Client: flatpak-spawn: Invalid byte sequence in conversion input

[BigmenPixel0]

Explain what happens

1. Install org.cockpit_project.CockpitClient on Fedora KDE 40 from Flathub.
2. Run it.

Version of Cockpit

322 (commit aa8a09e63bde47edfeaeb77d5c6fae1c2425c29a2471da472c43147207e21dbd)

Where is the problem in Cockpit?

None

Server operating system

None

Server operating system version

No response

What browsers are you using?

No response

System log

$ flatpak run org.cockpit_project.CockpitClient          

(cockpit-client:2): Gtk-WARNING **: 12:49:46.327: Locale not supported by C library.
        Using the fallback 'C' locale.

(cockpit-client:2): Handy-WARNING **: 12:49:46.364: Using GtkSettings:gtk-application-prefer-dark-theme together with HdyStyleManager is unsupported. Please use HdyStyleManager:color-scheme instead.
flatpak-spawn: Invalid byte sequence in conversion input
Try "flatpak-spawn --help" for more information.

[martinpitt]

This smells like the same as in flathub/org.cockpit_project.CockpitClient#33 (comment)

Can you please check your locale output, do you have mixed languages/locales? Can you please try something like

flatpak config --set languages "en;cs"
flatpak update

for the languages that you use?

[BigmenPixel0]

Yes

LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=ru_RU.UTF-8
LC_TIME=en_GB.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=ru_RU.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=ru_RU.UTF-8
LC_NAME=ru_RU.UTF-8
LC_ADDRESS=ru_RU.UTF-8
LC_TELEPHONE=ru_RU.UTF-8
LC_MEASUREMENT=ru_RU.UTF-8
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

But now I have another problem :)

$ flatpak run org.cockpit_project.CockpitClient 

(cockpit-client:2): Handy-WARNING **: 17:25:41.015: Using GtkSettings:gtk-application-prefer-dark-theme together with HdyStyleManager is unsupported. Please use HdyStyleManager:color-scheme instead.
Gdk-Message: 17:25:41.940: Error 71 (Protocol error) dispatching to Wayland display.

and the window closes
Without wayland:

flatpak run --nosocket=wayland org.cockpit_project.CockpitClient
Gtk-Message: 17:26:38.246: Failed to load module "colorreload-gtk-module"
Gtk-Message: 17:26:38.246: Failed to load module "window-decorations-gtk-module"

(cockpit-client:2): Handy-WARNING **: 17:26:38.253: Using GtkSettings:gtk-application-prefer-dark-theme together with HdyStyleManager is unsupported. Please use HdyStyleManager:color-scheme instead.

** (process:8418): WARNING **: 17:26:38.921: Error writing credentials to socket: Error sending message: Broken pipe
Failed to create GBM buffer of size 1280x800: Invalid argument