pinging #53843 because it will change that options name.

I think the commit msg should start like nixos/plasma5

Testing in a vm shortly

@bkchr I think it would be a good idea to possibly add a test for the wayland session?

Current test is broken because the session is now called plasma,
so we need to unset

services.xserver.desktopManager.default = "plasma5";

there.

And it seems that using sddm's autologin fails if we try to set the default session to plasma

- SDDM auto-login requires that services.xserver.desktopManager.default and
services.xserver.windowManager.default are set to valid values. The current
default session: plasma is not valid.

Not sure if the assertion is right there.

Hmm okay :( I will take a look.

Did a quick test today by applying the patch on top of 19.03.

Launching wayland session explicitly works (in fact, writing this comment from withing wayland session), but the default seession in SDDM becomes xterm, so you have to choose plasma explicitly.

Not sure if the assertion is right there.

Right autologin with an upstream session doesn't work in sddm and lightdm at the moment. I left these asserts when doing #44497. I reasoned that the assert was in place to avoid getting stuck in a bad auto login (the upstream sessions isn't available at eval time).

That's fixed in #53843, though it's a bit messy, partly due to the windowManager/desktopManager split which sessionPackages doesn't have. Though I think I've come up with a solution that would rework desktopManager.default so it could be used to pick sessions from sessionPackages instead of introducing a new displayManager.defaultSession option. That might be preferable.

As far as I can see, the only thing left to do is rename the commit to start with "nixos/plasma5". Anything else?

@infinisil It works but there's the breakages with upstream sessions noted by @hedning, @matklad, and I.

I don't really think it's a good idea to just leave autologin broken so we need something like #53843

Other things are:

1. Fix the NixOS test (noted in Plasma5: Use upstream xsession/wayland-session files #56988 (comment))
2. Possibly write a test for the wayland session
3. adjust commit msg (Plasma5: Use upstream xsession/wayland-session files #56988 (comment) Plasma5: Use upstream xsession/wayland-session files #56988 (comment))

Rebased

The wayland session is failing with log (~/.local/share/sddm/wayland-session.log):

dbus-update-activation-environment: warning: error sending to systemd: org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.systemd1 was not provided by any .service files
qt.qpa.plugin: Could not load the Qt platform plugin "wayland-org.kde.kwin.qpa" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: wayland-org.kde.kwin.qpa, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, minimal, offscreen, vnc, xcb.

/nix/store/9mlxan56vpqk33ask109pgqjwbiwl9xl-plasma-workspace-5.16.5/bin/startplasmacompositor: line 283:  2352 Aborted                 (core dumped) /nix/store/xvrlykra01fj12929nwf8sjpn7mlfd1c-kwin-5.16.5-bin/bin/kwin_wayland --xwayland --libinput --exit-with-session=/nix/store/9mlxan56vpqk33ask109pgqjwbiwl9xl-plasma-workspace-5.16.5/libexec/startplasma
startplasmacompositor: Shutting down...
startplasmacompositor: Done.

@adisbladis It looks like something that plasma-workspace-5.16.5/bin/startplasmacompositor calls into isn't wrapped etc.

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/wayland-sessions/4315/6

Is this now ready for prime time?

Is this now ready for prime time?

See #56988 (comment).

To paraphrase:

1. Autologin is still broken in sddm if you use upstream sessions.
   Needs nixos/displayManager: introduce defaultSession #53843 or similar idea from @hedning
2. there's no integration testing for plasma wayland
3. Something is improperly wrapped or missing a wrapper
   Plasma5: Use upstream xsession/wayland-session files #56988 (comment)

Also, since the session names have changed, what will happen for users that have done

services.xserver.desktopManager.default = "plasma5";

for the xsession?

1. Autologin is still broken in sddm if you use upstream sessions.
   Needs nixos/displayManager: introduce defaultSession #53843 or similar idea from @hedning

Looks like the mentioned PR has since been merged.

Correct, with #53843 merged you're not going to get any regressions with using upstream session. The options are renamed now as well.

So 2 and 3 now 😄

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/nixos-20-03-feature-freeze/5655/11

Moving this to 20.09 milestone. At a glance, it's not as simple as I thought. I need to know more about nixpkgs custom startup script for wayland.

I've "rebased"(copied from the source tree in my /etc/nixos then modified it) this pr and ,while the "plasma" session work perfectly(it even seem faster,probably by skipping all of our custom init) "plasmawayland" still crashes with:

giu 07 18:41:16 nixos xsession[28941]: qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
giu 07 18:41:16 nixos xsession[28941]: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
giu 07 18:41:16 nixos xsession[28941]: Available platform plugins are: wayland-org.kde.kwin.qpa, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

in the journal.
Weird that a wayland session still look for xcb.

@bkchr maybe I can publish a pr to use only the upstream xsession files,and to enable the wayland sessions in a later pr,maybe waiting for #84542 ?

(Assuming you're using SDDM). @pasqui23 I'd try setting SessionCommand in the wayland section of sddm:

This is done in X11 section:

I did apply @hedning's suggestion but unfortunately wayland still did not work.
Also my .local/share/sddm/wayland-session.log is empty.
To note that sddm's default wayland-session and xsession are wholly different.

https://github.com/sddm/sddm/blob/develop/data/scripts/Xsession
https://github.com/sddm/sddm/blob/develop/data/scripts/wayland-session
Wayland's,after a bit of initialization shared with xsession,jump straight to exec "$@",while xsession first import a bunch of stuff from x-related files.

I don't know how that relates to wayland

Right, wayland-session looks like it does the correct things (similar to how GDM handles wayland sessions). Looks like it's most likely something that isn't wrapped correctly as noted in #56988 (comment).

However that still leaves .local/share/sddm/wayland-session.log empty even after my failed session,where else do I look?

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/hardware-acceleration-on-firefox/7947/4

Upstream changed a lot. Is there anything in advance?

@oxalica I'm waiting for nixos-unstabe to proceed.

@bkchr I'm continuing your work in #100057
It's ok if you close this and continue the work on that?

The last rebase was a long time ago so you are continuing the work @pasqui23. Closing in favor of that PR for now

Guys, I'm spamming some of the old KDE wayland issues/PRs to ensure we get some testers. This comment is written from a plasma wayland session spawned from sddm after applying this PR (and the one-liner mentioned in a comment) which basically gets it going: #117102