xdg-desktop-portal 1.17.x introduces a new way to select which portals will
be used for which desktop environments, modelled on mimeapps.list:
- each desktop environment should provide a file like
/usr/share/xdg-desktop-portal/sxmo-portals.conf
- the filename is ${DESKTOP}-portals.conf where ${DESKTOP} is the desktop
environment's entry in $XDG_CURRENT_DESKTOP (the same as the DesktopNames
from /usr/share/{x,wayland-}sessions/*.desktop), folded to lower case
- sysadmins and users can override this via files named portals.conf or
${DESKTOP}-portals.conf in various locations like /etc/xdg-desktop-portal
and ~/.config/xdg-desktop-portal
Please see portals.conf(5) or its source code
https://github.com/flatpak/xdg-desktop-portal/blob/main/doc/portals-conf.rst
for full details.
If I'm reading correctly, I think sxmo-utils inconsistently uses either
XDG_CURRENT_DESKTOP="SXMO" or XDG_CURRENT_DESKTOP="sway"? (But perhaps I'm
reading it wrong...)
If it uses XDG_CURRENT_DESKTOP="SXMO", then it should provide a
sxmo-portals.conf that sets up the correct portal backends.
For example, if the intention is to use x-d-p-wlr for the interfaces
that it supports (screenshots and screencasting), and x-d-p-gtk for
other interfaces (such as File->Open and File->Save As... dialogs),
then the simplest way to write that would be:
[preferred]
default=wlr;gtk;
The desktop environment (either sxmo-utils or some larger metapackage)
should probably also have a Recommends, or at least a Suggests, on
whatever portals would be most appropriate for it. I see that it already
Depends on sway, which Suggests xdg-desktop-portal-wlr, but not -gtk.
If sxmo-utils is using XDG_CURRENT_DESKTOP="sway", then it has no ability
to choose its own portals, and will have to rely on Sway choosing something
vaguely appropriate (#1050913).
It might be better for it to use XDG_CURRENT_DESKTOP="SXMO:sway", which
means use SXMO-specific settings if they exist, or sway-specific settings
if not, in the same way that Ubuntu's customized GNOME session uses
"Ubuntu:GNOME".
Thanks,
smcv