Hey, I have some recent reports from Debian users, on Xfce 4.8, which end up with a broken session where a lot of Xfce components weren't running, including xfwm4. It's not really clear what happened (or even that the same thing happened everytime), but in the end they managed to get a session cache with only xfce4-session running, more or less (maybe xfwm4 crashed and the session still got saved, not sure) xfce4-session shouldn't make assumptions on what the user wants or does not want to use, so it should respect what's in the session cache, but at some point, it'd be nice if it could make sure the final session is usable. Would it be possible to check, when the desktop has completed init, if the mandatory components are present? Right now, the only mandatory one for me is a window manager (wether xfwm4 or anything else), but there might be others. If there's no window manager running, then maybe it makes sense to run xfwm4 just in case: what are the chances that a user would like to not use a window manager and still use xfce4-session? What do you think?
The user can choose to run whatever component he wants, the session manager cannot identify the "functionality" of the programs. For example, many users may choose to run xfce with compiz, metacity, kwin, openbox, whateverwm in place of xfwm4. How could xfce4-session tell if all mandatory components are present in this case? (and before someone asks for it, I don't think maintaining a white list of major components for each functionality is a viable solution in the long run).
The only fix is to identify why the components are missing and fix the bugs that cause this to happen.
I didn't ask for a whitelist. I'm was more thinking-out loud about a way to check if *a* window manager is running. xfwm4 is already able to do that in some way, I'm not sure how hard / desirable it is to have the same kind of check in xfce4-session. If at the end of desktop init there's no wm running at all, then it'd make sense to still run xfwm4 (even if it's not the desired choice of the Xfce user) so he can then chose to replace the wm by his own, instead of having an unusable session. It's just a kind of fallback/failsafe mode. I agree fixing bugs leading to that situation is a good idea, but it doesn't seem that easy, and enabling people to have a working session is still good imho.
Another report of missing xfwm4: http://bugs.debian.org/655949
*** This bug has been marked as a duplicate of bug 828 ***