PackageKit daemon fails at startup because of missing libpk_backend_nix.so

[peti]

I'm running a current version of nixos-unstable @ 179b814. When systemd tries to start packagekit.service, I get the following error:

Nov 05 17:55:26 peti PackageKit[8708]: daemon start
Nov 05 17:55:26 peti packagekitd[8708]: Failed to load the backend: opening module nix failed : /nix/store/mj9dw9d3j5ky5i0icg2pa665zdk1b1y7-packagekit-1.1.11/lib/packagekit-backend/libpk_backend_nix.so: cannot open shared object file: No such file or directory

Indeed, that shared object does not exist on my system:

# ls -l /nix/store/mj9dw9d3j5ky5i0icg2pa665zdk1b1y7-packagekit-1.1.11/lib/packagekit-backend                     
total 92
-r-xr-xr-x 2 root root  2117 Jan  1  1970 libpk_backend_test_fail.la
-r-xr-xr-x 3 root root 13016 Jan  1  1970 libpk_backend_test_fail.so
-r-xr-xr-x 2 root root  2111 Jan  1  1970 libpk_backend_test_nop.la
-r-xr-xr-x 3 root root  7624 Jan  1  1970 libpk_backend_test_nop.so
-r-xr-xr-x 2 root root  2123 Jan  1  1970 libpk_backend_test_spawn.la
-r-xr-xr-x 3 root root 12472 Jan  1  1970 libpk_backend_test_spawn.so
-r-xr-xr-x 2 root root  2135 Jan  1  1970 libpk_backend_test_succeed.la
-r-xr-xr-x 3 root root 13704 Jan  1  1970 libpk_backend_test_succeed.so
-r-xr-xr-x 2 root root  2129 Jan  1  1970 libpk_backend_test_thread.la
-r-xr-xr-x 3 root root 12664 Jan  1  1970 libpk_backend_test_thread.so

That doesn't seem right?

[matthewbauer]

So there once was a PackageKit backend for Nix but it broke with the update to Nix 2.0. I haven't had time to fix it yet.

You should try commenting out this line in the packagekit service:

https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/misc/packagekit.nix#L13

I think it's just pulling that value.

[wizeman]

Backporting a7afcff to my 18.09-based machine didn't work. PackageKit still complains about not being able to load the auto backend.

I fixed it by setting the default backend to test_nop instead of nix.