`nixos-rebuild switch` Crashes WM/DE


I mentioned this issue under this topic. With that topic being resolved I thought this issue would go away but apparently it hasn’t.

So, when I tried nixos-rebuild switch it upgrades the system as usual but during the process it just crashes/quits the window manager (I’m using Sway) and all I can see is just a black screen with a white cursor. I tried this on KDE Plasma too but got the same result. This first happened a little more than a month ago. Does anyone have any idea why would this happen? Thank you in advance!

I have also noticed this (only on Plasma as that’s what I use) but I haven’t yet taken the time to dig into why. Clearly something critical ends up getting restarted instead of just reloaded.

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same here with i3 (filler to reach 20 characters)

from what we could figure our so far it looks like systemd-logind is restarted if the rebuild includes a systemd update, which takes all currently active sessions down with it. (haven’t yet had the time to dig into verifying whether that’s the entire reason, nor attempting to fix anything)


This also affects me. Is there already a Nixpkgs issue?

EDIT: I found rebuild issues, grub · Issue #145249 · NixOS/nixpkgs · GitHub, but I am not sure if it is related.

I think this is a different issue. I also think it’s systemd-logind because it affects sway started from a systemd/user unit.

I’m not sure if we even can restart user units properly from nixos-rebuild. I think the biggest problem is that wayland isn’t quite solved and unified and the custom setup approaches don’t interact well with rebuilding.

Ideally there’d be a systemd unit for everything wayland (i. e. display-manager.service) that can be restarted by nixos-rebuild properly. While crashing is bad, the best case scenario was always going to be restart wayland…

The issue (maybe a different kind of crash though?) also appears when just starting sway manually.

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I created a nixpkgs issue: `nixos-rebuild switch` crashes/quits DE/WM · Issue #146727 · NixOS/nixpkgs · GitHub

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