appId title / Iconic dock launchers

[Damian Ivanov]

Hello,

Below appears to affect all wayland compositors / environments (and X),
respectively any panel / dock that has the ability to pin an
application for quick
launching when all it's surfaces are closed.

wayland api provides the appId / title (IIRC this is the xdg-shell protocol)
X api provides the appId / title / icon
custom wayland wlroots protocol wlr-foreign-toplevel-management
provides the same

The implementation of all desktops environments face the following problem,
they need to match the appId to a desktop file to create a launcher,
which is done by looking up in all the directories $XDG_DATA_DIRS
until a desktop file matching the appId is found.

This is completely broken by design, especially in the times of
flatpak and snap.
As an example take $application, it can be installed
1) from system package         - desktop file goes into /usr/share/applications/
2) from local build                   - desktop file goes into
/usr/local/share/applications/
3) from flatpak(system wide)  - desktop file goes into
/var/lib/flatpak/share/applications/
4) from flatpak(user wide)       - desktop file goes into
$HOME/.local/share/applications/
5) from flatpak(custom loc)     - desktop file goes into $custom
6) from snap                           - desktop file goes into snap directory

All of the above are exposed as $XDG_DATA_DIRS whatever application you pin
depends on the priority the lookup is done, very often it will not pin
the application it should!

How can wayland help solve this problem?
I imagine it could be possible additionally to appId and title to
expose maybe the path
to the actual binary?

I'd be happy to hear some ideas to resolve this for all Linux desktop
environments.

Br,
Damian