bug#28843: 26.0.90; gnus kills unsaved message buffer

[Nick Helm]

On Thu, 12 Apr 2018 at 23:36:15 +1200, Lars Ingebrigtsen wrote:

> Yeah, the Messsage buffers are kinda special, I guess, in that they're
> basically the only Gnus buffers what aren't generated somehow.
>
> So handling them the same way as Emacs does on shutdown does make some
> sense...  On the other hand, even if we prompt the user, they're still
> saved to a pretty obscure place (i.e., the drafts group), so I'm not
> sure we're gaining anything by prompting the user.

Personally, I think prompting gains us quite a bit. Most importantly, it
can remind users that an un-dealt-with message exists. Maybe they
intended to send it, but forgot, or mis-keyed? Or perhaps it contains
sensitive info that shouldn't be kept? By silently saving (to a
pretty obscure place) the user may never know about it.

Prompting can also give them immediate control over what to do – send,
save, discard? If they decide to save, they know to look for a draft
later. We could even pop up a message telling them where to look.

BTW, if auto-save is customized (say by changing
make-auto-save-file-name) can we always guarantee the current behaviour
will work?