Re: [RFC] Option to kill `emacs --daemon' when closing the last client frame

[Jim Porter <jporterbugs@gmail.com>]

On 10/20/2021 11:07 PM, Eli Zaretskii wrote:
>> From: Jim Porter <jporterbugs@gmail.com>
>> Date: Wed, 20 Oct 2021 13:07:02 -0700
>> Cc: emacs-devel@gnu.org
>>
>>> You will get that behaviour if you put (server-start) in your init.el
>>> and set --alternate-editor to the emacs binary, not just an empty string.
>>
>> Right, that's what I currently do. However, I've run into a couple
>> problems that have made me think `emacs --daemon' would be a better
>> solution. Under a non-daemon[1] configuration:
>>
>> 1) `org-protocol://' links don't work if Emacs isn't already running.
>> This is because org-protocol advises `server-visit-files' to detect when
>> a link with that protocol is passed as a file argument on the command
>> line. Since this argument is passed to the "alternate" Emacs, it's not
>> handled in `server-visit-files' and so the org-protocol code never runs.
> 
> This sounds like a problem in org-protocol that should be solved
> there.  If doing so requires some core feature we don't have, let's
> discuss that missing feature.  But changing the behavior of the
> daemon, which will affect also all the other use cases unrelated to
> this one, is not TRT, IMO.

Agreed. Before I came across issue (2) below, my plan was simply to fix 
this without changing the daemon's behavior. I think a core fix would be 
generally useful though, and once I've looked into it more, I'll send a 
message to the list with more thoughts.

>> 2) The first place Emacs is opened is the "primary" instance. This isn't
>> usually a problem when you only run Emacs graphically, but if mixing GUI
>> and terminal instances, it'd be nice to allow closing the first instance
>> and keep the others open. For example, if you start editing in a
>> terminal Emacs and open a GUI Emacs client, the GUI Emacs can only live
>> as long as the terminal one.
> 
> I don't follow this one.  What exactly do you mean by "primary" here,
> and what do you mean by "instance"?  In the scenario you described
> there's only one instance of Emacs running, as I'm sure you know very
> well.  Please elaborate.

I hope an example will illustrate what I mean[1]. I start with two 
terminals open, A and B[2]. In terminal A, I run `emacs -nw foo.txt'. In 
terminal B, I run `emacsclient -nw -c bar.txt'. Now, suppose I want to 
stop editing foo.txt in terminal A and go back to doing something else. 
I'd type `C-x C-c', but then my emacsclient in terminal B will close too.

However, using the daemon configuration with ALTERNATE_EDITOR="", I 
could run `emacsclient -nw -c ...' in each terminal. Then when I type 
`C-x C-c' in terminal A, it only kills that client, not the daemon 
process. I can then continue to edit in terminal B without interruption.

Of course, this isn't a bug, it's just how emacs and emacsclient work 
together when not using `emacs --daemon'. It just turned out to be 
inconvenient for how I use Emacs, so I've moved to using `emacs 
--daemon' instead.

- Jim

[1] It might be best to ignore my original terminology since it wasn't 
very clear. However, for completeness, by "primary" I meant "the actual 
`emacs' process", and by "instance" I meant "the set of frames 
associated with a particular Emacs client, including 'no client'".

[2] This happens in a GUI too, but I think it's easier to see with 
terminals.