we might want to add something like the following (as rms suggested):

"
If you know what you are doing, and you don't want the buffer
to collect undo information which uses memory internally,
do M-x buffer-disable-undo,  or (setq buffer-undo-list t)."