Bug#1143746: breeze: FTBFS: This application failed to start because no Qt platform plugin could be initialized.

Package: src:breeze
Version: 4:6.7.2-1
Severity: serious
Tags: ftbfs forky sid

Dear maintainer:

During a rebuild of all packages in unstable, this package failed to build.

Below you will find the last part of the build log (probably the most
relevant part, but not necessarily). If required, the full build log
is available here:

https://people.debian.org/~sanvila/build-logs/202608/

About the archive rebuild: The build was made on virtual machines from AWS,
using sbuild and a reduced chroot with only build-essential packages.

If you cannot reproduce the bug please contact me privately, as I
am willing to provide ssh access to a virtual machine where the bug is
fully reproducible.

If this is really a bug in one of the build-depends, please use
reassign and add an affects on src:breeze, so that this is still
visible in the BTS web page for this package.

Thanks.

--------------------------------------------------------------------------------
[...]
Connected to MAKE jobserver
test 1
    Start 1: breezestyleconfig_smoketest

1: Test command: /usr/bin/kcmshell6 "-style" "Breeze" "--smoke-test" "kstyle_config/breezestyleconfig"
1: Working Directory: /<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/kstyle6/config
1: Environment variable modifications: 
1:  QT_PLUGIN_PATH=path_list_prepend:/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/bin
1: Test timeout computed to be: 10000000
test 2
    Start 2: kcm_breezedecoration_smoketest

2: Test command: /usr/bin/kcmshell6 "-style" "Breeze" "--smoke-test" "org.kde.kdecoration3.kcm/kcm_breezedecoration"
2: Working Directory: /<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/kdecoration/config
2: Environment variable modifications: 
2:  QT_PLUGIN_PATH=path_list_prepend:/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/bin
2: Test timeout computed to be: 10000000
1: qt.qpa.xcb: could not connect to display 
1: qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
1: qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
1: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
1: 
1: Available platform plugins are: minimal, linuxfb, vkkhrdisplay, xcb, wayland-brcm, wayland-egl, wayland, offscreen, minimalegl, vnc, eglfs.
1: 
2: qt.qpa.xcb: could not connect to display 
2: qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
2: qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
2: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
2: 
2: Available platform plugins are: minimal, linuxfb, vkkhrdisplay, xcb, wayland-brcm, wayland-egl, wayland, offscreen, minimalegl, vnc, eglfs.
2: 
1/2 Test #1: breezestyleconfig_smoketest ......Subprocess aborted***Exception:   0.04 sec
qt.qpa.xcb: could not connect to display 
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: minimal, linuxfb, vkkhrdisplay, xcb, wayland-brcm, wayland-egl, wayland, offscreen, minimalegl, vnc, eglfs.


2/2 Test #2: kcm_breezedecoration_smoketest ...Subprocess aborted***Exception:   0.04 sec
qt.qpa.xcb: could not connect to display 
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: minimal, linuxfb, vkkhrdisplay, xcb, wayland-brcm, wayland-egl, wayland, offscreen, minimalegl, vnc, eglfs.



0% tests passed, 2 tests failed out of 2

Total Test time (real) =   0.04 sec

The following tests FAILED:
	  1 - breezestyleconfig_smoketest (Subprocess aborted)
	  2 - kcm_breezedecoration_smoketest (Subprocess aborted)
Errors while running CTest
make[1]: *** [Makefile:74: test] Error 8
make[1]: Leaving directory '/<<PKGBUILDDIR>>/obj-x86_64-linux-gnu'
dh_auto_test: error: cd obj-x86_64-linux-gnu && make -j2 test ARGS\+=--verbose ARGS\+=-j2 returned exit code 2
make: *** [debian/rules:8: binary] Error 25
dpkg-buildpackage: error: debian/rules binary subprocess failed with exit status 2
--------------------------------------------------------------------------------