[patch] Make dbus-launch always (if possible) save session information in X11

[Havoc Pennington]

Hi,

Thiago Macieira wrote:
> Patch looks ok to me. I think it addresses the most common use-cases.
>

Thanks for checking it out. (Sjoerd, OK to commit as far as I'm 
concerned also)

> I'd also argue for replacing the non-default --autolaunch with a 
> non-default --no-reuse. That way, the default behaviour would be to reuse a 
> bus if one is running. Those special cases that require a new bus would use 
> the flag to do it.

Hmm. When do you want to reuse, though, that isn't already handled by 
autolaunch? It seems like invoking dbus-launch by hand basically _means_ 
"give me a new bus," I mean, why else would you invoke it?

The main uses of dbus-launch I can think of are:
  - on login; reuse being triggered here would be a bug, either a
    dbus-using app starting before the dbus-launch in the login script,
    or login scripts with two dbus-launch in them
  - in test scripts and stuff; here you don't want reuse, since you
    want an isolated dbus daemon
  - running an app on a remote system, here you can just rely on
    autolaunch and not use dbus-launch by hand at all, if you
    want to reuse and have configured TCP connections

Possible downsides to changing the default to reuse:
  - somewhat not backward compatible, e.g. with test scripts and login
    scripts
  - slight inefficiency of messing with X server properties prior
    to starting new daemon on login

Havoc