Bug#1144505: kwin-wayland: clients disconnecting due to wl_fixes v2 from 6.7.3

Package: kwin-wayland
Version: 4:6.7.4-1
Severity: important
Tags: patch upstream
X-Debbugs-Cc: [email protected]

With mesa 26.2 from experimental and as of kwin 4:6.7.4-1 I'm seeing Wayland
clients disconnecting (i.e. crashing) when making surfaces visible. Journal
says:

kwin_wayland_wrapper[2472]: error in client communication (pid 4139)
firefox-nightly[4139]: [4139] WaylandProxy: wl_display.error: the given registry did not announce global 66
firefox-nightly[4139]: [GFX1-]: (kde) Wayland protocol error: wl_fixes#68: error 0: the given registry did not announce global 66

kwin_wayland_wrapper[2472]: error in client communication (pid 2653)
polkit-kde-authentication-agent-1[2653]: wl_fixes#43: error 0: the given registry did not announce global 66
polkit-kde-authentication-agent-1[2653]: The Wayland connection experienced a fatal error: Protocol error

This seems to be due to the backporting of wl_fixes v2 in 6.7.3 upstream:
https://invent.kde.org/plasma/kwin/-/commit/8b8d2b24d1298dffd5f7c7f8cd384cce466752ea

Vlad Zahorodnii recommends backporting another upstream commit to fix this:
https://mail.kde.org/pipermail/distributions/2026-August/001725.html

Regards,
Simon

PS Ignore the kwin version in my system info, I downgraded to stop clients
crashing.


-- System Information:
Debian Release: forky/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'testing'), (101, 'buildd-unstable'), (100, 'experimental'), (1, 'buildd-experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 7.1.8+deb14-amd64-simonp (SMP w/32 CPU threads; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages kwin-wayland depends on:
ii  hwdata                                    0.394-1
ii  kwin-common                               4:6.7.2-1
ii  libc6                                     2.43-3
ii  libcanberra0                              0.30-20+b1
ii  libcap2-bin                               1:2.78-1+b1
ii  libepoxy0                                 1.5.10-2+b2
ii  libkdecorations3-6                        4:6.7.4-1
ii  libkf6configcore6                         6.28.0-1
ii  libkf6configgui6                          6.28.0-1
ii  libkf6coreaddons6                         6.28.0-2
ii  libkf6crash6                              6.28.0-1
ii  libkf6dbusaddons6                         6.28.0-1
ii  libkf6globalaccel6                        6.28.0-1
ii  libkf6i18n6                               6.28.0-1
ii  libkf6idletime6                           6.28.0-1
ii  libkf6notifications6                      6.28.0-1
ii  libkf6svg6                                6.28.0-1
ii  libkf6windowsystem6                       6.28.0-2
ii  libkglobalacceld0                         6.7.4-1
hi  libkwin6                                  4:6.7.2-1
ii  libqaccessibilityclient-qt6-0             0.6.0-5
ii  libqt6core6t64 [qt6-base-private-abi]     6.10.2+dfsg-16
ii  libqt6dbus6                               6.10.2+dfsg-16
ii  libqt6gui6                                6.10.2+dfsg-16
ii  libqt6qml6 [qt6-declarative-private-abi]  6.10.2+dfsg-6
ii  libqt6quick6                              6.10.2+dfsg-6
ii  libqt6widgets6                            6.10.2+dfsg-16
ii  libstdc++6                                16.2.0-1
ii  libsystemd0                               261.2-1
ii  libxcb-composite0                         1.17.0-2+b2
ii  libxcb-randr0                             1.17.0-2+b2
ii  libxcb-xfixes0                            1.17.0-2+b2
ii  libxcb1                                   1.17.0-2+b2
ii  plasma-version [plasma-version-base-6.7]  6.7.0
ii  xwayland                                  2:24.1.13-1

Versions of packages kwin-wayland recommends:
ii  kde-style-breeze    4:6.7.4-1
pn  kwin-style-aurorae  <none>

kwin-wayland suggests no packages.

-- no debconf information