bug#58909: 29.0.50; [WIP PATCH] Deleting the last frame of an emacsclient doesn't ask to save

[Jim Porter]

On 11/2/2022 5:16 AM, Eli Zaretskii wrote:
> > Date: Tue, 1 Nov 2022 15:39:29 -0700
> > From: Jim Porter <jporterbugs@gmail.com>
> > Cc: 58909@debbugs.gnu.org
> >
> > Attached is a (hopefully) safer version of my change to 'delete-frame'.
> > In this patch, a hook can only cancel frame deletion if FORCE is
> > non-nil. This way, if there were ever some bug with a hook, you (or some
> > code) can still force-delete the frame.
>
> Sorry, but I still don't like this.  We currently call this hook via
> safe_call because we don't want to let the hook prevent the deletion
> of the frame.
>
> I prefer to solve this in server.el, not in lower-level primitives.

Hm, ok. That means I'd need to make sure 'C-x 5 0' calls something other 
than 'delete-frame', so that I could add a prompt to it that can prevent 
deletion of the frame.

Two questions then:

1. If 'delete-frame' is a lower-level primitive, should 'C-x 5 0' call 
it directly, or should there be a higher-level function for it to call? 
If we had some higher-level function, then user-level commands could 
call that, but low-level code could still use 'delete-frame'. This 
user-level command would then be able to run some hook that can prevent 
deletion of the frame.

2. Since server.el has a minor mode (unsurprisingly named 
'server-mode'), maybe one option is to do command remapping. If we remap 
'delete-frame' to some new 'server-delete-frame' when 'server-mode' is 
active, then this should work. See attached for a quick sketch of how 
this would look.

What do you think about one of these?

0001-WIP-Try-using-a-keymap-for-server-mode.patch
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