bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Alan Mackenzie]

(i) With desktop enabled, start emacs.

(ii) Start a second emacs session.

Emacs2 detects Emacs1 and the danger of contention over .emacs.desktop.
It prompts thusly:

    "Warning: desktop file appears to be in use by PID 3616.
     Using it may cause conflicts.  Use it anyway? (y or n)"

(iii) Type n.

(iv) Attempt C-c C-x.

Emacs2 decides, because desktop is "enabled", that it wants to save a
desktop file, and prompts:

    "Directory for desktop file: ~/"

At this point, C-g aborts the "end Emacs" command.  One now has the
unpleasant choice of killing Emacs2 from the (operating system) console
or typing in some random directory to dump the empty .emacs.desktop to.

This is a bug.

Even worse, accepting the prompt's default directory, ~/, might
overwrite the real .emacs.desktop.

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Lawrence Mitchell]

Alan Mackenzie wrote:
> (i) With desktop enabled, start emacs.

> (ii) Start a second emacs session.

> Emacs2 detects Emacs1 and the danger of contention over .emacs.desktop.
> It prompts thusly:

>     "Warning: desktop file appears to be in use by PID 3616.
>      Using it may cause conflicts.  Use it anyway? (y or n)"

> (iii) Type n.

> (iv) Attempt C-c C-x.

> Emacs2 decides, because desktop is "enabled", that it wants to save a
> desktop file, and prompts:

>     "Directory for desktop file: ~/"

> At this point, C-g aborts the "end Emacs" command.  One now has the
> unpleasant choice of killing Emacs2 from the (operating system) console
> or typing in some random directory to dump the empty .emacs.desktop to.

> This is a bug.

I cannot reproduce with the following sequence to enable desktop:

;; start an emacs that creates a desktop file and quit
$ emacs -Q --eval '(progn (setq desktop-path (list "/tmp/"))
(desktop-save-mode 1) (desktop-read) (dired "/tmp/")
(save-buffers-kill-emacs))'

;; now start an emacs to read the desktop file (acquiring a lock)
$ emacs -Q --eval '(progn (setq desktop-path (list "/tmp/"))
(desktop-save-mode 1) (desktop-read))' &

;; start a second emacs
$ emacs -Q --eval '(progn (setq desktop-path (list "/tmp/"))
(desktop-save-mode 1) (desktop-read))'

;; This one prompts

Warning: desktop file appears to be in use by PID XXXXX.
Using it may cause conflicts.  Use it anyway? (y or n)

;; I answer "n", the desktop file is not loaded.

;; Now I do save-buffers-kill-emacs and am asked:

Save desktop? (y or n)

;; I hit "n", the desktop is not saved and Emacs quits as
   expected.


How have you enabled desktop in your emacs session to produce
this problem?

-- 
Lawrence Mitchell <wence@gmx.li>

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Alan Mackenzie]

On Wed, Oct 22, 2008 at 12:12:28PM +0100, Lawrence Mitchell wrote:
> Alan Mackenzie wrote:
> > (i) With desktop enabled, start emacs.

> > (ii) Start a second emacs session.

[ .... ]

> > Emacs2 decides, because desktop is "enabled", that it wants to save a
> > desktop file, and prompts:

> >     "Directory for desktop file: ~/"

> > At this point, C-g aborts the "end Emacs" command.  One now has the
> > unpleasant choice of killing Emacs2 from the (operating system) console
> > or typing in some random directory to dump the empty .emacs.desktop to.

> > This is a bug.

> I cannot reproduce with the following sequence to enable desktop:

> ;; start an emacs that creates a desktop file and quit
> $ emacs -Q --eval '(progn (setq desktop-path (list "/tmp/"))
> (desktop-save-mode 1) (desktop-read) (dired "/tmp/")
> (save-buffers-kill-emacs))'

> ;; now start an emacs to read the desktop file (acquiring a lock)
> $ emacs -Q --eval '(progn (setq desktop-path (list "/tmp/"))
> (desktop-save-mode 1) (desktop-read))' &

> ;; start a second emacs
> $ emacs -Q --eval '(progn (setq desktop-path (list "/tmp/"))
> (desktop-save-mode 1) (desktop-read))'

> ;; This one prompts

> Warning: desktop file appears to be in use by PID XXXXX.
> Using it may cause conflicts.  Use it anyway? (y or n)

> ;; I answer "n", the desktop file is not loaded.

> ;; Now I do save-buffers-kill-emacs and am asked:

> Save desktop? (y or n)

> ;; I hit "n", the desktop is not saved and Emacs quits as
>    expected.


> How have you enabled desktop in your emacs session to produce
> this problem?

Sorry, I should have said this.  With a .emacs containing exactly one
line:

    (desktop-save-mode 1)

and with no existing .emacs.desktop, I started Emacs, visited two files,
did M-x desktop-save, and exited Emacs.

Then I started, successively, two Emacs sessions like this:

    /path/to/emacs --no-site-file

, where the emacs was a CVS version from last night.  I tried this (i) on
two Linux tty's; (ii) From an X-Windows (GNOME) terminal, 

> Lawrence Mitchell <wence@gmx.li>

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Glenn Morris]

Alan Mackenzie wrote:

> At this point, C-g aborts the "end Emacs" command.  One now has the
> unpleasant choice of killing Emacs2 from the (operating system) console
> or typing in some random directory to dump the empty .emacs.desktop to.

Another choice is of course just to turn off desktop-save-mode, then exit.

> This is a bug.

What should it do instead?

i) Not turn on desktop-save-mode if you answer no to the initial
question:

     "Warning: desktop file appears to be in use by PID 3616.
      Using it may cause conflicts.  Use it anyway? (y or n)"

ii) Or should this question offer a third alternative, eg "(q) -
disable desktop-save-mode for this session"?

iii) Or should the prompt

    Directory for desktop file: ~/"

somehow offer an option to turn off desktop-save-mode?

iv) Something else?

> Even worse, accepting the prompt's default directory, ~/, might
> overwrite the real .emacs.desktop.

If you try it, you will find you get adequate warning about overwriting
the existing desktop.

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Glenn Morris]

Glenn Morris wrote (on Wed, 22 Oct 2008 at 21:12 -0400):

> If you try it, you will find you get adequate warning about overwriting
> the existing desktop.

And if you answer "no" to the prompt about overwriting, Emacs exits
without saving the desktop (admittedly, perhaps a slightly obscure way
to get this functionality). So I don't see that you are being held
hostage here.

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Alan Mackenzie]

Hi, Glenn!

On Wed, Oct 22, 2008 at 09:12:29PM -0400, Glenn Morris wrote:
> Alan Mackenzie wrote:

> > At this point, C-g aborts the "end Emacs" command.  One now has the
> > unpleasant choice of killing Emacs2 from the (operating system)
> > console or typing in some random directory to dump the empty
> > .emacs.desktop to.

> Another choice is of course just to turn off desktop-save-mode, then
> exit.

I suppose so.  You have to have a cool head to think of this, though.

> > This is a bug.

> What should it do instead?

> i) Not turn on desktop-save-mode if you answer no to the initial
> question:

>      "Warning: desktop file appears to be in use by PID 3616.
>       Using it may cause conflicts.  Use it anyway? (y or n)"

> ii) Or should this question offer a third alternative, eg "(q) -
> disable desktop-save-mode for this session"?

> iii) Or should the prompt

>     Directory for desktop file: ~/"

> somehow offer an option to turn off desktop-save-mode?

> iv) Something else?

I think Lawrence Mitchell's suggestion of what should happen is right:
first prompt "save desktop (y/n): ", and after getting a y, prompt for a
directory to save in.

> > Even worse, accepting the prompt's default directory, ~/, might
> > overwrite the real .emacs.desktop.

> If you try it, you will find you get adequate warning about overwriting
> the existing desktop.

OK.

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Glenn Morris]

Alan Mackenzie wrote:

> I think Lawrence Mitchell's suggestion of what should happen is right:
> first prompt "save desktop (y/n): ", and after getting a y, prompt for a
> directory to save in.

It sounds like you want the variable desktop-save to have another option:

ask-if-old    -- ask if desktop file exists, otherwise just save.

Or perhaps one of the existing ask, ask-if-exists options?

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Juanma Barranquero]

On Thu, Oct 23, 2008 at 11:38, Alan Mackenzie <acm@muc.de> wrote:

> I think Lawrence Mitchell's suggestion of what should happen is right:
> first prompt "save desktop (y/n): ", and after getting a y, prompt for a
> directory to save in.

This is the behavior after revno:100049, I think. Could you please
check whether it does work as expected?

    Juanma

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Alan Mackenzie]

Hi, Juanma,

On Wed, Jul 06, 2011 at 04:08:29AM +0200, Juanma Barranquero wrote:
> On Thu, Oct 23, 2008 at 11:38, Alan Mackenzie <acm@muc.de> wrote:

> > I think Lawrence Mitchell's suggestion of what should happen is right:
> > first prompt "save desktop (y/n): ", and after getting a y, prompt for a
> > directory to save in.

> This is the behavior after revno:100049, I think. Could you please
> check whether it does work as expected?

That's perfect!  Thanks.

>     Juanma

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#1226: Desktop holds second Emacs session hostage; C-x C-c doesn't work properly.

[Juanma Barranquero]

On Fri, Jul 8, 2011 at 22:48, Alan Mackenzie <acm@muc.de> wrote:

> That's perfect!  Thanks.

I'm closing this one, then.

Thanks,

    Juanma