Bug#852680: 答复: Bug#852680: plasma-workspace: Please add dbus-user-session as alternative dependency for dbus-x11

[张 敬强 <zh_jq@outlook.com>]

Hi,
> Does it make any difference? What's the rationale behind this request?

According to dbus NEWS file, dbus-user-session provides systemd units for
a per-user bus listening (in effect, treating all concurrent graphical and
non-graphical login sessions as one large session)

> dbus-session-bus is a virtual package, which is also provided by dbus, so 
> that's most likely going be fulfilled by dbus if used as a dependency, also 
> dependencies against virtual packages need to be given a non virtual 
> preference. Probably depending on: dbus | dbus-session-bus would work.

The recommended way seems to be:
default-dbus-session-bus | dbus-session-bus
, which is already used by cinnamon-session, but not by gnome-session-bin.

And the binary package dbus itself doesn't provide dbus-session-bus.

> But breaking the session dbus for our users wouldn't be nice so this needs 
> a somewhat thorough testing, in an enviroment with only dbus installed, with
> only dbus-user-session installed, with only dbus-x11 installed, etc, checking 
> for differences in each session.

So now we only have to test dbus-x11 and dbus-user-session.
There is a check for dbus-user-session in dbus-x11 file
/etc/X11/Xsession.d/75dbus_dbus-launch, so in theory dbus-user-session
replace dbus-x11 if they both get installed.
I haven't encountered any difference when using only one graphical session.

Anyway we can default to dbus-x11, and allow users to switch to dbus-user-session
for a testing purpose.

Thanks