Re: Undo discard prompt

[Stefan Monnier]

>> however the recent updates in simple.el that cause the yes/no dialog  to
>> ask about discarding undo information does pop up in shell-mode --- 

>    BTW, I just wanted to say that since this undo-discard prompt was
>    introduced I've bumped into it also in "normal" circumstances (just
>    manual buffer editing) and have found it to be just really annoying
>    (half the time it occurred in the middle of some kbd-macro and breaks
>    the sequence of steps).

> It seems strange that you would routinely accumulate one large single
> undo entry in the process of manual buffer editing.  Are you sure that
> there is no inappropriate undo management involved somewhere?  Are
> keyboard macros what causes the problem?

Well I didn't say "routinely": it happened 4 times until now.
And I don't think they were the result of a bug.  They mostly (3 times)
occured because I did something like:
1 - copy a large file (or a buffer).
2 - work on the copy by removing most of its content.

The remaing case occured in conjunction with the command
diff-context->unified on a large patch file.  Maybe the command shouldn't
keep the undo info, but find that I do undo this command.  Now I can
also undo it by using diff-unified->context, so if I could replace
the large undo entries with just one entry that says "call
diff-unified->context" it would not be a problem any more.  The SES
spreadsheet also needs such a feature (and currently fakes it by using
a wrapper around primitive-undo).

> The prompt has turned out to be a great debugging tool, but it indeed
> can be a real nuisance.

I can live with it as a debugging tool, but I think that by default it
should not prompt.


        Stefan