Dbus-update-activation-environment & sway?

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1

I’m using sway, and I noticed that the dbus-update-activation-environment
executable provided by the dbus package is not in the path; so when
.config/sway/config includes /etc/sway/config.d/nixos, which has this contents:

# Import the most important environment variables into the D-Bus and systemd
# user environments (e.g. required for screen sharing and Pinentry prompts):
exec dbus-update-activation-environment --systemd DISPLAY WAYLAND_DISPLAY SWAYSOCK XDG_CURRENT_DESKTOP

it has no effect. Likewise, the dbus-sway-environment workaround in the example configuration shown in the NixOS Sway wiki page does not work, since the script that it creates tries to directly execute dbus-update-activation-environment, which is not in the path.

The dbus-update-activation-environment executable seems to be located under the dbus package in the nix store at a path similar to

./n742zqfsr1aa4c64h7801w66j3m0rc9f-dbus-1.14.10/bin/dbus-update-activation-environment

but there is no store entry for the dbus-update-activation-environment executable itself, and
no symlink for dbus-update-activation-environment under /run/current-system/sw/bin/.

Possibly because of this, the xdg-desktop-portal-wlr.service does not start as a user service, since it doesn’t find WAYLAND_DISPLAY in the appropriate environment. (Note, working from a shell inside a sway session, all of the environment variables DISPLAY WAYLAND_DISPLAY SWAYSOCK XDG_CURRENT_DESKTOP are set, but that apparently does not apply to the environment used to start xdg-desktop-portal-wlr.service).

Although I could probably find a hack workaround for the above, I’m quite new at NixOS and I’m not sure what the best way to fix it would be.

Suggestions are welcome!

2

Interesting, it does seem that the use of dbus-update-activation-environment is not a full store reference in the NixOS module. I might recommend going ahead and filing this as an Issue on nixos/nixpkgs.

From what I can tell, this issue does not affect the home-manager module, as it properly references the dbus store path. I’m a bit surprised this hasn’t been noticed. I wonder if most Sway users are using Home-Manager? As you observe, this missing in the NixOS module means that non-HM-users are likely having problems with user services that expect certain env vars to be set in the user-systemd environment.

EDIT: Alternatively, it seems like you understand the issue. If you want to just fix this in nixpkgs, I’d be happy to review/merge it for you.

3

Thanks for confirmation! I’ll file an issue, and if I’m feeling up to it, may try to provide a patch.

4

It turns out that adding pkgs.dbus to environment.systemPackages in configuration.nix
is enough to get the /run/current-system/sw/bin/dbus-update-activation-environment symlink
in PATH, which allows the calls to execute dbus-update-activation-environment (not specifiying a path) to succeed. I’ve updated the Sway wiki page accordingly.

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