The upstream session files display managers use have no concept of sessions being composed from
desktop manager and window manager. To be able to set upstream session files as default
session, we need a single option. Having two different ways to set default session would be confusing,
though, so we decided to deprecate the old method.
We also created separate script for each session, just like we already had a separate desktop
file for each one, and started using displayManager.sessionPackages mechanism to make the
session handling more uniform.
There's two ways of providing graphical sessions now:
- `displayManager.session` via. `desktopManager.session` and
`windowManager.session`
- `displayManager.sessionPackages`
`sessionPackages` doesn't make a distinction between desktop and window
managers. This makes selecting a session provided by a package using
`desktopManager.default` nonsensical.
We therefor introduce `displayManager.defaultSession` which can select a session
from either `displayManager.session` or `displayManager.sessionPackages`.
It will default to `desktopManager.default + windowManager.default` as before.
If the dm default is "none" it will select the first provided session from
`sessionPackages`.
Having a default session resulted in GDM not remembering the last used
session.
So do not force the session until setSessionScript is made aware of the
last session used.
A centralized list for these renames is not good because:
- It breaks disabledModules for modules that have a rename defined
- Adding/removing renames for a module means having to find them in the
central file
- Merge conflicts due to multiple people editing the central file
Unfortunately, you can't configure the default user-session
with GDM like lightdm. I've opened a feature request [0]
but I'd like to be able to do this now.
We use a GObject Python script using bindings to AccountsService
to achieve this. I'm hoping the reliable heuristic for session names
is the file's basename. We also have some special logic for which
method to use to set the default session. It seems set_x_session is
deprecated, and thusly the XSession key, but if that method isn't used
when it's an xsession it won't be the default in GDM.
[0]: https://gitlab.gnome.org/GNOME/gdm/issues/535
The SLIM project is abandoned and their last release was in 2013.
Because of this it poses a security risk to systems, no one is working
on it or picked up maintenance. It also lacks compatibility with systemd
and logind sessions. For users, there liikely isn't anything like slim
that's as lightweight in terms of dependencies.
Having `display-manager` conflict with `plymouth-quit` causes this lock up:
- `plymouth-quit-wait` starts up, waiting for plymouth-quit to run
- `lightdm` starts up
- `plymouth-quit` can't start, it conflicts with lightdm
- `plymouth-quit-wait` keeps waiting on plymouth-quit to kill plymouthd
The idea is having LightDM control when plymouth quits, but communication with
plymouth was broken: https://github.com/NixOS/nixpkgs/pull/71064
Unfortunately having the conflict breaks switching to configurations with
plymouth enabled. So we still need to remove the conflict.
fixes#71034
These improvements come from shopping around
at what other downstreams have done with their
systemd units and recent changes like [0] to gdm.
Note there's no requries or after on dbus.socket because
settings BusName will set this up automaticallly and
give it a type of dbus.
[0]: 2d57f45962
GDM is now killed if tty1 is started after gdm is launched. This follows
upstream's gdm service config.
This might cause problems with nixos-rebuild switch though. See the reasoning
and work that led to not following upstream on this:
https://github.com/NixOS/nixpkgs/issues/214394a180dac46d4da
Rules are a translation of what's done in the
GDM module and adjustments based of looking at
Arch Linux's configuration and upstream's.
A side effect of this change is that gnome-keyring
and kwallet modules should work as expected when in-
cluded.
Fixes#64259#62045
The custom session script is always executed (when it exists). This change
passes the selected session script and select session name to the custom session
script, so that it can defer to the selected session script based on the value
of the selected session name.
Previously, if you, for example, set
services.xserver.displayManager.sddm.enable, but forgot to set
services.xserver.enable, you would get an error message that looked like
this:
error: attribute 'display-manager' missing
Which was not particularly helpful.
Using assertions, we can make this message much better.
