Bug 496582

Summary:	KWin ignores request by Fedora installer to not draw decorations
Product:	[Plasma] kwin	Reporter:	Neal Gompa <ngompa>
Component:	decorations	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	agurenko, ales.astone, awilliam, kde, nicolas.fella
Priority:	NOR
Version First Reported In:	6.2.3
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
See Also:	https://bugzilla.redhat.com/show_bug.cgi?id=2328041
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	WAYLAND_DEBUG output from Anaconda liveinstaller

Description Neal Gompa 2024-11-22 15:20:08 UTC

SUMMARY
Anaconda, the Fedora installer, was just ported to run as a Wayland-native application. After porting to run as a Wayland-native application, it was observed that KWin is drawing decorations even though the application requested no decorations.

STEPS TO REPRODUCE
1. Download Rawhide KDE live nightly ISO from https://nightly.fedoraproject.org
2. Install the following packages
** https://kojipkgs.fedoraproject.org//packages/anaconda/42.15/1.fc42/noarch/anaconda-live-42.15-1.fc42.noarch.rpm
** https://kojipkgs.fedoraproject.org//packages/anaconda/42.15/1.fc42/x86_64/anaconda-gui-42.15-1.fc42.x86_64.rpm
** https://kojipkgs.fedoraproject.org//packages/anaconda/42.15/1.fc42/x86_64/anaconda-tui-42.15-1.fc42.x86_64.rpm
** https://kojipkgs.fedoraproject.org//packages/anaconda/42.15/1.fc42/x86_64/anaconda-core-42.15-1.fc42.x86_64.rpm
** https://kojipkgs.fedoraproject.org//packages/anaconda/42.15/1.fc42/x86_64/anaconda-widgets-42.15-1.fc42.x86_64.rpm
3. Run the installer

OBSERVED RESULT
The installer has decorations.

EXPECTED RESULT
The installer does not have decorations.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora Linux 42 (KDE Plasma)
KDE Plasma Version: 6.2.3
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.0

ADDITIONAL INFORMATION
This is causing automated qualification of Fedora KDE images to fail, and could result in a blocker bug if not resolved soon.

Comment 1 David Edmundson 2024-11-22 15:29:10 UTC

>even though the application requested no decorations.

I imagine the answer will be that it's not.

Can you attach 
WAYLAND_DEBUG=1 myAwesomeFedoraInstaller|& grep -i decoration

Comment 2 Neal Gompa 2024-11-22 16:12:41 UTC

Created attachment 176039 [details]
WAYLAND_DEBUG output from Anaconda liveinstaller

Sorry, I forgot to add the code snippet link for the relevant code: https://github.com/rhinstaller/anaconda/blob/e5be57a9623fd5056aea0b74634c22b7b2037ed4/pyanaconda/ui/gui/__init__.py#L522

I've also attached WAYLAND_DEBUG info, but here's the snippet:

[2220181.659] {Default Queue} org_kde_kwin_server_decoration_manager#11.default_mode(2)

Comment 3 Neal Gompa 2024-11-22 16:15:10 UTC

And further code links:
* from Anaconda: https://github.com/rhinstaller/anaconda/blob/e5be57a9623fd5056aea0b74634c22b7b2037ed4/pyanaconda/ui/gui/__init__.py#L289-L291
* relevant GTK doc: https://docs.gtk.org/gtk3/method.Window.set_decorated.html

Comment 4 Nicolas Fella 2024-11-23 09:48:44 UTC

The log has 

[2220216.820] {Default Queue}  -> org_kde_kwin_server_decoration#31.request_mode(2)

which means it's requesting server-side decoration: https://wayland.app/protocols/kde-server-decoration#org_kde_kwin_server_decoration:enum:mode:entry:Server

This looks like an Anaconda/GTK problem to me

Comment 5 Alessandro Astone 2024-11-23 09:51:29 UTC

Not a bug, kwin is doing what it is asked.
Gtk3 apparently wants a titlebar widget as a prerequisite for requesting CSD to the compositor