reopening the session management discussion...

[jannis at xfce.org]

Hey,

On Wed, Aug 27, 2008 at 04:27:42AM -0700, Brian J. Tarricone wrote:
> Hey guys,
> 
> A while ago, I suggested that perhaps xfwm4, xfdesktop, xfce4-panel,
> etc. shouldn't use X11 session management to ensure startup, but just
> use the fd.o autostart mechanism instead.  I believe I was shot down at
> the time -- I think Olivier was opposed to the idea for some reason
> that I can't remember.
> 
> However, I still see this as a good idea:
> 
> Pros:
> 
> * App can never "accidentally" fall out of the session due to a crash
> (I guess I'm the biggest offender here). App will always be started when
> the DE starts unless the user disables it.
> 
> * App can be programmatically removed from and added to the session by
> deleting the .desktop file (or copying the systemwide file and adding
> Hidden=true).  xfce4-session doesn't implement any method to do this.

I like both of these arguments. We could address the users needs to
edit the autostart list by improving xfce4-autostart-editor which I feel
is a bit too simple in its current state anyway. If we choose to do
it this way, I'd vote to make it a 4.8 or at least a 4.6 beta 1 issue.
IMHO its not worth delaying Pinkie even further.
 
> Cons:
> 
> * Can't control startup order.  Only issue here is xfdesktop starting
> before 'Thunar --daemon' on a system where dbus isn't set up properly.
> All other apps can be started whenever, save xfsettingsd (which
> xfce4-session explicitly starts).

Depends on how the autostart system is implemented. We could add a
simple dependency mechanism (like an optional setting for each autostart
app for defining one other program it depends on) but of course this
would slow down the startup process and make patches like the one from
Auke less of an improvement.
 
> Neutral:
> 
> * Can't respawn app if it crashes.  But xfce4-session
> (intentionally) doesn't implement that part of the SM spec anyway.  If
> we really want decent respawning, we should be using watchdog processes
> anyway.  Ideally we just fix the bugs causing the crash, but that's not
> always easy, and you can pretty much never verify that you've actually
> fixed all crasher bugs.

Since apps currently aren't respawned either I'd be ok with that. 
 
> So, what do people think?  I imagine there are some other cons I
> haven't thought of, and maybe some pros as well.  If no one comes up
> with convincing arguments against this idea, I'm definitely going to
> remove libSM support from xfdesktop before 4.6.0.

Even to me the session management has always been a bit opaque. I think
it's way more transparent and clear to the user if he's able to modify
the started applications on his own. I guess I'm all for it.

  - Jannis