Re: how to force auto-save of buffers not visiting files, right now?

[hw]

On Wed, 2022-03-16 at 01:51 +0100, Michael Heerdegen wrote:
> hw <hw@adminart.net> writes:
> 
> > Hi,
> > 
> > how do I force auto-saving of a particular buffer, or of all buffers,
> > that are not visiting a file, right now?
> > 
> > I would like to improve below function by auto-saving the backup:
> 
> Normally you should be able to `undo' if something went wrong.  Even
> when the buffer has no associated file.

Think it through: You can only undo when nothing goes wrong.  With
copies of buffers being autmatically saved to auto-save files, you
can recover from the auto-save files when something does go wrong.
When nothing goes wrong, these buffers and auto-save files automatically
go away.

Undo can't do that.

Can you save the undo information?  Can you swap the undo information
from one buffer to another just like you can swap buffer contents (with
(buffer-swap-text example_buffer))?

Why is there no undo information saved with auto-save files and none
with save-desktop-mode?