Login loop when using fish as login shell

[XYQuadrat]

When using fish as the user login shell, it is not possible to log in to KDE Plasma (X11) with sddm. After entering the correct password, the screen goes black for a short while and some logs (probably X Server startup stuff) flash. Afterwards, one is returned to the sddm login prompt.

Steps to reproduce:

1. Use chsh -s /usr/bin/fish to change the user login shell.
2. Log out.
3. Try to log in with the user where the login shell was changed.

I'm using version 0.19.0+p22.04+tunstable+git20220916.0023-0 from KDE Neon Unstable (upgraded to Ubuntu 22.04). Changing the login shell back to bash with chsh -s /bin/bash from a TTY resolves the issue. I have also set various environment variables in fish only. Potentially those could be related to the issue too; though most of them seem completely unrelated to sddm to me (e.g. KDEHOME or CARGO_HOME).

[mgunyho]

I am having this exact same, but with xonsh.

Which distro are you using? I am on openSUSE and I think I know what the problem is: based on the output of journalctl -b, Plasma is launched by sddm-helper with the command /usr/etc/X11/xdm/Xsession \"/usr/bin/startplasma-x11\". So it's using an Xsession script from xdm instead of sddm! I suppose that script is quite old, and doesn't support fish (nor xonsh). The Xsession script that comes with sddm (see here, on my machine it's located in /usr/share/sddm/scripts/Xsession) should support fish, though not xonsh.

[Saulimedes]

This is still reproducible in opensuse tumbleweed. The screen goes blank after login after switching to a non posix shell or adjusting the local .bashrc to drop into it like:

if [[ $(ps --no-header --pid=$PPID --format=comm) != "fish" && -z ${BASH_EXECUTION_STRING} ]]
then
	exec fish
fi

[Dieken]

Got this issue too on Slackware current, the script /usr/share/sddm/scripts/Xsession is outdated, it doesn't source /etc/profile which brings many important environment variables.

The Xsession at

sddm/data/scripts/Xsession

Line 29 in 37a39d0

[ -f /etc/profile ] && . /etc/profile

is correct, fixed by cf65e99, unfortunately that fix isn't released yet.

@aleixpol @Vogtinator could you release 0.20.0 or 0.19.1 to include that fix?

[mufeedali]

Shouldn't this be fixed in 0.20.0?

[JamesMcMahon]

Broken on OpenSuse Tumbleweed, SDDM version 0.20.0-3.2.

[mufeedali]

@JamesMcMahon

Try this:

In the meantime, openSUSE Fish users can add export -n PROFILEREAD to ~/.profile

From #1391

[JamesMcMahon]

@JamesMcMahon

Try this:

In the meantime, openSUSE Fish users can add export -n PROFILEREAD to ~/.profile

From #1391

Thanks, I ended up just keeping bash as my default shell and set Konsole to use Fish by default.

[korewaChino]

Broken on Fedora 40, sddm-0.21.0-4.fc40.x86_64

[svenjacobs]

@JamesMcMahon

Try this:

In the meantime, openSUSE Fish users can add export -n PROFILEREAD to ~/.profile

From #1391

Unfortunately this didn't work for me.

I'm using openSUSE Tumbleweed (20240701).
sddm 0.21.0-3.1. fish 3.7.1.

[Vogtinator]

Tumbleweed has the fix for fish backported for some time already. You're most likely hitting a different issue.

[svenjacobs]

Tumbleweed has the fix for fish backported for some time already. You're most likely hitting a different issue.

You're right. Weird, now it's working. Don't know what has changed 🤷🏼

[XYQuadrat]

I can confirm that this works for me with sddm 0.21.0-0zneon+22.04+jammy+release+build1. Given that the underlying problem I had has been fixed, and that Vogtinator says that cases of it not working are mostly likely hitting a different problem (which should get their own, separate issue), I'll close this.