sway (1.6) / wlroots (0.13.0) broke screen sharing and gnome3 pinentry popups

[etu]

Describe the bug
The recent update of sway and wlroots seems to have broken screen sharing as well as gnome3 pinentry popups.

To Reproduce
Steps to reproduce the behavior:

I've built a system on 311ceed (current nixos-unstable, there neither of the mentioned things works).

But if I build a system on 04a2b26 (previous unstable, there both of the mentioned things works.).

I've then checked out 04a2b26 and copied the folders pkgs/development/libraries/wlroots/ and pkgs/applications/window-managers/sway/ from master into my checkout and built a system based on the old unstable but with only those two packages updated. Then it's still broken. So it's at least isolated to those two packages.

Expected behavior
I expect screen sharing to work.

I also expect to be able to unlock my security key from places where the ncurses interface doesn't work (like within Emacs).

Additional context
Here's my complete sway setup: https://github.com/etu/nixconfig/blob/main/modules/my-sway.nix#L465-L516

Notify maintainers
cc @primeos @Synthetica9 @Ma27

Metadata

• system: "x86_64-linux"
• host os: Linux 5.11.9, NixOS, 21.05.git.04a2b269d89M (Okapi)
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.3.10
• channels(root): ""
• nixpkgs: /etc/nixos/nix/nixos-unstable

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute: sway wlroots
# a list of nixos modules affected by the problem
module:

[Ma27]

Related: #112914.

[primeos]

I can confirm the gnome3 pinentry (gcr-prompter) issue (wasn't aware of it but can reproduce it).

I'm not using screen sharing on Wayland (yet) so unfortunately I cannot have a look into that.
cc @minijackson (xdg-desktop-portal-wlr): FYI, in case you use Sway and can reproduce this.

Edit: Might be unrelated but yesterday I've also had a swaylock crash:

swaylock[70568]: swaylock: ../main.c:1183: main: Assertion `state.compositor && state.layer_shell && state.shm' failed.
systemd-coredump[70617]: Process 70568 (swaylock) of user 1001 dumped core.

Another thing that changed with Sway 1.6: $WAYLAND_DISPLAY now "defaults" to wayland-1 (https://github.com/swaywm/sway/blob/1.6/sway/server.c#L166) while it was previously wayland-0. This shouldn't matter (edit: nope, turns out that it does really matter :o :D) but I didn't reboot my system and noticed that at least the dbus-daemon still has WAYLAND_DISPLAY=wayland-0 (if the environment from that process is inherited to start gcr-prompter then that would certainly seem like a problem but only then). That's all I can say for today.

[jakobrs]

xdg-desktop-portal-wlr.service fails to start for me on nixos-unstable; presumably this is why screen sharing doesn't work. This appears in journalctl:

Apr 14 20:02:20 girafarig systemd[1244]: Starting Portal service (wlroots implementation)...
Apr 14 20:02:20 girafarig xdg-desktop-portal-wlr[1363]: 2021/04/14 20:02:20 [ERROR] - wayland: failed to connect to display
Apr 14 20:02:20 girafarig systemd[1244]: xdg-desktop-portal-wlr.service: Main process exited, code=exited, status=1/FAILURE
Apr 14 20:02:20 girafarig systemd[1244]: xdg-desktop-portal-wlr.service: Failed with result 'exit-code'.
Apr 14 20:02:20 girafarig systemd[1244]: Failed to start Portal service (wlroots implementation).

[etu]

@jakobrs I've have the same errors on latest unstable, may be related to $WAYLAND_DISPLAY as @primeos mentioned.

[primeos]

Ok, so I've had a closer look at this and all of my issues where surprisingly related to the $WAYLAND_DISPLAY change.

I've executed dbus-update-activation-environment WAYLAND_DISPLAY and now the Gnome3 Pinentry (gcr-prompter) works again. I guess that should fix the screen sharing issues too.

There are two things that surprised me:

1. I'd assume some of you did reboot and in my case dbus-deamon should've had the correct WAYLAND_DISPLAY due to our dbus-run-session (which should've caused my dbus-daemon to be "restarted" as well)
2. My systemd unit for swaylock uses neither D-Bus nor does it hard-code WAYLAND_DISPLAY

So I wondered where the wayland-0 comes from so I had a quick look at the Wayland source-code and, indeed, it's the default if $WAYLAND_DISPLAY isn't set: https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.19.0/src/wayland-client.c#L969

So it seems like Sway's WAYLAND_DISPLAY change is much more severe than I though and causes (all of) these regressions (but the change makes sense as this reveals that it was basically always "broken" as it worked with a default value instead of properly via WAYLAND_DISPLAY).

For a quick fix it should be enough to add exec dbus-update-activation-environment WAYLAND_DISPLAY to your ~/.config/sway/config (I already had exec systemctl --user import-environment WAYLAND_DISPLAY DISPLAY DBUS_SESSION_BUS_ADDRESS SWAYSOCK in there, which is useful as well). However, to fix this properly we need to find a nice solution for Nixpkgs.

[nixos-discourse]

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

https://discourse.nixos.org/t/screen-sharing-with-wayland-gnome/12449/4

[primeos]

However, to fix this properly we need to find a nice solution for Nixpkgs.

I've looked into that and opened #122605 as a potential fix (though it will only work for new users / when using the default /etc/sway/config as we've unfortunately removed include /etc/sway/config.d/* until now). Feedback is welcome.