Re: How to stop desktop.lock file creation

[Eli Zaretskii]

> Date: Sat, 26 Mar 2022 22:30:00 +0100 (CET)
> From: Angelo Graziosi <angelo.g0@libero.it>
> Cc: emacs-devel@gnu.org
> 
> > You don't need to play this game.  If you set
> > desktop-load-locked-desktop to t, Emacs will unconditionally load the
> > desktop even if locked, no questions asked.  Its effect is the same as
> > not having the lock at all, when the process which locked the desktop
> > no longer runs.
> 
> When Emacs ask for loading the desktop file it says
> 
> "Warning: desktop file appears to be in use by PID xyza.
> Using it may cause conflicts.  Use it anyway? (y or n)"
> 
> So, _if it says that could be conflicts_, in my opinion, the best way to go 
> is to accept it, close Emacs, restart Emacs, so that it starts in a clean 
> state.

What it wants to say that it doesn't know whether the process that
locked the desktop file is still running.  If it is still running,
then yes, using this file in two Emacs processes could cause
conflicts.  And please note that the process which locked it could run
on another computer.  If that process is not running, there could be
no conflicts, and it is safe to answer "y".

> Why I have to to all this? Really I need this? or should I accept with the 
> risk of conflicts (i am sure they do not occur!)?

You should verify (or in your case know in advance) that the locking
Emacs process no longer runs.

> > > Emacs worked the same before its introduction...
> > 
> > The lock was introduced in Emacs 22.2, quite some time ago.  It isn't
> > a new feature.
> 
> I know this and it is what I did mean. 
> 
> If users could live without the lock file until version 22 why can't they 
> live without it with the current version?

The lock was introduced to handle the cases in which users did
encounter conflicts by using the same desktop file from two or more
Emacs processes.  See

  https://lists.gnu.org/archive/html/emacs-devel/2006-04/msg01253.html

> In short: really we need this lock file?

Yes, IMO.

> really it is useful in all situations?

It is a safety net that is definitely useful in some situations.  As
any safety net, it can sometimes produce false positives, and we are
working on making those more rare.  For example, Emacs 29 will have an
additional value of desktop-load-locked-desktop that will be capable
of taking the lock silently if it was locked by a local process that
is no longer running.

> Why not adding a flag to avoid its creation and that the user sets at its own 
> risk?

Because we think desktop-load-locked-desktop is that flag.